Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"High temporal resolution paleoclimate reconstruction by the analysis of growth patterns and stable isotopes of fossil shells of the long-lived bivalve Mercenaria stimpsoni from MIS 5e, 7 and 9","authors":"Shiono Miki ,&nbsp;Kaoru Kubota ,&nbsp;Rei Nakashima ,&nbsp;Kazushige Tanabe ,&nbsp;Cornélia Brosset ,&nbsp;Bernd R. Schöne ,&nbsp;Asuka Yamaguchi ,&nbsp;Kotaro Shirai","doi":"10.1016/j.palaeo.2024.112537","DOIUrl":"10.1016/j.palaeo.2024.112537","url":null,"abstract":"<div><div>Paleoenvironments during past interglacial periods such as Marine Isotope Stages (MISs) 5e, 7 and 9 have been studied as possible analogues for current global warming. In central Japan, interglacial oceanic sediments of the Shimosa Group were deposited in the Paleo-Tokyo Bay between MIS 11 and MIS 5 when sea level was high. However, due to the scarcity of biogenic archives that recorded paleoenvironments over long intervals of time with high temporal resolution, seasonal variation of past seawater temperature in the bay during the Pleistocene warm periods remains unclear. Shells of the long-lived bivalve, <em>Mercenaria stimpsoni</em> (Stimpson's hard clam) can potentially provide such data from mid- to high-latitude northwestern Pacific coastal regions. Here we used growth patterns and oxygen isotope values of fossil shells of <em>M. stimpsoni</em> from the Shimosa Group to reconstruct the seasonal variation in seawater temperature of Paleo-Tokyo Bay during MIS 5e, 7, and 9 based on sclerochronological analysis.</div><div>Our study demonstrates that fossil shells of this species lived over 100 years and grew most rapidly during the first ten years of life. During each studied interglacial, the highest seawater temperatures equaled approx. 20 °C, <em>i.e.</em>, much lower than today in coastal regions of Chiba Prefecture (approx. 27 °C). Our results suggest that during interglacial periods when the sea level was high, cold-water masses of the Oyashio Current reached the Paleo-Tokyo Bay. The habitat of cold-water species including <em>M. stimpsoni</em> thus expanded southward following the distribution of this cold-water mass. Such climatic conditions likely lasted at least for 100 years, <em>i.e.</em>, during the lifespan of this species.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112537"},"PeriodicalIF":2.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142702533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large and rapid salinity fluctuations affected the eastern Mediterranean at the Tortonian–Messinian transition","authors":"Evangelia Besiou ,&nbsp;Iuliana Vasiliev ,&nbsp;George Kontakiotis ,&nbsp;Konstantina Agiadi ,&nbsp;Katharina Methner ,&nbsp;Andreas Mulch ,&nbsp;Wout Krijgsman ,&nbsp;Assimina Antonarakou","doi":"10.1016/j.palaeo.2024.112568","DOIUrl":"10.1016/j.palaeo.2024.112568","url":null,"abstract":"<div><div>Restricted marine basins are highly sensitive to climatic fluctuations, yet, paleoenvironmental responses to gateway restriction frequently remain unclear. Here, we investigate the Mediterranean Sea that experienced gradually restricted conditions starting during the late Tortonian and culminating with complete isolation from the Atlantic during the peak of the Messinian Salinity Crisis. We established sea surface temperature and salinity records during the Tortonian to Messinian transition (7.52–7.20 Ma) through coupled analysis of organic biomarkers and oxygen and carbon isotope ratios of planktonic foraminifera from the eastern Mediterranean basin (Potamida section, Crete Island, Greece). We further contrast these sea surface data with stable isotope records of benthonic foraminifera to identify periods of increased density-driven deterioration of bottom water ventilation in the basin. The combined results show that normal marine conditions, expressed by relatively warm (27.5 °C) Tortonian surface waters with normal salinity (38) prevailed until 7.36 Ma. The 7.36–7.32 Ma interval is characterized by pulses of increased bottom water salinity, that contrast the lasting normal salinity (39) at the sea surface, indicating strengthened water column stratification provoked by sluggish water circulation already prior to the Tortonian–Messinian boundary. A brief return to marine conditions, similar to the time prior to 7.36 Ma, re-appeared between 7.32 and 7.31 Ma. Between 7.31 and 7.28 Ma, a rebound to enhanced stratification took place accompanied by a high-amplitude, stepwise decrease in both sea surface temperature and sea surface salinity. Ultimately, the Tortonian–Messinian boundary was characterized by lower sea surface temperature and salinity accompanied by increased salinity and/or colder bottom waters. A ∼ 10 °C cooling episode (at 7.212 Ma) highlights the regional importance of the global Late Miocene cooling event.