Journal articles: 'Trace element palaeoredox proxies'

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Mänd, Kaarel, Stefan V. Lalonde, Kärt Paiste, Marie Thoby, Kaarel Lumiste, Leslie J. Robbins, Timmu Kreitsmann, et al. "Iron Isotopes Reveal a Benthic Iron Shuttle in the Palaeoproterozoic Zaonega Formation: Basinal Restriction, Euxinia, and the Effect on Global Palaeoredox Proxies." Minerals 11, no. 4 (March 31, 2021): 368. http://dx.doi.org/10.3390/min11040368.

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The Zaonega Formation in northwest Russia (~2.0 billion years old) is amongst the most complete successions that record the middle of the Palaeoproterozoic era. As such, geochemical data from the formation have played a central role in framing the debate over redox dynamics in the aftermath of the Great Oxidation Event (GOE). However, uncertainty over local redox conditions and the degree of hydrographic restriction in the formation has led to contradictory interpretations regarding global oxygen (O2) fugacity. Here, we provide new iron (Fe) isotope data together with major and trace element concentrations to constrain the local physiochemical conditions. The Zaonega Formation sediments show authigenic Fe accumulation (Fe/Al ≫ 1 wt.%/wt.%) and δ56Fe ranging from −0.58‰ to +0.60‰. Many of the data fall on a negative Fe/Al versus δ56Fe trend, diagnostic of a benthic Fe shuttle, which implies that Zaonega Formation rocks formed in a redox-stratified and semi-restricted basin. However, basin restriction did not coincide with diminished trace metal enrichment, likely due to episodes of deep-water exchange with metal-rich oxygenated seawater, as evidenced by simultaneous authigenic Fe(III) precipitation. If so, the Onega Basin maintained a connection that allowed its sediments to record signals of global ocean chemistry despite significant basinal effects.

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Li, Jun, Herong Gui, Luwang Chen, Pei Fang, Xiaoping Li, Jie Zhang, and Yingxin Wang. "Geochemistry of upper Palaeozoic ‘thin-layer’ limestones in the southern North China Craton: implications for closure of the northeastern Palaeotethys Ocean." Geological Magazine 159, no. 4 (November 8, 2021): 494–510. http://dx.doi.org/10.1017/s0016756821001126.

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AbstractDuring the late Palaeozoic Era, a series of related marine strata dominated by multi-layer limestones were deposited in the southern North China Craton. In order to gain new insights into the systematic geochemistry of the carbonate succession of the representative formation (Taiyuan Formation), we examined 59 limestone samples collected from the Huaibei Coal Basin (HCB), with a view towards quantitatively determining the major and trace elements and stable isotope compositions. The data obtained can provide essential evidence for reconstruction of the depositional palaeo-environment and tectonic setting of the Taiyuan Formation. Both X-ray diffraction analyses and palaeoredox proxies (e.g. V/Cr, V/(V + Ni) and authigenic U) indicated that the limestone layers were deposited in an oxic–dysoxic zone, with calcite as the main component. Moreover, palaeomagnetic evidence provided support for the conclusion that these limestones were laid down within an epicontinental sea depositional environment under a warm or hot palaeoclimate during the transition between late Carboniferous and early Permian time. Additionally, evidence obtained from our analyses of trace and rare earth elements revealed that the tectonic setting of the Taiyuan Formation (L1–L5) in the HCB transited from an open ocean to a passive continental margin, thereby indicating that this transformation stemmed from the subduction closure of the northeastern Palaeotethys Ocean. The findings of this study would be of interest to those working on the upper Palaeozoic marine strata in the southern North China Craton.

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Sondi, Ivan, Nevenka Mikac, Neda Vdović, Maja Ivanić, Martina Furdek, and Srečo D. Škapin. "Geochemistry of recent aragonite-rich sediments in Mediterranean karstic marine lakes: Trace elements as pollution and palaeoredox proxies and indicators of authigenic mineral formation." Chemosphere 168 (February 2017): 786–97. http://dx.doi.org/10.1016/j.chemosphere.2016.10.134.

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Pérez-Huerta, Alberto, Anthony E. Aldridge, Kazuyoshi Endo, and Teresa E. Jeffries. "Brachiopod shell spiral deviations (SSD): Implications for trace element proxies." Chemical Geology 374-375 (May 2014): 13–24. http://dx.doi.org/10.1016/j.chemgeo.2014.03.002.

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Xu, Guangping, Judith L. Hannah, Bernard Bingen, Svetoslav Georgiev, and Holly J. Stein. "Digestion methods for trace element measurements in shales: Paleoredox proxies examined." Chemical Geology 324-325 (September 2012): 132–47. http://dx.doi.org/10.1016/j.chemgeo.2012.01.029.

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Markulin, Krešimir, Melita Peharda, Regina Mertz-Kraus, Bernd R. Schöne, Hana Uvanović, Žarko Kovač, and Ivica Janeković. "Trace and minor element records in aragonitic bivalve shells as environmental proxies." Chemical Geology 507 (March 2019): 120–33. http://dx.doi.org/10.1016/j.chemgeo.2019.01.008.

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Oonk, Paul B. H., Harilaos Tsikos, Paul R. D. Mason, Susann Henkel, Michael Staubwasser, Lindi Fryer, Simon W. Poulton, and Helen M. Williams. "Fraction-specific controls on the trace element distribution in iron formations: Implications for trace metal stable isotope proxies." Chemical Geology 474 (December 2017): 17–32. http://dx.doi.org/10.1016/j.chemgeo.2017.10.018.

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Reuer, Matthew K., Edward A. Boyle, and Julia E. Cole. "A mid-twentieth century reduction in tropical upwelling inferred from coralline trace element proxies." Earth and Planetary Science Letters 210, no. 3-4 (May 2003): 437–52. http://dx.doi.org/10.1016/s0012-821x(03)00162-6.

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Johnson, K. R., C. Hu, and G. M. Henderson. "Testing seasonal resolution trace element and stable isotope proxies of East Asian monsoon rainfall." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A296. http://dx.doi.org/10.1016/j.gca.2006.06.600.

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Zinke, Jens, Juan P. D'Olivo, Christoph J. Gey, Malcolm T. McCulloch, J. Henrich Bruggemann, Janice M. Lough, and Mireille M. M. Guillaume. "Multi-trace-element sea surface temperature coral reconstruction for the southern Mozambique Channel reveals teleconnections with the tropical Atlantic." Biogeosciences 16, no. 3 (February 4, 2019): 695–712. http://dx.doi.org/10.5194/bg-16-695-2019.

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Abstract. Here we report seasonally resolved sea surface temperatures for the southern Mozambique Channel in the SW Indian Ocean based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores. Particularly, we assess the suitability of both separate and combined Sr∕Ca and Li∕Mg proxies for improved multielement SST reconstructions. Overall, geochemical records from Europa Island Porites sp. highlight the potential of Sr∕Ca and Li∕Mg ratios as high-resolution climate proxies but also show significant differences in their response at this Indian Ocean subtropical reef site. Our reconstruction from 1970 to 2013 using the Sr∕Ca SST proxy reveals a warming trend of 0.58±0.1 ∘C in close agreement with instrumental data (0.47±0.07 ∘C) over the last 42 years (1970–2013). In contrast, the Li∕Mg showed unrealistically large warming trends, most probably caused by uncertainties around different uptake mechanisms of the trace elements Li and Mg and uncertainties in their temperature calibration. In our study, Sr∕Ca is superior to Li∕Mg to quantify absolute SST and relative changes in SST. However, spatial correlations between the combined detrended Sr∕Ca and Li∕Mg proxies compared to instrumental SST at Europa revealed robust correlations with local climate variability in the Mozambique Channel and teleconnections to regions in the Indian Ocean and southeastern Pacific where surface wind variability appeared to dominate the underlying pattern of SST variability. The strongest correlation was found between our Europa SST reconstruction and instrumental SST records from the northern tropical Atlantic. Only a weak correlation was found with ENSO, with recent warm anomalies in the geochemical proxies coinciding with strong El Niño or La Niña. We identified the Pacific–North American (PNA) atmospheric pattern, which develops in the Pacific in response to ENSO, and the tropical North Atlantic SST as the most likely causes of the observed teleconnections with the Mozambique Channel SST at Europa.

