Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"A new regime of herbivory from diverse plant–arthropod interactions from the Middle Jurassic of northeastern China","authors":"Lifang Xiao ,&nbsp;Yuekun Wu ,&nbsp;Liang Chen ,&nbsp;Conrad C. Labandeira ,&nbsp;Chungkun Shih ,&nbsp;Qiaoling Ding ,&nbsp;Dong Ren ,&nbsp;Yongjie Wang","doi":"10.1016/j.palaeo.2024.112511","DOIUrl":"10.1016/j.palaeo.2024.112511","url":null,"abstract":"<div><div>Qualitative and quantitative evaluation of insect herbivory is important for understanding the complex and diverse plant–insect associations in terrestrial ecosystems during the mid Mesozoic. We examined 2503 plant specimens from the Mid-Jurassic (Callovian, 165 Ma) Jiulongshan Formation, a gymnosperm-dominant, fern subdominant plant assemblage at Daohugou, northeastern China, where 149 species/morphotypes from 11 plant groups were identified. Based on the functional feeding group–damage type (FFG-DT) system, we detected a richness of 11 FFGs and 78 DTs, frequency of 2329 DTs, 8045 feeding event occurrences, and herbivory index of 3.27 %. Major consumption occurred on broad-leaved of bennettitaleans, accounting for half of all herbivory indicated by multiple indices, and ginkgoaleans, less so for narrow-leaved of conifers. The top-four feeding groups were margin feeding, piercing and sucking, oviposition, and galling; all groups displayed a pattern of narrow DT functional-breadth (22.22 %) and twofold increase of broad DT functional-breadth (48.15 %). Physical plant defenses were found on the most herbivorized plant host implying trade-offs between host physiology and insect herbivory. Compared with other gymnosperm-dominated assemblages, the elevated richness and intensity of Daohugou herbivory indicates a new regime of resource consumption that occurred by late Middle Jurassic time associated with predator and especially parasitoid diversification.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112511"},"PeriodicalIF":2.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142416849","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":"Synchrotron-based P K-edge XANES spectroscopy reveals the transition of phosphorus cycling in the early Cambrian ocean","authors":"Pengcheng Ju ,&nbsp;Zhenfei Wang ,&nbsp;Chao Chang ,&nbsp;Zhangqin Zheng ,&nbsp;Run Li ,&nbsp;Wenpeng Xia ,&nbsp;Xuyang Cao ,&nbsp;Yigui Han ,&nbsp;Mingyu Zhao ,&nbsp;Chao Li ,&nbsp;Xingliang Zhang ,&nbsp;Kang-Jun Huang","doi":"10.1016/j.palaeo.2024.112506","DOIUrl":"10.1016/j.palaeo.2024.112506","url":null,"abstract":"<div><div>Phosphorus, as a long-term limiting nutrient, is essential for the rapid animal diversification in the early Cambrian ocean. However, the widespread occurrence of phosphorites during this period indicates anomalous phosphorus cycling mechanisms that remain inadequately explored. To investigate the interplay between marine redox conditions and phosphorus cycling, we used geochemical proxies and synchrotron-based P <em>K</em>-edge X-ray Absorption Near Edge Structure (XANES) spectroscopy to analyze the Cambrian Terreneuvian Yurtus Formation (Fortunian to Stage 2) from the Tarim Block. Redox-sensitive elements, iron speciation and nitrogen isotopes reveal an expansion of the surface oxygenated waters, despite persistent ferruginous bottom waters. Moreover, a shift of phosphorus speciation was observed in bedded cherts via P <em>K</em>-edge XANES, suggesting a transition of phosphorus cycling. Specifically, the samples exhibit low total phosphorus contents with a high rate of carbonate-fluorapatite authigenesis in the lower Yurtus Formation. This is followed by an increase in the proportion of terrestrial-derived fluorapatite and iron-bound phosphorus, corresponding to the expansion of surface oxygenated waters. Our findings reveal a significant shift in dominant phosphorus speciation in the early Cambrian marine sediments, which is intricately linked to the coupled phosphorus‑iron‑carbon‑oxygen cycles in the Cambrian ocean.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112506"},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142359698","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":"Sensitive response of erosion and weathering to the Indian Summer Monsoon changes in South Asia during Dansgaard-Oeschger oscillations","authors":"Jingrui Li ,&nbsp;Xuefa Shi ,&nbsp;Shengfa Liu ,&nbsp;Fangliang Li ,&nbsp;Xiaoming Miao ,&nbsp;Rui Jiang ,&nbsp;Somkiat Khokiattiwong ,&nbsp;Narumol Kornkanitnan","doi":"10.1016/j.palaeo.2024.112516","DOIUrl":"10.1016/j.palaeo.2024.112516","url":null,"abstract":"<div><div>Continental weathering plays a key role in regulating the long-term climate stability via negative feedback. However, whether and how erosion and weathering respond to