Marine Micropaleontology最新文献

{"title":"Integrated statistical analysis of calcareous nannofossil and elemental geochemistry of an outcrop from of the eastern Cenomanian Western Interior Seaway: Novel insights of shallow marine paleoceanography and nannoplankton paleoecology","authors":"Jonathan D. Schueth,&nbsp;Kelly Johnson","doi":"10.1016/j.marmicro.2023.102290","DOIUrl":"10.1016/j.marmicro.2023.102290","url":null,"abstract":"<div><p><span>Phytoplankton<span><span> assemblages in shallow marine environments are being impacted by anthropogenic climate change, but long-term outcomes of these changes are uncertain. Investigation of past neritic calcareous nannoplankton<span><span> can help us understand the fate these ecosystems face. In this study, a Canonical Correspondence Analysis (CCA) of calcareous nannofossils<span> and X-ray fluorescence geochemistry<span> was used to determine how past planktonic ecosystems were influenced by paleoenvironmental parameters on the eastern side of the Late Cretaceous Western Interior Seaway in the </span></span></span>Cenomanian (ca. 95–93 Ma). Samples were collected every 10 cm from the Graneros Shale Greenhorn Formation at an outcrop in northwestern Iowa to determine high resolution changes in assemblages and </span></span>paleoenvironments. Nannofossil diversity outside of a few small intervals ranges is high (generally 30–60 species) with abundant small </span></span><em>Biscutum constans</em><span><span>, confirming other publications that show elevated diversity in Cretaceous nearshore settings. The CCA results imply assemblages were most influenced by terrigenous influence, wet vs. dry climate, and changes in water mass source. Cretaceous nannofossil </span>paleoecology<span> was also revised based on the CCA results. Size differentiation of nannofossil taxa may highlight more complexity in environmental preferences that have been largely overlooked. After the initial transgression of the Greenhorn Sea into the region, the climate became wetter and terrigenous influence in the area was high. The peak of terrigenous influence corresponds with elevated nannofossil diversity but a lack of microfauna, which may indicate a similar oceanographic setting to the modern Gulf of Mexico nearshore dead zone. As sea level continued to rise above this point, nannoplankton assemblages indicate a potential shift to a higher productivity, stratified water column. As the muddy Graneros Shale transitioned to a further offshore chalky Greenhorn Formation, a normal marine, cosmopolitan nannofloral assemblage became established. Nannofossil and geochemical evidence indicates high productivity from upwelling might be related to the change of deposition to chalk in the Greenhorn Formation. While only a single outcrop was investigated, the novel use of an integrated micropaleontological and geochemical analysis has shed light on the dynamics of how phytoplankton ecosystems were established and modified in shallow marine environments of the Cretaceous and could have important implications on modern shallow marine settings.</span></span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102290"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46455724","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conodont size in time and space: Beyond the temperature-size rule","authors":"Catherine Girard ,&nbsp;Anne-Lise Charruault ,&nbsp;Anne-Béatrice Dufour ,&nbsp;Sabrina Renaud","doi":"10.1016/j.marmicro.2023.102291","DOIUrl":"10.1016/j.marmicro.2023.102291","url":null,"abstract":"<div><p><span>The temperature-size rule (TSR) states that ectotherms mature at smaller adult body size in warmer conditions. Such a rule may have the potential to explain size response of fossil<span> organisms to past temperature variations, but its validity in deep time has been seldom tested. The generality of this rule was investigated here by compiling data documenting the size record of three conodont genera (</span></span><em>Palmatolepis, Ancyrodella</em> and <em>Polygnathus</em><span><span>) at different spatial and temporal scales during the Late Frasnian<span> and the Famennian, characterized by short- and long-term temperature variations. Statistical models were used to investigate the relationship between conodont size and </span></span>oxygen isotope<span> values, considered as paleotemperature proxies. Comparison of evolutionary models further allowed to test alternative modes of size variation such as stasis or punctuation.</span></span></p><p>The TSR was not validated as a general rule explaining size variation in these fossil records, being only observed as a large-scale geographic trend during a time-slice. The only strong support for temperature being the driver of temporal variations was found regarding the size of <em>Palmatolepis</em> during the Kellwasser period, but the relationship was reverse to the expectation of the TSR. The absence of general TSR pattern is probably due to the interference of many other factors (demography and mortality patterns, temperature tolerance, size reduction due to stress) whose relative importance may depend on the time interval and the genus considered. Rather than a correlation with environmental proxies, evolutionary models suggested the occurrence of a synchronous shift in <em>Palmatolepis</em> size around 369 Ma (<em>Palmatolepis termini</em> conodont Zone) in several outcrops, raising questions about the environmental forcing beyond this shift. Departures from the expected TSR may thus provide relevant insights into the complex interplay of physical, tectonic and eco-evolutionary processes impacting size evolution in deep time.