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112568"},"PeriodicalIF":2.6,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593079","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment source-to-sink patterns along the southeast China coast during the late Quaternary: New insights from sediment geochemistry and OSL ages in Ningde Bay","authors":"Ping Liu ,&nbsp;Jie Zhang ,&nbsp;Yan Liu ,&nbsp;Qianli Sun ,&nbsp;Dan Zhang ,&nbsp;Yue Li ,&nbsp;Taoyuan Wei ,&nbsp;Junjie Yu ,&nbsp;Jilong Wang ,&nbsp;Jing Chen","doi":"10.1016/j.palaeo.2024.112577","DOIUrl":"10.1016/j.palaeo.2024.112577","url":null,"abstract":"<div><div>The geomorphology and environmental conditions of the southeast China coast are significantly influenced by sediment discharge from the Yangtze River, a major river located to the north. Nonetheless, the extent to which the Yangtze River affects sediment transport processes from source to sink along the southeast coast remains unclear. Our recent findings in coastal/marine deposits from the late Quaternary period (MIS5e, MIS3, and MIS1) in Ningde Bay offer new perspectives on this issue. Provenance discrimination of the late Quaternary boreholes was carried out using sediment geochemical analysis and OSL dating of fine- and medium-grained quartz. The results indicate varying provenances during sea-level fluctuation, with distal Yangtze River origins during MIS5e, MIS3, and MIS1, and a local source during MIS4. The findings also suggest that the southward transport of Yangtze sediments along the southeast China coast has occurred since MIS5e. However, OSL ages of the fine-grained quartz in the MIS3 deposit range from approximately 90 to 140 kyr, notably older than those of medium-grained quartz (40–80 kyr). This remarkable age discrepancy indicates that Yangtze-derived sediments previously deposited on the shelf of the East China Sea during MIS5 were reworked and transported southward in MIS3. This phenomenon can be elucidated by the insufficient supply of Yangtze sediments during MIS3, which could be linked to the weakened East Asian monsoon. This new source-to-sink pattern for the southeast China coast is characterized by a compensating mechanism of inner shelf old sediment in response to the inadequate supply of Yangtze sediments. This study contributes to a better understanding of the significant impacts of reduced Yangtze sediment input on its distal sedimentary systems over time.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112577"},"PeriodicalIF":2.6,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Using detrital zircon UPb geochronology to track the provenance of Miocene sediments in the northern Pearl River Mouth Basin, South China Sea","authors":"Chang Zhong ,&nbsp;Xiaoyin Tang ,&nbsp;Xinyan Zhao ,&nbsp;Shengbiao Hu","doi":"10.1016/j.palaeo.2024.112567","DOIUrl":"10.1016/j.palaeo.2024.112567","url":null,"abstract":"<div><div>The Late Cenozoic provenance study of the Pearl River Mouth Basin (PRMB) holds significant implications for understanding the tectonic-climatic interactions, drainage evolution, and oceanic circulation in the northern South China Sea. However, the Miocene sediment routing system remains poorly understood due to the paucity of zircon geochronological data and the effects of sediment mixing and homogenization. This study reconstructs the ancient source-to-sink system by means of detrital zircon analyses from the northern PRMB and zircon age-based mixture modeling of well-defined provenance end-members. The results disclose varied and complex source-to-sink scenarios since the Early Miocene, involving three primary contributors: the Pearl River drainage system, coastal SE China, and Taiwan Island. In combination with seismic facies and climatic proxies, the intensive addition of Precambrian zircons suggests that, during the Middle and Late Miocene, progressive drainage expansion within the Yangtze Block likely contributed to the increasing sediment supply from the western Pearl River drainage system. Furthermore, the provenance shift in the northern PRMB, as indicated by the Mesozoic ages, may reflect a response to the activation of oceanic circulation and intensification of the East Asian monsoon. Additionally, though less significant, contributions from the Hainan and Luzon Island are also observed, indicating the input of the branch of the Kuroshio Current during the Late Miocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112567"},"PeriodicalIF":2.