Quaternary International最新文献

{"title":"A new technique mapping submerged beachrocks using low-altitude UAV photogrammetry, the Altınova region, northern coast of the Sea of Marmara (NW Türkiye)","authors":"Mustafa Geyik ,&nbsp;Ufuk Tarı ,&nbsp;Orkan Özcan ,&nbsp;Gürsel Sunal ,&nbsp;Cenk Yaltırak","doi":"10.1016/j.quaint.2024.10.011","DOIUrl":"10.1016/j.quaint.2024.10.011","url":null,"abstract":"<div><div>High-resolution aerial imagery captured from low altitudes enables the detailed reconstruction of the geomorphological features of submerged beachrocks and the quantification of their topographic complexity. These coastal deposits serve as vital indicators for estimating past sea-level positions and deformation, contributing to our understanding of climate and tectonic processes across various temporal and spatial scales. This study focuses on submerged beachrocks identified in the nearshore coastal area of Tekirdağ city (Altınova), and the existing knowledge regarding such geological formations is limited.</div><div>Situated in the tectonically active western Marmara region, the coastal zone of The Tekirdağ-Altınova is influenced by the North Anatolian Fault Zone (NAFZ), which has significantly shaped the coastline over time. Utilizing unmanned aerial vehicle (UAV) data, we successfully isolated submerged beachrocks from other coastal deposits, identifying them at depths of 2 m below current sea level and extending approximately 5 km along the coast. This identification was facilitated by integrating high-resolution aerial imagery with morphological analysis techniques, specifically employing structure-from-motion photogrammetry to generate a dense point cloud for bathymetric mapping.</div><div>The utilization of cost-effective UAV imagery facilitated the efficient monitoring of beachrocks. Geographic information systems (GIS) and the TerraceM application were employed to analyze the high-resolution bathymetry data (with a 5 cm resolution), enabling the precise estimation of shoreline angles and associated errors. These shoreline angles, which correspond to the past sea levels high stand, were mapped using swath profiles oriented perpendicular to the isobaths. Our findings reveal that the majority of submerged beachrocks exhibit shoreline angles between ∼ −0.7 m and −1.1 m. This study presents innovative methodologies for mapping the height and spatial distribution of beachrocks, as well as for reliably estimating reliable uplift rates in the nearshore area of Tekirdağ-Altınova.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"712 ","pages":"Article 109579"},"PeriodicalIF":1.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-based identification of geomorphological units in Quintero Bay (32°S) and its implications for the search for early drowned archaeological sites on the western coast of South America","authors":"Valentina Flores-Aqueveque ,&nbsp;Hugo Neira-Santander ,&nbsp;Cristina Ortega ,&nbsp;César Méndez ,&nbsp;Isabel Cartajena ,&nbsp;Renato Simonetti ,&nbsp;Diego Carabias","doi":"10.1016/j.quaint.2024.11.003","DOIUrl":"10.1016/j.quaint.2024.11.003","url":null,"abstract":"<div><div>High-resolution predictive modeling of submerged landscapes has successfully allowed the detection of early archaeological sites that are presently underwater. These models have traditionally relied on geophysical techniques, which can be both time-consuming and expensive, especially for extensive survey areas. In contrast, geomorphological mapping using Machine Learning (ML) techniques has emerged as a rapid and accessible alternative with numerous advantages over conventional methods. In this work, we employ ML algorithms (Random Forest, Support Vector Machine, Partial Least Squares, and Principal Component Analysis) trained on land to analyze the seabed of Quintero Bay to identify relic landforms that characterize the paleolandscape within which the submerged early site GNLQ1 formed. The methodology also included a multicriteria analysis that integrated geological (geomorphological, tectonic, eustatic) and archaeological (attributes of non-submerged records in the region) approaches to delineate potential areas of archaeological interest. The findings of this work can guide and enhance future archaeological research. The results underscore the importance of possessing a comprehensive understanding of the study area and its associated variables to the successful application of ML techniques. This also applies to modeling drowned paleolandscapes. Nevertheless, despite these challenges, ML-based modeling of drowned paleolandscapes can provide an overview of the distribution of geoforms comprising the paleolandscape, which in turn can help identify future geophysical survey areas to focus on in the search for archaeological evidence, thereby improving our understanding of the relationship between early human groups and these landscapes.