This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-05-31 Creation time: 13:16:52 --- Number of references 47 article Irurzun2020113 Article 2020 10.1017/qua.2020.15 Quaternary Research (United States) 95 113 – 128 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85084759468&doi=10.1017%2fqua.2020.15&partnerID=40&md5=8618d6b8169bf90fead52abfdf8c90e0 Cited by: 3 Mariá A. Irurzun Pedro Palermo Claudia S. G. Gogorza Ana M. Sinito Milagrosa Aldana Vincenzo Costanzo-Álvarez Christian Ohlendorf Bernd Zolitschka article Palermo2019204 Article 2019 10.1016/j.jsames.2018.11.028 Journal of South American Earth Sciences 90 204 – 215 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85058949433&doi=10.1016%2fj.jsames.2018.11.028&partnerID=40&md5=221f1e780c8de5c553cf074960ff05b0 Cited by: 7 Pedro Palermo Mariá A. Irurzun Claudia S.G. Gogorza Ana M. Sinito Christian Ohlendorf Bernd Zolitschka article Smith2019137 This paper presents a detailed record of volcanism extending back to ∼80 kyr BP for southern South America using the sediments of Laguna Potrok Aike (ICDP expedition 5022; Potrok Aike Maar Lake Sediment Archive Drilling Project - PASADO). Our analysis of tephra includes the morphology of glass, the mineral componentry, the abundance of glass-shards, lithics and minerals, and the composition of glass-shards in relation to the stratigraphy. Firstly, a reference database of glass compositions of known eruptions in the region was created to enable robust tephra correlations. This includes data published elsewhere, in addition to new glass-shard analyses of proximal tephra deposits from Hudson (eruption units H1 and H2), Aguilera (A1), Reclus (R1, R2-3), Mt Burney (MB1, MB2, MBx, MB1910) and historical Lautaro/Viedma deposits. The analysis of the ninety-four tephra layers observed in the Laguna Potrok Aike sedimentary sequence reveals that twenty-five tephra deposits in the record are the result of primary fallout and are sourced from at least three different volcanoes in the Austral Andean Volcanic Zone (Mt Burney, Reclus, Lautaro/Viedma) and one in the southernmost Southern Volcanic Zone (Hudson). One new correlation to the widespread H1 eruption from Hudson volcano at 8.7 (8.6–9.0) cal ka BP during the Quaternary is identified. The identification of sixty-five discrete deposits that were predominantly volcanic ashes (glass and minerals) with subtle characteristics of reworking (in addition to three likely reworked tephra, and one unknown layer) indicates that care must be taken in the analysis of both visible and invisible tephra layers to decipher their emplacement mechanisms. © 2019 The Authors Article 2019 10.1016/j.quascirev.2019.06.001 Quaternary Science Reviews 218 137 – 156 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Southern Volcanic Zone; Deposits; Geochemistry; Glass; Minerals; Sedimentology; Stratigraphy; Lacustrine; PASADO; Patagonia; Quaternary; South America; Tephrochronology; Volcanic ash; emplacement; geochemistry; lacustrine environment; Quaternary; reworking; sediment chemistry; sedimentary sequence; stratigraphy; tephrochronology; volcanic ash; volcanic eruption; volcanism; volcano; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85067901780&doi=10.1016%2fj.quascirev.2019.06.001&partnerID=40&md5=0afe91df0b53c38bfb1ea5b72da75afc Cited by: 8; All Open Access, Green Open Access, Hybrid Gold Open Access Rebecca E. Smith Victoria C. Smith Karen Fontijn Stefan Wastegård Bernd Zolitschka Christian Ohlendorf Charles Stern Christoph Mayr article Vuillemin2018 Article 2018 10.1093/femsec/fiy029 FEMS Microbiology Ecology 94 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85043793404&doi=10.1093%2ffemsec%2ffiy029&partnerID=40&md5=41e2c4bc2c8f0b3be87c29a25bf1a707 Cited by: 45; All Open Access, Green Open Access, Hybrid Gold Open Access Aurèle Vuillemin Daniel Ariztegui Fabian Horn Jens Kallmeyer William Orsi Flavio Anselmetti Hugo Corbella Pierre Francus Andreas Lücke Nora I. Maidana Christian Ohlendorf Bernd Zolitschka Frank Schäbitz Stefan Wastegård article Jouve201733 Article 2017 10.1016/j.palaeo.2017.02.020 Palaeogeography, Palaeoclimatology, Palaeoecology 472 33 – 50 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85013018756&doi=10.1016%2fj.palaeo.2017.02.020&partnerID=40&md5=d5b39e238e519b8563fc6cb03b923d0e Cited by: 4; All Open Access, Green Open Access Guillaume Jouve Agathe Lisé-Pronovost Pierre Francus Arnaud S. De Coninck article Kliem2017110 Lacustrine sediments retrieved from Laguna Potrok Aike in the framework of the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO) offer the possibility to investigate climate variations of the past ~51 cal ka BP in Southern Hemispheric midlatitudes, Argentinean Patagonia. This study focuses on short-term cyclicities in the Ca and magnetic susceptibility data sets between 51 and 15 cal ka BP. The record yields a climate pattern with a periodicity of 1.5 ka during Marine Oxygen Isotope Stage 2 (MIS 2) detected in the Southern Hemisphere from 31 to 17 cal ka BP for the first time. MIS 2 is known for constantly cold temperatures, whereas prominent climate variations paced by a 1.5 ka periodicity occurred during MIS 3. Our study documents that minor latitudinal oscillations of the Southern Hemispheric westerlies and the polar easterlies with a 1.5 ka periodicity also took place during MIS 2. However, we assume that because of a major northward displacement of the Southern Hemispheric westerlies, these oscillations did not sufficiently affect the zone of Circumpolar Deep Waters and an increased greenhouse effect by upwelling of CO2-rich deep waters did not occur. This mechanism illustrates why prominent climate events fail to appear during MIS 2. Copyright © University of Washington. Published by Cambridge University Press, 2017. Article 2017 10.1017/qua.2017.13 Quaternary Research (United States) 88 110 – 120 1 Argentina; Patagonia; Greenhouse effect; Lakes; Magnetic susceptibility; Dansgaard-oeschger events; Frequency Analysis; Laguna potrok aike; Lake sediments; PASADO; Patagonia; climate variation; frequency analysis; lacustrine deposit; marine isotope stage; paleoclimate; Southern Hemisphere; westerly; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-85054518791&doi=10.1017%2fqua.2017.13&partnerID=40&md5=7107acca806e0ae0e15a597f69e7ef68 Cited by: 1; All Open Access, Bronze Open Access Pierre Kliem Henrike Baumgarten Catalina Gebhardt Annette Hahn Christian Ohlendorf Bernd Zolitschka article Sánchez-Pastor2016271 Article 2016 10.1016/j.gca.2015.12.006 Geochimica et Cosmochimica Acta 175 271 – 281 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953225342&doi=10.1016%2fj.gca.2015.12.006&partnerID=40&md5=b8d8b330080fb6d6341f8e6ccb00393f Cited by: 38; All Open Access, Green Open Access N. Sánchez-Pastor Markus Oehlerich José Manuel Astilleros Melanie Kaliwoda Christoph C. Mayr Lurdes Fernández-Díaz Wolfgang W. Schmahl article Vuillemin20162475 Article 2016 10.5194/bg-13-2475-2016 Biogeosciences 13 2475 – 2492 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84966425171&doi=10.5194%2fbg-13-2475-2016&partnerID=40&md5=1eb33421f3b5f2b79cacce210875a06b Cited by: 19; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin Daniel Ariztegui Peter R. Leavitt Lynda Bunting Flavio Anselmetti Hugo Corbella Pierre Francus Andreas Lücke Nora I. Maidana Christian Ohlendorf Frank Schäbitz Stefan Wastegård Bernd Zolitschka article Hockun2016110 When using biomarkers such as n-alkanes as tools for paleo-environmental reconstructions, it is imperative to determine their specific sources for each setting. Toward that goal, we analyzed a set of various potential organic matter (OM) sources such as aquatic and terrestrial plants, dust, and soils from Laguna Potrok Aike (LPA) and surrounding areas in southern Patagonia. We determined chain length distributions and hydrogen (δD) and carbon (δ13C) isotopic compositions of n-alkanes of different OM sources in order to quantify their relative contributions to lake sediments. Our results reveal that the mid-chain n-alkane, n-C23, is predominantly produced by submerged aquatic plants, whereas long-chain n-alkanes (n-C29–n-C31) are derived from various terrestrial sources. We estimated their relative contributions to the sediment using two approaches, i.e., based on the n-alkane distributions and their δD and δ13C values. Both approaches result in similar estimates of aquatic and terrestrial contributions for mid- and long-chain n-alkanes to the sediment. 62–73% of the mid-chain n-C23 alkanes originate from aquatic sources while 66–77% of the long-chain n-alkanes originate from dust and 14–30% from terrestrial plants. Our study shows that mid-chain n-alkanes such as the n-C23 alkane in LPA are derived mainly from aquatic macrophytes and thus have the potential to record changes in lake-water isotopic composition. In contrast, the n-C29 alkane reflects the isotopic signal of various terrestrial sources from southern Patagonia. © 2016 Elsevier Ltd Article 2016 10.1016/j.orggeochem.2016.10.001 Organic Geochemistry 102 110 – 119 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Biogeochemistry; Biological materials; Chains; Dust; Isotopes; Lakes; Sediments; Chain length distribution; Environmental reconstruction; ICDP; Isotopic composition; Long chain n-alkanes; n-Alkanes; PASADO; Relative contribution; alkane; biomarker; carbon isotope; hydrogen isotope; isotopic composition; lacustrine deposit; macrophyte; organic matter; paleoenvironment; reconstruction; sediment chemistry; spatial distribution; stable isotope; submerged vegetation; Paraffins https://www.scopus.com/inward/record.uri?eid=2-s2.0-84995752879&doi=10.1016%2fj.orggeochem.2016.10.001&partnerID=40&md5=8f884b34ac3a22c04773cd469bed5ce6 Cited by: 25; All Open Access, Green Open Access Katja Hockun Gesine Mollenhauer Sze Ling Ho Jens Hefter Christian Ohlendorf Bernd Zolitschka Christoph Mayr Andreas Lücke Enno Schefuß article Ariztegui20151655 Review 2015 10.1007/s00531-015-1148-4 International Journal of Earth Sciences 104 1655 – 1665 6 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84940958158&doi=10.1007%2fs00531-015-1148-4&partnerID=40&md5=0af1c04e97299773cc0ebbf26995db8d Cited by: 22; All Open Access, Green Open Access, Hybrid Gold Open Access Daniel Ariztegui Camille Thomas Aurèle Vuillemin article Lisé-Pronovost201572 The sedimentary archive from Laguna Potrok Aike is the only continuous record reaching back to the last Glacial