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Timing and origin of the Lomagundi-Jatuli Event: Insights from UPb geochronology, C-O-Fe isotopes and REE compositions from the Jingshan Group, North China Craton","authors":"Yuanlin Chen ,&nbsp;Huan Li ,&nbsp;Shangyi Gu ,&nbsp;Gary G. Lash ,&nbsp;Dadou Li ,&nbsp;Chaoyang Zheng ,&nbsp;Ligong Wang ,&nbsp;Liu'an Duan","doi":"10.1016/j.palaeo.2024.112574","DOIUrl":"10.1016/j.palaeo.2024.112574","url":null,"abstract":"<div><div>The Lomagundi-Jatuli Event (LJE) represents perhaps the largest and longest positive carbon isotope excursion of Earth history. However, the synchroneity, scale, and linkage of the LJE to Earth's early history of atmospheric oxygenation remain controversial. Strata of the Paleoproterozoic Jingshan Group of the North China Craton that preserve the isotopic record of the LJE excursion in marble layers and abundant graphite deposits provide an opportunity to elucidate the significance of the LJE. Carbon isotopic values (δ¹³C_V-PDB) of the LJE based on analysis of 20 samples of the Lugezhuang Formation, lower Jingshan Group, range from −0.8 to +9.6 ‰ and display positive co-variance with stable oxygen isotope values (δ¹⁸O_V-PDB). The positive carbon isotope excursion is constrained to 2140.6 ± 8.5 Ma (MSWD = 0.82, <em>n</em> = 25) based on magmatic zircon U<img>Pb geochronology of biotite granulite. Variation of facies-dependent carbon isotope values, the presence of graphite deposits of the Douya Formation, upper Jingshan Group, and the absence of a Ce anomaly in PAAS normalized REE patterns of marble samples suggest that the positive carbon isotope excursion is not linked to a marked increase of organic carbon burial and associated significant atmosphere oxygenation. Elevated concentrations of iron and PAAS-normalized middle REE enrichment of analyzed Jingshan Group marble samples point to anoxic and ferruginous oceanic conditions during accumulation of Jingshan Group carbonate. A positive Eu anomaly (average = 1.58), low La (average = 0.23), (Nd/Yb)_N (average = 1.27), and Y/Ho (average = 36.6) anomalies, and negative iron isotope values (average δ⁵⁶Fe = −0.12 ‰) are consistent with accumulation of Paleoproterozoic Jingshan Group carbonate in a restricted marine setting that was affected by high temperature hydrothermal fluids. Enrichment of the studied samples in heavy carbon isotope suggests elevated bio-productivity in the restricted, redox stratified marine setting in which Jingshan Group carbonate accumulated. Thus, it is likely that the positive stable carbon isotope excursion associated with Jingshan Group strata as well as other contemporaneous isotope excursions are local signals that are linked to a global perturbation of the carbon cycle.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112574"},"PeriodicalIF":2.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking the PETM and North Atlantic volcanism using tellurium in sediments","authors":"N.B. Baumann ,&nbsp;M. Regelous ,&nbsp;T. Adatte ,&nbsp;N.R. Thibault ,&nbsp;A. Regelous ,&nbsp;B.P. Schultz ,&nbsp;A. Fantasia ,&nbsp;H. Madsen ,&nbsp;K.M. Haase","doi":"10.1016/j.palaeo.2024.112575","DOIUrl":"10.1016/j.palaeo.2024.112575","url":null,"abstract":"<div><div>The Paleocene – Eocene Thermal Maximum (PETM) was a short period (∼170 kyr) of global temperature rise starting at 55.93 Ma, which occurred during the breakup of the North Atlantic and the emplacement of the North Atlantic Igneous Province (NAIP). Recently, mercury (Hg) concentrations in sediments have been used in an attempt to connect the eruptive history of the NAIP with environmental change during this period, at a higher resolution than possible using geochronology. Here we present sedimentary tellurium (Te) as a novel proxy to further reconstruct NAIP volcanism at high resolution. We measured 45 trace elements in 401 sediment samples from 3 sections across the PETM in the northern hemisphere. All study sites exhibit an increase in Te concentrations and Te/Th ratios close to the onset of the PETM and remain high until the end of the main North Atlantic ash phase about 1 Myr later. The trace element data indicate that changes in sediment lithology or in environmental conditions do not influence sedimentary Te concentrations suggesting a volcanic source instead. We used existing age models to remove the effect of changes in sedimentation rate and calculated volcanic Te fluxes. Our Te data suggest increased volcanism in the latest Paleocene and early Eocene. This fits existing radiometric ages of the NAIP, which demonstrate that a more than 5 km thickness of lava in eastern Greenland and the Faroes was erupted within about 1 Myr between ∼56 to ∼55 Ma. All our study sites show similar Te flux variations across the PETM. In contrast, sedimentary mercury (Hg) profiles from these and other sites are less consistent. Tellurium in sediments may represent a useful proxy to reconstruct NAIP volcanism.