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Crumpton-Banks, Jessica G. M., Thomas Tanner, Ivan Hernández Almeida, James W. B. Rae, and Heather Stoll. "Technical note: No impact of alkenone extraction on foraminiferal stable isotope, trace element and boron isotope geochemistry." Biogeosciences 19, no. 24 (December 14, 2022): 5633–44. http://dx.doi.org/10.5194/bg-19-5633-2022.

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Abstract. Recent advances in geochemical techniques mean that several robust proxies now exist to determine the past carbonate chemistry of the oceans. Foraminiferal δ11B and alkenone carbon isotopes allow us to reconstruct sea-surface pH and pCO2, respectively, and the ability to apply both proxies to the same sediment sample would give strongly paired datasets and reduce sample waste. However, no studies to date have examined whether the solvents and extraction techniques used to prepare alkenones for analysis also impact the geochemistry of foraminifera within those sediments. Here we examine six species pairs of planktic foraminifera, with half being taken from non-treated sediments and half being taken from sediments where alkenones have been extracted. We look for visual signs of contrasting preservation and compare analyses of δ18O, δ13C, δ11B and trace elements (Li, B, Na, Mn, Mg, Sr and U/Ca). We find no consistent geochemical offset between the treatments and excellent agreement in δ11B measurements between them. Our results show that boron isotope reconstructions of pH in foraminifera from alkenone-extracted sediments can be applied with confidence.

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Liu, Xiaokang, Jianbao Liu, Chuan-Chou Shen, Yan Yang, Jianhui Chen, Shengqian Chen, Xianfeng Wang, Chung-Che Wu, and Fahu Chen. "Inconsistency between records of δ18O and trace element ratios from stalagmites: Evidence for increasing mid–late Holocene moisture in arid central Asia." Holocene 30, no. 3 (November 22, 2019): 369–79. http://dx.doi.org/10.1177/0959683619887431.

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The interpretation of trace element/calcium ratios of speleothems as indicators of local hydroclimatic variability in the vicinity of caves has led to controversy in reconstructing the evolution of moisture conditions in arid central Asia (ACA) during the Holocene. Here we present records of Mg/Ca, Sr/Ca, Ba/Ca, and U/Ca from precisely dated stalagmites from Baluk cave in Xinjiang (northwest China), spanning the past 9370 years. The co-variations of the trace element ratios, together with the slopes of the regression lines of the corresponding logarithmically transformed data, suggest that they are dominated by prior calcite precipitation (PCP) and thus can be used as reliable proxies of changes in moisture/precipitation. The trace element ratios are relatively high during ~9 to 5 ka and lower from 5 ka to the present, indicating a trend of increasing mid–late Holocene moisture in ACA. The long-term trend of variation of the trace element ratios is correlative with two other records of speleothem trace element ratios from caves in ACA: Kesang cave (western Xinjiang) and Ton cave (Uzbekistan). This spatial coherency of the trend of inferred moisture conditions from three caves that are separated by hundreds of kilometers demonstrates that speleothem trace element ratios are indicative of large spatial scale rather than local hydroclimatic variability in ACA during the Holocene. However, the long-term trend of variation of the trace element ratios is the inverse of the corresponding oxygen isotope (δ18O) records from the same cave sites, which implies that Holocene speleothem δ18O records do not represent changes in the precipitation amount in ACA; rather, they most likely reflect moisture sources and related water vapor transport controlled by Northern Hemisphere summer insolation (NHSI). Our findings provide new evidence for a ‘westerlies-dominated climatic regime’, which influenced hydroclimatic changes in ACA during the Holocene.

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Hendy, E. J., M. K. Gagan, J. M. Lough, M. McCulloch, and P. B. deMenocal. "Impact of skeletal dissolution and secondary aragonite on trace element and isotopic climate proxies inPoritescorals." Paleoceanography 22, no. 4 (October 5, 2007): n/a. http://dx.doi.org/10.1029/2007pa001462.

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Helz, George R., and Jordan M. Adelson. "Trace Element Profiles in Sediments as Proxies of Dead Zone History; Rhenium Compared to Molybdenum." Environmental Science & Technology 47, no. 3 (February 5, 2013): 1257–64. http://dx.doi.org/10.1021/es303138d.

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Allen, Katherine A., Bärbel Hönisch, Stephen M. Eggins, Laura L. Haynes, Yair Rosenthal, and Jimin Yu. "Trace element proxies for surface ocean conditions: A synthesis of culture calibrations with planktic foraminifera." Geochimica et Cosmochimica Acta 193 (November 2016): 197–221. http://dx.doi.org/10.1016/j.gca.2016.08.015.

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Goodwin, David H., David P. Gillikin, and Peter D. Roopnarine. "Preliminary evaluation of potential stable isotope and trace element productivity proxies in the oyster Crassostrea gigas." Palaeogeography, Palaeoclimatology, Palaeoecology 373 (March 2013): 88–97. http://dx.doi.org/10.1016/j.palaeo.2012.03.034.

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Foster, G. L., Y. Ni, T. Elliott, and D. N. Schmidt. "A core-top assessment of foraminiferal isotopic and trace element proxies for the ocean carbonate system." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A183. http://dx.doi.org/10.1016/j.gca.2006.06.367.

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Aranha, Renita, Evan Edinger, Graham Layne, and Glenn Piercey. "Growth rate variation and potential paleoceanographic proxies in Primnoa pacifica: Insights from high-resolution trace element microanalysis." Deep Sea Research Part II: Topical Studies in Oceanography 99 (January 2014): 213–26. http://dx.doi.org/10.1016/j.dsr2.2013.07.001.

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Hernandez Nava, Andres, Benjamin A. Black, Sally A. Gibson, Robert J. Bodnar, Paul R. Renne, and Loÿc Vanderkluysen. "Reconciling early Deccan Traps CO2 outgassing and pre-KPB global climate." Proceedings of the National Academy of Sciences 118, no. 14 (March 29, 2021): e2007797118. http://dx.doi.org/10.1073/pnas.2007797118.

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A 2 to 4 °C warming episode, known as the Latest Maastrichtian warming event (LMWE), preceded the Cretaceous–Paleogene boundary (KPB) mass extinction at 66.05 ± 0.08 Ma and has been linked with the onset of voluminous Deccan Traps volcanism. Here, we use direct measurements of melt-inclusion CO2 concentrations and trace-element proxies for CO2 to test the hypothesis that early Deccan magmatism triggered this warming interval. We report CO2 concentrations from NanoSIMS and Raman spectroscopic analyses of melt-inclusion glass and vapor bubbles hosted in magnesian olivines from pre-KPB Deccan primitive basalts. Reconstructed melt-inclusion CO2 concentrations range up to 0.23 to 1.2 wt% CO2 for lavas from the Saurashtra Peninsula and the Thakurvadi Formation in the Western Ghats region. Trace-element proxies for CO2 concentration (Ba and Nb) yield estimates of initial melt concentrations of 0.4 to 1.3 wt% CO2 prior to degassing. Our data imply carbon saturation and degassing of Deccan magmas initiated at high pressures near the Moho or in the lower crust. Furthermore, we find that the earliest Deccan magmas were more CO2 rich, which we hypothesize facilitated more efficient flushing and outgassing from intrusive magmas. Based on carbon cycle modeling and estimates of preserved lava volumes for pre-KPB lavas, we find that volcanic CO2 outgassing alone remains insufficient to account for the magnitude of the observed latest Maastrichtian warming. However, accounting for intrusive outgassing can reconcile early carbon-rich Deccan Traps outgassing with observed changes in climate and atmospheric pCO2.

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Huang, Linjun, Yin Liu, Baoli Bian, Yongping Ma, Hailei Liu, Juanjuan Guo, and Jian Cao. "Chemically Active Elements of Reservoir Quartz Cement Trace Hydrocarbon Migration in the Mahu Sag, Junggar Basin, NW China." Geofluids 2021 (April 7, 2021): 1–19. http://dx.doi.org/10.1155/2021/6617945.