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"712 ","pages":"Article 109585"},"PeriodicalIF":1.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Late Holocene seismic uplift events depicted by coastal karst formations in Bali, Indonesia","authors":"Miklós Kázmér ,&nbsp;Rikza Nahar ,&nbsp;Krzysztof Gaidzik","doi":"10.1016/j.quaint.2024.10.009","DOIUrl":"10.1016/j.quaint.2024.10.009","url":null,"abstract":"<div><div>Limestone shores record earthquake-related uplift and subsidence worldwide. While comprehensive investigations exist for the Mediterranean and Japan, only limited studies are available in other regions. In this study, we analyze the carbonate shore of the Sunda Arc on Bali Island, Indonesia, in terms of tectonic uplift/subsidence. We surveyed coastal profiles of terraces and notches, identifying coastal karst features and bioerosion traces and determining their position relative to sea level. We found a set of marine terraces at Suluban Beach: <em>Level A</em> (lowest) <em>–</em> the active reef pavement with occasional surf potholes; <em>Level B</em> – 0.5–0.7 m above level <em>A,</em> with surf potholes and channels; <em>Level C –</em> 0.8 m above level <em>B</em>, heavily pitted by flat-bottomed pans, separated by heavily karstified ridges; <em>Level D –</em> 2 m above level C, karstified surface, with several decimetres deep karren. The increasing depth of coastal karst features marks a longer time of exposure to the sea, both in the intertidal and the supratidal zone. Holocene sea level reached its present-day position about 5000–6000 years ago; therefore, all coastal features, which require the action of the sea, salt water, and wave action to develop, formed following this period. Bali is on the front of the overriding plate in the Sunda arc. Seismicity is expressed by the uplift of the coastal zone. We propose that seismic events of moment magnitude 6.5–7, with a few hundred years return period, can produce the observed repeated surface uplift of 0.5–2 m in Bali.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"712 ","pages":"Article 109577"},"PeriodicalIF":1.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Environmental changes and historical occupation at Oued Laksar (Ksar Seghir), Morocco","authors":"Ana Maria Costa ,&nbsp;Maria da Conceição Freitas ,&nbsp;André Teixeira ,&nbsp;Pedro J.M. Costa ,&nbsp;Ricardo N. Santos ,&nbsp;Mário Cachão ,&nbsp;Francisco Fatela ,&nbsp;Ricardo Pereira ,&nbsp;João Pedro Tereso ,&nbsp;Vera Paio Lopes ,&nbsp;Roberto Bao ,&nbsp;Abdelatif El-Boudjay","doi":"10.1016/j.quaint.2024.10.010","DOIUrl":"10.1016/j.quaint.2024.10.010","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Laksar is a small river near the village of Ksar Seghir, located between Tangier and Ceuta (Morocco), strategic points to control the Strait of Gibraltar over centuries. The river outlets at the western part of a sandy beach that can block the fluvial discharge in years of low precipitation/river flow.&lt;/div&gt;&lt;div&gt;The area is densely occupied since the 5th century BC, during the roman period and Early Middle Age in the archaeological site of Dhar d’Aseqfane, located around 1 km from the mouth of the river. The coastal town of Ksar Seghir was founded on the eastern margin and was used as a shipyard for Moroccan dynasties after the 12th century. During the 15th and 16th centuries, Portugal occupied Ksar Seghir to control the Strait and to increase its power in North Africa. After the Portuguese left the site remained abandoned. The present-day Moroccan village developed in the 20th century, first expanding on the western river slope and gradually encompassing the archaeological site.&lt;/div&gt;&lt;div&gt;This work aims to i) characterize the environmental evolution of the Laksar River; ii) identify potential records of extreme events such as floods or tsunamis; and iii) explore the relationship between the landscape dynamics and human occupation.&lt;/div&gt;&lt;div&gt;To achieve these goals, a ∼5.4 m long sediment core - KS1 - was studied applying high-resolution multiproxy analyses (X-Ray, magnetic susceptibility, sedimentology, organic chemistry and micropalaeontology) together with &lt;sup&gt;14&lt;/sup&gt;C dating to establish a chronological model.