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112575"},"PeriodicalIF":2.6,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Widespread coastal upwelling along the marginal Yangtze Platform (South China) during the early Cambrian: Implications for hyper-enrichment of organic matter","authors":"Jinku Li ,&nbsp;Ping Gao ,&nbsp;Xianming Xiao ,&nbsp;Gary G. Lash ,&nbsp;Shuangjian Li ,&nbsp;Wei Liu","doi":"10.1016/j.palaeo.2024.112569","DOIUrl":"10.1016/j.palaeo.2024.112569","url":null,"abstract":"<div><div>Early Cambrian Earth history witnessed significant changes in marine environments and biological evolution contemporaneous with extensive accumulation of organic-rich shale. However, major factors controlling hyper-enrichment of organic matter (OM) of lower Cambrian shale deposits remain controversial. Black shale of the lower Cambrian Niutitang Formation (NTT) of the marginal Yangtze Platform (South China) deposited during the Cambrian middle Age 2 are especially organic-rich, with total organic carbon (TOC) concentrations of as much as 13.0 wt%. Geochemical evidence suggests that cool, dry paleo-climatic conditions that prevailed on the Yangtze Platform during the Cambrian Fortunian-late Age 2, induced vigorous coastal upwelling. Paleo-productivity level assessments indicate that the magnitude of primary productivity contemporaneous with deposition of the NTT shale deposits exceeded that of modern upwelling systems (e.g., Peruvian Margin). The widespread occurrence of phosphate nodules within these deposits and decreased Co-EF × Mn-EF values of associated lower Cambrian black shale successions deposited along the margin of the Yangtze carbonate platform suggest extensive coastal upwelling. Widespread and strong coastal upwelling in tandem with elevated surface water primary productivity and anoxic (even euxinic) bottom water conditions are manifested by deposition of OM hyper-enriched black shale during Cambrian Fortunian to middle Age 2 time. However, weakened seasonal upwelling that appears to have prevailed during the late Cambrian Age 2 was accompanied by accumulation of NTT shale deposits of diminished TOC content. In summary, this study provides robust evidence of extensive coastal upwelling along the marginal Yangtze Platform during early Cambrian time that favored accumulation of OM hyper-enriched shale. These results help to elucidate the distribution of high-quality lower Cambrian natural gas source rocks in South China.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112569"},"PeriodicalIF":2.6,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142552558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Terrestrial response to the Early Cretaceous Weissert Event: Insights from carbon isotope records of organic matter and leaf wax n-alkanes in an inland East Asian lake","authors":"Xiaoning Tong ,&nbsp;Jianfang Hu ,&nbsp;Yanhong Pan ,&nbsp;Zuohuan Qin ,&nbsp;Dangpeng Xi ,&nbsp;Ping’an Peng ,&nbsp;Thomas J. Algeo","doi":"10.1016/j.palaeo.2024.112570","DOIUrl":"10.1016/j.palaeo.2024.112570","url":null,"abstract":"<div><div>The Weissert Event (WE), a significant Early Cretaceous environmental disruption, is recognized globally in marine carbonate records for its positive carbon isotope excursion (CIE), organic matter (OM) enrichment, and widespread anoxia. However, records of its terrestrial impact are sparse. This study examines carbon isotope compositions (δ¹³C) from the lacustrine facies of North China's Dabeigou Formation (Yushuxia section, Luanping Basin). The synchronous positive CIEs of total organic carbon (TOC) and C₂₇–C₃₁ <em>n</em>-alkanes within Members 2 to 3 of the Dabeigou Formation corroborate the Weissert Event, marking its first terrestrial observation in North China. Ratios of the isoprenoids pristane and phytane (Pr/Ph), C_org/P ratios and enrichment factors (EFs) of redox-sensitive trace metals (Mo and U) indicate transient anoxic conditions within a mainly oxic-suboxic setting from the late Valanginian to early Hauterivian, which were unfavorable for OM preservation. This highlights that although a global positive CIE occurred during the Weissert Event, anoxia and/or high TOC deposition in inland lakes were not inherent features.