All ICDP Publications with Abstracts
From parent-sysfolder "Publications" + 2 folder-levels deep
2894.
Taxonomic and functional partitioning of Chloroflexota populations under ferruginous conditions at and below the sediment-water interface
FEMS Microbiol Ecol
2024
2893.
Supergene formation of sulfur-rich, tochilinite-bearing serpentinites in the Oman ophiolite
Nat Commun,
15
2024
2892.
Supergene formation of sulfur-rich, tochilinite-bearing serpentinites in the Oman ophiolite
Lithos,
488-489
2024
2891.
Subsurface Microbial Colonization at Mineral-Filled Veins in 2-Billion-Year-Old Mafic Rock from the Bushveld Igneous Complex, South Africa
Microbial Ecology,
87
(1)
2024
2890.
Spatio-temporal variations of climate along possible African-Arabian routes of H. sapiens expansion
Quaternary Science Advances,
14
2024
Abstract: ▾ Eastern Africa and Arabia were major hominin hotspots and critical crossroads for migrating towards Asia during the late Pleistocene. To decipher the role of spatiotemporal environmental change on human occupation and migration patterns, we remeasured the marine core from Meteor Site KL 15 in the Gulf of Aden and reanalyzed its data together with the aridity index from ICDP Site Chew Bahir in eastern Africa and the wet-dry index from ODP Site 967 in the eastern Mediterranean Sea using linear and nonlinear time series analysis. These analyses show major changes in the spatiotemporal paleoclimate dynamics at 400 and 150 ka BP (thousand years before 1950), presumably driven by changes in the amplitude of the orbital eccentricity. From 400 to 150 ka BP, eastern Africa and Arabia show synchronized wet-dry shifts, which changed drastically at 150 ka BP. After 150 ka BP, an overall trend to dry climate states is observable, and the hydroclimate dynamics between eastern Africa and Arabia are negatively correlated. Those spatio-temporal variations and interrelationships of climate potentially influenced the availability of spatial links for human expansion along those vertices. We observe positively correlated network links during the supposed out-of-Africa migration phases of H. sapiens. Furthermore, our data do not suggest hominin occupation phases during specific time intervals of humid or stable climates but provide evidence of the so far underestimated potential role of climate predictability as an important factor of hominin ecological competitiveness. © 2024 The Authors
2889.
Shaped and filled by the Rhine Glacier: the overdeepened Tannwald Basin in southwestern Germany
Scientific Drilling,
33
(2)
191 – 206
2024
2888.
Seismic structure of the Balmuccia Peridotite from a high-resolution refraction and reflection survey
Geophysical Journal International,
238
(3)
1612 – 1625
2024
2887.
Sedimentary Paleoenvironment and Organic Matter Enrichment
Characteristics of Lacustrine Shahezi Shale in Songliao Basin: Insights
from the Continental Scientific Drilling
ACS OMEGA,
9
(19)
21097-21115
2024
2886.
Rhenium-platinum group elements reveal seawater incursion induced massive lacustrine organic carbon burial
Geochimica et Cosmochimica Acta,
384168 – 177
2024
2885.
Integrated chronostratigraphic framework for Cretaceous strata in the Songliao Basin; [松辽盆地白垩纪综合年代地层格架]
Earth Science Frontiers,
31
(1)
431 – 445
2024
2884.
