Sedimentary Ce anomalies: Secular change and implications for paleoenvironmental evolution

Earth-Science Reviews, Journal Year: 2022, Volume and Issue: 229, P. 104015 - 104015

Published: March 29, 2022

Although Ce anomalies are commonly used to reconstruct past seawater redox conditions, published interpretations based on various proxy materials and analytical approaches, while no relatively complete compilation of sedimentary anomaly data has yet been made. Here, we report a new comprising >6000 carbonate, iron formation, phosphorite, chert samples all ages, which 1127 passed screening for near primary values. The 592 mudstones were also investigated found contain in some cases unambiguous traces negative anomaly, was likely inherited during early diagenetic organic degradation or directly from authigenic phases. Here show that seawater-like rare earth element (REE) patterns may be retained siliceous where the detrital REE signature diluted by silica. Mudstone weathering is shown have negligible effect magnitude moderately weathered samples. A critical appraisal literature, confirmed through La-Ce isotopic dating, implies oxygenic photosynthesis evolved 3.0–2.5 Ga. our does not capture onset Great Oxidation Episode, decreasing trend mean 2.5 2.1 Ga accordance with rise oxygen levels Paleoproterozoic. Sporadic might identify transient oxygenation events 1.8–1.2 minimum atmospheric concentrations up 1–6% present level. Statistical analysis consistent progressive surface ocean late Tonian-early Cambrian interval. While pronounced indicate shallow marine settings broadly well oxygenated Ediacaran-Cambrian transition, deeper environment remained largely anoxic, persistence dissolved carbon buffer. reveals expanded anoxia Paleozoic, followed more pervasive middle Devonian times, coincident emergence radiation secondary woody tissues forests. evolution estimated pO2 revealed generally compatible other proxies modelling results, therefore concur record responds sensitively oceanic changes can useful additional track Earth system evolution.

Language: Английский

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Diagenetic evolution in marine carbonate rocks based on the typical case studies: review and perspectives

Marine and Petroleum Geology, Journal Year: 2025, Volume and Issue: unknown, P. 107352 - 107352

Published: Feb. 1, 2025

Language: Английский

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Combined cadmium and chromium isotopes record a collapse of bioproductivity across the Cretaceous—Paleogene boundary in the Danish basin

Chemical Geology, Journal Year: 2024, Volume and Issue: 654, P. 122058 - 122058

Published: March 25, 2024

Cadmium (Cd) isotope signatures (δ114Cd) deduced from modern and ancient marine deposits are often used as a proxy for bioproductivity micronutrient cycling, whereas chromium (Cr) (δ53Cr) potential oxygenation. The Cretaceous—Paleogene (K/Pg) boundary records one of Earth's five big mass extinctions, which contains geochemical fingerprints the Chixculub asteroid impact is coeval with Deccan Trap volcanism. Here we present first time combined record Cd Cr isotopes Danish Basin to interrogate effects on across K/Pg boundary. δ114Cd values range between −0.28‰ 0.27‰ defining an average 0.05‰ ± 0.24 (2σ, n = 87). Authigenic δ53Cr 0.06‰ 1.06‰ define 0.59‰ 0.51 81). An abrupt jump, layer, consistently positively fractionated recorded in Late Maastrichtian white chalks towards less heterogeneous Early Danian carbonates, likely indicates decrease surface water bioproductivity. This accompanied by redox fluctuations column consequence environmental changes either related event and/or volcanic eruptions this Assuming efficient removal through consumption adsorption primary producers, or incorporation into skeleton/shells calcifiers, using fractionation factor reconstruct conditions during Masstrichtian—Early that compatible those oceans, varying 0.17 0.72‰. Overall, Cr-Cd over consistent scenario characterized climate-induced nutrient availability concomitant responses production levels, ultimately proceeding activities influenced ocean's chemistry. We anticipate our results point further studies other stratigraphic sections worldwide reveal extensive Cd-Cr its corresponding collapse decreasing ocean

Language: Английский

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No biological effect on magnesium isotope fractionation during stromatolite growth

Geochimica et Cosmochimica Acta, Journal Year: 2023, Volume and Issue: 358, P. 1 - 11

Published: Aug. 9, 2023

Language: Английский

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Barium isotopes in stromatolites through deep-time: A novel tracer for metal cycling in the photic zone

Earth and Planetary Science Letters, Journal Year: 2024, Volume and Issue: 632, P. 118639 - 118639

Published: March 7, 2024

Language: Английский

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Mineralogic control on the calcium and magnesium stable isotopic compositions of modern microbial carbonates

Geochimica et Cosmochimica Acta, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Language: Английский

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Untangling the Primary Biotic and Abiotic Controls on Oxygen, Inorganic and Organic Carbon Isotope Signals in Modern Microbialites

Geobiology, Journal Year: 2025, Volume and Issue: 23(1)