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112570"},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Salinity impacts on n-alkanes in lake sediments of the Badain Jaran Desert, Northwestern China: Implications for paleoclimate reconstruction","authors":"Meng Li ,&nbsp;Zhuolun Li ,&nbsp;Shipei Dong ,&nbsp;Lin Chen ,&nbsp;Xianbao Su ,&nbsp;Chen'ao Lu ,&nbsp;Aifeng Zhou ,&nbsp;Nai'ang Wang","doi":"10.1016/j.palaeo.2024.112571","DOIUrl":"10.1016/j.palaeo.2024.112571","url":null,"abstract":"<div><div><em>n-</em>Alkanes in lake sediments are essential biomarkers for paleoclimate research, yet the influence of lake salinity on their distribution remains unclear. This study investigates this relationship by analyzing sediments from eight lakes in the Badain Jaran Desert, all subject to similar climatic conditions but varying in salinity. Soil samples from the shoreline vegetation belt and suspended particle matter (SPM) were collected to identify the origin of plant input in the lake sediments. Additionally, sediment samples from the littoral zone to the lake center were all gathered to evaluate the salinity effects at different water depths. Key indexes such as content, the proportion of aquatic macrophyte (<em>P</em>_aq), average chain length (ACL), and carbon preference index (CPI) of <em>n-</em>alkanes were examined to elucidate salinity effects. The result showed that the surrounding vegetation belt is the primary source of <em>n-</em>alkanes in lake sediments, with minimal contributions from SPM. Increased salinity was found to decrease CPI in the littoral zone, while also reducing <em>P</em>_aq and increasing ACL in the lake bottom sediments. Changes of <em>P</em>_aq, ACL and CPI in sediments are not attribute to variations in vegetation belt input but rather suggest that high salinity enhances <em>n-</em>alkane degradation, particularly favoring the degradation of mid-chain compounds in lake bottom sediments. Consequently, the reliability of <em>n-</em>alkane indexes as indicators of aquatic macrophyte in deep lake cores may be compromised by salinity. This study underscores the importance of accounting for salinity effects when using <em>n-</em>alkanes in reconstructing paleoclimate and suggests that their potential as indicators of lake salinization merits further attention.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112571"},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142529053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reliability of the Strontium Isotope Stratigraphy approach in marginal seas: Insights from the Miocene Paratethys","authors":"Katarína Holcová ,&nbsp;Filip Scheiner ,&nbsp;Lukáš Ackerman ,&nbsp;Rastislav Milovský ,&nbsp;Natália Hudáčková ,&nbsp;Šárka Hladilová ,&nbsp;Slavomír Nehyba ,&nbsp;Danuta Peryt","doi":"10.1016/j.palaeo.2024.112566","DOIUrl":"10.1016/j.palaeo.2024.112566","url":null,"abstract":"<div><div>The robustness of the Strontium Isotope Stratigraphy (SIS) as a chemostratigraphic tool was tested in the Miocene epicontinental Central Paratethys using new ⁸⁷Sr/⁸⁶Sr results obtained for 129 foraminiferal tests and various marine invertebrate shells that were converted to numerical ages using the global ⁸⁷Sr/⁸⁶Sr curve for the Phanerozoic open oceans. These ages were compared with those expected from either magnetostratigraphic, radiometric or biostratigraphic studies applied to selected sections from different Central Paratethys basins. The results from different basins showed variations in ⁸⁷Sr/⁸⁶Sr values for specific time intervals; therefore, it is not possible to construct a unique ⁸⁷Sr/⁸⁶Sr curve for the Central Paratethys region that can be used for chemostratigraphic purposes. The ⁸⁷Sr/⁸⁶Sr signal in semi-enclosed basins tends to reflect the lithology of the source areas. For example, marine basins surrounded by areas of Mesozoic carbonate rock cover are associated with a reduced ⁸⁷Sr/⁸⁶Sr signal compared to the global ⁸⁷Sr/⁸⁶Sr signal primarily due to the drainage of these Mesozoic carbonate rocks and transfer of their specific Sr signal. By contrast, areas affected by continental runoff from crystalline terrains in combination with limited connection to surrounding marine domains were found to show an elevated ⁸⁷Sr/⁸⁶Sr signal compared to the global one. Additionally, it was demonstrated that infaunal, eutrophic and hypoxic species (foraminiferal genus <em>Uvigerina</em> and molluscs) show a shift towards a relatively higher ⁸⁷Sr/⁸⁶Sr signal. Therefore, our data show that variable ⁸⁷Sr/⁸⁶Sr patterns occur in semi-enclosed domains, primarily reflecting local settings and thus hampering reliable SIS ages. In particular, the best SIS results in the studied Paratethys area occur during periods of maximum marine connectivity, when other (biostratigraphic) methods can be applied, and then become unreliable as connectivity diminishes.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"656 ","pages":"Article 112566"},"PeriodicalIF":2.6,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142561073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}