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Element exchange and enrichment during fluid-rock interactions are common, providing potentially novel proxies to trace hydrocarbon migration in addition to the traditional organic geochemistry tracers. However, the processes, mechanisms, and geological and geochemical fingerprints of these interactions are complex, hampering the applications of hydrocarbon migration tracers. To investigate such interactions, we conducted a petrological, mineralogical, and in situ and bulk geochemical study of authigenic quartz and whole-rock samples from the Mahu Sag, northwestern Junggar Basin, northwest China. We found that dissolution, clay and chlorite formation, and overgrowth occurred on quartz grains in hydrocarbon fluid migration pathways, suggestive of strong fluid-rock interactions. In situ quantitative elemental analysis of quartz grains revealed elemental enrichment (e.g., Mn, Fe, Al, Sr, and W) in quartz overgrowth rims compared with their cores, indicating that migration of hydrocarbon-bearing fluids in reservoirs may promote elemental exchange between fluids and minerals. Whole-rock geochemical analysis showed that decreasing contents of some elements may reflect the direction of hydrocarbon-bearing fluid migration and can be monitored with three geochemical proxies, which are the MnO contents and MnO/Zr and Y/Ho ratios. Our data provide new constraints on fluid-rock interactions in petroleum reservoirs and have implications for using inorganic geochemical methods to trace hydrocarbon migration.

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ETEMAD-SAEED, NAJMEH, and MAHDI NAJAFI. "Provenance and geochemical variations across the Ediacaran–Cambrian transition in the Soltanieh Formation, Alborz Mountains, Iran." Geological Magazine 156, no. 07 (July 9, 2018): 1157–74. http://dx.doi.org/10.1017/s001675681800050x.

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AbstractThe Soltanieh Formation in the Alborz Mountains of northern Iran is not only a key lithostratigraphic unit for reconstruction of the Iranian geological history, but also a globally outstanding succession to reveal variations in seawater composition across the Precambrian–Cambrian (PC–C) transition. Mineralogical and geochemical data from a continuous stratigraphic record of Lower and Upper Shale members of the Soltanieh Formation are used to define their provenance, tectonic setting as well as geochemical variations during the PC–C transition. The Soltanieh mudrocks are composed of quartz and plagioclase, with minor constituents of illite, chlorite and montmorillonite. The chemical index of alteration, A-CN-K (Al2O3 – CaO + Na2O – K2O) relations, index of compositional variability, and Th/Sc versus Zr/Sc ratios indicate low chemical weathering in source areas, compositionally immature and first-cycle sediments. Immobile trace-element ratios and discrimination diagrams, chondrite-normalized rare Earth element (REE) patterns and negative Eu anomaly, along with low total REE abundances and negligible Ce anomalies, demonstrate that the Soltanieh Formation was mainly derived from proximal felsic-intermediate Cadomian magmatic arc sources and deposited in a continental-arc-related basin on the proto-Tethyan active margin of Gondwana. The palaeoredox indicators exhibit a remarkable change in environmental condition from a suboxic to an oxic state across the PC–C transition from the Kahar Formation to the Upper Shale Member of the Soltanieh Formation. Moreover, a significant upwards increase of P, Ba, and Ca is likely associated with enhanced fluxes of nutrient elements during the PC–C transition, coeval with the building of collisional mountain belts during the amalgamation of Gondwana.

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de Winter, Niels J., Clemens V. Ullmann, Anne M. Sørensen, Nicolas Thibault, Steven Goderis, Stijn J. M. Van Malderen, Christophe Snoeck, Stijn Goolaerts, Frank Vanhaecke, and Philippe Claeys. "Shell chemistry of the boreal Campanian bivalve <i>Rastellum diluvianum</i> (Linnaeus, 1767) reveals temperature seasonality, growth rates and life cycle of an extinct Cretaceous oyster." Biogeosciences 17, no. 11 (June 3, 2020): 2897–922. http://dx.doi.org/10.5194/bg-17-2897-2020.

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Abstract. The Campanian age (Late Cretaceous) is characterized by a warm greenhouse climate with limited land-ice volume. This makes this period an ideal target for studying climate dynamics during greenhouse periods, which are essential for predictions of future climate change due to anthropogenic greenhouse gas emissions. Well-preserved fossil shells from the Campanian (±78 Ma) high mid-latitude (50∘ N) coastal faunas of the Kristianstad Basin (southern Sweden) offer a unique snapshot of short-term climate and environmental variability, which complements existing long-term climate reconstructions. In this study, we apply a combination of high-resolution spatially resolved trace element analyses (micro-X-ray fluorescence – µXRF – and laser ablation inductively coupled plasma mass spectrometry – LA-ICP-MS), stable isotope analyses (IRMS) and growth modeling to study short-term (seasonal) variations recorded in the oyster species Rastellum diluvianum from the Ivö Klack locality. Geochemical records through 12 specimens shed light on the influence of specimen-specific and ontogenetic effects on the expression of seasonal variations in shell chemistry and allow disentangling vital effects from environmental influences in an effort to refine paleoseasonality reconstructions of Late Cretaceous greenhouse climates. Growth models based on stable oxygen isotope records yield information on the mode of life, circadian rhythm and reproductive cycle of these extinct oysters. This multi-proxy study reveals that mean annual temperatures in the Campanian higher mid-latitudes were 17 to 19 ∘C, with winter minima of ∼13 ∘C and summer maxima of 26 ∘C, assuming a Late Cretaceous seawater oxygen isotope composition of −1 ‰ VSMOW (Vienna standard mean ocean water). These results yield smaller latitudinal differences in temperature seasonality in the Campanian compared to today. Latitudinal temperature gradients were similar to the present, contrasting with previous notions of “equable climate” during the Late Cretaceous. Our results also demonstrate that species-specific differences and uncertainties in the composition of Late Cretaceous seawater prevent trace element proxies (Mg∕Ca, Sr∕Ca, Mg∕Li and Sr∕Li) from being used as reliable temperature proxies for fossil oyster shells. However, trace element profiles can serve as a quick tool for diagenesis screening and investigating seasonal growth patterns in ancient shells.

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Zhong, S., and C. Qu. "Experimental study of trace element coprecipitation in marine carbonate minerals: Reexamining current proxies and identifying new potential ones." Geochimica et Cosmochimica Acta 70, no. 18 (August 2006): A749. http://dx.doi.org/10.1016/j.gca.2006.06.1350.

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Bauwens, M., H. Ohlsson, K. Barbé, V. Beelaerts, J. Schoukens, and F. Dehairs. "A nonlinear multi-proxy model based on manifold learning to reconstruct water temperature from high resolution trace element profiles in biogenic carbonates." Geoscientific Model Development 3, no. 2 (November 12, 2010): 653–67. http://dx.doi.org/10.5194/gmd-3-653-2010.

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Abstract. A long standing problem in paleoceanography concerns the reconstruction of water temperature from δ18O carbonate. It is problematic in the case of freshwater influenced environments because the δ18O isotopic composition of the ambient water (related to salinity) needs to be known. In this paper we argue for the use of a nonlinear multi-proxy method called Weight Determination by Manifold Regularization (WDMR) to develop a temperature reconstruction model that is less sensitive to salinity variations. The motivation for using this type of model is twofold: firstly, observed nonlinear relations between specific proxies and water temperature motivate the use of nonlinear models. Secondly, the use of multi-proxy models enables salinity related variations of a given temperature proxy to be explained by salinity-related information carried by a separate proxy. Our findings confirm that Mg/Ca is a powerful paleothermometer and highlight that reconstruction performance based on this proxy is improved significantly by combining its information with the information for other trace elements in multi-proxy models. Although the models presented here are black-box models that do not use any prior knowledge about the proxies, the comparison of model reconstruction performances based on different proxy combinations do yield useful information about proxy characteristics. Using Mg/Ca, Sr/Ca, Ba/Ca and Pb/Ca the WDMR model enables a temperature reconstruction with a root mean squared error of ± 2.19 °C for a salinity range between 15 and 32.