The optimum fire window: applying the fire-productivity hypothesis to Jurassic climate states
Biogeosciences,
21
(11)
2795 – 2809
2024
Keywords:▾
aridity; grass; grassland; Jurassic; paleoecology; paleoenvironment; rainfall; seasonality; wildfire
Abstract: ▾ Present-day fire frequency is related to a productivity-aridity gradient on regional and global scales. Optimum fire conditions occur at times of intermediate productivity and aridity, whereas fire is limited at the high productivity (moisture) and aridity (no fuel) endmembers. However, the current global fire activity pattern is reinforced by the predominant burning of grasslands. Here we test the intermediate fire-productivity hypothesis for a period on Earth before the evolution of grasses, the Early Jurassic, and explore the fire regime of two contrasting climatic states: the cooling of the Late Pliensbachian Event (LPE) and the warming of the Sinemurian-Pliensbachian Boundary (SPB). Palaeo-fire records are reconstructed from fossil charcoal abundance, and changes in the hydrological cycle are tracked via clay mineralogy, which allows inference of changes in fuel moisture status. Large fluctuations in the fossil charcoal on an eccentricity timescale indicate two modes of fire regime at the time. Wildfires were moisture-limited in a high-productivity ecosystem during eccentricity minima for both the SPB and the LPE. During eccentricity maxima fires increased, and an optimum fire window was reached, in which periodically greater seasonality in rainfall and temperatures led to intermediate states of productivity and aridity. The LPE experienced more extreme climatic endmembers compared to the SPB, with the fire regime edging closer to "moisture limitation"during eccentricity minima, and experienced more pronounced seasonality during eccentricity maxima, explained by the overall cooler climate at the time. This study illustrates that the intermediate-productivity gradient holds up during two contrasting climatic states in the Jurassic. © 2024 Copernicus Publications. All rights reserved.
2883.
Impact-Generated Fragmentation, Porosity, and Permeability Within the Chicxulub Impact Structure
Earth and Space Science,
11
(5)
2024
2882.
Analyzing complex single grain feldspar equivalent dose distributions for luminescence dating of glacially derived sediments
Quaternary Geochronology,
85
2024
Abstract: ▾ Overdeepened valleys are structures scoured into the underlying substrate by glaciers that have been subsequently filled with sediment, which recorded the environmental history of the adjacent landscape. Investigated here is an overdeepened structure that was formed beneath the Salzach Paleoglacier west of Freilassing, Bavaria (southern Germany). In a previous study, infinite infrared stimulated luminescence (IRSL) ages have been determined for the lower part of the core using a multi-grain approach. Applying single-grain feldspar luminescence dating allows to identify the unsaturated signals, previously masked by multi-grain signal averaging. Identification of the normally distributed leading edge in equivalent dose (De) distributions allows for the dismissal of low value De (LOVED) grains that appear to reflect underestimating outliers. Measurement of eleven samples distributed along the entire length of the core yielded two distinct age clusters, for which fading corrected IRSL50 and uncorrected pIRIR225 ages agree within uncertainties. Whereas the younger age cluster at the top of the sequence is attributed to Marine Isotope Stage (MIS) 3, the older age cluster is assigned to MIS 6. It is shown that single grain pIRIR measurements will allow to resolve the infill chronology of overdeepened structures in the Alps, at least for the last ca. 200 ka. Overall, the present study represents a further step towards understanding and handling complex De distributions often encountered in single grain feldspar luminescence dating. This contributes to better understand the frequently observed age offset between single grain and single-aliquot measurements. © 2024 The Authors
2881.
Combined Geophysical Methods in Extreme Environments—An Example from the Dead Sea
Remote Sensing,
16
(11)
2024
Keywords:▾
Boreholes; C (programming language); Flow of fluids; Frequency domain analysis; Geophysics; Structural geology; Continental tectonics; Dead sea; Downhole methods; Extreme environment; Geophysical methods; Neotectonics; Saline environment; Shallow subsurface; Strike-slip and transform; Subsurface geology; Strike-slip faults
Abstract: ▾ The application of geophysical methods in saline environments is limited in their ability to discern shallow subsurface geology and tectonics due to the high subsurface conductivity, which can play havoc with the geophysical signal. Recent changes in the hypersaline Dead Sea provided the opportunity to demonstrate the effectiveness and adequacy of the terrestrial frequency domain electromagnetic (henceforth FDEM) method in such settings. Since the International Continental Drilling Program (ICDP) 5017-3-C borehole was cored in 2011 in a water depth of ~2.1 m, the lake level has dropped by almost 15 m, exposing some 320 m of a new, salt-encrusted shore. An FDEM survey was carried out on what is now land across the borehole. The results of the survey were compared to downhole gamma ray logging data. Three lithologies were found based on gamma-ray cutoff values, and they are in agreement with changes in apparent electric conductivity. The FDEM survey supplied additional spatial information on the subsurface geology, highlighting areas of fluid flow and fracturing, which were found to be aligned with the trend of small strike-slip faults and earthquake clusters from previous studies. The FDEM method is a reliable way of discerning shallow subsurface geology, even in harsh conditions where other geophysical methods are limited. © 2024 by the authors.
