This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-04-23 Creation time: 13:57:20 --- Number of references 49 article Guglielmi2025425 Article 2025 10.1007/s10040-025-02886-3 Hydrogeology Journal 33 425 – 448 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105003306358&doi=10.1007%2fs10040-025-02886-3&partnerID=40&md5=cba290aefcd5e5de5179b06c4680ea35 Cited by: 0 Yves Guglielmi Auli Niemi Chin-Fu Tsang Patrick Dobson Paul Cook Christopher Juhlin Benoît Dessirier Alexandru Tatomir Farzad Basirat Henning Lorenz Jan-Erik Rosberg Emil Lundberg Bjarne Almqvist Roland Roberts article Löwe2025405 Article 2025 10.1093/gji/ggaf046 Geophysical Journal International 241 405 – 436 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85218474170&doi=10.1093%2fgji%2fggaf046&partnerID=40&md5=b78daef0d3b00982d9531651b8b85e0d Cited by: 0; All Open Access, Gold Open Access R. Löwe J. Renner C. Pascal B. Adl-Zarrabi N. Balling T.S. Bording M. Long G. Schwarz J. Sundberg article 2024 10.1038/s42003-024-07027-2 Commun Biol 7 1332 1 G. Westmeijer F. van Dam Riikka Kietäväinen C. Gonzalez-Rosales Stefan Bertilsson H. Drake Mark Dopson article Westmeijer2024591 Scientific drilling expeditions offer a unique opportunity to characterize microbial communities in the subsurface that have long been isolated from the surface. With subsurface microbial biomass being low in general, biological contamination from the drilling fluid, sample processing, or molecular work is a major concern. To address this, characterization of the contaminant populations in the drilling fluid and negative extraction controls are essential for assessing and evaluating such sequencing data. Here, rock cores down to 2250m depth, groundwater-bearing fractures, and the drilling fluid were sampled for DNA to characterize the microbial communities using a broad genomic approach. However, even after removing potential contaminant populations present in the drilling fluid, notorious contaminants were abundant and mainly affiliated with the bacterial order Burkholderiales. These contaminant microorganisms likely originated from the reagents used for isolating DNA despite stringent quality standards during the molecular work. The detection of strictly anaerobic sulfate reducers such as Candidatus Desulforudis audaxviator suggested the presence of autochthonous deep biosphere taxa in the sequenced libraries, yet these clades represented only a minor fraction of the sequence counts (<0.1 %), hindering further ecological interpretations. The described methods and findings emphasize the importance of sequencing extraction controls and can support experimental design for future microbiological studies in conjunction with continental drilling operations. © 2024 George Westmeijer et al. Article 2024 10.5194/bg-21-591-2024 Biogeosciences 21 Copernicus Publications 591 – 604 2 Sweden; bacterium; bedrock; biomass; biosphere; DNA; drilling fluid; microbiology https://www.scopus.com/inward/record.uri?eid=2-s2.0-85184077946&doi=10.5194%2fbg-21-591-2024&partnerID=40&md5=2ca1bd5a9879232b51f567b9c4472a9e Cited by: 0 George Westmeijer Cristina Escudero Claudia Bergin Stephanie Turner Magnus Ståhle Maliheh Mehrshad Prune Leroy Moritz Buck Pilar López-Hernández Jens Kallmeyer Ricardo Amils Stefan Bertilsson Mark Dopson article Lehnert2024134 Article 2024 10.3176/earth.2024.13 Estonian Journal of Earth Sciences 73 134 – 140 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85208604776&doi=10.3176%2fearth.2024.13&partnerID=40&md5=1e9be94c8232875533d7650b143f47f5 Cited by: 1; All Open Access, Gold Open Access Oliver Lehnert Bjarne Almqvist Mark Anderson Jenny Andersson Simon Cuthbert Mikael Calner Isabel Carter Riccardo Callegari Christopher Juhlin Henning Lorenz Claudio Madonna Guido Meinhold Luca Menegon Iwona Klonowska Christophe Pascal Markus Rast Nick M. W. Roberts Jonas B. Ruh Grzegorz Ziemniak article jeanneret_deciphering_2023 The Seve Nappe Complex is a subduction-related high-grade metamorphic unit that was emplaced onto the margin of Baltica during Caledonian orogenesis. In this paper, the tectonometamorphic evolution of the Lower Seve Nappe in the Scandinavian Caledonides was characterized with the help of the continuous Collisional Orogeny in the Scandinavian Caledonides (COSC-1) drill core, using a combination of various P–T estimation techniques based on garnet–quartz mineral pairs (quartz-in-garnet and Ti-in-quartz [QuiG–TiQ]), conventional thermobarometry and thermodynamic modelling of phase equilibria. This multi-method approach yields complementary results and delivers critical data to constrain a comprehensive pressure–temperature–deformation–time (P–T–D–t) evolutionary path for the metasedimentary rocks of the Lower Seve Nappe. In the garnetiferous metasedimentary rocks, quartz inclusions in garnet preserve the P–T conditions of three distinct garnet growth stages corresponding to three metamorphic stages Ms1 to Ms3, including prograde and peak metamorphic conditions. Ms1 and Ms2 stages were constrained via quartz inclusions in garnet core and mantle. They are relatively close in the P–T space and could be considered as one single continuous prograde event occurring at epidote–amphibolite facies conditions of 460–520°C and 0.6–0.85 GPa. The growth of the garnet outermost rim defines the Ms3 stage at amphibolite facies conditions of 590–610°C and 1.13–1.18 GPa and corresponds to the peak metamorphic conditions. The microstructural analysis shows that the finite ductile strain pattern of the Lower Seve Nappe results from the superposition of four deformation phases. The initial phase D1 is defined by the S1 foliation that is still preserved as a curved inclusion trail in the garnet core. The D2 phase initiated contemporaneously with garnet core growth and the development of muscovite–biotite–plagioclase S2 foliation. Garnet outermost rim growth marks the end of the prograde path and peak metamorphic conditions. This stage is overprinted by the D3 phase and Ms4 stage associated with the development of the main regional metamorphic and mylonitic fabric S3 associated with C′-type shear bands along the retrograde path. Ms4 stage, which was constrained using traditional thermobarometric techniques, corresponds to the chemical re-equilibration of the metasedimentary minerals and occurred under amphibolite facies conditions at 570–610°C and 0.78–1.00 GPa. The D3 phase is then generally weakly to strongly overprinted by later lower grade deformation D4 phase at greenschist facies conditions (Ms5). 40Ar/39Ar ages of syn-kinematic white mica and biotite indicate that the final stage of the thrusting of the Lower Seve Nappe and thus the timing of its emplacement onto the Offerdal Nappe occurred at c. 423 Ma. Collectively, these results are consistent with previous estimates of the timing and conditions of metamorphism derived from the Lower Seve Nappe especially in west-central Jämtland. However, application of QuiG–TiQ thermobarometry demonstrated that quartz inclusions in garnet can preserve different aspects of garnet growth, which are not accessible by traditional methods especially in complex terranes, and therefore provided new significant insights into the Lower Seve prograde evolution. 