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Tadros, Carol V., Pauline C. Treble, Andy Baker, Ian Fairchild, Stuart Hankin, Regina Roach, Monika Markowska, and Janece McDonald. "ENSO–cave drip water hydrochemical relationship: a 7-year dataset from south-eastern Australia." Hydrology and Earth System Sciences 20, no. 11 (November 17, 2016): 4625–40. http://dx.doi.org/10.5194/hess-20-4625-2016.

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Abstract. Speleothems (cave deposits), used for palaeoenvironmental reconstructions, are deposited from cave drip water. Differentiating climate and karst processes within a drip-water signal is fundamental for the correct identification of palaeoenvironmental proxies and ultimately their interpretation within speleothem records. We investigate the potential use of trace element and stable oxygen-isotope (δ18O) variations in cave drip water as palaeorainfall proxies in an Australian alpine karst site. This paper presents the first extensive hydrochemical and δ18O dataset from Harrie Wood Cave, in the Snowy Mountains, south-eastern (SE) Australia. Using a 7-year long rainfall δ18O and drip-water Ca, Cl, Mg / Ca, Sr / Ca and δ18O datasets from three drip sites, we determined that the processes of mixing, dilution, flow path change, carbonate mineral dissolution and prior calcite precipitation (PCP) accounted for the observed variations in the drip-water geochemical composition. We identify that the three monitored drip sites are fed by fracture flow from a well-mixed epikarst storage reservoir, supplied by variable concentrations of dissolved ions from soil and bedrock dissolution. We constrained the influence of multiple processes and controls on drip-water composition in a region dominated by El Niño–Southern Oscillation (ENSO). During the El Niño and dry periods, enhanced PCP, a flow path change and dissolution due to increased soil CO2 production occurred in response to warmer than average temperatures in contrast to the La Niña phase, where dilution dominated and reduced PCP were observed. We present a conceptual model, illustrating the key processes impacting the drip-water chemistry. We identified a robust relationship between ENSO and drip-water trace element concentrations and propose that variations in speleothem Mg / Ca and Sr / Ca ratios may be interpreted to reflect palaeorainfall conditions. These findings inform palaeorainfall reconstruction from speleothems regionally and provide a basis for palaeoclimate studies globally, in regions where there is intermittent recharge variability.

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Mischel, Simon A., Denis Scholz, Christoph Spötl, Klaus Peter Jochum, Andrea Schröder-Ritzrau, and Sabine Fiedler. "Holocene climate variability in Central Germany and a potential link to the polar North Atlantic: A replicated record from three coeval speleothems." Holocene 27, no. 4 (September 30, 2016): 509–25. http://dx.doi.org/10.1177/0959683616670246.

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Here, we present high-resolution trace element and stable isotope records from three coeval Holocene stalagmites from the Herbstlabyrinth cave system, Central Germany. All stalagmites were precisely dated using MC-ICPMS 230Th/U-dating. One stalagmite started to grow at 13.62 ± 0.13 ka BP, covering the late Glacial; the other two speleothems started to grow at 11.13 ± 0.08 and 10.26 ± 0.08 ka BP, respectively. The combined record covers the entire Holocene. The interpretation of the different climate proxies is supported by data from a detailed cave monitoring programme. Cold conditions during the Younger Dryas are reflected by intermittent stalagmite growth at the Herbstlabyrinth. The δ18O records are in general agreement with the NGRIP δ18O record on millennial time scales indicating that speleothem δ18O values at the Herbstlabyrinth reflect large-scale climate variability in the North Atlantic area. The 8.2 ka event is clearly visible as a pronounced negative excursion in the δ18O records. In all other proxies, it is not reflected as a major excursion. Correlation and principal component analysis enable us to disentangle the various processes affecting the stable isotope and trace element signals. Phases with higher P, Ba and U concentrations and more negative δ13C values are interpreted as reflecting more productive vegetation above the cave. The negative correlation of Mg with P, Ba and U and the positive correlation with δ13C indicate more recharge during phases of more productive vegetation, probably because of increased rainfall. The majority of the observed phases of reduced vegetation productivity and drier climate coincide with cooler periods in the polar North Atlantic as reflected by a higher abundance of hematite-stained grains (i.e. the Bond events), suggesting a close relationship between terrestrial climate in Central Europe and the polar North Atlantic.

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Borreggine, Marisa, Sarah E. Myhre, K. Allison S. Mislan, Curtis Deutsch, and Catherine V. Davis. "A database of paleoceanographic sediment cores from the North Pacific, 1951–2016." Earth System Science Data 9, no. 2 (September 28, 2017): 739–49. http://dx.doi.org/10.5194/essd-9-739-2017.

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Abstract. We assessed sediment coring, data acquisition, and publications from the North Pacific (north of 30° N) from 1951 to 2016. There are 2134 sediment cores collected by American, French, Japanese, Russian, and international research vessels across the North Pacific (including the Pacific subarctic gyre, Alaskan gyre, Japan margin, and California margin; 1391 cores), the Sea of Okhotsk (271 cores), the Bering Sea (123 cores), and the Sea of Japan (349 cores) reported here. All existing metadata associated with these sediment cores are documented here, including coring date, location, core number, cruise number, water depth, vessel metadata, and coring technology. North Pacific sediment core age models are built with isotope stratigraphy, radiocarbon dating, magnetostratigraphy, biostratigraphy, tephrochronology, % opal, color, and lithological proxies. Here, we evaluate the iterative generation of each published age model and provide comprehensive documentation of the dating techniques used, along with sedimentation rates and age ranges. We categorized cores according to the availability of a variety of proxy evidence, including biological (e.g., benthic and planktonic foraminifera assemblages), geochemical (e.g., major trace element concentrations), isotopic (e.g., bulk sediment nitrogen, oxygen, and carbon isotopes), and stratigraphic (e.g., preserved laminations) proxies. This database is a unique resource to the paleoceanographic and paleoclimate communities and provides cohesive accessibility to sedimentary sequences, age model development, and proxies. The data set is publicly available through PANGAEA at https://doi.org/10.1594/PANGAEA.875998.

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Johnson, Kathleen R. "Tales from the Underground: Speleothem Records of Past Hydroclimate." Elements 17, no. 2 (April 1, 2021): 93–100. http://dx.doi.org/10.2138/gselements.17.2.93.

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Geochemical records from speleothems have significantly advanced our understanding of natural climate variability over the last ~600,000 years. Speleothems are sensitive recorders of past changes in hydroclimate because they can be precisely dated and contain multiple hydrologically sensitive geochemical proxies. Oxygen isotope records from speleothems tell us about the timing and mechanisms of past changes in precipitation amount, temperature, atmospheric circulation, and/or global monsoon intensity. Variations in speleothem carbon isotope ratios or trace element concentrations reflect changes in local water balance, vegetation, and karst hydrology. Speleothem paleoclimate records represent a window into the past that can provide crucial information for understanding how anthropogenic climate change and natural climate variability will impact future water resources on Earth.

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Ma, Qing, Yaoqi Zhou, Hongyu Mu, Tengfei Zhou, Hanjie Zhao, Xingcheng Yin, and Yanzi Liu. "Geochemistry of the Laiyang Group from outcrops and Lingke-1 core on Lingshan Island, Shandong Province, Eastern China: implications for provenance, tectonic setting and palaeo-environment." Geological Magazine 159, no. 1 (November 2, 2021): 37–54. http://dx.doi.org/10.1017/s0016756821000819.