2880.
Climate, environment and human history in lowland Central America: Insights from Guatemalan lake sediments
Past Global Changes Magazine,
32
(2)
80-81
2024
2879.
Chicxulub's Legacy: Breakthroughs from scientific drilling, tsunamis, global climate upheaval and mass extinction
Past Global Changes Magazine,
32
(2)
82-83
2024
2878.
Characterizing shallow fault zones by integrating profile, borehole and
array measurements of seismic data and distributed acoustic sensing
NEAR SURFACE GEOPHYSICS,
22
(3)
298-312
2024
Keywords:▾
borehole; seismic array; tomography; traveltime
2877.
Candidatus Desulforudis audaxviator dominates a 975 m deep groundwater community in central Sweden
Commun Biol,
7
(1)
1332
2024
2876.
CALDERA: a scientific drilling concept to unravel Connections Among Life, geo-Dynamics and Eruptions in a Rifting Arc caldera, Okataina Volcanic
Centre, Aotearoa New Zealand
Scientific Drilling,
33
(1)
67--88
2024
2875.
BASE (Barberton Archean Surface Environments) - drilling Paleoarchean coastal strata of the Barberton Greenstone Belt
Scientific Drilling,
33
(2)
129 – 172
2024
ISSN: 18168957
Publisher: Copernicus Publications
Keywords:▾
Boreholes; Infill drilling; Iron; Shale; Stratigraphy; Sulfur compounds; Weathering; Archaean; Banded iron formations; Banded iron-formations; Banded-iron formations; Barberton; Greenstone belts; Paleoarchean; Scientific drilling; Siltstones; Surface environments; Sandstone
Abstract: ▾ The BASE (Barberton Archean Surface Environments) scientific drilling project aimed at recovering an unweathered continuous core from the Paleoarchean Moodies Group (ca. 3.2Ga), central Barberton Greenstone Belt (BGB), South Africa. These strata comprise some of the oldest well-preserved sedimentary strata on Earth, deposited within only a few million years in alluvial, fluvial, coastal-deltaic, tidal, and prodeltaic settings. They represent a very-high-resolution record of Paleoarchean surface conditions and processes. Moodies Group strata consist of polymict conglomerates, widespread quartzose, lithic and arkosic sandstones, siltstones, shales, and rare banded-iron formations (BIFs) and jaspilites, interbedded with tuffs and several thin lavas. This report describes objectives, drilling, and data sets; it supplements the operational report. Eight inclined boreholes between 280 and 495m length, drilled from November 2021 through July 2022, obtained a total of 2903m of curated core of variable quality through steeply to subvertically dipping, in part overturned stratigraphic sections. All drilling objectives were reached. Boreholes encountered a variety of conglomerates, diverse and abundant, mostly tuffaceous sandstones, rhythmically laminated shale-siltstone and banded-iron formations, and several horizons of early-diagenetic silicified sulfate concretions. Oxidative weathering reached far deeper than expected. Fracturing was more intense, and BIFs and jaspilites were thicker than anticipated. Two ca. 1km long mine adits and a water tunnel, traversing four thick stratigraphic sections within the upper Moodies Group in the central BGB, were also sampled. All boreholes were logged by downhole wireline geophysical instruments. The core was processed (oriented, slabbed, photographed, described, and archived) in a large, publicly accessible hall in downtown Barberton. A geological exhibition provided background explanations for visitors and related the drilling objectives to the recently established Barberton Makhonjwa Mountains World Heritage Site. A substantial education, outreach, and publicity program addressed the information needs of the local population and of local and regional stakeholders. © 2024 Christoph Heubeck et al.