2023 en 1525-1314 10.1111/jmg.12693 Journal of Metamorphic Geology n/a n/a 40Ar/39Ar dating, Scandinavian Caledonides, P–T–D–t evolution, quartz-in-garnet, Ti-in-quartz thermobarometry https://onlinelibrary.wiley.com/doi/abs/10.1111/jmg.12693 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12693 Pauline Jeanneret Iwona Klonowska Christopher Barnes Jarosław Majka Johanna Holmberg Mattia Gillio William Nachlas Matteo Alvaro Karolina Kośmińska Henning Lorenz Thomas Zack Anna Ladenberger Hemin Koyi article Kästner202266 Strong anisotropy of seismic velocity in the Earth's crust poses serious challenges for seismic imaging. Where in situ seismic properties are not available, the anisotropy can be determined from velocity analysis of surface and borehole seismic profiles. This is well established for dense, long-offset reflection seismic data. However, it is unknown how applicable this approach is for sparse seismic reflection data with low fold and short offsets in anisotropic metamorphic rocks. Here, we show that anisotropy parameters can be determined from a sparse 3-D data set at the COSC-1 borehole site in the Swedish Caledonides and that the results agree well with the seismic anisotropy parameters determined from seismic laboratory measurements on core samples. Applying these anisotropy parameters during 3-D seismic imaging improves the seismic image of the high-amplitude reflections especially in the vicinity of the lower part of the borehole. Strong reflections in the resulting seismic data show good correlation with the borehole-derived lithology. Our results aid the interpretation and extrapolation of the seismic stratigraphy of the Lower Seve Nappe in Jämtland and other parts in the Caledonides. Article 2022 jan 0956-540X 10.1093/gji/ggab339 Geophysical Journal International 228 66 – 77 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85116561589&doi=10.1093%2fgji%2fggab339&partnerID=40&md5=953ebafe73044d2db97c4b99005abc76 Cited by: 2; All Open Access, Hybrid Gold Open Access Felix Kästner Dirk Klaeschen Christian Berndt Simona Pierdominici Peter Hedin article lorenz_cosc-2_2022 {\textless}p{\textgreater}{\textless}strong class="journal-contentHeaderColor"{\textgreater}Abstract.{\textless}/strong{\textgreater} The Collisional Orogeny in the Scandinavian Caledonides (COSC) scientific drilling project aims to characterise the structure and orogenic processes involved in a major collisional mountain belt by multidisciplinary geoscientific research. Located in western central Sweden, the project has drilled two fully cored deep boreholes into the bedrock of the deeply eroded Early Paleozoic Caledonide Orogen. COSC-1 (2014) drilled a subduction-related allochthon and the associated thrust zone. COSC-2 (2020, this paper) extends this section deeper through the underlying nappes (Lower Allochthon), the main Caledonian décollement, and the upper kilometre of basement rocks. COSC-2 targets include the characterisation of orogen-scale detachments, the impact of orogenesis on the basement below the detachment, and the Early Paleozoic palaeoenvironment on the outer margin of palaeocontinent Baltica. This is complemented by research on heat flow, groundwater flow, and the characterisation of the microbial community in the present hard rock environment of the relict mountain belt. COSC-2 successfully, and within budget, recovered a continuous drill core to 2276 m depth. The retrieved geological section is partially different from the expected geological section with respect to the depth to the main décollement and the expected rock types. Although the intensity of synsedime{\textless}span id="page44"/{\textgreater}ntary deformation in the rocks in the upper part of the drill core might impede the analysis of the Early Paleozoic palaeoenvironment, the superb quality of the drill core and the borehole will facilitate research on the remaining targets and beyond. Protocols for sampling in the hard rock environment and subsequent sample preservation were established for geomicrobiological research and rock mechanical testing. For the former, a sparse sample series along the entire drill core was taken, while the target of the latter was the décollement. COSC-2 was surveyed by a comprehensive post-drilling downhole logging campaign and a combined borehole/land seismic survey in autumn 2021. This paper provides an overview of the COSC-2 (International Continental Scientific Drilling Project – ICDP 5054\_2\_A and 5054\_2\_B boreholes) operations and preliminary results. It will be complemented by a detailed operational report and data publication.{\textless}/p{\textgreater} 2022 feb English 1816-8957 10.5194/sd-30-43-2022 Scientific Drilling 30 43--57 https://sd.copernicus.org/articles/30/43/2022/ Publisher: Copernicus GmbH Henning Lorenz Jan-Erik Rosberg Christopher Juhlin Iwona Klonowska Rodolphe Lescoutre George Westmeijer Bjarne S. G. Almqvist Mark Anderson Stefan Bertilsson Mark Dopson Jens Kallmeyer Jochem Kück Oliver Lehnert Luca Menegon Christophe Pascal Simon Rejkjær Nick N. W. Roberts article lescoutre_large-scale_2022 The Fennoscandian Shield in central Sweden displays a complex structural and compositional architecture that is mainly related to the Proterozoic history of the Baltica paleocontinent. In its western parts, the Precambrian basement is covered by the allochthonous rocks of the Caledonide orogen, and direct information about the underlying crust is restricted to a few unevenly distributed basement windows in western Sweden and Norway. In this study, we use preliminary results from the second borehole of the Collisional Orogeny in the Scandinavian Caledonides project (COSC-2), new gravity data, forward gravity, and magnetic modeling and interpretation of seismic reflection profiles to assess the 3-D architecture of the basement. Our results reveal a wide (∼100 km) and dense network of mainly flat-lying and saucer-shaped dolerites intruding the volcanic and granitic upper crustal rocks of the Transscandinavian Igneous Belt. Similar intrusion geometries related to 1.2 Ga dolerites can be recognized in the Fennoscandian Shield. We discuss that the formation of these sill complexes occurred in a lithologically and structurally heterogeneous crust during transtension, which is in disagreement with the current understanding of sill emplacement that involves crustal shortening, layering, or anisotropy of the host rock. Our seismic interpretation and the structural observations from the COSC-2 drilling show that part of the Caledonian-related basement deformation was localized along the margins of the dolerite sheets. We propose that the dolerite intrusion geometry, akin to a flat-ramp geometry, guided the basement deformation during the Caledonian orogeny. 2022 mar 0016-7606 10.1130/B36202.1 GSA Bulletin https://doi.org/10.1130/B36202.1 Rodolphe Lescoutre Bjarne Almqvist Hemin Koyi Théo Berthet Peter Hedin Olivier Galland Sonia Brahimi Henning Lorenz Christopher Juhlin article green_post-caledonian_2022 The evolution of Fennoscandia following the early Devonian collapse of the Caledonian mountains is a matter of debate, due largely to the scarcity of post-Caledonian cover rocks. The preserved geological record therefore provides only partial documentation of the geological evolution. A more complete understanding is obtained by also considering evidence of rocks that were formerly present but have since been removed. We report apatite fission track data and associated thermal history constraints in 331 samples of Precambrian basement, younger sedimentary cover, Paleozoic and Mesozoic igneous rocks from outcrops and boreholes (up to 6 km depth) across Fennoscandia, which define thirteen phases of cooling (each representing kilometre-scale exhumation) over the last 1100 Myr. Key post-Caledonian episodes began in the intervals 311–307 Ma (late Carboniferous), 245–244 Ma (Middle Triassic), 170–167 Ma (Middle Jurassic), 102–92 Ma (mid-Cretaceous) and 23–21 Ma (early Miocene). These episodes, varying in magnitude, are recognised across Fennoscandia, and their effects are documented in the stratigraphic record and as prominent regional peneplains. The results define a history involving repeated episodes of regional burial and exhumation. Major offsets in Mesozoic paleotemperatures over short distances define kilometre-scale differential vertical displacements, emphasising the tectonic nature of the history. Results from Finland record the same events recognised in Norway and Sweden (though less pronounced), and are not consistent with long-term cratonic stability. The lack of preserved Phanerozoic sedimentary cover in Finland is interpreted to be due to complete removal during multiple episodes of denudation. In southern Norway and Sweden, early Miocene exhumation led to creation of a peneplain, which in Pliocene times was uplifted and dissected, producing the modern landscape. Post-Caledonian exhumation episodes defined here are broadly synchronous with similar events in Greenland, the British Isles and North America. Far-field transmission of plate-tectonic stress and/or mantle processes may explain the vertical movements described here. 2022 jul en 1342-937X 10.1016/j.gr.2022.03.007 Gondwana Research 107 201--234 Exhumation, AFTA, Craton, Missing section, Peneplain