rapid climate change (e.g millennial scale) in large river basins remains unclear, partly due to the lack of archives with robust age models and high sampling resolution. As one of the largest sediment source-to-sink systems, the Himalaya-Ganga/Brahmaputra River-Bay of Bengal system is considered as an ideal laboratory for examining the weathering-climate relationships over the past. Here we present the elemental and mineralogical data from well age-constrained core sediments in the Bay of Bengal, which document the erosion and weathering conditions in South Asia during the last glacial period. All proxies generally show larger values during glacial interstadials than the stadials, consistent with the millennial variabilities of regional sea surface temperature (SST) and the Indian Summer Monsoon (ISM) strength. We confirm that the erosion and chemical weathering signals in Ganga/Brahmaputra River basins, which sensitively respond to the ISM strength and/or temperature change, could be propagated through the large river systems and faithfully preserved in the South Asian marginal seas, without noticeable time lag on a millennial scale. Our findings provide valuable data for response of erosion and weathering dynamics in a large river basin to rapid climate changes, and highlight the immense potential of monsoon-driven continental silicate weathering in floodplains as a substantial short-term carbon sink, thus underscoring a pivotal natural carbon sequestration mechanism amidst the escalating threat of global warming.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112516"},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314939","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":"Outburst floods and their impact on Chinese Neolithic cultures during the 4.2 ka BP event: Evidence from Dayeze Lake in the lower reaches of the Yellow River","authors":"Jinjia Wu ,&nbsp;Yuan Li ,&nbsp;Yingying Liu ,&nbsp;Xingxing Liu ,&nbsp;Zhanfang Hou ,&nbsp;Rui Zhang ,&nbsp;Shiyue Chen","doi":"10.1016/j.palaeo.2024.112513","DOIUrl":"10.1016/j.palaeo.2024.112513","url":null,"abstract":"<div><div>Abrupt climate fluctuations between 4.2 and 3.5 ka BP, and in particular the 4.2 ka BP event, exerted a profound impact on the global ancient civilizations. However, hydroclimatic conditions within the Asian Summer Monsoon (ASM) regions during this event remain uncertain. Here we report a multi-proxy analysis of a sediment core obtained from Dayeze Lake in the lower reaches of the Yellow River in monsoonal China, to elucidate the hydroclimatic variabilities over the past 4.2 ka. Core intervals (4.2–3.5, 1.1–0.6 cal ka BP) containing high levels of sand fraction, low-frequency magnetic susceptibility and zirconium, and low levels of organic matter and calcium oxide, reflect outburst floods from the Yellow River. This is supported by the widespread fluvial deposits and slackwater deposits preserved in archaeological sites and loess-paleosol profiles from the middle and lower reaches of the Yellow River. In contrast, various climate records, such as lake level, pollen, and tree ring data, from the marginal regions of the ASM reflect widespread droughts during the same time period. This finding highlights the significant spatial heterogeneity of hydroclimate within ASM regions associated with the 4.2 ka BP event, which may be related to migrations of the monsoonal rain belt and the West Pacific subtropical high, as well as frequent El Niño–Southern Oscillation events. Referring to archaeological data, we conclude that the decline and collapse of Chinese Neolithic cultures were related to a pattern of droughts in the marginal regions of the ASM and floods in the middle and lower reaches of the Yellow River.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112513"},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142314979","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":"Large river expansion and global cooling controlled the Plio-Pleistocene weathering intensity records in East Asian margin","authors":"Fangliang Li ,&nbsp;Shouye Yang ,&nbsp;Daniel O. Breecker ,&nbsp;Yulong Guo ,&nbsp;Evan J. Ramos ,&nbsp;Xiangtong Huang ,&nbsp;Kai Deng ,&nbsp;Jimin Yu ,&nbsp;Sanzhong Li","doi":"10.1016/j.palaeo.2024.112517","DOIUrl":"10.1016/j.palaeo.2024.112517","url":null,"abstract":"<div><div>Silicate weathering has long been considered to maintain the Earth's climate stability, yet how the weathering responds to the late Cenozoic cooling remains unclear, partly because of the complicated factors which obscure the weathering records. Large rivers in East Asia integrate continental weathering history, but how the source-to-sink system evolution affected the weathering signals need to be clarified. We compile proxy data of Nd