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102291"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44392034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distribution of modern benthic foraminiferal assemblages across the Northeast Greenland continental shelf","authors":"Joanna Davies ,&nbsp;Jeremy Lloyd ,&nbsp;Christof Pearce ,&nbsp;Marit-Solveig Seidenkrantz","doi":"10.1016/j.marmicro.2023.102273","DOIUrl":"10.1016/j.marmicro.2023.102273","url":null,"abstract":"<div><p>Analysis of benthic foraminifera in surface samples from 23 sites on the Northeast Greenland continental shelf reveal key assemblage differences between sites. Cluster analysis creates two clear geographical faunal assemblage zones: the 1) inner shelf, and 2) mid and outer shelf sites. These assemblages differ significantly, with the inner shelf sites being characterised by a high percentage and concentration of calcareous species, whilst the mid and outer shelf sites are dominated by agglutinated taxa. At almost all sites, the calcareous assemblages are dominated by <em>Cassidulina neoteretis</em> and <em>Cassidulina reniforme</em>, suggesting that they thrive across the shelf. <em>Stetsonia horvathi</em>, <em>Oridorsalis tener</em>, as well as <em>Glomulina oculus</em> and other miliolid species are found to be key calcareous species at many sites in the inner shelf zone, but they are rare-to-absent on the mid and outer shelf. Canonical correspondence analysis shows that September sea-ice cover and bottom water oxygen content are positively correlated with benthic foraminiferal assemblages at inner shelf sites, whereas organic carbon content is correlated with those in the mid and outer shelf. The formation of seasonal sea-ice and the Northeast Water polynya rejects brine into surrounding waters and transports CO₂ to the seafloor, creating a highly corrosive environment for calcium carbonate. These environments are also highly productive, as indicated by the high organic carbon content and low bottom water oxygen content. The oxidation of this organic material creates CO₂. We propose that these processes are key drivers in the dissolution of calcareous tests. In contrast, extensive sea-ice, high bottom water oxygen content and low primary productivity in the glacier-proximal region facilitates carbonate preservation.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102273"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45984035","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"No dramatic changes observed in subtropical radiolarian plankton assemblages during the Middle Eocene Climatic Optimum (MECO); evidence from the North Atlantic ODP Site 1051","authors":"Mathias Meunier,&nbsp;Taniel Danelian","doi":"10.1016/j.marmicro.2023.102272","DOIUrl":"10.1016/j.marmicro.2023.102272","url":null,"abstract":"<div><p><span>The Middle Eocene Climatic Optimum (MECO; ca. 40 Ma) was a prominent </span>global warming<span> event that lasted 400 kyr and was characterized by a 4–6 °C rise in high latitude surface and deep-water temperatures. As the radiolarian<span> plankton response to this warming event is practically unknown, whole assemblage quantitative analyses were undertaken on well-preserved radiolarian assemblages from ODP Site 1051 (western North Atlantic). Although radiolarians have apparently benefited at this site from increase in oceanic fertility induced by the MECO, this event does not appear to have had a severe impact on subtropical radiolarian fauna. No prominent faunal turnover was found in the studied interval, suggesting that subtropical radiolarians are relatively resilient to transient warming events. Likewise, variations in radiolarian assemblage composition establish that ocean warming induced only a weak ecological response. One of the most striking faunal changes associated with the MECO is the clear increase in radiolarian diversity (taxic richness), as a result of the northward migration of warm tropical radiolarian species. Similarly, several typical middle Eocene tropical species are found to be more abundant in the warmest interval. In addition to these poleward migrations, we identified three radiolarian clusters composed of warm-water or cool-water species, as well as two abundant artostrobiid species which may represent nutrient opportunists.</span></span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102272"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45542818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model of phylomorphogeny of P1 elements of the Tournaisian (Mississippian) siphonodellids","authors":"Artem N. Plotitsyn,&nbsp;Andrey V. Zhuravlev","doi":"10.1016/j.marmicro.2023.102294","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102294","url":null,"abstract":"<div><p><span>Conodonts are a group of extinct marine organisms widely used in Paleozoic and Triassic biostratigraphy. The genus </span><em>Siphonodella</em><span><span> comprises ozarkodinid conodonts from the latest Famennian to the middle </span>Tournaisian. The phylogenetic model of this genus plays an important role in biostratigraphy. This study is based on the authors' and published data on 