https://www.sciencedirect.com/science/article/pii/S1342937X22000892 Paul F. Green Peter Japsen Johan M. Bonow James A. Chalmers Ian R. Duddy Ilmo T. Kukkonen article bazargan_pressure_2021 As a petrofabric indicator, anisotropy of magnetic susceptibility (AMS) can potentially be used to infer seismic properties of rocks, and in particular seismic anisotropy. To evaluate the link between AMS and seismic anisotropy we present laboratory measurements of elastic wave velocities and anisotropy of magnetic susceptibility (AMS) for eight samples from the deep drilling investigation forming a part of the Collisional Orogeny in the Scandinavian Caledonides (COSC) project. The samples consist of a representative suite of mid crustal, deformed rock types, namely felsic and biotite-rich gneisses, and amphibolites (mafic gneisses). Compressional (P) and shear (S) waves were measured at confining pressures from room pressure to 600 MPa and temperature from room condition to 600 °C. Seismic anisotropy changes with increasing temperature and pressure, where the effect of pressure is more significant than temperature. Increasing pressure, considering the range of samples, results in an increase in mean wave speed values from 4.52 to 7.86 km/s for P waves and from 2.75 to 4.09 km/s for S waves. Biotite gneiss and amphibolite exhibit the highest anisotropy with P wave anisotropy (AVp) in the ranges of {\textasciitilde}9% to {\textasciitilde}20%, and maximum S- wave anisotropy exceeds 10%. In contrast, Felsic gneisses are significantly less anisotropic, with AVp of {\textless}7% and AVs of {\textless}6%. Up to 20% anisotropy may be generated by microcracks at 600 MPa and 600 °C, which is likely originating from thermal expansion of anisotropic minerals. An agreement is found between AMS and seismic anisotropy, although this is only a case if mean magnetic susceptibility (kmean) ranges between {\textasciitilde}1 × 10−5 to {\textasciitilde}1 × 10−3 [SI]. Such kmean values are common in rocks dominated by paramagnetic matrix minerals. Based on our results we propose that such samples are the most likely to be useful for the prediction of seismic anisotropy based on their AMS. 2021 dec en 0040-1951 10.1016/j.tecto.2021.229113 Tectonophysics 820 229113 Amphibolite, Anisotropy of magnetic susceptibility, Gneiss, Petrophysics, Scandinavian Caledonites, Seismic anisotropy https://www.sciencedirect.com/science/article/pii/S0040195121003954 Mohsen Bazargan Hem Bahadur Motra Bjarne Almqvist Sandra Piazolo Christoph Hieronymus article li_timing_2021 Recent studies in the context of the International Continental Scientific Drilling Project “Collisional Orogeny in the Scandinavian Caledonides” have focused on the importance of the Seve Nappe Complex (SNC) for understanding the subduction history of the Baltoscandian margin during closure of the Iapetus Ocean. In the classical Åre area of western central Jämtland, granulite facies migmatites and leucogranites of the Åreskutan Nappe provide evidence of Early Silurian (c. 440 Ma) high temperature metamorphism and a previous prograde, ultra-high pressure history, with microdiamonds. New LA-ICPMS zircon isotope age investigations of the underlying amphibolite facies Lower Seve Nappes, reported here, have also identified an Early Silurian tectonothermal history with pegmatitic leucogranite (c. 443 Ma) and, at lower structural levels, another felsic intrusion of earliest Middle Ordovician age (c. 469 Ma). The latter intrudes isoclinally folded host rock amphibolites and calcareous psammitic paragneisses and is itself tightly folded. Zircons in an amphibolite proved to be highly discordant but indicate Early Silurian metamorphism during isoclinal folding. Detrital zircons in a paragneiss are dominated by Sveconorwegian populations, but also include a range of younger Neoproterozoic grains down to the Early Ediacaran (c. 600 Ma). This new evidence of early Caledonian deformation and metamorphism indicates that, as farther north in the orogen, the Seve tectonothermal history in central Jämtland probably started early in the Ordovician, or before. Subduction and accretion along the Baltoscandian outer margin occurred prior to Scandian continent-continent collision, with Siluro-Devonian emplacement of the SNC across the foreland basins onto the Baltoscandian platform. 2021 jan 1103-5897 10.1080/11035897.2020.1858341 GFF 143 55--70 1 Scandinavian Caledonides, amphibolite, hf isotopes, leucogranite, lower Seve, paragneiss, u-Pb geochronology https://doi.org/10.1080/11035897.2020.1858341 Publisher: Taylor & Francis \_eprint: https://doi.org/10.1080/11035897.2020.1858341 Yuan Li David G. Gee Anna Ladenberger Håkan Sjöström article almqvist_seismic_2021 We report compositional, microstructural and seismic properties from 24 samples collected from the Middle Allochthon (Seve Nappe) of the central Scandinavian Caledonides, and its bounding shear zones. The samples stem both from field outcrops and the continental drilling project COSC-1 and include quartzofeldspathic gneisses, hornblende gneisses, amphibolites, marbles, calc-silicates, quartzites and mica schists, of medium to high-strain. Seismic velocities and anisotropy of P (AVp) and S (AVs) waves of these samples were calculated using microstructural and crystal preferred orientation data obtained from Electron Backscatter Diffraction analysis (EBSD). Mica-schist exhibits the highest anisotropy (AVP {\textasciitilde} 31%; max AVs {\textasciitilde}34%), followed by hornblende-dominated rocks (AVp {\textasciitilde}5–13%; max AVs 5–10%) and quartzites (AVp {\textasciitilde}6.5–10.5%; max AVs {\textasciitilde}7.5–12%). Lowest anisotropy is found in calc-silicate rocks (AVp {\textasciitilde}4%; max AVs 3–4%), where the symmetry of anisotropy is more complex due to the contribution to anisotropy from several phases. Anisotropy is attributed to: 1) modal mineral composition, in particular mica and amphibole content, 2) CPO intensity, 3) crystallization of anisotropic minerals from fluids circulating in the shear zone (calc-silicates and amphibolites), and to a lesser extent 4) compositional banding of minerals with contrasting elastic properties and density. Our results link observed anisotropy to the rock composition and strain in a representative section across the Central Scandinavian Caledonides and indicate that the entire Seve Nappe is seismically anisotropic. Strain has partitioned on the nappe scale, and likely on the microstructural scale. High- strain shear zones that develop at boundaries of the allochthon and internally within the allochthon show higher anisotropy than a more moderately strained interior of the nappe. The Seve Nappe may be considered as a template for deforming, ductile and flowing middle crust, which is in line with general observations of seismic anisotropy in mid-crustal settings. 2021 nov en 0040-1951 10.1016/j.tecto.2021.229045 Tectonophysics 819 229045 Strain, Seismic anisotropy, Shear zone, Scandinavian Caledonides, Orogeny https://www.sciencedirect.com/science/article/pii/S0040195121003279 Bjarne S. G. Almqvist Daria Cyprych Sandra Piazolo article lorenz_cosc-2_2021 2021 https://doi.org/10.5880/ICDP.5054.002 GFZ German Research Centre for Geosciences https://doi.org/10.5880/ICDP.5054.003 H. Lorenz C. Juhlin J.E. Rosberg M. Bazargan I. Klonowska R. Lescoutre S. Rejkjær G. Westmeijer G. Ziemniak conference Guglielmi2021 Conference paper 2021 55th U.S. Rock Mechanics / Geomechanics Symposium 2021 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85123352503&partnerID=40&md5=463ea1a31bc52cdb588642e1f874c250 Cited by: 3 Y. Guglielmi P. Cook F. Soom P. Dobson T. Kneafsey B. Valley M. Kakurina A. Niemi C.F. Tsang A. Tatomir C. Juhlin F. Basirat article kastner_cross-scale_2021 Metamorphic and deformed rocks in thrust zones show particularly high seismic anisotropy causing challenges for seismic imaging and interpretation. A good example is the Seve Nappe Complex in central Sweden, an old exhumed orogenic thrust zone that is characterized by a strong but incoherent seismic reflectivity and considerable seismic anisotropy. However, only little is known about their origin in relation to composition and structural influences on measurements at different seismic scales. Here, we present a new integrative study of cross-scale seismic anisotropy analyses combining mineralogical composition, microstructural analyses, and seismic laboratory experiments from the COSC-1 borehole, which sampled a 2.5-km-deep section of metamorphic rocks deformed in an orogenic root now preserved in the Lower Seve Nappe. While there is strong crystallographic preferred orientation in most samples in general, variations in anisotropy depend mostly on bulk mineral composition and dominant core lithology as shown by a strong correlation between these. This relationship enables to identify three distinct seismic anisotropy facies providing a continuous anisotropy profile along the borehole. Moreover, comparison of laboratory seismic measurements and electron-backscatter diffraction data reveals a strong scale dependence, which is more pronounced in the highly deformed, heterogeneous samples. This highlights the need for comprehensive cross-validation of microscale anisotropy analyses with additional lithological data when integrating seismic anisotropy over seismic scales. 