&lt;/div&gt;&lt;div&gt;The sedimentary sequence corresponds to intercalations of fine sand and mud. Results point to deposition in subtidal conditions between the core base (ca. 2500 cal BP) and the 15th century AD (388 cm below surface). The dominance of marine foraminifera assemblages with high number of juveniles and high diversity index suggests an environment under open marine conditions during this period. Conversely, the low δ&lt;sup&gt;13&lt;/sup&gt;C values, coupled with the presence of charophytes and Cretaceous, Paleogene and Neogene reworked calcareous nannofossils reflect the contribution of fluvial processes. The sedimentary record underscores fluctuations in fluvial discharge, beach morphology and marine influence. The accumulation of magnetic (heavy) minerals at the core base is the likely result of at least one high-energy event.&lt;/div&gt;&lt;div&gt;Following the onset of Portuguese occupation of Ksar Seghir (15th century), the sedimentation rate increases, silting-up the channel margins. Deposition occurs under low subtidal to intertidal conditions. Foraminifera assemblages point to a low salinity environment; coarse materials are mostly constituted by minerogenic particles transported by the fluvial network. Changes in the sedimentary succession (heavy-minerals accumulation, higher marine influence and rip-up clasts) were detected between 219 cm and 140 cm depth below surface that, according to the age-model, overlap temporally with the Lisb","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"712 ","pages":"Article 109578"},"PeriodicalIF":1.9,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143148425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Mapping Early Holocene to contemporary surface processes and human landscapes west of the lower White Nile (central Sudan)","authors":"Stefano Costanzo ,&nbsp;Andrea Zerboni ,&nbsp;Mauro Cremaschi ,&nbsp;Donatella Usai","doi":"10.1016/j.quaint.2024.109592","DOIUrl":"10.1016/j.quaint.2024.109592","url":null,"abstract":"<div><div>Morphogenetic surface processes and anthropogenic landscape alterations have been tied together throughout the ages in the so-called <em>human-environmental nexus</em> since the inception of humankind as an active agent in the shaping of ecosystems. Here, we present instances of such interactions from an archaeologically paramount area west of the lower White Nile (central Sudan), where the sprawling mega conurbation of Sudan's capital city, and its peripheral infrastructural anthromes, intermingle with prehistoric human-inhabited landscapes, masking and disrupting natural and archaeological features while, in turn, increasing the rich and complex stratification of the human presence in the Sahel. A comprehensive examination of the geomorphological palimpsest, carried out in the field and through remote sensing, is provided, and is accompanied by a contextualised illustration of the known regional Holocene prehistoric, protohistoric and later archaeology.</div><div>This research highlights the importance of carrying out geomorphological, geoarchaeological and remote sensing investigations to reach a fuller comprehension of the archaeological palimpsest of a region, while also providing a vivid tool for promoting survey activities in underexplored areas and stimulating novel research questions.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"715 ","pages":"Article 109592"},"PeriodicalIF":1.9,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142748630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Depositional history of the Holocene Faiyum Paleolake (Egypt) inferred from a petrographic analysis","authors":"M.A. Hamdan ,&nbsp;R.H. Badawy ,&nbsp;A.S. Zaky ,&nbsp;R. Osman ,&nbsp;F.A. Hassan ,&nbsp;R.J. Flower ,&nbsp;A.M. Afify ,&nbsp;M.S. Mabrouk","doi":"10.1016/j.quaint.2024.11.006","DOIUrl":"10.1016/j.quaint.2024.11.006","url":null,"abstract":"<div><div>The Faiyum Depression basin was fed by the Nile River during high-flow seasons in the Holocene. A large freshwater lake persisted in the basin during most of the Holocene. The geological setting and geomorphological characteristics of this basin has made it a topic in North African hydrology, climate, and environment, especially in Egypt. The ancient shore sediments today are fragmentary, discontinuous, and suffer from extensive erosion but substantial records of the ancient lake remain. Continuous sediment records from drill cores provided a near complete record of the Holocene history of Faiyum Lake. The recovered sedimentary sequence of one core F3-08 consists of predominantly siliciclastic lacustrine facies divisible into six informal units. Petrographic analysis provides high resolution evidence of major hydrological changes affecting the lake system. In the early-middle Holocene this lake persisted but with a lower water level and thicker sediment layers. The middle Holocene Lake experienced repetitive variations in lake level as the amount of Nile water entering the depression fluctuated. During the late Holocene, the lake level dramatically lowered in part due to the construction of earthen dams during the late Holocene and to changes in the Nile headwaters.