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AbstractLower Cretaceous sedimentary rocks of Lingshan Island, located along the continental margin of East Asia, have received increased attention. The Lingke-1 core mainly belongs to the Lower Cretaceous Laiyang Group. We investigate provenance, tectonic setting, palaeoclimate and palaeoredox conditions in the study area using elemental geochemistry, thereby elucidating the depositional history of the Lower Cretaceous sediments and reconstructing the palaeo-environment. To achieve this, 90 siltstones and 76 mudstones were sampled from this core and other outcrops on Lingshan Island. The chemical index of alternation (CIA) values for the majority of the samples and the bivariate diagrams indicate that the sedimentary rocks were subjected to minor weathering processes. Geochemical results suggest that source rocks for the region are felsic igneous and metamorphic rocks, along with minor proportions of intermediate igneous rocks. Major- and trace-element discrimination diagrams, deciphering the tectonic history, indicate that source rocks mainly originated from the continental island-arc and active continental margin. Several representative geochemical indices and the bivariate plots based on elemental contents show that the Laiyang Group was predominantly deposited in arid conditions. Sr/Ba values suggest a palaeosalinity transition from brackish to saline, demonstrating a depositional transformation from lacustrine facies for the lower Laiyang Group to marine facies in the upper Laiyang Group. U/Th and V/(V+Ni) ratios and Ce anomalies in the rocks indicate anoxic conditions. We conclude that the conspicuous decline in the trends of the above three geochemical indices, ranging between 400 and 800 m, may be related to the latest Hauterivian oceanic anoxic event.

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Badry, Alexander, Luis Palma, Pedro Beja, Tomasz M. Ciesielski, Andreia Dias, Syverin Lierhagen, Bjørn Munro Jenssen, Nicolas Sturaro, Igor Eulaers, and Veerle L. B. Jaspers. "Using an apex predator for large-scale monitoring of trace element contamination: Associations with environmental, anthropogenic and dietary proxies." Science of The Total Environment 676 (August 2019): 746–55. http://dx.doi.org/10.1016/j.scitotenv.2019.04.217.

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Evans, Guy N., Margaret K. Tivey, Brian Monteleone, Nobumichi Shimizu, Jeffrey S. Seewald, and Olivier J. Rouxel. "Trace element proxies of seafloor hydrothermal fluids based on secondary ion mass spectrometry (SIMS) of black smoker chimney linings." Geochimica et Cosmochimica Acta 269 (January 2020): 346–75. http://dx.doi.org/10.1016/j.gca.2019.09.038.

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Gaspar, Miguel, Nuno Grácio, Rute Salgueiro, and Mafalda Costa. "Trace Element Geochemistry of Alluvial TiO2 Polymorphs as a Proxy for Sn and W Deposits." Minerals 12, no. 10 (September 30, 2022): 1248. http://dx.doi.org/10.3390/min12101248.

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The Segura mining field, the easternmost segment of the Góis–Panasqueira–Segura tin–tungsten metallogenic belt (north–central Portugal), includes Sn-W quartz veins and Li-Sn aplite-pegmatites, which are believed to be genetically related to Variscan Granites. Sediment geochemistry indicates granite-related Ti-enrichments, locally disturbed by mineralization, suggesting magmatic and metamorphic/metasomatic titaniferous phases. Therefore, Segura alluvial samples and the geochemistry of their TiO2 polymorphs (rutile, anatase, and brookite) were investigated, and their potential as exploration tools for Sn and W deposits was evaluated. The heavy-mineral assemblages proved to be good proxies for bedrock geology, and TiO2 polymorph abundances were found to be suitable indicators of magmatic and/or metasomatic hydrothermal processes. The trace element geochemistry of Segura’s alluvial rutile, anatase, and brookite is highly variable, implying multiple sources and a diversity of mineral-forming processes. The main compositional differences between TiO2 polymorphs are related to intrinsic (structural) factors, and to the P-T-X extrinsic parameters of their forming environments. Anomalous enrichments, up to 9% Nb, 6% Sn and W, 3% Fe, 2% Ta, and 1% V in rutile, and up to 1.8% Fe, 1.7% Ta, 1.2% Nb, 1.1% W 0.5% Sn and V in anatase, were registered. Brookite usually has low trace element content (<0.5%), except for Fe (~1%). HFSE-rich and granitophile-rich rutile is most likely magmatic, forming in extremely differentiated melts, with Sn and W contents enabling the discrimination between Sn-dominant and W-dominant systems. Trace element geochemical distribution maps show pronounced negative Sn (rutile+anatase) and W (rutile) anomalies linked to hydrothermal cassiterite precipitation, as opposed to their hydrothermal alteration halos and to W-dominant cassiterite-free mineralized areas, where primary hydrothermal rutile shows enrichments similar to magmatic rutile. This contribution recognizes that trace element geochemistry of alluvial TiO2 polymorphs can be a robust, cost- and time-effective, exploration tool for Sn(W) and W(Sn) ore deposit systems.

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AVAK, SVEN ERIK, MARGIT SCHWIKOWSKI, and ANJA EICHLER. "Impact and implications of meltwater percolation on trace element records observed in a high-Alpine ice core." Journal of Glaciology 64, no. 248 (October 1, 2018): 877–86. http://dx.doi.org/10.1017/jog.2018.74.

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ABSTRACTPast atmospheric pollution can be reconstructed from ice core trace element records retrieved from mountain glaciers. However, the current global temperature increase can result in post-depositional melt processes, significantly altering the originally stored information. Here, we present a comprehensive study on the behaviour of 35 trace elements (TEs) during meltwater percolation in a high-Alpine ice core segment from upper Grenzgletscher, Switzerland. Some TEs revealed significant concentration depletion, whereas others were well preserved depending on their water solubility and location at the grain scale. TEs present in insoluble minerals, typically enriched at grain boundaries, were found to be mostly preserved because their insolubility in water results in immobility with meltwater percolation. Water-soluble TEs revealed a variable meltwater-mobility. Whereas ultra-TEs tend to be preserved, likely due to incorporation into the ice lattice, abundant TEs are prone to relocation from grain-boundary regions. We propose that at Alpine sites, Ag, Al, Bi, Cu, Cs, Fe, Li, Mo, Pb, Rb, Sb, Th, Tl, U, V, W, Zr and the rare-earth elements may still be applicable as robust environmental proxies even if partial melting occurred, whereas Ba, Ca, Cd Co, Mg, Mn, Na, Ni, Sr and Zn are prone to significant depletion.

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Vidović, Jelena, Rafał Nawrot, Ivo Gallmetzer, Alexandra Haselmair, Adam Tomašových, Michael Stachowitsch, Vlasta Ćosović, and Martin Zuschin. "Anthropogenically induced environmental changes in the northeastern Adriatic Sea in the last 500 years (Panzano Bay, Gulf of Trieste)." Biogeosciences 13, no. 21 (November 1, 2016): 5965–81. http://dx.doi.org/10.5194/bg-13-5965-2016.

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Abstract. Shallow and sheltered marine embayments in urbanized areas are prone to the accumulation of pollutants, but little is known about the historical baselines of such marine ecosystems. Here we study foraminiferal assemblages, geochemical proxies and sedimentological data from 1.6 m long sediment cores to uncover ∼ 500 years of anthropogenic pressure from mining, port and industrial activities in the Gulf of Trieste, Italy. From 1600 to 1900 AD, normalized element concentrations and foraminiferal assemblages point to negligible effects of agricultural activities. The only significant anthropogenic activity during this period was mercury mining in the hinterlands of the gulf, releasing high amounts of mercury into the bay and significantly exceeding the standards on the effects of trace elements on benthic organisms. Nonetheless, the fluctuations in the concentrations of mercury do not correlate with changes in the composition and diversity of foraminiferal assemblages due to its non-bioavailability. Intensified agricultural and maricultural activities in the first half of the 20th century caused slight nutrient enrichment and a minor increase in foraminiferal diversity. Intensified port and industrial activities in the second half of 20th century increased the normalized trace element concentrations and persistent organic pollutants (PAH, PCB) in the topmost part of the core. This increase caused only minor changes in the foraminiferal community because foraminifera in Panzano Bay have a long history of adaptation to elevated trace element concentrations. Our study underlines the importance of using an integrated, multidisciplinary approach in reconstructing the history of environmental and anthropogenic changes in marine systems. Given the prolonged human impacts in coastal areas like the Gulf of Trieste, such long-term baseline data are crucial for interpreting the present state of marine ecosystems.

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Brudner, Adam, Hehe Jiang, Xu Chu, and Ming Tang. "Crustal thickness of the Grenville orogen: A Mesoproterozoic Tibet?" Geology 50, no. 4 (December 16, 2021): 402–6. http://dx.doi.org/10.1130/g49591.1.