2021 en 2169-9356 10.1029/2020JB021154 Journal of Geophysical Research: Solid Earth 126 e2020JB021154 5 COSC, core measurements, electron-backscatter diffraction, seismic anisotropy https://onlinelibrary.wiley.com/doi/abs/10.1029/2020JB021154 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020JB021154 Felix Kästner Simona Pierdominici Alba Zappone Luiz F. G. Morales Franziska D. H. Wilke Christian Berndt article elger_core-log-seismic_2021 Continental collision causes deformation in the crust along shear zones. However, the physical and chemical conditions at which these zones operate and the deformation processes that enable up to hundreds of km of tectonic transport are still unclear because of the depth at which they occur and the challenges in imaging them. Ancient exhumed collision zones allow us to investigate these processes much better, for example at the COSC-1 borehole in the central Scandinavian Caledonides. This study combines data from the COSC-1 borehole with different seismic measurements to provide constraints on the spatial lithological and textural configuration of the Seve Nappe Complex. This is one of the few studies that shows that core-log-seismic integration in metamorphic rocks allows to identify the spatial distribution of major lithological units. Especially gamma ray logs in combination with density data are powerful tools to distinguish between mafic and felsic lithologies in log-core correlation. Our results indicate that reflections along the borehole are primarily caused by compositional rather than textural changes. Reflections in the Seve Nappe Complex are not as distinct as in greater depths but continuous and several of them can be linked to magmatic intrusions, which have been metamorphically overprinted. Their setting indicates that the Seve Nappe Complex consists of the remnants of a volcanic continental margin. Our results suggest that ductile-deformed middle crustal reflectivity is primarily a function of pre-orogenic lithological variations which has to be considered when deciphering mountain building processes. 2021 en 1525-2027 https://doi.org/10.1029/2020GC009376 Geochemistry, Geophysics, Geosystems 22 e2020GC009376 3 central Scandinavian Caledonides, core-log-seismic integration, COSC-1 https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GC009376 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC009376 Judith Elger Christian Berndt Felix Kästner Simona Pierdominici Jochem Kück Bjarne S. G. Almqvist Christopher Juhlin Henning Lorenz article kastner_correlation_2020 {\textless}p{\textgreater}{\textless}strong{\textgreater}Abstract.{\textless}/strong{\textgreater} Deeply rooted thrust zones are key features of tectonic processes and the evolution of mountain belts. Exhumed and deeply eroded orogens like the Scandinavian Caledonides allow us to study such systems from the surface. Previous seismic investigations of the Seve Nappe Complex have shown indications of a strong but discontinuous reflectivity of this thrust zone, which is only poorly understood. The correlation of seismic properties measured on borehole cores with surface seismic data can constrain the origin of this reflectivity. To this end, we compare seismic velocities measured on cores to in situ velocities measured in the borehole. For some intervals of the COSC-1 borehole, the core and downhole velocities deviate by up to 2&thinsp;km&thinsp;s{\textless}span class="inline-formula"{\textgreater}$^{\textrm{−1}}${\textless}/span{\textgreater}. These differences in the core and downhole velocities are most likely the result of microcracks mainly due to depressurization. However, the core and downhole velocities of the intervals with mafic rocks are generally in close agreement. Seismic anisotropy measured in laboratory samples increases from about 5&thinsp;% to 26&thinsp;% at depth, correlating with a transition from gneissic to schistose foliation. Thus, metamorphic foliation has a clear expression in seismic anisotropy. These results will aid in the evaluation of core-derived seismic properties of high-grade metamorphic rocks at the COSC-1 borehole and elsewhere.{\textless}/p{\textgreater} 2020 apr English 1869-9510 https://doi.org/10.5194/se-11-607-2020 Solid Earth 11 607--626 2 https://se.copernicus.org/articles/11/607/2020/ Publisher: Copernicus GmbH Felix Kästner Simona Pierdominici Judith Elger Alba Zappone Jochem Kück Christian Berndt techreport guglielmi_crystalline_2020 Within the Spent Fuel & Waste Science and Technology (SFWST) Program, research work continues further with the goal to better understand long-term performance of disposal systems in three main geologic rock types: clay/shale, salt, and crystalline rock. This report documents LBNL’s research activities related to investigations of crystalline host rock according to the scope of two work packages: SF-20LB01030207 “Crystalline International Collaborations – LBNL,” and SF-20LB01030203 “Crystalline Disposal R&D – LBNL.” These research activities correspond are related to key Features, Events, and Processes (FEPs), ranked in importance from medium to high, as listed in Table 7 of the Used Fuel Disposition Campaign Disposal Research and Development Roadmap (FCR&D-USED-2011-000065 REV0) (Nutt, 2011). Specifically, these research activities address FEP 2.2.01, Excavation Disturbed Zone (EZD). The results of these research activities provide important insights into understanding and predicting flow and transport processes that could occur in low-permeability crystalline rocks, in which fractures might serve as main conduits for fluid flow and radionuclide transport. The evolution of the EDZ during the excavation of the tunnel as well as the evolution of microcrack growth within the EDZ after the emplacement of backfill are critical for predicting the long- term behavior of the EDZ. A number of factors including stress, temperature, water activity, capillary pressure, chemistry, and mineralogy can affect the rock evolution, which require advanced experimental tools to study it. 2020 jul English 10.2172/1642697 Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States) LBNL-2001334 https://doi.org/10.2172/1642697 Yves Guglielmi Chun Chang Paul Cook Patrick Dobson Florian Soom Seiji Nakagawa Auli Niemi Chris Juhlin Henning Lorenz Jan-Erik Rosberg Benoît Dessirier Chinfu Tsang Alexandru Tatomir Farzad Basirat Emil Lundberg Bjarne Almqvist Sharon Borglin Christine Doughty Lian Zheng article drake_geochronology_2020 The deep biosphere hosted in fractured rocks within the upper continental crust is one of the least understood and studied ecological realms on Earth. Scarce knowledge of ancient life and paleo-fluid flow within this realm is owing to the lack of deep drilling into the crust. Here we apply microscale high spatial-resolution analytical techniques to fine-grained secondary minerals in a deep borehole (COSC-1) drilled into the Silurian-Devonian Scandinavian Caledonide mountain range in central Sweden. The aim is to detect and date signs of ancient microbial activity and low-temperature fluid circulation in micro-karsts (foliation-parallel dissolution cavities in the rock) and fractures at depth in the nappe system. Vein carbonates sampled at 684 