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"714 ","pages":"Article 109588"},"PeriodicalIF":1.9,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The late Middle Pleistocene Zhongshan cave fauna from the Bubing Basin, southern China","authors":"Yaobin Fan ,&nbsp;Yanyan Yao ,&nbsp;Anne-Marie Bacon ,&nbsp;Thijs van Kolfschoten ,&nbsp;Jinyan Li ,&nbsp;Christopher J. Bae ,&nbsp;Wei Liao ,&nbsp;Wei Wang","doi":"10.1016/j.quaint.2024.11.005","DOIUrl":"10.1016/j.quaint.2024.11.005","url":null,"abstract":"<div><div>The karstic caves in the Bubing Basin, Guangxi, southern China, contain abundant Quaternary mammalian fossils. These cave sites are located at varying altitudes that have been roughly correlated with chronological age (higher caves are older, lower caves are younger). A growing number of recent studies have established a regional biochronological sequence for these Bubing caves from the Early to the Late Pleistocene. Here, we describe a new mammalian assemblage from the Zhongshan Cave, that dates to the late Middle Pleistocene - Marine Isotope Stage 6 (191–130 ka). The age is supported by minimum ages derived from U-series dating of the deposits, and the ESR/U-series dating of one <em>Rhinoceros</em> tooth (∼184 ka). The Zhongshan mammalian assemblage, comprising 33 taxa of large-sized mammals, belongs to the Middle Pleistocene “<em>Ailuropoda</em>-<em>Stegodon</em>” faunal unit and, in this respect, most closely resembles the Ganxian fauna (362–168.9 ka). The high diversity and abundance of ruminant Artiodactyla (versus Perissodactyla) in the Zhongshan fauna suggest a diversity of forest to more open habitats in the Bubing Basin during this period.</div><div>The Zhongshan fauna fills a gap in the biochronological framework of southern China, offering new insights into the evolutionary history of some mammalian lineages in the Bubing Basin. Overall, data indicate major changes in the Early to Late Pleistocene faunal sequence, particularly with more turnover during the Early-Middle Pleistocene transition compared to the Middle-Late Pleistocene transition.</div><div>Comparison between faunas from the Bubing Basin with those from sites in the Chongzuo area, also in Guangxi, southern China, highlights two major phases in the general decline of large-sized mammals during the Middle to Late Pleistocene transitional period. In that respect, our results provide an updated biochronological background for further analyses of the region.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"714 ","pages":"Article 109587"},"PeriodicalIF":1.9,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Anthropic and climatic impacts on biodiversity during the Mesolithic-Neolithic transition in North-Western France","authors":"Nathan Martin ,&nbsp;Kevin Nota ,&nbsp;Cédric Aumont ,&nbsp;Grégor Marchand ,&nbsp;Dominique Marguerie","doi":"10.1016/j.quaint.2024.11.004","DOIUrl":"10.1016/j.quaint.2024.11.004","url":null,"abstract":"<div><div>The Neolithic transition, which began around 10,000 BCE in Western Asia, has significantly impacted the biodiversity dynamics and the hunter-gatherer communities due to the beginning of anthropization and climate fluctuations during this period. Neolithic farmers gradually spread to the Atlantic margins of North-Western Europe during the 6th millennium BCE, arriving later than in other parts of the continent.</div><div>This systematic review aims to shed a light on the landscape transformations and shifts in the ecological niches that occurred during neolithization in the Armorican Massif, driven by human and climatic influences, through an interdisciplinary examination of palynology, archaeology and palaeogenomics. This Massif is situated in North-Western France which hosted well established Mesolithic and Neolithic societies that have been extensively studied. However, recent research has called into question the coexistence of these two cultural groups in this area, necessitating a reevaluation of the literature in light of these new findings.</div><div>This systematic review coupled with an analysis of pollen sequences reveals spatial and temporal heterogeneity in vegetation composition, openness, and the gradual introduction of domesticated taxa into the region. This analysis should be seen in the context of the delayed adoption of the agro-pastoral lifestyle in North-Western Europe, attributed to the different climatic conditions encountered, which required time for these societies and their domesticated taxa to adapt.</div><div>Further investigation is needed to clearly differentiate between anthropogenic and climatic impacts and paleo-climatic reconstruction based on pollen sequences looks promising for addressing this issue.