period in continental southeastern Patagonia. Located in the path of the Southern Hemisphere westerly winds and in the source region of dust deposited in Antarctica during Glacial periods, southern Patagonia is a vantage point to reconstruct past changes in aeolian activity. Here we use high-resolution rock-magnetic and physical grain size data from site 2 of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO) in order to develop magnetic proxies of dust and wind intensity at 52°S since 51,200 cal BP. Rock-magnetic analysis indicates the magnetic mineral assemblage is dominated by detrital magnetite. Based on the estimated flux of magnetite to the lake and comparison with distal dust records from the Southern Ocean and Antarctica, kLF is interpreted as a dust indicator in the dust source of southern Patagonia at the millennial time scale, when ferrimagnetic grain size and coercivity influence are minimal. Comparison to physical grain-size data indicates that the median destructive field of isothermal remanent magnetization (MDFIRM) mostly reflects medium to coarse magnetite bearing silts typically transported by winds for short-term suspension. Comparison with wind-intensity proxies from the Southern Hemisphere during the last Glacial period and with regional records from Patagonia since the last deglaciation including marine, lacustrine and peat bog sediments as well as speleothems reveals similar variability with MDFIRM up to the centennial time scale. MDFIRM is interpreted as a wind-intensity proxy independent of moisture changes for southeastern Patagonia, with stronger winds capable of transporting coarser magnetite bearing silts to the lake. © 2014 Elsevier B.V. Article 2015 10.1016/j.epsl.2014.11.007 Earth and Planetary Science Letters 411 72 – 86 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Dust; Glacial geology; Grain size and shape; Infill drilling; Lakes; Lithology; Magnetism; Magnetite; Minerals; Rocks; Salinity measurement; Silt; Wind; Lake sediments; PASADO; Rock magnetism; Westerly winds; Wind intensity; dust; grain size; lacustrine deposit; Last Glacial; magnetic property; magnetite; remanent magnetization; rock property; Southern Hemisphere; westerly; wind field; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918839701&doi=10.1016%2fj.epsl.2014.11.007&partnerID=40&md5=614e44a37d57463b7df4f18aceec2056 Cited by: 15 Agathe Lisé-Pronovost Guillaume St-Onge Claudia Gogorza Torsten Haberzettl Guillaume Jouve Christian Ohlendorf Catalina Gebhardt Bernd Zolitschka article Oehlerich2015189 First results of strontium, calcium, carbon and oxygen isotope analyses of bulk carbonates from a 106m long sediment record of Laguna Potrok Aike, located in southern Patagonia are presented. Morphological and isotopic investigations of μm-sized carbonate crystals in the sediment reveal an endogenic origin for the entire Holocene. During this time period the calcium carbonate record of Laguna Potrok Aike turned out to be most likely ikaite-derived. As ikaite precipitation in nature has only been observed in a narrow temperature window between 0 and 7°C, the respective carbonate oxygen isotope ratios serve as a proxy of hydrological variations rather than of palaeotemperatures. We suggest that oxygen isotope ratios are sensitive to changes of the lake water balance induced by intensity variations of the Southern Hemisphere Westerlies and discuss the role of this wind belt as a driver for climate change in southern South America. In combination with other proxy records the evolution of westerly wind intensities is reconstructed. Our data suggest that weak SHW prevailed during the Lateglacial and the early Holocene, interrupted by an interval with strengthened Westerlies between 13.4 and 11.3kacalBP. Wind strength increased at 9.2kacalBP and significantly intensified until 7.0kacalBP. Subsequently, the wind intensity diminished and stabilised to conditions similar to present day after a period of reduced evaporation during the "Little Ice Age". Strontium isotopes (87Sr/86Sr ratio) were identified as a potential lake-level indicator and point to a lowering from overflow conditions during the Glacial (~17kacalBP) to lowest lake levels around 8kacalBP. Thereafter the strontium isotope curve resembles the lake-level curve which is stepwise rising until the "Little Ice Age". The variability of the Ca isotope composition of the sediment reflects changes in the Ca budget of the lake, indicating higher degrees of Ca utilisation during the period with lowest lake level. © 2015 Elsevier Ltd. Article 2015 10.1016/j.quascirev.2015.02.006 Quaternary Science Reviews 114 189 – 202 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Budget control; Calcite; Calcium; Calcium carbonate; Carbon; Carbonation; Climate change; Glacial geology; Isotopes; Lakes; Oxygen; Sediments; Calcium isotopes; Carbon isotopes; ICDP; Ikaite; Lake sediments; Oxygen isotopes; PASADO; Southern south america; Strontium isotopes; carbonate; climate variation; evaporation; Holocene; ikaite; isotopic composition; lacustrine deposit; late glacial; oxygen isotope; paleoclimate; paleotemperature; proxy climate record; strontium isotope; westerly; Strontium https://www.scopus.com/inward/record.uri?eid=2-s2.0-84924232224&doi=10.1016%2fj.quascirev.2015.02.006&partnerID=40&md5=0dead064d49658e62990ecf4dccbcb2a Cited by: 16 M. Oehlerich C. Mayr N. Gussone A. Hahn S. Hölzl A. Lücke C. Ohlendorf S. Rummel B.M.A. Teichert B. Zolitschka article Zimmermann201520 Article 2015 10.1016/j.palaeo.2015.03.006 Palaeogeography, Palaeoclimatology, Palaeoecology 427 20 – 31 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84961362678&doi=10.1016%2fj.palaeo.2015.03.006&partnerID=40&md5=f1601a2513e23c9a06285de679190485 Cited by: 4; All Open Access, Green Open Access Claudia Zimmermann Guillaume Jouve Reinhard Pienitz Pierre Francus Nora I. Maidana article Recasens2015309 Southern South America is a key site to study climate variability in the Southern Hemisphere, allowing for a wide variety of climatic archives. Recently, several investigations using lacustrine sediments have provided an enormous amount of information to reconstruct past environmental changes. In the framework of the Potrok Aike Maar Lake Sediment Archive Drilling Project (PASADO) more than 500. m of sediment cores were retrieved from the center of this lake.This contribution is centered in the diatom record of a core covering over the last 50. cal. ka BP. Nine statistically significant zones were determined based on changes in the assemblages of more than 200 species of diatoms, showing changes in productivity throughout time. Although it appears that the presence of mass waste events may have triggered some peaks in productivity, large fluctuations in diatom abundance and changes in species assemblages coincide with distinctive Antarctic warm events, A2 and A1, described for Antarctic ice cores at around 44.5 and 38.5 kyr BP respectively (Blunier and Brook, 2001). Furthermore, a smaller diatom peak may account for the A3 event compatible with a new OSL-based chronological model. Up to now they have only been described for Antarctica, but the fact that these events are recorded in southern Patagonia indicates their magnitude and importance for climate in the Southern Hemisphere. © 2014 Elsevier B.V. Article 2015 10.1016/j.palaeo.2014.09.021 Palaeogeography, Palaeoclimatology, Palaeoecology 417 309 – 319 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacillariophyta; bioindicator; climate variation; diatom; hydrological change; lacustrine deposit; maar; paleoclimate; Pleistocene; Southern Hemisphere https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918575207&doi=10.1016%2fj.palaeo.2014.09.021&partnerID=40&md5=2834f79b66f176a216063b62da424993 Cited by: 20 Cristina Recasens Daniel Ariztegui Nora I. Maidana Bernd Zolitschka article Zhu2014212 Article 2014 10.1016/j.gca.2014.01.013 Geochimica et Cosmochimica Acta 130 212 – 228 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894372938&doi=10.1016%2fj.gca.2014.01.013&partnerID=40&md5=463130c31fdfe5995dfe4a491b0e85e1 Cited by: 14 Jiayun Zhu Andreas Lücke Holger Wissel Christoph Mayr Christian Ohlendorf Bernd Zolitschka article Hahn2014349 During the lake deep drilling campaign PASADO in 2008, more than 500 m of lacustrine sediment was recovered from the maar lake Laguna Potrok Aike, Argentina. The major element composition was assessed at high resolution with an ITRAX X-ray fluorescence core scanner. The sharp boundary between a carbonate-bearing and a carbonate-free depositional system occurs at 13.5 cal. ka BP and marks the transition from glacial to Late Glacial sediments. Holocene and Late Glacial sediments can be distinguished by elements that are indicative of organic matter (Br, Cl) or calcite (Ca). Glacial sediments are characterized by elements that represent terrigenous clastic input (Fe, Ti, K, Si). Trace elements (Mn, Rb, V, Ni) accumulate with the bulk of lithogenic elements indicating frequent oxic conditions and rare diagenetic remobilization. Based on principal component analysis we interpret the scores of the first principle component as a summarizing indicator for climate-related variations of depositional conditions. During the Holocene climate changes mirror the total inorganic carbon profile, which was used as a proxy for lake-level reconstructions of the past 16 ka in previous studies. High scores in the first principle component probably reflect periods of increased chemical over mechanical weathering and developing soils and vegetation cover limiting sediment availability for erosional processes. These intervals often also show increases in total organic carbon values and total organic carbon/total nitrogen ratios, which are associated with periods of Antarctic warming in the last glacial. Geochemical variations of the clastic glacial sediments are explored by excluding carbonate-bearing sediments from principal component analysis. Although, in this lake, Ca is a purely clastic signal in carbonate-free sediments, it does not correlate with the bulk of indicators for terrigenous input. Instead Ca dominates a second principal component together with Sr. This component mainly distinguishes coarse grained layers from the remaining sediment. The main provenance of this coarse-grained material is suggested to be a basalt outcrop at the western shore. Low lake levels, high waves and flash-flood events may have increased the