31 species of siphonodellids of cosmopolitan and East European groups. A new phylomorphogeny of </span><em>Siphonodella</em> is proposed on the basis of known mechanisms of morphological transformations of siphonodellid P₁<span> elements during speciation processes, presence of interspecies transitional forms, and data on ontogeny. The main morphogenetic pathways in the evolution of siphonodellids are the following: formation and transformation of the rostrum, transformation of the platform outline, transformation of the platform ornamentation, transformation of the keel, and histological transformations. In the process of modeling the phylomorphogeny of </span><em>Siphonodella</em>, some taxonomic problems are solved: a new species <em>S. thompfelli</em> is described, a new variant of the division of <em>S. lobata</em><span> (Branson and Mehl) into morphotypes is proposed, the validity of </span><em>S. plana</em> (Huddle), <em>S. praeplana</em> Bardasheva, Bardashev, Weddige and Ziegler, and <em>S. gladia</em><span> Zhuravlev and Plotitsyn is clarified, and the knowledge of the morphospace of most representatives of the genus is extended. The phylogeny of siphonodellids provides a basis for the new phylogenetic zonal sequences based on the conodont phylogenetic-zone concept.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102294"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49723104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Shape diversity in conodont elements, a quantitative study using 3D topography","authors":"Alexandre Assemat ,&nbsp;Ghislain Thiery ,&nbsp;Thibaud Lieffroy ,&nbsp;Catherine Girard","doi":"10.1016/j.marmicro.2023.102292","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102292","url":null,"abstract":"<div><p>The flourishment of conodont<span> diversity through the Paleozoic is evidenced by the strong diversification of the shape of the elements composing their feeding apparatus. Among the different elements that compose the feeding apparatus, the platform elements (P1) are the most robust. However, the P1 elements also represent the most posterior dental elements of the apparatus, performing therefore the ultimate stage of food processing before ingestion of the food bowl. Thus, characterizing the shape of these elements across various species of conodonts could be relevant to decipher the diversity of feeding behavior among this group. Here we use topographic indices initially developed for the description of teeth relief (RFI, Slope), orientation (OPCr) and sharpness (ARC, DNE) to discriminate quantitatively P1 element shapes among conodont communities of the Late Famennian from the Montagne Noire Area (south France). We evidence methodological considerations such as voxel size impact on topographic indices that should be imperatively considered before conducing these methods on conodonts. Under several homogeneous conditions, this quantification of shape diversity, even on poorly damaged specimens, could bring new clues for the understanding of P1 elements kinematics and feeding strategies among conodonts.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"184 ","pages":"Article 102292"},"PeriodicalIF":1.9,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49737070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pseudofurnishius (Conodonta) from the Triassic Drežnica section, Bosnia and Herzegovina","authors":"Tea Kolar-Jurkovšek ,&nbsp;Carlos Martínez-Pêrez ,&nbsp;Hazim Hrvatović ,&nbsp;Dunja Aljinović ,&nbsp;Špela Goričan ,&nbsp;Ferid Skopljak ,&nbsp;Bogdan Jurkovšek","doi":"10.1016/j.marmicro.2023.102271","DOIUrl":"10.1016/j.marmicro.2023.102271","url":null,"abstract":"<div><p>Triassic strata in the Drežnica section, Bosnia and Herzegovina have been examined biostratigraphically. The limestone and dolostone strata were deposited in deep pelagic environment. The conodont faunas are marked by prevailing elements of the genus <em>Pseudofurnishius</em> including clusters that enabled to distinguish the <em>huddlei</em> (lower Longobardian) and <em>murcianus</em> (upper Longobardian–?Cordevolian) Zones, the later fauna is characterized by the presence of <em>Budurovignathus</em> with rare representation of <em>Gladigondolella</em> and <em>Paragondolella.</em> This is the first report on recovery of <em>Pseudofurnishius</em> in the region.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"183 ","pages":"Article 102271"},"PeriodicalIF":1.9,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46191620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Origin and evolution of the Early Ordovician conodont genus Prioniodus Pander, 1856 — New evidence from South China","authors":"Yong Yi Zhen ,&nbsp;Yuan-Dong Zhang ,&nbsp;Zhong-Yang Chen ,&nbsp;Long-Wu Wang","doi":"10.1016/j.marmicro.2023.102269","DOIUrl":"10.1016/j.marmicro.2023.102269","url":null,"abstract":"<div><p><span>A conodont<span> fauna of late Tremadocian to early Floian age (Early Ordovician) is documented from the Yinchufu Formation of Zhejiang Province, South China. It is characterized by the occurrence of two species of Prioniodontidae, a new species of </span></span><em>Prioniodus</em> and <em>Acodus triangularis</em>. <em>Prioniodus antiquus</em> sp. nov. may represent the most primitive species of <em>Prioniodus</em>, which is one of the earliest conodont genera with a ramiform—pectiniform apparatus. Based on the review of nearly 