2874.
Automatic lithology identification in meteorite impact craters using machine learning algorithms
Scientific Reports,
14
(1)
2024
2873.
Assessment of branched glycerol monoalkyl glycerol tetraether (brGMGT)-based paleothermometry in the 250,000-year sediment record of Lake Chala, equatorial East Africa
Organic Geochemistry,
195
2024
Keywords:▾
East Africa; Glycerol; Lipids; Surficial sediments; Branched glycerol dialkyl glycerol tetraether; Branched glycerol monoalkyl glycerol tetraether; DeepCHALLA; East Africa; H-shaped; H-shaped GDGT; ICDP; Lake chala; Lake sediments; Paleoclimates; Tetraethers; air temperature; crater lake; lipid; paleoclimate; relative abundance; sediment transport; water column; Lakes
Abstract: ▾ Branched glycerol monoalkyl glycerol tetraethers (brGMGTs), a relatively understudied group of bacterial membrane lipids structurally similar to branched glycerol dialkyl glycerol tetraethers (brGDGTs), appear to be strongly influenced by temperature in terrestrial settings. In surficial bottom sediments of East African lakes, the abundance of brGMGTs relative to the sum of brGMGTs and brGDGTs (%brGMGT) and brGMGT distribution are strongly related to local mean annual air temperature (MAAT), stimulating development of new paleothermometers. However, applications of these methods to lake-sediment records are currently lacking. Here we investigate brGMGT concentrations and distributions in 916 samples throughout the 250,000-year (250-kyr) sediment sequence from Lake Chala, a presently fresh and permanently stratified (meromictic) tropical crater lake. All seven previously identified brGMGTs occur abundantly, reflected in a relatively high average %brGMGT of 19%. BrGMGTs and brGDGTs concentrations throughout the sequence are strongly correlated (R = 0.83, p < 0.001), suggesting that their producers and/or associated ecological niches substantially overlap. Clear distinction can be made between brGMGTs produced predominantly in the bottom sediments (H1034a and H1034c) versus the anoxic lower water column (H1020a-c and H1034b). Although a 17-month monitoring study of Lake Chala suggested brGMGTs are primarily produced in the sediments, down-core data assign greater importance to aquatic production than previously estimated. Instead of reflecting temperature, %brGMGT variations showed greatest similarity to GDGT proxies reflecting lake depth and/or mixing regime. BrGMGT-based temperature models produce ambiguous reconstructions, showing little similarity to known global temperature trends or the brGDGT-based mean summer temperature (MST) reconstruction from the same sediments. © 2024 The Authors
2872.
Aspects of the biological carbon cycle in a ca. 3.42-billion-year-old marine ecosystem
Precambrian Research,
402
2024
Keywords:▾
Archean; carbon cycle; chert; geochemistry; greenstone belt; marine ecosystem; metabolism; paleoecology; species diversity
Abstract: ▾ Microbial life on Earth was well established in the Paleoarchean, but insight into early ecosystem diversity and thus, the complexity of the early biological carbon cycle is limited. Here we investigated four carbonaceous chert samples from the lower platform facies of the ca. 3.42-billion-year-old Buck Reef Chert, Barberton greenstone belt. The analysis on multiple scales revealed exceptionally well-preserved carbonaceous matter, even on molecular level (aliphatic and aromatic hydrocarbons), resulting from rapid silicification. Geochemical evidence from stable carbon and multiple sulfur isotopes supports the presence of different microbial metabolisms in the Paleoarchean ecosystem. The local biological carbon cycle was dominated by photoautotrophs, but autotrophic sulfate reducers and methane- or acetate-producing microbes were also present. In areas of microbial methane or acetate release, methanotrophs or acetotrophs contributed to the overall biomass. These results highlight the metabolic diversity in the lower platform environment of the Buck Reef Chert, and underline that an advanced biological carbon cycle already existed in the early Archean. © 2024 The Authors
2871.