availability of basaltic sand during extremely cold, arid and windy conditions. High wind speeds and lack of vegetation may have facilitated the increased transport of coarse-grained material into the center of Laguna Potrok Aike. Decreases in the second principal component can be observed during Oxygen Isotope Stage 2 when increased dust input has been found in cores from Laguna Potrok Aike, the Southern Ocean and Antarctica. © 2014, Springer Science+Business Media Dordrecht. Article 2014 10.1007/s10933-014-9798-y Journal of Paleolimnology 52 349 – 366 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84921938721&doi=10.1007%2fs10933-014-9798-y&partnerID=40&md5=d61ecd5740a23ff28901aa0959dc8b86 Cited by: 22 Annette Hahn Pierre Kliem Markus Oehlerich Christian Ohlendorf Bernd Zolitschka article Vuillemin2014285 Article 2014 10.1080/01490451.2013.824050 Geomicrobiology Journal 31 285 – 298 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84894386725&doi=10.1080%2f01490451.2013.824050&partnerID=40&md5=902a67e02c2ab4433f23b26c1973bbcd Cited by: 9; All Open Access, Green Open Access A. Vuillemin D. Ariztegui G. Nobbe C.J. Schubert article Vuillemin2014101 Article 2014 10.1007/s00027-013-0317-4 Aquatic Sciences 76 101 – 114 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84891648336&doi=10.1007%2fs00027-013-0317-4&partnerID=40&md5=0537648b112f488df732a8d85118f1d7 Cited by: 14 Aurèle Vuillemin Daniel Ariztegui Andreas Lücke Christoph Mayr article Lisé-Pronovost2014110 A 106-m long sediment sequence from the maar lake Laguna Potrok Aike in southern Patagonia was recovered in the framework of the International Continental Scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). About half of the sedimentary sequence is composed of mass movement deposits (MMDs) and the event-corrected record reaches back to 51,200calBP. Here we present a high-resolution rock-magnetic study revealing two sedimentary facies associated with MMDs and characterized by two different types of spurious gyroremanent magnetization (GRM) acquired during static alternating field demagnetization. The first rock-magnetic signature is detected in MMDs composed of reworked sand and tephra material. The signature consists of GRM acquired during demagnetization of the natural remanent magnetization (NRM) and other rock-magnetic properties typical of iron sulfides such as greigite. We interpret these intervals as authigenic formation of iron sulfides in suboxic conditions within the MMD. The second rock-magnetic signature consists of a series of 10 short intervals located on the top of MMDs characterized by GRM acquisition during demagnetization of the isothermal remanent magnetization (IRM). Based on geological, limnological, stratigraphic and climatic evidence these layers are interpreted as reflecting pedogenic hematite and/or goethite brought to the lake by runoff events related to precipitation and permafrost melt. The pedogenic iron minerals mobilized from the catchment most likely settled out of suspension on top of MMDs after a rapid remobilization event. The series of runoff events corresponds to periods of increased lacustrine productivity in Laguna Potrok Aike and are coeval within the limit of the chronology to warm periods of the Last Glacial as recorded in Antarctica, the deglaciation in the mid-latitudes of the Southern Hemisphere and enhanced precipitation during the Early Holocene in southeastern Patagonia. © 2014 Elsevier Ltd. Article 2014 10.1016/j.quascirev.2014.05.029 Quaternary Science Reviews 98 110 – 125 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Catchments; Demagnetization; Deposits; Geomagnetism; Iron; Lakes; Magnetization; Runoff; Sedimentology; Sediments; Stratigraphy; Lacustrine sediments; Laguna potrok aike; Mass movement; Paleo-environment; Rock magnetism; facies; geochronology; hematite; isotherm; lacustrine deposit; last glaciation; magnetization; paleoenvironment; precipitation (climatology); runoff; sedimentary sequence; sulfide; Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-84902986374&doi=10.1016%2fj.quascirev.2014.05.029&partnerID=40&md5=9c803f06f52f8358fea1d231957d4d3a Cited by: 14 A. Lisé-Pronovost G. St-Onge C. Gogorza G. Jouve P. Francus B. Zolitschka article Buylaert201370 We have measured and tested a luminescence chronology for the PASADO core 5022-1D from the maar lake of Laguna Potrok Aike. Because of unsuitable quartz OSL characteristics, sand-sized K-feldspar extracts were chosen as a dosimeter and the dose was measured using a post-IR IRSL (pIRIR290) measurement protocol. Using this approach we were able to access a stable signal and thus avoid the ubiquitous problem of feldspar signal instability. Extensive laboratory tests show that the chosen pIRIR290 protocol is applicable to these samples. We also developed a new criterion based on known relative bleaching rates of the conventional IRSL signal (IR50) and the pIRIR290 signal and the relationship between resulting equivalent doses; this is used to identify and reject poorly bleached samples. Eighteen samples out of 47 were rejected based on this criterion, without reference to absolute doses or stratigraphy; the resulting age-depth profile is self-consistent, increases smoothly with depth and is in agreement with independent age control based on volcanic ash layers (Reclús, Mt Burney and Hudson tephras) at the top and middle of the core. Our new luminescence chronology suggests that the 5022-1D core reaches back to ~65ka at ~96m below lake floor. © 2013 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2013.03.018 Quaternary Science Reviews 71 70 – 80 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Bleaching; Cleaning; Feldspar; Lakes; Quartz; Stratigraphy; ICDP-project PASADO; Independent age control; K-feldspar; Laguna potrok aike; Luminescence dating; Measurement protocol; Post-IR IRSL; Signal instabilities; bleaching; chronology; feldspar; luminescence dating; signal; volcanic ash; Luminescence https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878917033&doi=10.1016%2fj.quascirev.2013.03.018&partnerID=40&md5=afbbbb2c8217cda9c5a9a9cf956386d5 Cited by: 67 J.-P. Buylaert A.S. Murray R. Sohbati C. Ohlendorf C. Thiel S. Wastegård B. Zolitschka article Wastegård201381 A total of 18 tephra samples have been analysed from the composite sediment sequence from Site 2 of the Laguna Potrok Aike ICDP expedition 5022 from southern Patagonia, Argentina, which extends back to ca 51kacalBP. Analyses of the volcanic glass show that all layers but one are rhyolitic in composition, with SiO2 contents ranging between ca 74.5 and 78wt% and suggest an origin in the Austral Andean Volcanic Zone (AVZ; 49-55°S). Nonetheless, two main data clusters occur, one group with K2O contents between ca 1.5 and 2.0wt%, indicating an origin in the Mt. Burney volcanic area, and one group with K2O contents between ca 2.7 and 3.9wt%, tentatively correlated with Viedma/Lautaro and the Aguilera volcanoes in the northern part of the AVZ. The early Holocene Tephra, MB1 and the late Pleistocene Reclus R1 tephra occur in the upper part of the sequence. Periods with significant tephra deposition occurred between ca 51-44kacalBP, and ca 31-25kacalBP, with a decrease in tephra layer frequency between these two periods. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.10.019 Quaternary Science Reviews 71 81 – 90 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Geology; Natural sciences; Chronology; ICDP-project PASADO; Mt. Burney; Pleistocene; Tephra; Volcanic; community composition; oxide; Quaternary; sediment analysis; tephrochronology; volcanic eruption; Volcanoes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878926863&doi=10.1016%2fj.quascirev.2012.10.019&partnerID=40&md5=9815d7f066a70570c70de3fdeaaf8105 Cited by: 38 S. Wastegård D. Veres P. Kliem A. Hahn C. Ohlendorf B. Zolitschka article Zhu2013205 An investigation of stable isotope (δ13CTOC and δ15NTN) and elemental parameters (TOC, TN contents and TOC/TN ratios) of bulk organic matter (<200μm) from sediment cores recovered from the Patagonian lake Laguna Potrok Aike (Argentina) in the framework of the ICDP deep drilling project PASADO provided insights into past changes in lake primary productivity and environmental conditions in South Patagonia throughout the last Glacial-Interglacial transition. Stratigraphically constrained cluster analyses of all proxy parameters suggest four main phases. From ca 26,100 to 17,300cal.yearsBP, lacustrine phytoplankton was presumably the predominant organic matter source in an aquatic environment with low primary productivity rates. At around 17,300cal.years BP, abrupt and distinct shifts of isotopic and elemental values indicate that the lacustrine system underwent a rapid reorganization. Lake primary productivity (phytoplankton and aquatic macrophytes) shows higher levels albeit with large variations during most of the deglaciation until 13,000cal.yearsBP. The main causes for this development can be seen in improved growing conditions for primary producers because of deglacial warming in combination with expedient availability of nutrients and likely calm wind conditions. After 13,000cal.yearsBP, decreased δ13CTOC values, TOC, TN contents and TOC/TN ratios indicate that the lake approached a new state with reduced primary productivity probably induced by unfavourable growing conditions for primary producers like strengthened winds and reduced nutrient availability. The steady increase in δ15NTN values presumably suggests limitation of nitrate supply for growth of primary producers resulting from a nutrient shortage after the preceding phase with high productivity. Nitrate limitation and consequent decreased lacustrine primary productivity continued into the early Holocene (10,970-8400cal.yearsBP) as reflected by isotopic and elemental values. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.025 Quaternary Science Reviews 71 205 – 218 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Biogeochemistry; Biological materials; Cluster analysis; Isotopes; Lakes; Nitrates; Nutrients; Organic compounds; Photosynthesis; Sedimentology; ICDP; Lake sediments; Last deglaciation; PASADO; Primary productivity; South America; Stable carbon and nitrogen isotopes; carbon isotope; cluster analysis; deglaciation; environmental conditions; glacial-interglacial cycle; growing season; Last Glacial Maximum; macrophyte; nitrogen isotope; organic matter; phytoplankton; primary production; proxy climate record; sediment chemistry; sediment core; stable isotope; Phytoplankton https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878919582&doi=10.1016%2fj.quascirev.2012.05.025&partnerID=40&md5=1e5f4e5972bba6b56bf43621978db9ff Cited by: 16 Jiayun Zhu Andreas Lücke Holger Wissel Daniela Müller Christoph Mayr Christian Ohlendorf Bernd Zolitschka article Schäbitz2013175 Based on modern pollen samples from different vegetation units in southern Patagonia, showing a close relation to yearly amounts of precipitation and mean annual temperatures, different pollen-climate transfer functions are developed and tested. Comparing the performance of MAT (Modern Analogue Techniques), WA (Weighted Average), as well as WAPLS (Weighted Average Partial Least Square) statistical techniques, it is possible to determine the statistically most robust model (WAPLS for precipitation). This transfer function is then used to estimate palaeoprecipitation amounts based on Laguna Potrok Aike pollen results for the last 16,000 years. Generally, the results of the precipitation model indicate less precipitation during the Lateglacial and alternating wet and dry periods during the Holocene. The Holocene started with higher amounts of precipitation until about 8kacal.BP, followed by a period with lower amounts between 8 and 2.5kacal.BP, while the Late Holocene shows a general increase in precipitation. Comparisons with former shoreline reconstructions and carbonate concentrations in the sediments of Laguna Potrok Aike not always show similarities due to the complex environmental factors recorded by these proxies. Moreover, changes in the moisture availability due to the interplay of precipitation and temperature, cannot be reconstructed directly. Nevertheless, the general long-term trend of palaeoprecipitation is in accordance with the absolute moisture content in the air, which is determined mainly by temperature: during cold periods with less absolute moisture, the model shows less precipitation. Moreover, the model also points to a relation with the position and strength of the Southern Hemisphere Westerlies. © 2013 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.12.006 Quaternary Science Reviews 71 175 – 190 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Moisture; Statistical methods; Transfer functions; ICDP-project PASADO; Late quaternary; Modern pollen samples; Palaeoclimate; Pollen; Precipitation reconstruction; Southern Hemisphere; carbonate; concentration (composition); environmental factor; Holocene; numerical model; pollen; precipitation (climatology); reconstruction; Southern Hemisphere; temperature effect; Lasers https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878921228&doi=10.1016%2fj.quascirev.2012.12.006&partnerID=40&md5=07458a9862ea79d982cdc0398e922c9b Cited by: 42 Frank Schäbitz Michael Wille Jean-Pierre Francois Torsten Haberzettl Flavia Quintana Christoph Mayr Andreas Lücke Christian Ohlendorf Virginia Mancini Marta M. Paez Aldo R. Prieto Bernd Zolitschka article Vuillemin2013275 Authigenic minerals can form in the water column and sediments of lakes, either abiotically or mediated by biological activity. Such minerals have been used as paleosalinity and paleoproductivity indicators and reflect trophic state and early diagenetic conditions. They are also considered potential indicators of past and perhaps ongoing microbial activity within sediments. Authigenic concretions, including vivianite, were described in late glacial sediments of Laguna Potrok Aike, a maar lake in southernmost Argentina. Occurrence of iron phosphate implies specific phosphorus sorption behavior and a reducing environment, with methane present. Because organic matter content in these sediments was generally low during glacial times, there must have been alternative sources of phosphorus and biogenic methane. Identifying these sources can help define past trophic state of the lake and diagenetic processes in the sediments. We used scanning electron microscopy, phosphorus speciation in bulk sediment, pore water analyses, in situ ATP measurements, microbial cell counts, and measurements of methane content and its carbon isotope composition (δ13CCH4) to identify components of and processes in the sediment. The multiple approaches indicated that volcanic materials in the catchment are important suppliers of iron, sulfur and phosphorus. These elements influence primary productivity and play a role in microbial metabolism during early diagenesis. Authigenic processes led to the formation of pyrite framboids and revealed sulfate reduction. Anaerobic oxidation of methane and shifts in pore water ion concentration indicated microbial influence with depth. This study documents the presence of active microbes within the sediments and their relationship to changing environmental conditions. It also illustrates the substantial role played by microbes in the formation of Laguna Potrok Aike concretions. Thus, authigenic minerals can be used as biosignatures in these late Pleistocene maar sediments. © 2013 Springer Science+Business Media Dordrecht. Article 2013 10.1007/s10933-013-9723-9 Journal of Paleolimnology 50 275 – 291 3 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; diagenesis; environmental conditions; late glacial; maar; metabolism; methane; microbial activity; paleoproductivity; paleosalinity; phosphorus; porewater; pyrite; scanning electron microscopy; sorption; vivianite; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-84883780186&doi=10.1007%2fs10933-013-9723-9&partnerID=40&md5=9fb78e69d9e1a48f21228ee31af91e8f Cited by: 32; All Open Access, Green Open Access A. Vuillemin D. Ariztegui A.S. De Coninck A. Lücke C. Mayr C.J. Schubert article Jouve2013191 Article 2013 10.1016/j.quascirev.2012.06.003 Quaternary Science Reviews 71 191 – 204 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878924540&doi=10.1016%2fj.quascirev.2012.06.003&partnerID=40&md5=a6df16e5909b688d8f93c01072037079 Cited by: 59 Guillaume Jouve Pierre Francus Scott Lamoureux Laurence Provencher-Nolet Annette Hahn Torsten Haberzettl David Fortin Laurence Nuttin article Ohlendorf201327 Laguna Potrok Aike is an exceptional site in the southern hemisphere's mid-latitudes because it records changes in the hydrological regime through lake-level variations in a continuous, high-resolution sediment record back into the late Pleistocene. In this study, driving forces of lake-level changes at Laguna Potrok Aike are evaluated by means of process studies using data from an extensive multi-year monitoring in and around the lake. Lake-volume changes were calculated with an energy-budget/bulk-transfer approach and translated into lake-level variations, which were then compared to pressure sensor data. Calculated lake levels are in broad agreement with measured data. We hypothesize that on short time scales, lake-level fluctuations are mainly driven by the precipitation-to-evaporation ratio. Apart from changing catchment conditions, relative humidity, precipitation, temperature, wind strength and wind direction have the most important influence on the hydrological balance of the lake. Lake level decreases during periods of persistently high wind speeds from westerly directions, whereas, during periods with more frequent occurrences of easterly winds, it increases. These situations are linked to a strengthening of the Southern Hemispheric Westerlies in the first and more frequent blocking situations in the latter case. Although lake-level changes at Laguna Potrok Aike show some degree of similarity to variations of the El Niño Southern Oscillation (ENSO) and the Southern Hemisphere Annular Mode (SAM), a persistent correspondence remains to be documented.Water chemistry and sediment-trap data suggest that lake-internal carbonate precipitation is highly sensitive to short-term changes in the lake water volume and, thus, to lake-level variations. However, it becomes obvious that the sedimentary carbonate record, representing changes on longer time scales, is not linearly linked to lake-level changes, hence complicating quantitative lake-level reconstructions back in time. We suggest that short-term changes in authigenic carbonate production are mainly driven by changing precipitation/evaporation ratios probably superimposed on longer-term changes in groundwater input that represent a buffered climate signal.Scenario calculations for a period of 60 years show that changes of the controlling meteorological parameters in the range of 15-17% can lead to lake-level changes with a magnitude comparable to the reconstructed Holocene and Lateglacial extreme situations. In addition, modifications in the water-retaining capacity of the lake can also produce large lake-level changes. It is hypothesized that the development or disappearance of permafrost in the catchment of Laguna Potrok Aike during the Last Glacial/Interglacial transition may have changed the water-retaining capacity tremendously. The lake-level reconstructions for Laguna Potrok Aike might express some of the meridional climate variability observed in coupled general circulation model (CGCM) simulations for southern South America for the Last Glacial Maximum (LGM) and the mid Holocene. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.10.040 Quaternary Science Reviews 71 27 – 45 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Atmospheric pressure; Carbonation; Catchments; Climatology; Digital storage; Groundwater; Lasers; Monitoring; Runoff; Sediment traps; Sedimentology; Authigenic carbonates; Carbonate precipitation; Coupled general circulation models; ICDP-project PASADO; Meteorological parameters; Southern Hemisphere; Southern hemisphere annular modes; Southern south america; carbonate; energy budget; environmental monitoring; evaporation; general circulation model; hydrochemistry; hydrological change; lacustrine environment; mathematical analysis; permafrost; precipitation (chemistry); sediment chemistry; sediment trap; Southern Hemisphere; timescale; volume; wind velocity; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878937235&doi=10.1016%2fj.quascirev.2012.10.040&partnerID=40&md5=2a14220abd360aaca2511814d6ea5fc4 Cited by: 37 Christian Ohlendorf Michael Fey Catalina Gebhardt Torsten Haberzettl Andreas Lücke Christoph Mayr Frank Schäbitz Michael Wille Bernd Zolitschka article Kliem2013131 Laguna Potrok Aike is a large maar lake located in the semiarid steppe of southern Patagonia known for its Lateglacial and Holocene lake level fluctuations. Based on sedimentary, seismic and geomorphological evidences, the lake level curve is updated and extended into the Last Glacial period and the geomorphological development of the lake basin and its catchment area is interpreted.Abrasion and lake level oscillations since at least ~50ka caused concentric erosion of the surrounding soft rocks of the Miocene Santa Cruz Formation and expanded the basin diameter by approximately 1km. A high lake level and overflow conditions of the lake were dated by luminescence methods and tephra correlation to the early Lateglacial as well as to ~45ka. The lowest lake level of record occurred during the mid-Holocene. A further lake level drop was probably prevented by groundwater supply. This low lake level eroded a distinct terrace into lacustrine sediments. Collapse of these terraces probably caused mass movement deposits in the profundal zone of the lake. After the mid-Holocene lake level low stand a general and successive transgression occurred until the Little Ice Age maximum; i.e. ca 40m above the local groundwater table. Frequent lake level oscillations caused deflation of emerged terraces only along the eastern shoreline due to prevailing westerly winds. Preservation of eolian deposits might be linked to relatively moist climate conditions during the past 2.5ka.Precisely dated lake level reconstructions in the rain-shadow of the Andes document high Last Glacial and low Holocene lake levels that could suggest increased precipitation during the Last Glacial period. As permafrost in semiarid Patagonia is documented and dated to the Last Glacial period we argue that the frozen ground might have increased surficial runoff from the catchment and thus influenced the water balance of the lake. This is important for investigating the glacial to Holocene latitudinal shift and/or strengthening of the Southern Hemispheric Westerlies by using lake level reconstructions as a means to assess the regional water balance. Our interpretation explains the contradiction with investigations based on pollen data indicating drier climatic conditions for the Last Glacial period. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.08.023 Quaternary Science Reviews 71 131 – 146 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Catchments; Curve fitting; Deposits; Glacial geology; Groundwater; Permafrost; Rain; Runoff; Salinity measurement; Sedimentary rocks; Soils; Glacial; Holocenes; ICDP-project PASADO; Lacustrine sediments; Lake level fluctuations; Regional water balance; Southern Hemispheric Westerlies; Surrounding soft rock; catchment; data set; geomorphology; groundwater; Last Glacial Maximum; Little Ice Age; luminescence; maar; magnitude; mass movement; Miocene; oscillation; permafrost; precipitation (climatology); semiarid region; Southern Hemisphere; steppe; tephrochronology; transgression; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878946242&doi=10.1016%2fj.quascirev.2012.08.023&partnerID=40&md5=911db3958ecb47af674415cbfed3dcf6 Cited by: 33 P. Kliem J.P. Buylaert A. Hahn C. Mayr A.S. Murray C. Ohlendorf D. Veres S. Wastegård B. Zolitschka article Fortin2013147 Density measurements play a central role in the characterization of sediment profiles. When working with long records (>100m), such as those routinely obtained within the frame of the International Continental Scientific Drilling Program, several methods can be used, all of them varying in resolution, time-cost efficiency and source of errors within the measurements. This paper compares two relatively new non-destructive densitometric methods, CT-Scanning and the coherent/incoherent ratio from an Itrax XRF core Scanner, to data acquired from a Multi-sensor core logger Gamma Ray Attenuation Porosity Evaluator (MSCL Grape) and discrete measurements of dry bulk density, wet bulk density and water content. Quality assessment of density measurements is performed at low and high resolution along the Laguna Potrok Aike (LPA) composite sequence. Giving its resolution (0.4mm in our study), its high signal to noise ratio, we conclude that CT-Scan provides a precise, fast and cost-efficient way to determine density variation of long sedimentary record. Although more noisy that the CT-Scan measurements, coherent/incoherent ratio from the XRF core scanner also provides a high-resolution, reliable continuous measure of density variability of the sediment profile. The MSCL Grape density measurements provide actual density data and have the significant advantage to be completely non-destructive since the acquisition is performed on full cores prior to opening. However, the quality MSCL Grape density measurements can potentially be reduced by the presence of voids within the sediment core tubes and the dry and bulk density measurements suffers from sampling challenges and are time-consuming. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.08.024 Quaternary Science Reviews 71 147 – 153 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Vitaceae; Density measurement (specific gravity); Fruits; Gamma rays; Scanning; Sedimentology; Sediments; Bulk density measurement; Continental scientific drillings; CT-scan; Density variabilities; High signal-to-noise ratio; ICDP-project PASADO; Sediment densities; XRF; bulk density; cost-benefit analysis; measurement method; resolution; sampling; sediment core; signal-to-noise ratio; X-ray fluorescence; Computerized tomography https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878920976&doi=10.1016%2fj.quascirev.2012.08.024&partnerID=40&md5=6b483615cf49844c544f5d8abbcb758e Cited by: 44 David Fortin Andrea Catalina Gebhardt Annette Hahn Pierre Kliem Agathe Lisé-Pronovost Rajarshi Roychowdhury Jacques Labrie Guillaume St-Onge article Kliem201354 The 106m long composite profile from site 2 of ICDP expedition 5022 (PASADO) at Laguna Potrok Aike documents a distinct change in sedimentation patterns from pelagic sediments at the top to dominating mass movement deposits at its base. The main lithological units correspond to the Holocene, to the Lateglacial and to the last glacial period and can be interpreted as the result of distinct environmental variations. Overflow conditions might have been achieved during the last glacial period, while signs of desiccation are absent in the studied sediment record. Altogether, 58 radiocarbon dates were used to establish a consistent age-depth model by applying the mixed-effect regression procedure which results in a basal age of 51.2cal.kaBP. Radiocarbon dates show a considerable increase in scatter with depth which is related to the high amount of reworking. Validation of the obtained chronology was achieved with geomagnetic relative paleointensity data and tephra correlation. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.07.019 Quaternary Science Reviews 71 54 – 69 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Deposits; Geomagnetism; Salinity measurement; Sedimentology; Sediments; Argentina; Holocenes; ICDP-project PASADO; Lake level fluctuations; Late Pleistocene; Mass movement; Mixed-effect regression; Patagonia; climate variation; data set; geochronology; glacial environment; Holocene; lacustrine deposit; Last Glacial; lithology; mass movement; numerical model; radiocarbon dating; sedimentation; tephrochronology; Lithology https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878896037&doi=10.1016%2fj.quascirev.2012.07.019&partnerID=40&md5=31e2d9a5847388acb98de7e7c4e735ff Cited by: 56 Pierre Kliem Dirk Enters Annette Hahn Christian Ohlendorf Agathe Lisé-Pronovost Guillaume St-Onge Stefan Wastegård Bernd Zolitschka article Oehlerich201346 The monoclinic mineral ikaite (CaCO3 · 6H2O) and its pseudomorphs are potentially important archives for palaeoenvironmental reconstructions. Natural ikaite occurs in a small temperature range near freezing point and is reported mainly from marine and only rarely from continental aquatic environments. Ikaite transforms to more stable anhydrous forms of CaCO3 after an increase in temperature or when exposed to atmospheric conditions. The knowledge about conditions for natural ikaite formation, its stable isotope fractionation factors and isotopic changes during transformation to calcite is very restricted. Here, for the first time, primary precipitation of idiomorphic ikaite and its calcite pseudomorphs are reported from a subsaline lake, Laguna Potrok Aike, in southern Argentina. The calculated stable oxygen isotope fractionation factor between lake water and ikaite-derived calcite (αPAI=1.0324 at a temperature of 4.1°C) is close to but differs from that of primarily inorganically precipitated calcite. Pseudomorphs after ikaite rapidly disintegrate into calcite powder that is indistinguishable from μm-sized calcite crystals in the sediment record of Laguna Potrok Aike suggesting an ikaite origin of sedimentary calcites. Therefore, the Holocene carbonates of Laguna Potrok Aike have the potential to serve as a recorder of past hydrological variation. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.024 Quaternary Science Reviews 71 46 – 53 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Calcium carbonate; Isotopes; Lakes; Lasers; Minerals; Oxygen; Sedimentary rocks; Aquatic environments; Atmospheric conditions; ICDP project PASADO; Oxygen isotope fractionations; Palaeoenvironmental reconstruction; Stable isotope fractionations; Stable isotopes; Stable oxygen isotopes; calcite; calcium carbonate; freezing; Holocene; ikaite; isotopic fractionation; lacustrine deposit; lacustrine environment; marine environment; oxygen isotope; paleoenvironment; precipitation (chemistry); reconstruction; sediment chemistry; stable isotope; temperature effect; Calcite https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878948287&doi=10.1016%2fj.quascirev.2012.05.024&partnerID=40&md5=0f1d2783c26f26f8215a298c18d989fe Cited by: 27 Markus Oehlerich Christoph Mayr Erika Griesshaber Andreas Lücke Oliver M. Oeckler Christian Ohlendorf Wolfgang W. Schmahl Bernd Zolitschka article Lisé-Pronovost201391 Paleomagnetic inclination, declination and relative paleointensity were reconstructed from the sediments of Laguna Potrok Aike in the framework of the International Continental scientific Drilling Program (ICDP) Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO). Here we present the u-channel-based full vector paleomagnetic field reconstruction since 51.2ka cal BP. The relative paleointensity proxy (RPI) was built by normalising the natural remanent magnetisation with the anhysteretic remanent magnetisation using the average ratio at 4 demagnetisation steps part of the ChRM interval (NRM/ARM10-40mT). A grain size influence on the RPI was removed using a correction based on the linear relationship between the RPI and the median destructive field of the natural remanent magnetisation (MDFNRM). The new record is compared with other lacustrine and marine records and stacks from the mid- to high-latitudes of the Southern Hemisphere, revealing consistent millennial-scale variability, the identification of the Laschamp and possibly the Mono Lake geomagnetic excursions, and a direction swing possibly associated to the Hilina Pali excursion at 20ka cal BP. Nonetheless, a global-scale comparison with other high-resolution records located on the opposite side of the Earth and with various dipole field references hint at a different behaviour of the geomagnetic field around southern South America at 46ka cal BP. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.05.012 Quaternary Science Reviews 71 91 – 108 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; South America; Lakes; Magnetization; Sedimentology; ICDP-project PASADO; Laguna potrok aike; Paleomagnetism; Relative paleointensity; Secular variation; Southern Hemisphere; geomagnetism; grain size; lacustrine deposit; paleomagnetism; Pleistocene; proxy climate record; reconstruction; resolution; secular variation; Southern Hemisphere; Geomagnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878954637&doi=10.1016%2fj.quascirev.2012.05.012&partnerID=40&md5=7a63f9b83c846ae22d3d848cb22d410c Cited by: 42 Agathe Lisé-Pronovost Guillaume St-Onge Claudia Gogorza Torsten Haberzettl Michel Preda Pierre Kliem Bernd Zolitschka article Vuillemin2013119 Living microorganisms inhabit every environment of the biosphere but only in the last decades their importance governing biochemical cycles in deep sediments has been widely recognized. Most investigations have been accomplished in the marine realm whereas there is a clear paucity of comparable studies in lacustrine sediments. One of the main challenges is to define geomicrobiological proxies that can be used to identify different microbial signals in the sediments. Laguna Potrok Aike, a maar lake located in Southeastern Patagonia, has an annually not stratifying cold water column with temperatures ranging between 4 and 10°C, and most probably an anoxic water/sediment interface. These unusual features make it a peculiar and interesting site for geomicrobiological studies. Living microbial activity within the sediments was inspected by the first time in a sedimentary core retrieved during an ICDP-sponsored drilling operation. The main goals to study this cold subsaline environment were to characterize the living microbial consortium; to detect early diagenetic signals triggered by active microbes; and to investigate plausible links between climate and microbial populations. Results from a meter long gravity core suggest that microbial activity in lacustrine sediments can be sustained deeper than previously thought due to their adaptation to both changing temperature and oxygen availability. A multi-proxy study of the same core allowed defining past water column conditions and further microbial reworking of the organic fraction within the sediments. Methane content shows a gradual increase with depth as a result of the fermentation of methylated substrates, first methanogenic pathway to take place in the shallow subsurface of freshwater and subsaline environments. Statistical analyses of DGGE microbial diversity profiles indicate four clusters for Bacteria reflecting layered communities linked to the oxidant type whereas three clusters characterize Archaea communities that can be linked to both denitrifiers and methanogens. Independent sedimentary and biological proxies suggest that organic matter production and/or preservation have been lower during the Medieval Climate Anomaly (MCA) coinciding with a low microbial colonization of the sediments. Conversely, a reversed trend with higher organic matter content and substantial microbial activity characterizes the sediments deposited during the Little Ice Age (LIA). Thus, the initial sediments deposited during distinctive time intervals under contrasting environmental conditions have to be taken into account to understand their impact on the development of microbial communities throughout the sediments and their further imprint on early diagenetic signals. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.04.011 Quaternary Science Reviews 71 119 – 130 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacteria (microorganisms); Bacteria; Biogeochemistry; Biological materials; Deposits; Lakes; Methanation; Methane; Organic compounds; Sedimentology; DGGE; Early diagenesis; Laguna potrok aike; LIA; MCA; Methane production; Microbial activities; PASADO; Patagonia; Subsaline; bacterium; biosphere; colonization; community structure; environmental conditions; fermentation; lacustrine deposit; Little Ice Age; maar; methane; microorganism; organic matter; oxygen; population structure; salinity; sediment core; species diversity; temperature effect; water column; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878949027&doi=10.1016%2fj.quascirev.2012.04.011&partnerID=40&md5=8ea1f2d2d5d5a7fa34d4c829bbeefa11 Cited by: 28 Aurèle Vuillemin Daniel Ariztegui article Zolitschka20131 In this introductory paper we summarize the history and achievements of the Potrok Aike maar lake Sediment Archive Drilling prOject (PASADO), an interdisciplinary project embedded in the International Continental Scientific Drilling Program (ICDP). The stringent multiproxy approach adopted in this research combined with radiocarbon and luminescence dating provided the opportunity to synthesize a large body of hydrologically relevant data from Laguna Potrok Aike (southern Patagonia, Argentina). At this site, lake level was high from 51ka until the early Holocene when the Southern Hemisphere Westerlies (SHW) were located further to the north. At 9.3kacal.BP the SHW moved southward and over the latitude of the study area (52°S) causing a pronounced negative water balance with a lake level decrease of more than 50m. Two millennia later, the SHW diminished in intensity and lake level rose to a subsequent maximum during the Little Ice Age. Since the 20th century, a strengthening of the SHW increased the evaporative stress resulting in a more negative water balance. A comparison of our data with other hydrological fluctuations at a regional scale in south-eastern Patagonia, provides new insights and also calls for better chronologies and high-resolution records of climate variability. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.11.024 Quaternary Science Reviews 71 1 – 12 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Climatology; Sedimentology; Argentina; Holocenes; ICDP; Lake levels; Last glacial; Patagonia; Southern Hemispheric Westerlies; Water balance; Holocene; interdisciplinary approach; lacustrine deposit; luminescence dating; maar; radiocarbon dating; Southern Hemisphere; twentieth century; water budget; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878907739&doi=10.1016%2fj.quascirev.2012.11.024&partnerID=40&md5=32b2de9829b840e05937afa6d2c3066f Cited by: 61 B. Zolitschka F. Anselmetti D. Ariztegui H. Corbella P. Francus A. Lücke N.I. Maidana C. Ohlendorf F. Schäbitz S. Wastegård article Recasens2013467 Article 2013 10.1080/0269249X.2013.842613 Diatom Research 28 467 – 472 4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84888006966&doi=10.1080%2f0269249X.2013.842613&partnerID=40&md5=5af95b17f8bbdeab0a2c553b37803a09 Cited by: 8; All Open Access, Green Open Access Cristina Recasens Nora I. Maidana article Hahn2013154 Total organic carbon, total inorganic carbon, biogenic silica content and total organic carbon/total nitrogen ratios of the Laguna Potrok Aike lacustrine sediment record are used to reconstruct the environmental history of south-east Patagonia during the past 51ka in high resolution. High lake level conditions are assumed to have prevailed during the Last Glacial, as sediments are carbonate-free. Increased runoff linked to permafrost and reduced evaporation due to colder temperatures and reduced influence of Southern Hemispheric Westerlies (SHW) may have caused these high lake levels with lake productivity being low and organic matter mainly of algal or cyanobacterial origin. Aquatic moss growth and diatom blooms occurred synchronously with southern hemispheric glacial warming events such as the Antarctic A-events, the postglacial warming following the LGM and the Younger Dryas chronozone. During these times, a combination of warmer climatic conditions with related thawing permafrost could have increased the allochthonous input of nutrients and in combination with warmer surface waters increased aquatic moss growth and diatom production. The SHW were not observed to affect southern Patagonia during the Last Glacial. The Holocene presents a completely different lacustrine system because (a) permafrost no longer inhibits infiltration nor emits meltwater pulses and (b) the positioning of the SHW over the investigated area gives rise to strong and dry winds. Under these conditions total organic carbon, total organic carbon/total nitrogen ratios and biogenic silica cease to be first order productivity indicators. On the one hand, the biogenic silica is influenced by dissolution of diatoms due to higher salinity and pH of the lake water under evaporative stress characterizing low lake levels. On the other hand, total organic carbon and total organic carbon/total nitrogen profiles are influenced by reworked macrophytes from freshly exposed lake level terraces during lowstands. Total inorganic carbon remains the most reliable proxy for climatic variations during the Holocene as high precipitation of carbonates can be linked to low lake levels and high autochthonous production. The onset of inorganic carbon precipitation has been associated with the southward shift of the SHW over the latitudes of Laguna Potrok Aike. The refined age-depth model of this record suggests that this shift occurred around 9.4cal.kaBP. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.09.015 Quaternary Science Reviews 71 154–s166 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; algae; Bacillariophyta; Bryophyta; Cyanobacteria; Biogeochemistry; Biological materials; Carbonates; Fourier transform infrared spectroscopy; Glacial geology; Lakes; Nitrogen; Permafrost; Phytoplankton; Sediments; Silica; Argentina; Biogenic silica; Diffuse reflectance fourier transform infrared; ICDP project PASADO; Lake levels; Patagonia; Primary productivity; algal bloom; allochthon; carbon; carbonate; climate change; climate conditions; FTIR spectroscopy; global warming; growth rate; infiltration; latitude; moss; paleoenvironment; permafrost; primary production; proxy climate record; reconstruction; sediment analysis; silica; Southern Hemisphere; surface water; temperature effect; Organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878930433&doi=10.1016%2fj.quascirev.2012.09.015&partnerID=40&md5=2ab6a8b8322adf4a5b5c7b805f45d129 Cited by: 42 A. Hahn P. Kliem C. Ohlendorf B. Zolitschka article Nuttin2013109 The ~100m-long Laguna Potrok Aike sediment sequence yielded a record spanning the Last Glacial period to the Holocene. This paper presents and discusses two aspects of the mineralogy of the lake. The first aspect is based on a semi-quantitative X-ray diffraction analysis of bulk and clay mineralogical assemblages. Minor mineralogical changes are observed throughout the glacial section suggesting relatively uniform sediment sources. The transition into the Holocene is characterized by increasing fluxes of endogenic calcite thought to relate to lower lake levels. The second aspect is based on analysis of uranium-series disequilibria in diagenetic vivianite from the glacial section. U-series ages were expected to yield minimum ages for the host-sediment. Unfortunately, very little authigenic U is present in vivianite grains. The low primary productivity of the lake and thus low organic carbon fluxes might have prevented the development of strong redox gradients at the water-sediment interface and thus reduced diagenetic U-uptake into the sediment. One vivianite sample, at a 56.9m composite depth, yielded enough authigenic uranium to calculate a 230Th-age of 29.4±5.9ka (±2σ). This age is younger than the one indicated by the radiocarbon chronology. It is thus concluded that a relatively late diagenetic evolution of the U-Th system characterizes the recovered vivianite minerals. The authigenic U displays a very high excess in 234U (over 238U) with an activity ratio of 4.58±0.58 (±2σ). It suggests that it originates from the transfer of highly fractionated U from surrounding detrital minerals through very low U-content pore waters. © 2012 Elsevier Ltd. Article 2013 10.1016/j.quascirev.2012.09.027 Quaternary Science Reviews 71 109 – 118 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Clay; Crystallography; Glacial geology; Lakes; Mineralogy; Sedimentology; Sediments; Uranium; X ray diffraction analysis; Argentina; ICDP-PASADO; Late quaternary; Paleoclimates; Vivianite; XRD; authigenesis; calcite; carbon flux; geochronology; Holocene; Last Glacial Maximum; mineral; mineralogy; primary production; radiocarbon dating; redox potential; vivianite; X-ray diffraction; Phosphate minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878950591&doi=10.1016%2fj.quascirev.2012.09.027&partnerID=40&md5=500466f10693c10f031fe0c92a06df87 Cited by: 17 L. Nuttin P. Francus M. Preda B. Ghaleb C. Hillaire-Marcel article Pollock2013219 Article 2013 10.1016/j.quascirev.2012.09.019 Quaternary Science Reviews 71 219 – 228 https://www.scopus.com/inward/record.uri?eid=2-s2.0-84878946415&doi=10.1016%2fj.quascirev.2012.09.019&partnerID=40&md5=024bbd0bb04b5c5aa0f5827cd29581ec Cited by: 11 Edward W. Pollock Andrew B.G. Bush article Recasens20121323 A series of long sediment cores was retrieved from Laguna Potrok Aike, Southern Patagonia, within the framework of PASADO (Potrok Aike Maar Lake Sediment Archive Drilling Project), an ICDP (International Continental Scientific Drilling Program) lake drilling project. This maar lake, located at 52°S, 70°W in the Province of Santa Cruz (Argentina), in the southernmost continental area of the world, is one of the few permanent lakes in the region, providing a unique continuous paleoclimatic and paleoecological lacustrine record for the last glacial cycle. Previous multiproxy studies of this site have characterized the environmental history of these dry lands in the Patagonian Steppe for the last 16 cal. ka BP. This new series of sediment cores provides a much longer record of climate variability in Southern Patagonia since 51.3 cal. ka BP. Using a multiproxy strategy, a set of samples (mostly from core catcher material) was analyzed for physical properties, rock magnetism, geochemistry, CNS elemental analysis, stable isotopes, pollen and diatoms. This preliminary multiproxy limnogeological interpretation sheds new light on the regional Pleistocene and Holocene environmental history, revealing lake-level variations through time and identifying time windows of interest where higher resolution analyses will be carried out. © The Author(s) 2011. Article 2012 10.1177/0959683611429833 Holocene 22 1323 – 1335 11 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; diatom; lacustrine deposit; paleoclimate; paleoecology; paleoenvironment; palynology; Pleistocene; proxy climate record; sediment core; stable isotope https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867669582&doi=10.1177%2f0959683611429833&partnerID=40&md5=65e04f1777f20a54e5cc8523a8bb6b99 Cited by: 40; All Open Access, Green Open Access Cristina Recasens Daniel Ariztegui Catalina Gebhardt Claudia Gogorza Torsten Haberzettl Annette Hahn Pierre Kliem Agathe Lisé-Pronovost Andreas Lücke Nora Maidana Christoph Mayr Christian Ohlendorf Frank Schäbitz Guillaume St-Onge Michael Wille Bernd Zolitschka article Gebhardt20121087 Maar lake Laguna Potrok Aike is located north of the Strait of Magellan (south-eastern Patagonia). Seismic reflection profiles revealed a highly dynamic palaeoclimate history. Dunes were identified in the eastern part of the lake at approximately 30 to 80m below the lake floor, overlying older lacustrine strata, and suggest that the region experienced dry conditions probably combined with strong westerly winds. It is quite likely that this can be linked to a major dust event recorded in the Antarctic ice cores during Marine Isotope Stage 4. The dunes are overlain by a series of palaeo-shorelines indicating a stepwise water-level evolution of a new lake established after this dry period, and thus a change towards wetter conditions. After the initial, rapid and stepwise lake-level rise, the basin became deeper and wider, and sediments deposited on the lake shoulder at approximately 33m below present-day lake level point towards a long period of lake-level highstand between roughly 53·5kacal. bp and 30kacal. bp with a maximum lake level some 200m higher than the desiccation horizon. This highstand was then followed by a regressional phase of uncertain age, although it must have happened some time between approximately 30kacal. bp and 6750yrscal. bp. Dryer conditions during the Mid-Holocene are evidenced by a dropping lake level, resulting in a basin-wide erosional unconformity on the lake shoulder. A second stepwise transgression between ca 5·8 to 5·4kacal. bp and ca 4·7 to 4kacal. bp with palaeo-shorelines deposited on the lake shoulder unconformity again indicates a change towards wetter conditions. © 2011 The Authors. Journal compilation © 2011 International Association of Sedimentologists. Article 2012 10.1111/j.1365-3091.2011.01296.x Sedimentology 59 1087 – 1100 3 Argentina; Laguna Potrok Aike; Magellan Strait; Patagonia; Santa Cruz [Argentina]; Anoxic sediments; Climate change; Glacial geology; Isotopes; Seismic waves; Argentina; ICDP project PASADO; Laguna potrok aike; Lake-level variations; Patagonia; Seismic reflection profiles; climate variation; desiccation; dune; ice core; lacustrine deposit; lake level; marine isotope stage; paleoclimate; sedimentation; seismic reflection; shoreline; transgression; unconformity; water level; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84858705630&doi=10.1111%2fj.1365-3091.2011.01296.x&partnerID=40&md5=f3184194f141f7ebb24a6fb746c5d539 Cited by: 23 Andrea Catalina Gebhardt Christian Ohlendorf Marc De Batist Flavio S. Anselmetti Daniel Ariztegui Pierre Kliem Stefan Wastegård Bernd Zolitschka article Hahn2011 Analysis of sediment samples in the visible to mid infrared (IR) region requires small amounts of sample material and enables rapid and cost efficient geochemical analysis of mineral and organic sediment components. Here we use geochemical properties (total organic and inorganic carbon, biogenic silica, total nitrogen) from the ICDP deep drilling project PASADO to compare three different IR spectroscopy techniques: Diffuse Reflectance Fourier Transform IR Spectrometry (DRIFTS), Attenuated Total Reflectance Fourier Transform IR Spectroscopy (ATR-FTIRS) and Visible Near IR Spectroscopy (VNIRS). ATR-FTIRS and VNIRS are more rapid techniques compared to DRIFTS. Results show that calibration models developed using DRIFTS are most robust (correlation coefficient: R = 0.92 for TIC, R = 0.84 for BSi, R = 0.97 for TOC, R = 0.95 for TN). However, good statistical performance was also obtained by using ATR-FTIRS and VNIRS. When time and costs are limiting factors, these tools may be given preference for rapid biogeochemical screening. Copyright © 2011 by the American Geophysical Union. Article 2011 10.1029/2011GC003686 Geochemistry, Geophysics, Geosystems 12 10 Analytical geochemistry; Anoxic sediments; Biogeochemistry; Carbon; Cost benefit analysis; Fourier transform infrared spectroscopy; Near infrared spectroscopy; Organic carbon; Reflection; Sedimentology; Silica; Spectrometry; Spectrum analysis; Attenuated total reflectance; Biogenic silica; Biogeochemical sediments; Calibration model; Comparative studies; Correlation coefficient; Cost-efficient; Deep drilling; Diffuse reflectance; Diffuse reflectance fourier transform infrared; Fourier transform IR spectroscopy; Geochemical analysis; Geochemical properties; Infrared technique; Inorganic carbon; IR spectrometry; Limiting factors; Midinfrared; Near-IR spectroscopy; Organic sediments; Sediment samples; Statistical performance; Total inorganic carbon; Total nitrogen; total organic carbon (TOC); Visible-near infrared spectroscopy; biogeochemistry; calibration; comparative study; FTIR