{"title":"基于矿物和生物成因碳酸钙组成的Kikai岛附近晚更新世至全新世浊积岩源区估算","authors":"Ryo Nakanishi , Ayumi Maeda , Atsuko Amano , Juichiro Ashi , Asuka Yamaguchi , Yusuke Yokoyama , Yosuke Miyairi","doi":"10.1016/j.margeo.2025.107593","DOIUrl":null,"url":null,"abstract":"<div><div>Identifying the initial location of a turbidity current can help reveal a paleogeography, potential petroleum reservoir rocks, and a paleoseismic history. Therefore, a method for estimating the source area of turbidites is crucial. This study estimates the source area of turbidites using marine core sediments and surface sediments obtained around Kikai Island, located in the central Ryukyu Arc. We focus especially on mineral composition, variations of grain-size distribution and microfossil assemblages to estimate the water depth and hinterland geology of the source sand. Calcareous turbidites exhibiting normal grading or laminated structures were identified in the marine core at the fore-arc slope. We compare the calcium carbonate mineral compositions of these calcareous turbidites with those of surface sediments by X-ray diffraction (XRD) analysis. The proportion of aragonite and magnesium calcite, as opposed to calcite, decreases with increasing water depth, corresponding to the habitat of foraminifera and pteropods. A regression equation was obtained from the calcium carbonate mineral ratio and water depth. The predicted water depth of the turbidite source was equivalent to that based on benthic/planktonic foraminiferal ratios. In addition, principal component analysis of XRD results and grain size analysis spatially constrained the source area of turbidites by comparison with surface sediments in the hinterland geology. Since turbidite deposition was limited to 14.7–9.7 ka, we interpret that increased sediment supply resulting from coral-reef drowning during rapid sea-level rise, and calcareous sand beds were unstable and transported by turbidity currents. The method developed in this study provides a framework for estimating the supply source of turbidites and is expected to be used in paleoseismic studies and petroleum reservoir evaluation.</div></div>","PeriodicalId":18229,"journal":{"name":"Marine Geology","volume":"487 ","pages":"Article 107593"},"PeriodicalIF":2.6000,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Estimation of turbidite source area in late Pleistocene to Holocene around Kikai Island based on mineral and biogenic calcium carbonate composition\",\"authors\":\"Ryo Nakanishi , Ayumi Maeda , Atsuko Amano , Juichiro Ashi , Asuka Yamaguchi , Yusuke Yokoyama , Yosuke Miyairi\",\"doi\":\"10.1016/j.margeo.2025.107593\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Identifying the initial location of a turbidity current can help reveal a paleogeography, potential petroleum reservoir rocks, and a paleoseismic history. Therefore, a method for estimating the source area of turbidites is crucial. This study estimates the source area of turbidites using marine core sediments and surface sediments obtained around Kikai Island, located in the central Ryukyu Arc. We focus especially on mineral composition, variations of grain-size distribution and microfossil assemblages to estimate the water depth and hinterland geology of the source sand. Calcareous turbidites exhibiting normal grading or laminated structures were identified in the marine core at the fore-arc slope. We compare the calcium carbonate mineral compositions of these calcareous turbidites with those of surface sediments by X-ray diffraction (XRD) analysis. The proportion of aragonite and magnesium calcite, as opposed to calcite, decreases with increasing water depth, corresponding to the habitat of foraminifera and pteropods. A regression equation was obtained from the calcium carbonate mineral ratio and water depth. The predicted water depth of the turbidite source was equivalent to that based on benthic/planktonic foraminiferal ratios. In addition, principal component analysis of XRD results and grain size analysis spatially constrained the source area of turbidites by comparison with surface sediments in the hinterland geology. Since turbidite deposition was limited to 14.7–9.7 ka, we interpret that increased sediment supply resulting from coral-reef drowning during rapid sea-level rise, and calcareous sand beds were unstable and transported by turbidity currents. The method developed in this study provides a framework for estimating the supply source of turbidites and is expected to be used in paleoseismic studies and petroleum reservoir evaluation.</div></div>\",\"PeriodicalId\":18229,\"journal\":{\"name\":\"Marine Geology\",\"volume\":\"487 \",\"pages\":\"Article 107593\"},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2025-05-29\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Marine Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0025322725001185\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Marine Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0025322725001185","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
Estimation of turbidite source area in late Pleistocene to Holocene around Kikai Island based on mineral and biogenic calcium carbonate composition
Identifying the initial location of a turbidity current can help reveal a paleogeography, potential petroleum reservoir rocks, and a paleoseismic history. Therefore, a method for estimating the source area of turbidites is crucial. This study estimates the source area of turbidites using marine core sediments and surface sediments obtained around Kikai Island, located in the central Ryukyu Arc. We focus especially on mineral composition, variations of grain-size distribution and microfossil assemblages to estimate the water depth and hinterland geology of the source sand. Calcareous turbidites exhibiting normal grading or laminated structures were identified in the marine core at the fore-arc slope. We compare the calcium carbonate mineral compositions of these calcareous turbidites with those of surface sediments by X-ray diffraction (XRD) analysis. The proportion of aragonite and magnesium calcite, as opposed to calcite, decreases with increasing water depth, corresponding to the habitat of foraminifera and pteropods. A regression equation was obtained from the calcium carbonate mineral ratio and water depth. The predicted water depth of the turbidite source was equivalent to that based on benthic/planktonic foraminiferal ratios. In addition, principal component analysis of XRD results and grain size analysis spatially constrained the source area of turbidites by comparison with surface sediments in the hinterland geology. Since turbidite deposition was limited to 14.7–9.7 ka, we interpret that increased sediment supply resulting from coral-reef drowning during rapid sea-level rise, and calcareous sand beds were unstable and transported by turbidity currents. The method developed in this study provides a framework for estimating the supply source of turbidites and is expected to be used in paleoseismic studies and petroleum reservoir evaluation.
期刊介绍:
Marine Geology is the premier international journal on marine geological processes in the broadest sense. We seek papers that are comprehensive, interdisciplinary and synthetic that will be lasting contributions to the field. Although most papers are based on regional studies, they must demonstrate new findings of international significance. We accept papers on subjects as diverse as seafloor hydrothermal systems, beach dynamics, early diagenesis, microbiological studies in sediments, palaeoclimate studies and geophysical studies of the seabed. We encourage papers that address emerging new fields, for example the influence of anthropogenic processes on coastal/marine geology and coastal/marine geoarchaeology. We insist that the papers are concerned with the marine realm and that they deal with geology: with rocks, sediments, and physical and chemical processes affecting them. Papers should address scientific hypotheses: highly descriptive data compilations or papers that deal only with marine management and risk assessment should be submitted to other journals. Papers on laboratory or modelling studies must demonstrate direct relevance to marine processes or deposits. The primary criteria for acceptance of papers is that the science is of high quality, novel, significant, and of broad international interest.