An age-depth model for Lake Bosumtwi (Ghana) to reconstruct one million years of West African climate and environmental change
Quaternary Science Reviews,
325
2024
Keywords:▾
Ashanti; Ghana; Lake Bosumtwi; Sahara; Climate change; Climate models; Dust; Gamma rays; Meteorites; Rain; Sediments; Tropics; Climate dynamics; Depth models; Environmental change; ICDP; Lake bosumtwi; Natural gamma ray; Quaternary; Tie points; West Africa; Western africa; atmospheric circulation; climate variation; crater; environmental change; gamma radiation; potash; Quaternary; sedimentary sequence; Lakes
Abstract: ▾ Situated within a 1.07 million-year-old meteorite crater, Lake Bosumtwi in Ghana stands as a pivotal location for comprehending climatic, ecological and environmental fluctuations within the sub-Saharan region of West Africa. The region's susceptibility to seasonal environmental shifts and climate oscillations is heightened by the annual movements of the tropical rain belt driven by atmospheric circulation. Yet, there is no satisfying age-depth model available for the entire sedimentary sequence strongly limiting our understanding of changes in this circulation pattern and associated (broad-scale) environmental responses during the last million years in the local to regional context of Lake Bosumtwi. To overcome this, we statistically examine the cyclicity in total natural gamma ray (NGR) data on a core from the lake's centre and create a cyclostratigraphic age-depth model. The calculated maximum age of 946 ka agrees well with the meteorite impact age (∼10 % offset). In order to refine this purely statistical approach, we also perform a correlative age-depth model using 33 tie points accounting for the complexity of climatic and environmental imprints to the NGR record that may exceed direct insolation related effects. Special attention is paid to the core's robustly dated (14C, OSL, U/Th) uppermost part covering the last 200 ka. Here, high NGR and co-varying K counts coincide with warm periods (except of the water-saturated and unconsolidated Holocene part) and the inverse for glacials and stadials. Based on this, we define tie points for correlating our NGR data to the age-depth model of a NE Atlantic SST record. Comparing our results to the correlation target, other global climate records and Sahara dust flux data reveals striking similarities and supports a proxy understanding with increased in wash of K-enriched terrigenous material from the crater rims in warm and moist periods (high NGR) and K-depleted dust input in stadials possibly contributing to low NGR values in addition to reduced input of K-enriched sediments from the crater rims. Our correlative age model results in precession amplitudes matching eccentricity well, providing further support especially because an over-tuning is unlikely with the used 33 tie points. Overall we provide crucial chronological context to numerous datasets along with environmental constrains that can be used to study the potential habitat availability of early anatomically modern humans in West Africa. © 2023
2870.
Combining orbital tuning and direct dating approaches to age-depth model development for Chew Bahir, Ethiopia
Quaternary Science Advances,
15
2024
Abstract: ▾ The directly dated RRMarch2021 age model (Roberts et al., 2021) for the ∼293 m long composite core from Chew Bahir, southern Ethiopia, has provided a valuable chronology for long-term climate changes in northeastern Africa. However, the age model has limitations on shorter time scales (less than 1–2 precession cycles), especially in the time range <20 kyr BP (kiloyears before present or thousand years before 1950) and between ∼155 and 428 kyr BP. To address those constraints we developed a partially orbitally tuned age model. A comparison with the ODP Site 967 record of the wetness index from the eastern Mediterranean, 3300 km away but connected to the Ethiopian plateau via the River Nile, suggests that the partially orbitally tuned age model offers some advantages compared to the exclusively directly dated age model, with the limitation of the reduced significance of (cross) spectral analysis results of tuned age models in cause-effect studies. The availability of this more detailed age model is a prerequisite for further detailed spatiotemporal correlations of climate variability and its potential impact on the exchange of different populations of Homo sapiens in the region. © 2024 The Authors