to 2210 m show a decreased C isotope variability at depths below 1050 m; likely due to decreased influence of organic-C at great depth. Micro-karsts at 122\–178 m depth feature at least two generations of secondary calcite and pyrite growth in the voids as shown by secondary ion mass spectrometry analytical transects within individual grains. The younger of these two precipitation phases shows 34S-depleted &delta;34Spyrite values (&minus;19.8 &plusmn; 1.6&permil; vs. Vienna-Canyon Diablo Troilite (V-CDT)) suggesting microbial sulfate reduction in situ. The calcite of this late phase can be distinguished from the older calcite by higher &delta;18Ocalcite values that correspond to precipitation from ambient meteoric water. The late stage calcite gave two separate laser ablation inductively coupled mass spectrometry-derived U-Pb ages (9.6 &plusmn; 1.3 Ma and 2.5 &plusmn; 0.2 Ma), marking a minimum age for widespread micro-karst formation within the nappe. Several stages of fluid flow and mineral precipitation followed karst formation; with related bacterial activity as late as the Neogene-Quaternary; in structures presently water conducting. The results show that our combined high spatial-resolution stable isotope and geochronology approach is suitable for characterizing paleo-fluid flow in micro-karst; in this case, of the crystalline crust comprising orogenic nappe units. 2020 feb en 10.3390/geosciences10020056 Geosciences 10 56 2 stable isotopes, Caledonides, deep drilling (COSC-1), in situ U-Pb geochronology, secondary minerals https://www.mdpi.com/2076-3263/10/2/56 Henrik Drake Nick M. W. Roberts Martin J. Whitehouse article wiersberg_identification_2020 On-line monitoring of drilling mud gas was for the first time applied during continuous wireline coring of the COSC-1 borehole (Jämtland, central Sweden) to analyse formation gases and to identify inflow gas zones. Nearly complete gas records were obtained with 3 m depth resolution from 662 m (installation of the separator for gas extraction) to 1709 m and 6 m resolution from 1709 m to 2490 m depth (COSC-1 final depth: 2496 m) for H2, CH4, CO2, and He. Between 662 m and 1400 m, both He and CH4 form broad peaks superimposed by several spike-like features. Zones with gas spikes coincide with high resistivity intervals from dual laterolog (DLL) geophysical borehole logging and show fractures in borehole televiewer (BHTV) images, drill core scans, and visual core inspection. Therefore, we assume gas inflow through open fractures where DLLd/DLLs ratios {\textgreater}1.5 imply the presence of free gas. The correlation between helium and DLLd/DLLs ratios no longer appears at depths greater than {\textasciitilde}1550 m, probably because the formation gases are dissolved in formation fluids at higher pressure. Below 1550 m depth, the He concentration drops significantly, whereas the CH4 concentration remains relatively high and H2 and CO2 reach maximum values. The high amount of H2 and CH4 at depths below 1616 m, from where friction between the casing and the drill string was reported, imply that these gases are most certainly artificially generated at depths below 1616 m and at least partly of artificial origin at shallower depths. 2020 mar en 0883-2927 10.1016/j.apgeochem.2019.104513 Applied Geochemistry 114 104513 COSC, Downhole logging, Drilling mud gas analysis, Formation fluids, Natural fractures http://www.sciencedirect.com/science/article/pii/S0883292719303221 Simona Pierdominici Henning Lorenz Bjarne Almqvist Iwona Klonowska article giuntoli_protracted_2020 During continental collision, large tracts of crust are mobilized along major shear zones. The metamorphic conditions at which these zones operate, the duration of thrusting, and the deformation processes that facilitated hundreds of km of tectonic transport are still unclear. In the Scandinavian Caledonides, the Lower Seve Nappe displays a main mylonitic foliation with thickness of 1 km. This foliation is overprinted by a brittle-to-ductile deformation pattern localized in C- and C′-type shear bands proximal to the tectonic contact with the underlying Särv Nappe. Thermobarometry of amphibolites and micaschists suggests a first high-pressure stage at 400–500°C and 1–1.3 GPa recorded in mineral relics. The main mylonitic foliation developed under epidote amphibolite facies conditions along the retrograde path from 600°C and 1 GPa to 500°C and 0.5 GPa. Age dating of synkinematic titanite grains in the amphibolites indicates that this mylonitic fabric formed at around 417 ± 9 Ma but older ages spanning 460–430 Ma could represent earlier stages of mylonitization. The shear bands developed at lower metamorphic conditions of 300–400°C and 0.3 GPa. In the micaschists, the recrystallized grain size of quartz decreases toward the shear bands. Monomineralic quartz layers are eventually dismembered to form polyphase aggregates deforming by dominant grain size sensitive creep accompanied by slip in muscovite and chlorite. Plagioclase zoning truncations suggest that the shear bands originated by fracturing followed by ductile deformation. The results suggest protracted and long-lasting shearing under amphibolite to greenschist facies conditions during the juxtaposition, stacking, and exhumation of the Lower Seve Nappe. 2020 en 1944-9194 10.1029/2020TC006267 Tectonics 39 e2020TC006267 9 U-Pb dating, Caledonides, electron backscatter diffraction, deformation mechanisms, petrochronology, thrusting, U-Pb dating https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020TC006267 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020TC006267 Francesco Giuntoli Luca Menegon Clare J. Warren James Darling Mark W. Anderson article merz_magnetic_2019 The COSC-1 project drilled the several hundred meters thick basal shear zone of the Lower Seve nappe with mylonites in mica schists, amphibole schists and gneisses. In zones of high magnetic susceptibility from 1910 to 2450 m we studied magnetic and petrographic fabrics, and magnetic mineralogy. Borehole imaging allowed for geographic reorientation of the samples and offered the opportunity to study anisotropy of magnetic susceptibility (AMS) in relation to tectonic evolution of the Seve thrust. We measured AMS at room temperature, added low-temperature and field-dependent AMS for a subset of samples, and compared magnetic with petrographic fabrics. Triaxial and prolate magnetic fabrics with degree of anisotropy (P′) up to 3.2 together with abundant S-C fabrics and strain partitioning around porphyroclasts indicate dominant simple shear until 2300 m. Magnetite and ilmenohematite mimic the rock fabric due to fabric parallel alignment and/or magnetic interaction and either contribute to increase or decrease of P′, depending on the dominating rock fabric elements. Field-dependency of pyrrhotite and magnetite in kmax-direction further increases P′. Homogeneous and oblate petrographic and magnetic fabrics in the greenschist-grade overprinted rocks below 2300 m with subhorizontal kmax-kint-girdle distributions indicate dominant flattening. AMS depicts shear fabrics including magnetite and ilmenohematite, and is additionally increased by retrograde magnetite-rutile intergrowth in ilmenohematites. We interpret that shape and degree of AMS are controlled by (a) tectonic deformation and strain, (b) alteration and magnetic grain interaction, and (c) field-dependency of deformed pyrrhotite and/or magnetite. We observed that all petrographic and magnetic subfabrics are coaxial, and lineations are mainly E-W to SE-NW directed confirming the transport direction of the Caledonian allochthonous. From our microstructural and AMS results we suggest that thrusting of the Lower Seve unit commenced under simple shear conditions at higher metamorphic grades and subsequently switched to more pure shear under greenschist-grade conditions. 2019 jan en 0040-1951 10.1016/j.tecto.2018.12.018 Tectonophysics 751 212--228 Anisotropy of magnetic susceptibility (AMS), Crustal shear zone, Magnetic fabric, Seve nappe complex http://www.sciencedirect.com/science/article/pii/S0040195118304311 Lena Merz Bjarne S. G. Almqvist Jens C. Grimmer Agnes Kontny techreport guglielmi_crystalline_2019 2019 en Lawrence Berkeley National Laboratory (LBNL)

Berkeley