isotopes, zircon ages and Chemical Index of Alteration (CIA) in East Asian margin and source terranes, along with new proxy data from core CSDP-2 in the shelf region, to understand the large river evolution and assess their influence on weathering proxy records. The median εNd values of East Asian marginal sediments increased from −18.8 in pre-3.6 Ma period to −11.3 since the 1.0 Ma, corresponding to the isotopic signatures in North China Craton and Northeastern (NE) Tibetan Plateau/Loess Plateau terranes, respectively. The zircon ages further confirmed the provenance shift, hinting that the modern-like Huanghe (Yellow River) system has been fully integrated during early Pleistocene, no later than ∼1.0 Ma. This integration facilitated the sediment transportation from plateaus into the continental margin. Consequently, the CIA records in marginal regions show a more significant decrease than other Asian regions, within the context of Plio-Pleistocene cooling. Our study found that the upland expansion of large river system and global cooling jointly controlled the decline in the weathering intensity records, highlighting the importance to understand the evolution of source-to-sink system before interpreting the weathering signals from the continental margin sediments.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112517"},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324113","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":"Multi-proxy reconstruction of climate changes from the Medieval Climate Anomaly to the Little Ice Age in Southeast China","authors":"Lin Zhao ,&nbsp;Chunmei Ma ,&nbsp;Xiaojian Zhang ,&nbsp;Liang Li ,&nbsp;Huayu Lu","doi":"10.1016/j.palaeo.2024.112510","DOIUrl":"10.1016/j.palaeo.2024.112510","url":null,"abstract":"<div><div>Exploring climate fluctuations across geological eras provides crucial historical context for addressing contemporary global climate challenges. This research leverages multi-proxies records analytical techniques, including pollen and charcoal analysis, X-ray fluorescence (XRF), and assessments of humification degree and loss on ignition (LOI), alongside paleoclimate simulations based on an alpine peat bog in Jiangxi Province, Southeast China. The study aims to provide a comprehensive review of vegetation evolution, climatic shifts, East Asian summer monsoon (EASM) intensity, and the potential drivers behind EASM behavior over the past two millennia. Our findings reveal a significant transition in precipitation and temperature patterns from the Medieval Climate Anomaly (MCA, 960–1420 CE) to the Little Ice Age (LIA, 1420–1850 CE). A distinct pattern emerges, highlighting particularly wet periods occurring between 960–1050 CE, 1190–1250 CE, and 1350–1400 CE, as well as significant droughts during 1430–1550 CE, 1590–1650 CE, 1680–1720 CE, and 1750–1800 CE. When compared to our temperature reconstruction series and precipitation data, a clear correlation emerges—wet phases align with warmer period characteristic of the MCA. Based on our simulation results, we suggest that ENSO oscillations and the Indo-Pacific warm pool played a substantial role in driving climate dynamics from the MCA to the LIA.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112510"},"PeriodicalIF":2.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324114","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":"Blue carbon storage of tidal flats and salt marshes: A comparative assessment in two Chinese coastal areas","authors":"Jinge Zhou ,&nbsp;Lulu Zhang ,&nbsp;Jingfan Zhang ,&nbsp;Shuchai Gan ,&nbsp;Zhe Lu ,&nbsp;Guoming Qin ,&nbsp;Xingyun Huang ,&nbsp;Han Chen ,&nbsp;Hua He ,&nbsp;Yongxing Li ,&nbsp;Yingwen Li ,&nbsp;Hui Li ,&nbsp;Faming Wang","doi":"10.1016/j.palaeo.2024.112509","DOIUrl":"10.1016/j.palaeo.2024.112509","url":null,"abstract":"<div><div>Coastal wetlands are blue carbon (C) reservoirs and play an important role in mitigating climate change by efficiently capturing and storing organic carbon (OC). However, assessments of blue C sequestration focus primarily on soil organic carbon (SOC) inventories of vegetated coastal ecosystems and often neglect the potential of tidal flats to sequestrate C. To address the issue, a comparative assessment was carried out for two representative coastal wetlands in China: the Yellow River Delta and Yancheng coastal wetlands. The study focused on distinct types of coastal ecosystems including unvegetated tidal flats and three types of salt marshes vegetated by either <em>Spartina alterniflora</em>, <em>Suaeda salsa</em>, or <em>Phragmites australis</em>. We combined field sampling and data synthesis to assess the OC stock of different coastal areas and evaluate the regional OC storage. The results indicated that vegetated salt marshes