200 species originally assigned to <em>Prioniodus</em>, six multielement species are confirmed to belong to this genus. Morphological changes of these six species shows that they form an evolutionary lineage directly evolved from an adentate species, likely <em>Acodus triangularis</em> which has been reported from South China, Australia and from the Precordillera of western Argentina. Origination of the ramiform—pectiniform apparatuses as represented by the appearances of <em>Prioniodus</em><span><span> through late Tremadocian to Floian of the Early Ordovician might be a major response of the 'conodont animals' to occupy and adapt to the increasingly diversified environments in the shelf and slope settings. The </span>biofacies distribution of the six </span><em>Prioniodus</em> species indicates that <em>Prioniodus</em> might have originated in deep-water slope settings and progressively spread into distal and then interior shelves in the late Tremadocian and diversified in the Floian, with <em>Prioniodus amadeus</em><span><span> possibly representing a relict species that survived into the </span>Middle Ordovician and was restricted to shallow water environments.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"183 ","pages":"Article 102269"},"PeriodicalIF":1.9,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45265909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations in benthic foraminifera biofacies since Mid-Pleistocene (MIS 7) in the Campos Basin slope, Eastern Brazil: Assessing present-day and past controlling factors","authors":"Sarah Pereira Gasparini ,&nbsp;Claudia Gutterres Vilela ,&nbsp;Mark Maslin ,&nbsp;Kimmolly Ferrari Ferreira","doi":"10.1016/j.marmicro.2023.102270","DOIUrl":"10.1016/j.marmicro.2023.102270","url":null,"abstract":"<div><p>Benthic and planktonic foraminifera faunal and stable isotopic (δ¹⁸O and δ¹³<span><span>C) analyses on foraminiferal tests were carried out on a piston core, collected from the Campos Basin slope at a water depth of 1475 m. The core location is in front of Cape São Tomé and exhibits landslide scars features. Benthic foraminifera </span>biofacies<span> with ecological indexes and statistics, lithological facies, biostratigraphy<span><span> and stable isotopic analysis were used to understand the paleoenvironmental evolution of the region by comparison with modern foraminiferal assemblage. Six biofacies were identified between </span>Marine Isotope Stage (MIS) 7 to MIS 1. The main ecological factors controlling the modern assemblages are: bottom currents, slope stability, oxygen concentration, and nutrient input. However, the last two factors are linked to oceanic processes associated with the Paraíba do Sul river, the influence of which has changed in the past. In particular, Biofacies 3, contains infaunal species, points to dysoxic or anoxic periods in the environment, which are interpreted as periods of increased river influence. Changing environmental conditions were observed as the dominant benthic foraminifera species varied down the core, from </span></span></span><em>Epistominella exigua</em> that thrives in stressful conditions, such as sea level oscillations to <em>Globocassidulina crassa</em>, that prefers mild environments during periods of sea level stability.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"183 ","pages":"Article 102270"},"PeriodicalIF":1.9,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46234300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Convolutional neural network application on a new middle Eocene radiolarian dataset","authors":"Veronica Carlsson ,&nbsp;Taniel Danelian ,&nbsp;Martin Tetard ,&nbsp;Mathias Meunier ,&nbsp;Pierre Boulet ,&nbsp;Philippe Devienne ,&nbsp;Sandra Ventalon","doi":"10.1016/j.marmicro.2023.102268","DOIUrl":"10.1016/j.marmicro.2023.102268","url":null,"abstract":"<div><p><span>A new radiolarian image database was used to train a Convolutional Neural Network (CNN) for automatic </span>image classification<span>. The focus was on 39 commonly occurring nassellarian species, which are important for biostratigraphy.</span></p><p>The database consisted of tropical radiolarian assemblages from 129 middle Eocene<span> samples retrieved from ODP Holes 1258A, 1259A, and 1260A (Demerara Rise). A total of 116 taxonomic classes were established, with 96 classes used for training a ResNet50 CNN. To represent the diverse radiolarian assemblage, some classes were formed by grouping forms based on external morphological criteria. This approach resulted in an 86.6% training accuracy.</span></p><p>A test set of 800 images from new samples obtained from Hole 1260A was used to validate the CNN, achieving a 75.69% accuracy. The focus then shifted to 39 well-known nassellarian species, using a total of 15,932 images from the new samples. The goal was to determine if the targeted species were correctly classified and explore potential real-world applications of the trained CNN.</p><p>Different prediction threshold values were experimented with. In most cases, a lower threshold value was preferred to ensure that all species were captured in the correct groups, even if it resulted in lower accuracies within the classes.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"183 ","pages":"Article 102268"},"PeriodicalIF":1.9,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49463236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}