Published: Jan. 1, 2025

ABSTRACT Microbialites are organo‐sedimentary structures formed throughout most of the Earth history, over a wide range geological contexts, and under multitude environmental conditions affecting their composition. The carbon oxygen isotope records carbonates, which often main constituents, have been used as widespread tool for paleoenvironmental reconstructions. However, multiplicity factors that influence microbialites formation is not always properly distinguished in isotopic record, both ancient modern settings. It therefore crucial to refine our understanding processes controlling signal. Here, we analyzed compositions from bulk micro‐drilled carbonates well organic four Mexican volcanic crater lakes increasing alkalinity. survey allows comparing microbialite geochemical record within distinct physico‐chemical contexts. analyses were performed parallel petrographic mineralogical characterization interpreted light known microbial community composition same lakes. Combining these data, show potential biosignature preservation primarily depends on conditions. Carbon biosignatures pointing out an autotrophic carbonate precipitation preserved lowest alkalinity By contrast, higher lakes, where more massive, favor equilibrium with lake water, secondary heterotrophic degradation. From results, suggest C can be balance between net primary productivity amount relates forcing. signals highlight lack relatively rare phases such hydromagnesite. Nonetheless, influenced by basins' hydrology, though biological effects may also play (minor) role. Overall, mixture different local/global biotic/abiotic phenomena, making intricate archives growth environment, should thus cautions surrounding sediments.

Language: Английский

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Assessment of the Conditions of Carbonate Rock Formation on the Karelian Craton in the Paleoproterozoic Based on Geochemical Data

Lithology and Mineral Resources, Journal Year: 2025, Volume and Issue: 60(1), P. 90 - 113

Published: Feb. 1, 2025

Language: Английский

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Spatio-temporal distribution of global stromatolites through geological time identified by a large language model approach

Frontiers in Earth Science, Journal Year: 2025, Volume and Issue: 13

Published: March 31, 2025

Introduction A substantial amount of data embedded within diverse literature makes it time-consuming to manually extract and compile extensive datasets. The use large language models has become essential for the efficient extraction analysis big data. This study utilizes ChatGPT-4 reconstruct a global database stromatolites, spanning from Precambrian present, enhance our understanding their spatial temporal dynamics throughout geological time. Methods process involved several steps: First, PDF documents containing stromatolite were gathered converted into text format. Second, was employed on occurrences, including locations, ages, strata, facies types each sentence in documents. Third, duplicates removed, organized three categories: 3,248 unique location-age pairs, 2,723 strata-age 1,723 strata-age-facies type combinations. Additionally, 2,565 paleogeographical locations stromatolite-bearing rocks reconstructed using modern latitude longitude coordinates corresponding Phanerozoic ages. Results newly obtained dataset reveals that occurrences peaked during Proterozoic, declined Early Phanerozoic, exhibited fluctuations Phanerozoic. Seven hotspots identified: United States, Australia, India, Canada, China, England, Russia. From Cambrian Jurassic, stromatolites predominantly distributed low middle latitudes, shifting higher latitudes Cretaceous Quaternary. proportion inland aquatic relative marine varied, ranging 10% 30% Mesoarchean Middle Mesoproterozoic, decreasing less than Late Mesoproterozoic Paleozoic, increasing 10%–30% Devonian remaining high (39%–53%) Discussion findings highlight variability shedding light evolution these microbial structures over distribution patterns suggest significant shifts environmental conditions provide valuable insights ecological dynamics. organize body demonstrates potential advancing research paleobiology geology.

Language: Английский

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Biogeochemical sulfide mineralization in the volcanic-hosted Tongguan hydrothermal field, southern Mid-Atlantic Ridge

Frontiers in Marine Science, Journal Year: 2025, Volume and Issue: 12

Published: April 7, 2025

Biogeochemical mineralization is increasingly recognized as a significant factor in the formation of submarine hydrothermal sulfide deposits. While several mechanisms by which organisms may facilitate metal deposition have been documented many seafloor deposits, potential involvement biogenic processes deposits southern Mid-Atlantic Ridge (SMAR) has largely overlooked until now. In this study, we investigate chimney sample from volcanic-hosted Tongguan field on SMAR and present lines evidence for biogeochemical mineralization. Mineralogical analysis infers four types pyrite chalcopyrite structures: macrobiotic-related tube structures, microbial-related quasi-stromatolite, quasi-oncolite globular structures. These structures exhibit selective enrichment elements such Mn, Pb, Cu compared to abiotic pyrite. In-situ sulfur isotope studies indicate that minerals possess lower δ 34 S values than minerals. We identified three biomineralization mechanisms: an “active” process mediated macro-organism, “passive” associated with microbial mats, assimilatory sulfate reduction process. Our research suggests role should be given further consideration.

Language: Английский

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