47 Yves Guglielmi Paul Cook Patrick Dobson Seiji Nakagawa Liange Zheng Auli Niemi Chris Juhlin Henning Lorenz Jan-Erik Rosberg Benoît Dessirier Chin-Fu Tsang Alexandru Tatomir Farzad Basirat Emil Lundberg Bjarne Almqvist Sharon Borglin Chris Doughty article simon_anisotropic_2019 SUMMARY. A remarkably well preserved representation of a deeply eroded Palaeozoic orogen is found in the Scandinavian Caledonides, formed by the collision of t 2019 oct en 0956-540X 10.1093/gji/ggz286 Geophysical Journal International 219 66--79 1 https://academic.oup.com/gji/article/219/1/66/5522608 Publisher: Oxford Academic H. Simon P. Hedin C. Juhlin F. Krauß R. Giese article giuntoli_replacement_2018 The deformation of the middle to lower crust in collisional settings occurs via deformation mechanisms that vary with rock composition, fluid content, pressure, and temperature. These mechanisms are responsible for the accommodation of large tectonic transport distances during nappe stacking and exhumation. Here, we show that fracturing and fluid flow triggered coupled dissolution–precipitation and dissolution–precipitation creep processes, which were responsible for the formation of a mylonitic microstructure in amphibolites. This fabric is developed over a crustal thickness {\textgreater}500 m in the Lower Seve Nappe (Scandinavian Caledonides). Amphibolites display a mylonitic foliation that wraps around albite porphyroclasts appearing dark in panchromatic cathodoluminescence (CL). The albite porphyroclasts were dissected and fragmented by fractures preferentially developed along the (001) cleavage planes and display lobate edges with embayments and peninsular features. Two albite/oligoclase generations, bright in CL, resorbed and overgrew the porphyroclasts, sealing the fractures. Electron backscattered diffraction shows that the two albite/oligoclase generations grew both pseudomorphically and topotaxially at the expense of the albite porphyroclasts and epitaxially around them. These two albite/oligoclase generations also grew as neoblasts elongated parallel to the mylonitic foliation. The amphibole crystals experienced a similar microstructural evolution, as evidenced by corroded ferrohornblende cores surrounded by ferrotschermakite rims that preserve the same crystallographic orientation of the cores. Misorientation maps highlight how misorientations in amphibole are related to displacement along fractures perpendicular to its c-axis. No crystal plasticity is observed in either mineral species. Plagioclase and amphibole display a crystallographic preferred orientation that is the result of topotaxial growth on parental grains and nucleation of new grains with a similar crystallographic orientation. Amphibole and plagioclase thermobarometry constrains the mylonitic foliation development to the epidote amphibolite facies (˜600°C, 0.75–0.97 GPa). Our results demonstrate that at middle to lower crustal levels, the presence of H2O-rich fluid at grain boundaries facilitates replacement reactions by coupled dissolution–precipitation and favours deformation by dissolution–precipitation creep over dislocation creep in plagioclase and amphibole. 2018 en 1525-1314 10.1111/jmg.12445 Journal of Metamorphic Geology 36 1263--1286 9 Caledonides, dissolution–precipitation processes, electron backscatter diffraction, replacement reactions, X-ray mapping https://onlinelibrary.wiley.com/doi/abs/10.1111/jmg.12445 \_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/jmg.12445 Francesco Giuntoli Luca Menegon Clare J. Warren article Yan20171465 Article 2017 0956-540X 10.1093/gji/ggw457 Geophysical Journal International 208 1465 – 1489 3 inverse theory, Magnetotellurics, Europe, Downhole methods, Continental tectonics https://www.scopus.com/inward/record.uri?eid=2-s2.0-85014384679&doi=10.1093%2fgji%2fggw457&partnerID=40&md5=390b9d27000d3f817619b4eebec29808 Cited by: 19; All Open Access, Green Open Access Ping Yan Maria A. Garcia Juanatey Thomas Kalscheuer Christopher Juhlin Peter Hedin Alexandros Savvaidis Henning Lorenz Jochem Kück article Doughty2017501 Article 2017 10.1007/s10040-016-1497-5 Hydrogeology Journal 25 501 – 517 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85000443571&doi=10.1007%2fs10040-016-1497-5&partnerID=40&md5=f751598f66a12c91f8d3914ab489f27c Cited by: 10; All Open Access Christine Doughty Chin-Fu Tsang Jan-Erik Rosberg Christopher Juhlin Patrick F. Dobson Jens T. Birkholzer article wenning_image_2017 Stress-induced borehole deformation analysis in the Collisional Orogeny in the Scandinavian Caledonide deep scientific borehole establishes in situ stress orientation in a poorly characterized region in central Sweden. Two acoustic televiewer logging campaigns, with more than 1 year between campaigns, provide detailed images along the full length of the 2.5 km deep borehole for breakout, drilling-induced tensile fracture (DITF), and natural occurring structural analysis. Borehole breakouts occur in 13 distinct zones along total length of 22 m, indicating an average maximum horizontal stress, SHmax, orientation of 127° ± 12°. Infrequent DITFs are constrained within one zone from 786 to 787 m depth (SHmax orientation: 121° ± 07°). These SHmax orientations are in agreement with the general trend in Scandinavia and are in accordance with many mechanisms that generate crustal stress (e.g., ridge push, topographic loading, and mantel driven stresses). The unique acquisition of image logs in two successions allows for analysis of time-dependent borehole deformation, indicating that six breakout zones have crept, both along the borehole axis and radially around the borehole. Strong dynamic moduli measured on core samples and an inferred weak in situ stress anisotropy inhibit the formation of breakouts and DITFs. Natural fracture orientation below 800 m is congruent to extensional or hybrid brittle shear failure along the same trend as the current SHmax. Analysis of foliation in the image logs reinforces the interpretation that the discontinuous seismic reflectors with fluctuating dip observed in seismic profiles are due to recumbent folding and boudinage. 2017 en 2169-9356 10.1002/2016JB013776 Journal of Geophysical Research: Solid Earth 122 3999--4019 5 breakout growth, elastic properties, foliation and fracture, in situ stress, time dependency https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016JB013776 \_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2016JB013776 Quinn C. Wenning Théo Berthet Maria Ask Alba Zappone Jan-Erik Rosberg Bjarne S. G. Almqvist article simon_derivation_2017 2017 sep 0956-540X 10.1093/gji/ggx223 Geophysical Journal International 210 1332--1346 3 https://academic.oup.com/gji/article/210/3/1332/3837696/The-derivation-of-an-anisotropic-velocity-model H. Simon F. Krauß R. Giese P. Hedin C. Juhlin article conze_utilizing_2017 Article: Utilizing the International Geo Sample Number Concept in Continental Scientific Drilling During ICDP Expedition COSC-1 2017 jan en 1683-1470 10.5334/dsj-2017-002 Data Science Journal 16 1 http://datascience.codata.org/articles/10.5334/dsj-2017-002/ Henning Lorenz Damian Ulbricht Kirsten Elger Thomas Gorgas techreport eriksson_methods_2016 2016 SKB report R-16-09 p 61 SKB report R-16-09 p 61 http://www.skb.com/publication/2484526/R-16-09.pdf Lena Eriksson Johanna Edlund Linda Johansson Lisa Rabe Andreas Bengtsson Karsten Pedersen article juhlin_seismic_2016 2016 may en 1869-9529 10.5194/se-7-769-2016 Solid Earth 7 769--787 3 http://www.solid-earth.net/7/769/2016/ Christopher Juhlin Peter Hedin David G. Gee Henning Lorenz Thomas Kalscheuer Ping Yan article wenning_seismic_2016 Recent drilling of the first Collisional Orogeny in the Scandinavian Caledonides scientific borehole (COSC-1) near Åre, Sweden permitted a laboratory investigation of seismic anisotropy on high metamorphic grade and highly deformed core samples. The 2.5km deep borehole crosscuts the amphibolite-grade Lower Seve Nappe and intersects a high-strain shear zone in the lowermost 800m. Measurements of ultrasonic compressional (Vp) and shear (Vs) velocities are conducted at room temperature and pressures ranging from room conditions up to 260MPa on six core sections that represent the most abundant lithologies in the borehole. The core sections consist of two amphibolites, a