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Abstract The Grenville Province on the eastern margin of Laurentia is a remnant of a Mesoproterozoic orogenic plateau that comprised the core of the ancient supercontinent Rodinia. As a protracted Himalayan-style orogen, its orogenic history is vital to understanding Mesoproterozoic tectonics and paleoenvironmental evolution. In this study, we compared two geochemical proxies for crustal thickness: whole-rock [La/Yb]N ratios of intermediate-to-felsic rocks and europium anomalies (Eu/Eu*) in detrital zircons. We compiled whole-rock geochemical data from 124 plutons in the Laurentian Grenville Province and collected trace-element and geochronological data from detrital zircons from the Ottawa and St. Lawrence River (Canada) watersheds. Both proxies showed several episodes of crustal thickening and thinning during Grenvillian orogenesis. The thickest crust developed in the Ottawan phase (~60 km at ca. 1080 Ma and ca. 1045 Ma), when the collision culminated, but it was still up to 20 km thinner than modern Tibet. We speculate that a hot crust and several episodes of crustal thinning prevented the Grenville hinterland from forming a high Tibet-like plateau, possibly due to enhanced asthenosphere-lithosphere interactions in response to a warm mantle beneath a long-lived supercontinent, Nuna-Rodinia.

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Bordiga, Manuela, Claudia Lupi, Mario Zanoni, Stefania Bianco, Marina Cabrini, Giulia Fiorentino, Silvia Garagna, Maurizio Zuccotti, and Andrea Di Giulio. "A New Method to Speed Up Nannofossil Picking for Monospecific Geochemical Analyses." Journal of Marine Science and Engineering 10, no. 12 (November 29, 2022): 1829. http://dx.doi.org/10.3390/jmse10121829.

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Investigating the trace elements contained in the coccoliths, i.e., the carbonate exoskeleton, of unicellular marine phytoplankton called coccolithophores, is fundamental for calibrating environmental climate proxies, which are key tools for studying past and future climate changes. To date, lab-cultivated coccolithophores have been mainly used for measuring the elements retained within the coccoliths, whereas geochemical studies in fossil records have been limited by the difficulty in isolating monospecific samples from sediments containing highly diversified fossil assemblages. Since a comparison of the geochemical data collected from both fossil and living species is fundamental for calibrating the environmental proxies, an improvement of coccolith-picking methodology should be envisaged. Here, we present a significant advancement in the isolation of fossil species-specific coccolith achieved using a hydraulic micromanipulation system together with wet samples, never applied before on coccoliths. Our technique allows the picking of around 100 monospecific coccoliths per h, a number never achieved before with other isolation methodologies. This method opens up new possibilities in applying monospecific geochemical analyses to the fossil record not attainable before (e.g., the use of the mass spectrometer), leading to an increase in knowledge of environmental proxy calibration and coccolithophore element incorporation strategies.

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Kalliomäki, Henrik, Thomas Wagner, Tobias Fusswinkel, and Grigorios Sakellaris. "Major and trace element geochemistry of tourmalines from Archean orogenic gold deposits: Proxies for the origin of gold mineralizing fluids?" Ore Geology Reviews 91 (December 2017): 906–27. http://dx.doi.org/10.1016/j.oregeorev.2017.08.014.

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Kanouo, Nguo Sylvestre, Arnaud Patrice Kouske, Gabriel Ngueutchoua, Akella Satya Venkatesh, Prabodha Ranjan Sahoo, and Emmanuel Archelaus Afanga Basua. "Eoarchean to Neoproterozoic Detrital Zircons from the South of Meiganga Gold-Bearing Sediments (Adamawa, Cameroon): Their Closeness with Rocks of the Pan-African Cameroon Mobile Belt and Congo Craton." Minerals 11, no. 1 (January 15, 2021): 77. http://dx.doi.org/10.3390/min11010077.

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The core of detrital zircons from the southern Meiganga gold-bearing placers were analyzed by Laser Ablation Split Stream analytical techniques to determine their trace element abundances and U-Pb ages. The obtained data were used to characterize each grain, determine its formation condition, and try to trace the provenance. The Hf (5980 to 12,010 ppm), Y (27–1650 ppm), U (25–954 ppm), Th (8–674 ppm), Ti (2–256 ppm), Ta, Nb, and Sr (mainly <5 ppm), Th/U (0.06–2.35), Ti zircon temperature (617–1180 °C), ∑REE (total rare earth element) (98–1030 ppm), and Eu/Eu* (0.03 to <1.35) are predominant values for igneous crustal-derived zircons, with very few from mantle sources and of metamorphic origin. Crustal igneous zircons are mainly inherited grains crystallized in granitic magmas (with some charnockitic and tonalitic affinities) and a few from syenitic melts. Mantle zircons were crystallized in trace element depleted mantle source magmatic intrusion during crustal opening. Metamorphic zircons grown in sub-solidus solution in equilibrium with garnet “syn-metamorphic zircons” and in equilibrium with anatectic melts “anatectic zircons” during crustal tectono-metamorphic events. The U-Pb (3671 ± 23–612 ± 11 Ma) ages distinguish: Eoarchean to Neoproterozoic igneous zircons; Neoarchean to Mid Paleoproterozoic anatectic zircons; and Late Neoproterozoic syn-metamorphic grains. The Mesoarchean to Middle Paleoproterozoic igneous zircons are probably inherited from pyroxene-amphibole-bearing gneiss (TTGs composition) and amphibole-biotite gneiss, whose features are similar to those of the granites, granodiorites, TTG, and charnockites found in the Congo Craton, south Cameroon. The youngest igneous zircons could be grains eroded from Pan-African intrusion(s) found locally. Anatectic and syn-metamorphic zircons could have originated from amphibole-biotite gneiss underlying the zircon-gold bearing placers and from locally found migmatized rocks that are from the Cameroon mobile belt, which could be used as proxies for tracking gold.

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Pozo, Manuel, Francisco Ruiz, María Luz González-Regalado, María Isabel Carretero, Guadalupe Monge, Joaquín Rodríguez Vidal, Luis Miguel Cáceres, et al. "The Origin and Evolution of Late Holocene Tsunamiites in the Doñana National Park (SW Spain): Trace Elements as Geochemical Proxies." Minerals 10, no. 11 (October 26, 2020): 956. http://dx.doi.org/10.3390/min10110956.

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The elemental content—mainly trace elements—of samples from two boreholes (PLN, CM) with evidence of tsunamiites, located in the Doñana National Park (SW Spain), were studied. The geochemical variations of the REE, LILE, HFSE, and other elements (Al, Ti, S, Na, Br, Sc, Co, Cr) were interpreted according to the mineralogy present in the samples. The results obtained show the geochemical complexity of the estuarine paleoenvironments, in this case with the existence of three Holocene-age tsunamigenic deposits (around 4.25, 3.56 and 2.2–2 kyr BP). The statistical analysis of the samples’ geochemistry, by means of linear correlation and factor analysis, made it possible to differentiate two associations. The first is representative of an inherited mineralogy (REE-Y-Rb-Sr-Cs-Th-U-Hf-Al-Ti-Co-Cr-Sc); the second includes elements (Br-Na) linked to mineral formation under evaporite conditions (halite). The trace element geochemistry of sediments thus becomes an excellent tool to identify tsunamiites in the studied zone, especially those elements that are clear proxies for marine incursions (Na, Br, Sr) and high energy events (Hf, Ti). The parent area of the provenance of the materials is mainly of felsic composition.

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Georgiev, Svetoslav, Gatien L. F. Morin, Lora Bidzhova, and Nikola Botoucharov. "Depositional conditions for Lower–Middle Jurassic sedimentary rocks from Northern Bulgaria inferred from whole-rock elemental composition." Review of the Bulgarian Geological Society 83, no. 3 (December 2022): 81–84. http://dx.doi.org/10.52215/rev.bgs.2022.83.3.81.