spectroscopy; inorganic carbon; near infrared; sediment analysis; total organic carbon; Fourier transforms https://www.scopus.com/inward/record.uri?eid=2-s2.0-80054048820&doi=10.1029%2f2011GC003686&partnerID=40&md5=9d48e10c9515f3cd41e25dc1ecd6afea Cited by: 13 A. Hahn P. Kliem C. Ohlendorf B. Zolitschka article Gebhardt2011357 Laguna Potrok Aike is a bowl-shaped maar lake in southern Patagonia, Argentina, with a present mean diameter of ~3.5km and a maximum water depth of ~100m. Seismic surveys were carried out between 2003 and 2005 in order to get a deeper knowledge on the lake sediments and the deeper basin geometries. A raytracing model of the Laguna Potrok Aike basin was calculated based on refraction data while sparker data were additionally used to identify the crater-wall discordance and thus the upper outer shape of the maar structure. The combined data sets show a rather steep funnel-shaped structure embedded in the surrounding Santa Cruz Formation that resembles other well-known maar structures. The infill consists of up to 370m lacustrine sediments underlain by probably volcanoclastic sediments of unknown thickness. The lacustrine sediments show a subdivision into two sub-units: (a) the upper with seismic velocities between 1500 and 1800ms-1, interpreted as unconsolidated muds, and (b) the lower with higher seismic velocities of up to 2350ms-1, interpreted as lacustrine sediments intercalated with mass transport deposits of different lithology and/or coarser-grained sediments. The postulated volcanoclastic layer has acoustic velocities of >2400ms-1. The lake sediments were recently drilled within the PASADO project in the framework of the International Continental Scientific Drilling Program (ICDP). Cores penetrated through lacustrine unconsolidated sediments down to a depth of ~100m below lake floor. This minimal thickness for the unconsolidated and low-velocity lithologies is in good agreement with our raytracing model. © 2011 Elsevier B.V. Article 2011 10.1016/j.jvolgeores.2010.12.019 Journal of Volcanology and Geothermal Research 201 357 – 363 1-4 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Anoxic sediments; Lakes; Lithology; Refraction; Seismic waves; Seismology; Settling tanks; Submarine geophysics; Surveys; Velocity; Explosive volcanism; Maars; PASADO project; Sedimentary basin; South America; drilling; explosive volcanism; lithology; maar; ray tracing; sedimentary basin; seismic reflection; seismic refraction; seismic survey; seismic velocity; volcaniclastic deposit; Sedimentology https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953048051&doi=10.1016%2fj.jvolgeores.2010.12.019&partnerID=40&md5=8a2f6e76f46d5869ff34a4886eee05d5 Cited by: 33; All Open Access, Green Open Access M. De Batist F.S. Anselmetti D. Ariztegui T. Haberzettl C. Kopsch C. Ohlendorf B. Zolitschka article Ross2011253 Article 2011 10.1016/j.jvolgeores.2010.07.018 Journal of Volcanology and Geothermal Research 201 253 – 271 1-4 https://www.scopus.com/inward/record.uri?eid=2-s2.0-79953040914&doi=10.1016%2fj.jvolgeores.2010.07.018&partnerID=40&md5=301e0f9249417fb361fdd3d5564bbf03 Cited by: 99 Pierre-Simon Ross Séverine Delpit Miguel J. Haller Karoly Németh Hugo Corbella article Gogorza201141 High-resolution paleo- and rock magnetic studies were performed on a group of four sediment cores from Laguna Potrok Aike (Santa Cruz, Argentina) representing the time period AD 1300-2000. The rock magnetic analyses show that the main magnetic mineral is (titano)magnetite with a concentration between 0.01 and 0.08%, and a grain size of 4-15 μm. This study is helpful in order to complete the paleosecular variation (PSV) and paleointensity type curves for South America which do not have a detailed record for the last millennium. The comparison with the study carried out for Lake El Trébol shows a very good agreement, supporting that PSV records of south-western Argentina can be developed into a stratigraphic correlation tool on a regional scale. © 2010 Elsevier B.V. Article 2011 10.1016/j.pepi.2010.10.011 Physics of the Earth and Planetary Interiors 184 41 – 50 1-2 Argentina; Laguna Potrok Aike; Santa Cruz [Argentina]; Iron ores; Lithology; Stratigraphy; ICDP; Paleointensity; Paleosecular variations; PASADO; Southern Hemisphere; core analysis; geochronology; Holocene; magnetic intensity; magnetic survey; paleomagnetism; secular variation; sediment core; Southern Hemisphere; stratigraphic correlation; Minerals https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651472900&doi=10.1016%2fj.pepi.2010.10.011&partnerID=40&md5=b001a09c839264ce3251d0f76634e59d Cited by: 16 C.S.G. Gogorza A.M. Sinito C. Ohlendorf S. Kastner B. Zolitschka article Ohlendorf2011104 Using the ICDP (International Continental Scientific Drilling Program) deep lake drilling expedition no. 5022 as an example, we describe core processing and sampling procedures as well as new tools developed for subsampling. A manual core splitter is presented that is (1) mobile, (2) able to cut plastic core liners lengthwise without producing swarf of liner material and (3) consists of off-the-shelf components. In order to improve the sampling of sediment cores, a new device, the core sampling assembly (CSA), was developed that meets the following targets: (1) the partitioning of the sediment into discs of equal thickness is fast and precise, (2) disturbed sediment at the inner surface of the liner is discarded during this sampling process, (3) usage of the available sediment is optimised, (4) subsamples are volumetric and oriented, and (5) identical subsamples are taken. The CSA can be applied to D-shaped split sediment cores of any diameter and consists of a divider and a D-shaped scoop. The sampling plan applied for ICDP expedition 5022 is illustrated and may be used as a guideline for planning the efficient partitioning of sediment amongst different lake research groups involved in multidisciplinary projects. For every subsample, the use of quality flags is suggested (1) to document the sample condition, (2) to give a first sediment classification and (3) to guarantee a precise adjustment of logging and scanning data with data determined on individual samples. Based on this, we propose a protocol that might be applied across lake drilling projects in order to facilitate planning and documentation of sampling campaigns and to ensure a better comparability of results. © 2011 Elsevier B.V. Article 2011 10.1016/j.sedgeo.2011.06.007 Sedimentary Geology 239 104 – 115 1-2 Argentina; Patagonia; Information retrieval systems; Lakes; Sedimentology; Well drilling; Argentina; Core processing; Core sampling; Core slicing; Drilling projects; Inner surfaces; Liner material; Multidisciplinary projects; New devices; New protocol; Off-the-shelf components; Patagonia; Research groups; Sampling campaigns; Sampling plans; Sampling procedures; Sampling process; Scanning data; Scientific drilling; Sediment classification; Sediment core; core logging; deep drilling; lake; partitioning; sampling; sediment core; Anoxic sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-79960980659&doi=10.1016%2fj.sedgeo.2011.06.007&partnerID=40&md5=f67c99225f0370013c5fc9d689ac94a2 Cited by: 28 Christian Ohlendorf Catalina Gebhardt Annette Hahn Pierre Kliem Bernd Zolitschka article Kastner2010887 We studied the internal lake processes that control the spatial distribution and characteristics of modern sediments at the ICDP (International Continental Scientific Drilling Program) deep drilling site in Laguna Potrok Aike, southern Patagonia, Argentina. Sediment distribution patterns were investigated using a dense grid of 63 gravity cores taken throughout the lake basin and 40 additional shoreline samples. Analysis of the surficial sediment distribution points to distinct internal depositional dynamics induced by wind-driven lake internal currents. Distribution maps illustrate that the spatial characteristics of analysed variables are linked to high erosional wave activity. Persistent wave action and littoral erosion along all shores, especially the eastern shore, is caused by prevailing Southern Hemispheric Westerlies. Several sediment variables (grain size, benthic diatoms, total inorganic carbon and calcium) indicate re-suspension of littoral sediment followed by re-distribution to profundal accumulation areas near the eastern shore. Variations within the catchment influence sediment characteristics in the north-eastern bay. That area is characterized by different mineralogical and sedimentological conditions as well as greater accumulation of pollen, inorganic carbon and diatoms. These findings are related to the influence of episodic inflow into this bay. Spatial differences in stable isotope values throughout the lake suggest that ephemeral tributaries around the lake basin may also contribute to the detected spatial sediment variations. © 2010 Springer Science+Business Media B.V. Article 2010 10.1007/s10933-010-9462-0 Journal of Paleolimnology 44 887 – 902 4 Argentina; Laguna Potrok Aike; Patagonia; Santa Cruz [Argentina]; Bacillariophyta; bioaccumulation; calcium; catchment; deep drilling; diatom; grain size; gravity; inorganic carbon; intertidal environment; lacustrine deposit; microfossil; mineralogy; pollen; sediment; sediment chemistry; sedimentology; shoreline; Southern Hemisphere; spatial distribution; stable isotope; surficial sediment; wave action https://www.scopus.com/inward/record.uri?eid=2-s2.0-78049269851&doi=10.1007%2fs10933-010-9462-0&partnerID=40&md5=863cf294df8d52bb4a1c18986975a3d7 Cited by: 27 Stephanie Kastner Christian Ohlendorf Torsten Haberzettl Andreas Lücke Christoph Mayr Nora I. Maidana Frank Schäbitz Bernd Zolitschka article Zolitschka200929 Article 2009 10.2204/iodp.sd.8.04.2009 Scientific Drilling 29 – 34 8 https://www.scopus.com/inward/record.uri?eid=2-s2.0-78651552433&doi=10.2204%2fiodp.sd.8.04.2009&partnerID=40&md5=c3f037244d233387fecd967253117577 Cited by: 26; All Open Access, Gold Open Access, Green Open Access Bernd Zolitschka Flavio Anselmetti Daniel Ariztegui Hugo Corbella Christian Ohlendorf Frank Schäbitz article Zolitschka200654 Note 2006 10.2204/iodp.sd.3.13.2006 Scientific Drilling 1 54 – 55 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-77952669088&doi=10.2204%2fiodp.sd.3.13.2006&partnerID=40&md5=14943bbe7f8bcb6fe21165e20eb6bf26 Cited by: 3; All Open Access, Gold Open Access, Green Open Access Bernd Zolitschka Hugo Corbella Nora Maidana Christian Ohlendorf