calc-silicate gneiss, a felsic gneiss, an amphibole-rich gneiss, and a garnet-bearing micaschist from the shear zone. Three mutually perpendicular samples were taken to characterize the anisotropy induced by the clear foliation and lineation. The intrinsic (crack-free velocities) Vp0 and Vs0 in the direction perpendicular to foliation ranges from 5.51 to 6.67km/s and 3.31 to 4.13km/s, respectively. In the direction parallel to foliation the Vp0 and Vs0 ranges from 6.31 to 7.25km/s and 3.53 to 4.35km/s, respectively. Vp anisotropy ranges from 3% in the calc-silicate gneiss to 19% in the micaschist. In the upper crustal seismic reflection survey around the COSC-1 borehole, reflection coefficient analysis suggests that reflectors occur due to impedance contrast between commonly occurring amphibolites and gneisses in the upper 1800m and the micaschists below. When extrapolated to mid-crustal levels the analysis indicates that both rock types can produce reflection coefficients between adjacent lithologies in excess of 0.1. Similarities in lithologies, shear zone thickness, and reflectivity pattern in the Central Scandinavian Caledonides compared to other orogens (e.g., the Himalaya) demonstrate the importance of these measurements as a proxy for in-situ strongly anisotropic shear zones in the middle crust. 2016 dec 0040-1951 10.1016/j.tecto.2016.07.002 Tectonophysics 692 {SI}:{Crustal} seismology 14--28 Shear zone, Seismic anisotropy seismic velocity, Caledonian orogen, Middle crust reflectivity, Deep scientific drilling http://www.sciencedirect.com/science/article/pii/S0040195116302529 Quinn C. Wenning Bjarne S. G. Almqvist Peter Hedin Alba Zappone article tsang_hydrologic_2016 Drilling of a deep borehole does not normally allow for hydrologic testing during the drilling period. It is only done when drilling experiences a large loss (or high return) of drilling fluid due to penetration of a large-transmissivity zone. The paper proposes the possibility of conducting flowing fluid electrical conductivity (FFEC) logging during the drilling period, with negligible impact on the drilling schedule, yet providing important information on depth locations of both high- and low-transmissivity zones and their hydraulic properties. The information can be used to guide downhole fluid sampling and post-drilling detailed testing of the borehole. The method has been applied to the drilling of a 2,500-m borehole at Åre, central Sweden, firstly when the drilling reached 1,600 m, and then when the drilling reached the target depth of 2,500 m. Results unveil eight hydraulically active zones from 300 m down to borehole bottom, with depths determined to within the order of a meter. Further, the first set of data allows the estimation of hydraulic transmissivity values of the six hydraulically conductive zones found from 300 to 1,600 m, which are very low and range over one order of magnitude. 2016 apr en 1431-2174, 1435-0157 10.1007/s10040-016-1405-z Hydrogeology Journal 24 1333--1341 6 http://link.springer.com/article/10.1007/s10040-016-1405-z Chin-Fu Tsang Jan-Erik Rosberg Prabhakar Sharma Théo Berthet Christopher Juhlin Auli Niemi article doughty_flowing_2016 Flowing fluid electrical conductivity (FFEC) logging is a hydrogeologic testing method that is usually conducted in an existing borehole. However, for the 2,500-m deep COSC-1 borehole, drilled at Åre, central Sweden, it was done within the drilling period during a scheduled 1-day break, thus having a negligible impact on the drilling schedule, yet providing important information on depths of hydraulically conductive zones and their transmissivities and salinities. This paper presents a reanalysis of this set of data together with a new FFEC logging data set obtained soon after drilling was completed, also over a period of 1 day, but with a different pumping rate and water-level drawdown. Their joint analysis not only results in better estimates of transmissivity and salinity in the conducting fractures intercepted by the borehole, but also yields the hydraulic head values of these fractures, an important piece of information for the understanding of hydraulic structure of the subsurface. Two additional FFEC logging tests were done about 1 year later, and are used to confirm and refine this analysis. Results show that from 250 to 2,000 m depths, there are seven distinct hydraulically conductive zones with different hydraulic heads and low transmissivity values. For the final test, conducted with a much smaller water-level drawdown, inflow ceased from some of the conductive zones, confirming that their hydraulic heads are below the hydraulic head measured in the wellbore under non-pumped conditions. The challenges accompanying 1-day FFEC logging are summarized, along with lessons learned in addressing them. 2016 nov en 1431-2174, 1435-0157 10.1007/s10040-016-1497-5 Hydrogeology Journal 1--17 http://link.springer.com/article/10.1007/s10040-016-1497-5 Christine Doughty Chin-Fu Tsang Jan-Erik Rosberg Christopher Juhlin Patrick F. Dobson Jens T. Birkholzer techreport dobson_deep_2016 2016 Lawrence Berkeley National Laboratory (LBNL)

Berkeley, CA (United States)

124 http://www.osti.gov/scitech/biblio/1306290 Patrick Dobson Chin-Fu Tsang Timothy Kneafsey Sharon Borglin Yvette Piceno Gary Andersen Seiji Nakagawa Kurt Nihei Jonny Rutqvist Christine Doughty others article hedin_3d_2016 2016 oct en 00401951 10.1016/j.tecto.2015.12.013 Tectonophysics 689 40--55 http://linkinghub.elsevier.com/retrieve/pii/S0040195115006769 Peter Hedin Bjarne Almqvist Théo Berthet Christopher Juhlin Helge Simon Rüdiger Giese Felix Krauß Jan-Erik Rosberg Per-Gunnar Alm article sjoqvist_innovative_2015 2015 may 1816-3459 10.5194/sd-19-13-2015 Scientific Drilling 19 13--16 http://www.sci-dril.net/19/13/2015/ 00000 A. S. L. Sjöqvist M. Arthursson A. Lundström E. Calderón Estrada A. Inerfeldt H. Lorenz article lorenz_cosc-1_2015 2015 may 1816-3459 10.5194/sd-19-1-2015 Scientific Drilling 19 1--11 http://www.sci-dril.net/19/1/2015/ 00000 Henning Lorenz J.-E. Rosberg C. Juhlin L. Bjelm B. S. G. Almqvist T. Berthet R. Conze D. G. Gee I. Klonowska C. Pascal K. Pedersen N. M. W. Roberts C.-F. Tsang article lorenz_h._cosc-1_2015 2015 https://doi.org/10.1594/GFZ.SDDB.ICDP.5054.2015 GFZ German Research Centre for Geosciences https://doi.org/10.5880/ICDP.5054.002 00000 H. Lorenz J.-E. Rosberg Christopher Juhlin L. Bjelm B.S.G. Almqvist T. Berthet R. Conze D. G. Gee I. Klonowska C. Pascal K. Pedersen N. Roberts C.F. Tsang phdthesis hedin_geophysical_2015 The Collisional Orogeny in the Scandinavian Caledonides (COSC) project aims to provide a deeper understanding of mountain belt dynamics through scientific deep drilling in the central parts of the ... Ph.{D}. thesis 2015 eng Uppsala University

Uppsala, Sweden

http://uu.diva-portal.org/smash/record.jsf?pid=diva2:849748 Peter Hedin article lorenz_h._operational_2015 2015 10.2312/ICDP.2015.002 55 https://doi.org/10.2312/ICDP.2015.002 00000 H. Lorenz J. E. Rosberg C. Juhlin L. Bjelm B. Almquist T. Berthet R. Conze D. Gee I. Klonowska C. Pascal K. Pedersen N. Roberts C. F. Tsang inproceedings simon_derivation_2015 The project COSC (Collisional Orogeny in the Scandinavian Caledonides) focuses on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, from the past and in recent active mountain belts. The Scandinavian Caledonides provide a well preserved example of a Paleozoic continent-continent collision, where the surface geology in combination with geophysical data provide control of the geometry of the Caledonian structure. In 2014 the COSC-1 borehole was successfully drilled through the Seve Nappe Complex (SNC) to {\textasciitilde} 2.5 km depth near the town of Åre (central Sweden). Subsequently a major seismic survey was conducted in and around the COSC-1 borehole which comprised both seismic reflection and transmission experiments. This will allow extrapolation of results from core analysis and downhole logging to the structures around the borehole. The survey consisted of three simultaneous experiments: 1) a high-resolution zero-offset Vertical Seismic Profile (VSP), 2) a multi-azimuthal walkaway VSP in combination with three long offset surface receiver lines, and 3) a limited 3D seismic survey. In this study data from the multi-azimuthal walkaway VSP experiment and the long offset surface lines were used to derive a detailed velocity model around the borehole from the inversion of first arrival traveltimes. The P-wave velocity profile at the borehole obtained by this tomography approach correlates in general with sonic velocities measured during borehole logging and with interval velocities calculated from the zero-offset VSP data, however the absolute values are always significantly higher. This is probably due to the presence of significant seismic anisotropy in the SNC which has also been observed in ultrasonic lab measurements. The obtained anisotropic velocity model serves as the basis for the ongoing application of imaging approaches like pre-stack depth migration techniques. 2015 American Geophysical Union