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The Lower–Middle Jurassic sedimentary rocks from Northern Bulgaria represent important stratigraphic markers and a potential source for oil and gas accumulation. Here, we present preliminary major and trace element results for 22 sedimentary rock samples from the Bachiishte, Ozirovo, and Etropole Formations collected from the Balkanides and the Moesian Platform in Central-northern and Northwestern Bulgaria. The three studied formations have largely similar geochemical characteristics. The application of established geochemical proxies and comparison with recent and ancient sediments suggests that the samples were deposited in a shallow, high-energy environment with no water restriction. Eroding mafic to intermediate lithologies provided the sediment into the submerging Moesian Platform. Most redox-sensitive geochemical parameters suggest an overall oxygenated environment during sediment deposition, although specific samples show evidence for periodically dysoxic or anoxic water column conditions.

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Heidke, Inken, Denis Scholz, and Thorsten Hoffmann. "Lignin oxidation products as a potential proxy for vegetation and environmental changes in speleothems and cave drip water – a first record from the Herbstlabyrinth, central Germany." Climate of the Past 15, no. 3 (June 14, 2019): 1025–37. http://dx.doi.org/10.5194/cp-15-1025-2019.

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Abstract. Here, we present the first quantitative speleothem record of lignin oxidation products (LOPs), which has been determined in a Holocene stalagmite from the Herbstlabyrinth Cave in central Germany. In addition, we present LOP results from 16 months of drip water monitoring. Lignin is only produced by vascular plants and therefore has the potential to be an unambiguous vegetation proxy and to complement other vegetation and climate proxies in speleothems. We compare our results with stable isotope and trace element data from the same sample. In the stalagmite, LOP concentrations show a similar behavior to P, Ba and U concentrations, which have previously been interpreted as vegetation proxies. The LOP S∕V and C∕V ratios, which are usually used to differentiate between angiosperm and gymnosperm and woody and non-woody vegetation, show complex patterns suggesting additional influencing factors, such as transport and microbiological effects. The drip water from a fast drip site shows a seasonal pattern of LOPs with low LOP concentrations in winter and higher LOP concentrations in summer. These results indicate the potential of LOPs as a new proxy for vegetational and environmental changes in speleothems but also demonstrate the complexity and the current limitations of our understanding of the transport of lignin from the soil into the cave and the speleothems.

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Liang, Yijia, Yongjin Wang, Quan Wang, Jiangying Wu, Qingfeng Shao, Zhenqiu Zhang, Shaohua Yang, Xinggong Kong, and R. Lawrence Edwards. "East Asian summer monsoon climates and cave hydrological cycles over Dansgaard-Oeschger events 14 to 11 revealed by a new stalagmite record from Hulu Cave." Quaternary Research 92, no. 3 (August 5, 2019): 725–37. http://dx.doi.org/10.1017/qua.2019.39.

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AbstractA 230Th/U-dated stalagmite from Hulu Cave was analyzed for δ18O, δ13C, and trace elements. A ~10-yr-resolution δ18O record, spanning 51.7–42.6 ka, revealed Dansgaard-Oeschger (DO) events 14 to 11. A similar rapid transition and synchronous timing of the onset of DO 12 is evident between the Greenland and Hulu Cave records, which suggests a common forcing mechanism of DO cycles in the North Atlantic and monsoonal region of Asia. Centennial-scale monsoonal oscillations in the cave δ18O record are indicative of hydroclimatic instability during interstadials. After removing the signals of remote moisture sources, the proportion of moisture from nearby sources is found to be higher during stadials than during interstadials. To explain this, we propose that the movement of the westerly jet is an important control on the balance of nearby and distant moisture sources in East Asia. In addition, the records of δ13C and trace element ratios, which are proxies of local environmental changes, resemble the δ18O record on the scale of DO cycles, as well as on even shorter timescales. This suggests that hydrological processes and biological activity at the cave site respond sensitively to the monsoonal changes.

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Wu, Bin. "The Sedimentary Geochemical Characteristics and Geological Significance of the Wufeng-Longmaxi Formation Accumulation of Organic Matter Black Shale on the Southeastern Sichuan Basin, China." Geofluids 2022 (July 7, 2022): 1–22. http://dx.doi.org/10.1155/2022/1900158.

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At present, the understanding of the sedimentary paleoenvironment and organic matter enrichment law of black shale in the Wufeng-Longmaxi Formation is still insufficient. This time, we investigated the total organic carbon (TOC) content, X-ray diffraction mineralogical composition, and the major and trace element abundances of the newly recovered cores of three shale gas exploration wells in Changning, Qianjiang, and Xiushan areas which were, respectively, selected to discuss and compare the varying paleoenvironmental conditions and the factors that control organic matter accumulation, such as terrigenous input, redox conditions, primary productivity, and the degree of water retention in the basin. The results show that black siliceous shale lithofacies, gray-black shale lithofacies, gray-black silty shale lithofacies, gray argillaceous siltstone lithofacies, and gray shell marl lithofacies are mainly deposited in the Wufeng-Longmaxi Formation in the southeastern Sichuan Basin. Organic-rich black shale is mainly concentrated in the lower part of the Wufeng Formation and Longmaxi Formation. The continuous thickness of organic carbon content greater than 2% in the Changning area is 32 m, the continuous thickness in the Qianjiang area is 22 m, and the continuous thickness in the Xiushan area is 11 m. The hydrocarbon generation potential gradually weakens from west to east. The identification of the geochemical behavior characteristics of major and trace elements shows that enrichment of the organic matter black shale section in the Changning-Qianjiang-Xiushan areas is mainly formation in the anoxic-moderate water mass restriction environment with high primary productivity and less terrigenous detritus input under the low hydrodynamic conditions. However, the correlations of terrigenous detrital proxies Ti/Al, redox proxies V/Cr, Ni/Co, and paleoproductivity proxies Babio with the TOC contents show that the Changning area is a favorable area for the formation of organic-rich black shale and the Qianjiang area is affected by the Wuling underwater uplift; the thickness of the black shale deposits becomes thinner; the Xiushan area is adjacent to the Xuefeng uplift, and the deposition conditions of the accumulation of organic matter black shale deteriorate, which is unfavorable for shale gas exploration.

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DeGraaff Surpless, Kathleen, Diane Clemens-Knott, Andrew P. Barth, and Michelle Gevedon. "A survey of Sierra Nevada magmatism using Great Valley detrital zircon trace-element geochemistry: View from the forearc." Lithosphere 11, no. 5 (June 27, 2019): 603–19. http://dx.doi.org/10.1130/l1059.1.

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AbstractThe well-characterized Sierra Nevada magmatic arc offers an unparalleled opportunity to improve our understanding of continental arc magmatism, but present bedrock exposure provides an incomplete record that is dominated by Cretaceous plutons, making it challenging to decipher details of older magmatism and the dynamic interplay between plutonism and volcanism. Moreover, the forearc detrital record includes abundant zircon formed during apparent magmatic lulls, suggesting that understanding the long-term history of arc magmatism requires integrating plutonic, volcanic, and detrital records. We present trace-element geochemistry of detrital zircon grains from the Great Valley forearc basin to survey Sierra Nevadan arc magmatism through Mesozoic time. We analyzed 257 previously dated detrital zircon grains from seven sandstone samples of volcanogenic, arkosic, and mixed compositions deposited ca. 145–80 Ma along the length of the forearc basin. Detrital zircon trace-element geochemistry is largely consistent with continental arc derivation and shows similar geochemical ranges between samples, regardless of location along strike of the forearc basin, depositional age, or sandstone composition. Comparison of zircon trace-element data from the forearc, arc, and retroarc regions revealed geochemical asymmetry across the arc that was persistent through time and demonstrated that forearc and retroarc basins sampled different parts of the arc and therefore recorded different magmatic histories. In addition, we identified a minor group of Jurassic detrital zircon grains with oceanic geochemical signatures that may have provenance in the Coast Range ophiolite. Taken together, these results suggest that the forearc detrital zircon data set reveals information different from that gleaned from the arc itself and that zircon compositions can help to identify and differentiate geochemically distinct parts of continental arc systems. Our results highlight the importance of integrating multiple proxies to fully document arc magmatism, demonstrating that detrital zircon geochemical data can enhance understanding of a well-characterized arc, and these data may prove an effective means by which to survey an arc that is inaccessible and therefore poorly characterized.