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"714 ","pages":"Article 109586"},"PeriodicalIF":1.9,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759040","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Was LIA synchronous with equa-tropical climate? A multiproxy study from the southwest coast of India","authors":"Pooja Tiwari ,&nbsp;Biswajeet Thakur ,&nbsp;Purnima Srivastava ,&nbsp;Sanjay Kumar Singh Gahlaud ,&nbsp;Trina Bose ,&nbsp;Anurag Kumar ,&nbsp;Ravi Bhushan ,&nbsp;Rajesh Agnihotri","doi":"10.1016/j.quaint.2024.09.004","DOIUrl":"10.1016/j.quaint.2024.09.004","url":null,"abstract":"<div><div>A comprehensive study of the Mundrothruthu (MT) core (70 cm) from the Asthamudi wetland in Kollam, Kerala, India reveals three climate phases during the Little Ice Age (LIA) through multi-proxy investigations. The period (1507–1518 CE) shows high agricultural activity indicated by abundant diatom diversity, significant terrestrial influx, and freshwater runoff. Elevated TOC% and δ¹³C_TOC values suggest high temperature and a warm, humid climate, likely driven by high terrestrial influx and transport of organic matter from the nearby surroundings. This may have increased the organic matter influx to the estuary leading to high TOC% and more negative δ¹³C values. The second phase (1519–1548 CE) is characterized by increased marine incursion due to enhanced tidal currents, evidenced by a rise in marine palynomorphs, mixed terrestrial and marine organic matter, less negative δ¹³C values, and increased mud content. This shift likely reflects changes in sea level or tidal dynamics. The final period (1548–1804 CE) is marked by further enhancement of marine taxa, lower TOC%, and δ¹³C_TOC values, indicating reduced atmospheric CO₂ and a temperature decrease of about 1 °C. This period is associated with reduced solar insolation and a southward shift of the Inter Tropical Convergence Zone (ITCZ). The study highlights both synchronous and asynchronous climatic behavior on the southwest coast of India relative to global changes during the LIA. Initially warm and humid with high agricultural productivity, the region gradually shifted to marine-dominated conditions due to tidal dynamics and broader climatic shifts. These findings underscore the complex interplay between local and global climatic factors during the LIA.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"709 ","pages":"Pages 66-81"},"PeriodicalIF":1.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Trace element variations in Indian speleothems: Insights into the Holocene climate","authors":"Ipsita Roy,&nbsp;Naveen Gandhi","doi":"10.1016/j.quaint.2024.08.007","DOIUrl":"10.1016/j.quaint.2024.08.007","url":null,"abstract":"<div><div>Speleothems from the Gupteswar and Kadapa caves were investigated using trace element (TE) ratios (Mg, Ba, Sr, Rb, Mn, Ti, U) over the last 7000 years, supported by ²³⁰Th/²³⁴U dating, to understand the regional and local climate variability induced by the Indian Summer Monsoon. The behavior of TE in calcite is influenced by temperature, seepage pathways, bedrock chemistry, and vegetation cover above the cave. A continuous decrease in the Ba/Sr ratio since 7 ka BP indicates changes in regional precipitation or local moisture availability during this period. However, determining changes in drip water rate and chemical composition is challenging due to the lack of supporting data. Variations in the TE ratios suggest significant climate and depositional changes at ∼4.2 ka BP and ∼2.8 ka BP. A decline in precipitation was observed between 4.2 and 3.8 ka BP and at ∼2.8 ka BP, with an increase in aeolian deposition at the study site since 3.8 ka BP because of preceding dry conditions. The moist and dry climate phases deduced from stable isotope values corroborate the variations in trace element ratios, affirming the paleoclimatic significance of the studied trace elements in tropical cave deposits. A probable explanation for the decline in precipitation at the study location around 4.2 ka BP is the southward migration of the Intertropical Convergence Zone (ITCZ) along with a negative phase of the Indian Ocean Dipole. The prevailing dry conditions in this region could have impacted the northward monsoonal winds, contributing to the decline of the Indus Valley Civilization. Another abrupt change observed at ∼2.8 ka BP can be linked to low solar activity and the southward movement of the ITCZ, coupled with enhanced El Niño-Southern Oscillation activity.</div></div>","PeriodicalId":49644,"journal":{"name":"Quaternary International","volume":"709 ","pages":"Pages 55-65"},"PeriodicalIF":1.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}