San Francisco

H11B--1327 https://agu.confex.com/agu/fm15/meetingapp.cgi/Paper/71897 00000 Helge Simon Felix Krauß Peter Hedin Rüdiger Giese Christopher Juhlin article kraus_zero-offset_2015 2015 Geophysical Research Abstracts 17 EGU2015--3255 http://meetingorganizer.copernicus.org/EGU2015/EGU2015-3255.pdf 00000 Felix Krauß Helge Simon Rüdiger Giese Peter Hedin Christopher Juhlin Henning Lorenz article hedin_3d_2014 Skip to Next Section The scientific drilling project COSC (Collisional Orogeny in the Scandinavian Caledonides), designed to study key questions concerning orogenic processes, aims to drill two fully cored boreholes to depths of c. 2.5 km each at carefully selected locations in west-central Sweden. The first of these, COSC-1, is scheduled for start late spring 2014 and will target the Seve Nappe Complex, characterized by inverted metamorphism and with parts that have evidently been subjected to hot ductile extrusion. In this study available seismic sections have been combined with surface geology to produce a 3D interpretation of the tectonic structures in the vicinity of the COSC-1 borehole. Constrained 3D inverse gravity modelling over the same area supports the interpretation, and the high-density Seve Nappe Complex stands out clearly in the model. Interpretation and models show that the maximum depth extent of the Seve Nappe Complex is less than 2.5 km, consistent with reflection seismic data. The gravity modelling also requires underlying units to comprise low-density material, consistent with the Lower Allochthon, but the modelling is unable to discern the décollement separating the allochthons from the crystalline Precambrian basement. 2014 jan en 0305-8719, 2041-4927 10.1144/SP390.15 Geological Society, London, Special Publications 390 301--319 1 https://sp.lyellcollection.org/content/390/1/301 Publisher: Geological Society of London Section: Development of the Seve nappe complex and its position within the orogen Peter Hedin Alireza Malehmir David G. Gee Christopher Juhlin Dan Dyrelius article hedin_seismic_2012 A 36 kilometer long high resolution 2D seismic reflection profile was acquired in the summer of 2010 to be used in the planning of the COSC (Collisional Orogeny in the Scandinavian Caledonides) Deep Drilling Project. Two fully cored boreholes, each to c. 2.5 km depth, are planned for the Åre-Mörsil area of west-central Sweden in order to increase our understanding of orogenic processes and, in particular, the tectonic evolution of the Scandinavian Caledonides. Besides providing important sub-surface structural information in the vicinity of the potential drill sites, the seismic profile also provides detailed, high resolution images previously not available for the uppermost few kilometers in the region. The subsurface is highly reflective and very complex down to at least 9 km depth (the limit of decoded data) with clear reflections spanning the entire length of the profile. Correlation with previous regional reflection seismic and magnetotelluric surveys has been achieved by acquisition of a short (7 km) connecting profile. A clearly defined reflection, present in the new profile at depths between c. 2.5 km in the east and c. 4.5 km in the west and with an average westwards dip of c. 3.5°, apparently defines the base of the Lower Allochthon. Closer to the Caledonian front, this sole thrust overlies the Cambrian alum shale formation, which rests unconformably on the autochthonous Precambrian crystalline basement. The latter is remarkable for its deep internal reflectivity which is probably related to mafic intrusions in a dominantly granitic host-rock; their deformation may be of both Caledonian and older (e.g. Sveconorwegian) age. The new high resolution seismic data provide the basis for locating the first borehole in the Seve Nappe Complex. They also demonstrate that the second hole, designed to penetrate the Caledonian basement, will have to be located further east than was originally planned. 2012 jul 0040-1951 10.1016/j.tecto.2012.05.026 Tectonophysics 554–557 30--41 Reflection seismic, Collisional orogeny, Borehole, Migration, Continental Scientific Drilling, Scandinavian Caledonides http://www.sciencedirect.com/science/article/pii/S0040195112003174 00000 P. Hedin C. Juhlin D. G. Gee inproceedings hedin_high_2011 The Caledonides were once a mountain range of Himalayan dimensions, but are today eroded down to mid crustal levels. In the Scandes, major allochthons are inferred to have been transported hundreds of kilometers from subduction zones along the margin of the Paleozoic Baltica continent onto the Baltoscandian platform. A proposal has been sent to the International Continental Scientific Drilling Program (ICDP) to drill through the long transported allochthons into the Baltica basement. During the summer of 2010 a seismic reflection survey was acquired in the Åre region of western Sweden as a preparation for the COSC deep drilling project. The COSC project will study the fossilized orogenic processes that governed the formation of the Scandinavian Caledonides and test different hypothesis related to orogenesis. The seismic section correlates well with older surveys made in the area, but it also provides a much higher resolution image of the upper few kilometers of the crust. The subsurface is extremely reflective and we interpret a basal décollement, which is one of the main targets with the drilling, to be located at a depth of about 1.5 to 2 km in the eastern parts of the section. 2011 AGH University of Science and Technology

Krakow, Poland

P. Hedin C. Juhlin D. G. Gee A. Malehmir article gee_collisional_2010 The COSC project is focused on the mid Paleozoic Caledonide Orogen in Scandinavia in order to better understand orogenic processes, both in the past and in today's active mountain belts. It relates to two of ICDP's main themes – the fundamental physics of plate tectonics and heat, mass and fluid transfer through Earth's crust, and on improving interpretation of geophysical data used to determine the structure and properties of the Earth's crust. Lateral transport of Caledonian allochthons over distances of several hundreds of kilometers in the Scandes, by a combination of thrusting and ductile extrusion, is comparable to that recognized in the Himalayas. The Caledonides in Scandinavia provide special opportunities for understanding Himalayan-type orogeny and the Himalayan Orogen itself, thanks to the deep level of erosion and the paucity of superimposed post-Paleozoic deformation. The surface geology in combination with the seismic, magnetotelluric, magnetic and gravity data provide control of the geometry of the Caledonian structure, both of the allochthon and the underlying parautochthon-autochthon, and define the locations for drilling. The latter will investigate both the high-grade, ductile Caledonian nappes and the underlying allochthons and basement, with two c. 2.5 km deep boreholes, located near Åre and Järpen in western Jämtland. The two boreholes will also provide unique information about other important aspects of the Scandinavian bedrock, including the heat flow and potential for geothermal energy, mineralization in the Seve nappes and alum shales, the uplift history of the Scandes, the Holocene paleoclimatological changes and the deep biosphere. 2010 1103-5897 10.1080/11035891003759188 GFF 132 29 -- 44 1 http://www.informaworld.com/10.1080/11035891003759188 D. G. Gee C. Juhlin C. Pascal P. Robinson