exhibited higher OC stocks per unit area compared to unvegetated tidal flats in both regions. Interestingly, tidal flats in the Yellow River Delta displayed comparable OC stocks to <em>S. salsa</em> marsh on the Yancheng coast. The regional OC storage was estimated to be 5.64 ± 0.61 Tg C for the Yellow River Delta and 9.96 ± 1.52 Tg C for the Yancheng coast. Tidal flats with low SOC stock per unit area were the primary contributors to regional OC storage, accounting for over 75 % of the total. This predominance was attributed to the extensive distribution of tidal flats along China's coast, indicating their significant potential as blue C sinks. Overall, this study provides insights into the OC storage potential of various wetland types in China and highlights the importance of considering tidal flats in estimates of blue C sequestration.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112509"},"PeriodicalIF":2.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320002","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":"Extreme drought events and land surface temperature variations on the northeastern Tibetan Plateau over the last 350 ka","authors":"Shaohua Tian ,&nbsp;Gaowen Dai ,&nbsp;Guoqiao Xiao ,&nbsp;Huan Yang ,&nbsp;Xiaoqing Meng ,&nbsp;Qiuzhen Yin","doi":"10.1016/j.palaeo.2024.112507","DOIUrl":"10.1016/j.palaeo.2024.112507","url":null,"abstract":"<div><div>The northeastern Tibetan Plateau (NETP) is located in the ecologically vulnerable northwestern China, with semi-humid and semi-arid conditions. Long-term paleo-hydrological and paleo-temperature variations and their mechanisms over the NETP remain ambiguous, primarily due to the limited availability of well-dated, long-term depositional archives and suitable proxies. In this paper, we investigate climate variations and their underlying mechanisms in the region using Glycerol Dialkyl Glycerol Tetraethers (GDGTs) spanning the last 350 ka. Our results suggest that the NETP underwent substantial drying during glacial periods, with the driest period occurring during the last glacial period. The intensity of drought during glacial periods is comparable to that in the Westerlies-dominated region but differs from that in the East Asian monsoon region. This suggests that the influence of the Westerlies surpassed that of the East Asian summer monsoon (EASM), becoming the major driver of warm-season drought events on the NETP during glacial periods. Additionally, the peaks of aridity events coincide with summer insolation maxima during glacial periods, which may be related to the direct influence of local insolation on regulating evaporation. The reconstructed land surface temperatures were about 6.7 °C during interglacial periods and 2.6 °C during glacial periods, which may be linked to a combination of variations in insolation, CO₂ levels, and other internal feedback mechanisms. However, an unusual warming occurred during the last glaciation, with an average temperature of about 4.8 °C. This warming may be related to variations in soil moisture and vegetation resulting from extreme drought. Our study highlights the sensitivity of hydrological variations over the NETP to insolation and Westerlies, as well as the critical roles of soil moisture and vegetation in land surface temperature variations.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112507"},"PeriodicalIF":2.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312128","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":"Environmental changes in the Fleuve Manche paleoriver drainage system (Western Europe) linked to North Atlantic sub-millennial climate variability across Heinrich Stadial 1: Palynological evidence from the Bay of Biscay","authors":"Aurélie Penaud ,&nbsp;Wiem Fersi ,&nbsp;Samuel Toucanne ,&nbsp;Maria Fernanda Sánchez Goñi ,&nbsp;Linda Rossignol ,&nbsp;Filipa Naughton ,&nbsp;Mélanie Wary ,&nbsp;Frédérique Eynaud","doi":"10.1016/j.palaeo.2024.112512","DOIUrl":"10.1016/j.palaeo.2024.112512","url":null,"abstract":"<div><div>Marine microfossils (dinoflagellate cysts and planktonic foraminifera) and geochemical (XRF-Ti/Ca)-based climatic records from a core (MD13–3438) located off the Fleuve Manche (FM) paleo-mouth have revealed that sustained warm summer sea surface temperatures (SSTs) during sub-millennial climate changes within HS1 (∼18–14.7 ka) may have played a key role in the FM regime related to the European Ice Sheet (EIS) melting rate. In this study, we have analyzed the MD13–3438 pollen content over the HS1 at a mean resolution of ∼50 years to test whether vegetation-based air temperatures were coupled to SSTs face to this rapid climate variability. First, our results highlight two major phases of pollen sources at site MD13–3438, preventing the pollen record to be