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Thresher, Ronald E., Stewart J. Fallon, and Ashley T. Townsend. "A “core-top” screen for trace element proxies of environmental conditions and growth rates in the calcite skeletons of bamboo corals (Isididae)." Geochimica et Cosmochimica Acta 193 (November 2016): 75–99. http://dx.doi.org/10.1016/j.gca.2016.07.033.

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Bauwens, M., H. Ohlsson, K. Barbé, V. Beelaerts, F. Dehairs, and J. Schoukens. "A nonlinear multi-proxy model based on manifold learning to reconstruct water temperature from high resolution trace element profiles in biogenic carbonates." Geoscientific Model Development Discussions 3, no. 3 (July 22, 2010): 1105–38. http://dx.doi.org/10.5194/gmdd-3-1105-2010.

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Abstract. A long standing problem in paleoceanography concerns the reconstruction of water temperature from δ18O carbonate, which for freshwater influenced environments is hindered because the isotopic composition of the ambient water (related to salinity) affects the reconstructed temperature. In this paper we argue for the use of a nonlinear multi-proxy method called Weight Determination by Manifold Regularization to develop a temperature reconstruction model that is less sensitive to salinity variations. The motivation for using this type of model is twofold: Firstly, observed nonlinear relations between specific proxies and water temperature motivate the use of nonlinear models. Secondly, the use of multi-proxy models enables salinity related variations of a given temperature proxy to be explained by salinity-related information carried by a separate proxy. Our findings confirm that Mg/Ca is a powerful paleothermometer and highlight that reconstruction performance based on this proxy is improved significantly by combining its information with the information of other trace elements in multi-proxy models. Using Mg/Ca, Sr/Ca, Ba/Ca and Pb/Ca the WDMR model enabled a temperature reconstruction with a root mean squared error of ±2.19 °C for a salinity range between 15 and 32.

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Sinisi, Rosa. "Mineralogical and Geochemical Features of Cretaceous Bauxite from San Giovanni Rotondo (Apulia, Southern Italy): A Provenance Tool." Minerals 8, no. 12 (December 4, 2018): 567. http://dx.doi.org/10.3390/min8120567.

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In this study, the mineralogical and chemical compositions of bauxite from San Giovanni Rotondo (SGR) on the Gargano Promontory (northern Apulia, Italy) are presented and discussed with the aim of assessing the nature of its source material. Bauxite from the SGR, which is known as the “Montecatini mine”, was exploited intensively until the 1970s to recover alumina. As with most of the autochthonous peri-Mediterranean bauxites, the studied deposit is a karst bauxite with a massive, matrix-supported texture and an oolitic structure. Boehmite and hematite are the main mineral phases, and anatase, rutile, and kaolinite are present in lesser amounts along with detrital zircons and monazite grains. Calcite is abundant only in the deposit’s lower portion, triggering a significant dilution effect on trace element concentrations. However, with respect to the average crust and chondrite compositions, strong enrichments of trace metals (up to 10X Upper Continental Crust’s (UCC)) and rare earth elements (REEs, up to 800X chondrite) exist throughout the studied deposit. The distribution of REEs, the (La/Yb)N and Eu/Eu* ratios, and an Eu/Eu* versus Sm/Nd diagram have been used for determining the bauxite’s provenance. These geochemical proxies point to a parental material consisting of a mixture of distant magmatic and siliciclastic components.

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48

Geerken, Esmee, Lennart Jan de Nooijer, Inge van Dijk, and Gert-Jan Reichart. "Impact of salinity on element incorporation in two benthic foraminiferal species with contrasting magnesium contents." Biogeosciences 15, no. 7 (April 16, 2018): 2205–18. http://dx.doi.org/10.5194/bg-15-2205-2018.

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Abstract. Accurate reconstructions of seawater salinity could provide valuable constraints for studying past ocean circulation, the hydrological cycle and sea level change. Controlled growth experiments and field studies have shown the potential of foraminiferal Na ∕ Ca as a direct salinity proxy. Incorporation of minor and trace elements in foraminiferal shell carbonate varies, however, greatly between species and hence extrapolating calibrations to other species needs validation by additional (culturing) studies. Salinity is also known to impact other foraminiferal carbonate-based proxies, such as Mg ∕ Ca for temperature and Sr ∕ Ca for sea water carbonate chemistry. Better constraints on the role of salinity on these proxies will therefore improve their reliability. Using a controlled growth experiment spanning a salinity range of 20 units and analysis of element composition on single chambers using laser ablation-Q-ICP-MS, we show here that Na ∕ Ca correlates positively with salinity in two benthic foraminiferal species (Ammonia tepida and Amphistegina lessonii). The Na ∕ Ca values differ between the two species, with an approximately 2-fold higher Na ∕ Ca in A. lessonii than in A. tepida, coinciding with an offset in their Mg content (∼ 35 mmol mol−2 versus ∼ 2.5 mmol mol−1 for A. lessonii and A. tepida, respectively). Despite the offset in average Na ∕ Ca values, the slopes of the Na ∕ Ca–salinity regressions are similar between these two species (0.077 versus 0.064 mmol mol−1 change per salinity unit). In addition, Mg ∕ Ca and Sr ∕ Ca are positively correlated with salinity in cultured A. tepida but show no correlation with salinity for A. lessonii. Electron microprobe mapping of incorporated Na and Mg of the cultured specimens shows that within chamber walls of A. lessonii, Na ∕ Ca and Mg ∕ Ca occur in elevated bands in close proximity to the primary organic lining. Between species, Mg banding is relatively similar, even though Mg content is 10 times lower and that variation within the chamber wall is much less pronounced in A. tepida. In addition, Na banding is much less prominent in this species than it is in A. lessonii. Inter-species differences in element banding reported here are hypothesized to be caused by differences in biomineralization controls responsible for element uptake.

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Carlson, Peter E., Nathaniel R. Miller, Jay L. Banner, Daniel O. Breecker, and Richard C. Casteel. "The potential of near-entrance stalagmites as high-resolution terrestrial paleoclimate proxies: Application of isotope and trace-element geochemistry to seasonally-resolved chronology." Geochimica et Cosmochimica Acta 235 (August 2018): 55–75. http://dx.doi.org/10.1016/j.gca.2018.04.036.

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Yelwa, Nura Abdulmumini, Khairul Azlan Mustapha, Mimonitu Opuwari, and Azharuddin Abd Aziz. "Biomarkers, stable carbon isotope, and trace element distribution of source rocks in the Orange Basin, South Africa: implications for paleoenvironmental reconstruction, provenance, and tectonic setting." Journal of Petroleum Exploration and Production Technology 12, no. 2 (November 27, 2021): 307–39. http://dx.doi.org/10.1007/s13202-021-01317-9.

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AbstractAptian to Campanian sediments from the Western offshore to Central Orange Basin were studied by integrating molecular geochemistry, inorganic and isotopic studies to recognize their geochemical characteristics via the reconstruction of the Orange basin’s paleoweathering, paleosalinity, paleovegetation, paleoclimate, and tectonic records. Molecular analyses of both aliphatic and aromatic compounds reveal an input dominantly from a marine source. The source rocks accumulated in a reduced, anoxic, saline water column. Based on various biomarker proxies and vitrinite reflectance data, some samples are thermally mature to produce petroleum, while others are not. According to the V/Ni ratio, samples from the Orange Basin in South Africa are mainly anoxic, with only a few samples ranging from suboxic to anoxic. This is congruent with biomarker and isotope analyses that further indicate the presence of marine-derived source rocks with some terrestrial remains generating hydrocarbons. The investigated sediments are made up of intermediate igneous rocks that have undergone moderate chemical weathering. Geochemical figures on tectonic setting discriminant function diagrams revealed a continental rift of passive margin settings. As a result, the extrapolated crustal processes are directly analogous to the genesis and evolution of the Orange Basin, demonstrating Gondwana’s breaking up and the opening of the Atlantic Ocean Margin.

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Journal articles on the topic 'Trace element palaeoredox proxies'

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