interpreted as a continuous record of the evolution of vegetation and climate occupying a single watershed across HS1. The first phase, i.e. the HS1-a interval (∼18–16.8 ka), is marked by strong occurrences of boreal pollen taxa (especially <em>Picea-Abies</em>). Considering their spatial distribution and the coalescence of the British and Scandinavian ice sheets into the North Sea during the Last Glacial Maximum, these taxa probably originated from the North European Plain, i.e., eastern FM tributaries (east of the Rhine River), where cool-humid conditions generally prevailed. Then, the second phase, i.e. the HS1-b interval (∼16.8–14.7 ka BP), is characterized by a deceleration of the EIS retreat and the drop of boreal pollen values at site MD13–3438 further signing a less influence of the upstream FM drainage system and thus a better characterization of pollen sources related with western FM tributaries. Superimposed to these two HS1 main phases, pollen fluctuations are concomitant with sub-millennial variability in the EIS deglaciation intensity. During the early HS1 (HS1-a), we discuss two short-term increases in the ratio between deciduous trees (<em>Quercus-Corylus-Alnus)</em> and herbaceous plants (<em>Plantago</em>-Amaranthaceae-<em>Artemisia)</em>. These events are coeval with phases of increasing dinocyst-based SST seasonality (i.e. through summer SST amplification). We associate these events with lower contribution of the upstream FM catchment as well as, possibly, atmospheric warming and regional sea-level positive oscillations. The HS1-b is composed of three main phases that appear more influenced by the downstream FM drainage system. HS1-b1 (16.8–16.3 ka BP) corresponds to the driest and coldest conditions west of the Rhine River. HS1-b2 (16.3–15.5 ka BP) is coeval with large arrivals of iceberg from the Hudson strait in the Bay of Biscay and thus likely to a major sea-level positive oscillation associated with a phase of FM valley reworking. HS1-b3 (15.5–14.7 ka BP) corresponds to persistent arid conditions that preceded the subsequent more humid conditions recorded from 14.7 ka BP at the start of the Bölling-Alleröd.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112512"},"PeriodicalIF":2.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312129","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":"Multiple controls on the preservation of organic matter in the lower Mississippian Luzhai Formation black shale in southern China","authors":"Zeyang Liu ,&nbsp;Hui Tian ,&nbsp;Bradley B. Sageman ,&nbsp;Yaowen Wu ,&nbsp;Tengfei Li ,&nbsp;Xinyu Wang ,&nbsp;Wenpan Cen ,&nbsp;Jiyu Chen","doi":"10.1016/j.palaeo.2024.112508","DOIUrl":"10.1016/j.palaeo.2024.112508","url":null,"abstract":"<div><div>The early Carboniferous experienced profound climate cooling that drove the Earth's climate from a mid-Paleozoic greenhouse into the Late Paleozoic Ice Age. Several climate cooling events have been reported, including the Tournaisian and Visean (early to mid-Early Carboniferous). In this study, we perform multi-proxy analyses (organic carbon isotopes, nitrogen isotopes, major and trace elements and organic petrology/geochemistry) of samples from an early Carboniferous section in Nandan region (Guangxi, China). Our goal is to investigate the global carbon‑nitrogen cycle, and associated oceanic productivity and redox perturbations, during a key climatic transition interval, as well as the controls on organic matter enrichment in the sediments. The carbon and nitrogen isotope profiles of the Nandan section record major perturbations during the mid-Tournaisian and early Visean. The mid-Tournaisian carbon isotope excursion (TICE) is marked by a positive δ¹³C_org shift of 1.8 ‰ (from −27.7 ‰ to −25.9 ‰), correlating with a positive δ¹⁵N shift. The early Visean carbon isotope excursion (VICE) is characterized by a positive shift in δ¹³C_org (from −28.2 to −25.5 ‰, with an excursion magnitude of 2.7 ‰), but associated with a negative shift in δ¹⁵N (from +5 ‰ to +4 ‰). The positive δ¹³C_org excursions during these events most likely reflect enhanced organic matter burial with expansion of anoxic seafloor in the global ocean. The drop in nitrogen isotope values in the early Visean is interpreted to be linked with less denitrification under more oxic conditions. The decrease of organic matter contents up section is consistent with the shift to more oxic conditions and increased sedimentary dilution caused by sea-level fall, which is ultimately controlled by orogenic events and climate cooling.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"655 ","pages":"Article 112508"},"PeriodicalIF":2.6,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142312127","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}