Acta Oceanologica Sinica最新文献_第7页

Geochemistry of volcanic glass from Mahanadi offshore region, eastern continental margin of India: Constraints on the contribution of latest Toba super-eruption 印度东部大陆边缘马哈纳迪近海地区火山玻璃的地球化学：对最近一次鸟羽超级喷发的影响的制约因素

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-29 DOI: 10.1007/s13131-023-2195-5

Muralidhar Kocherla, Durbar Ray, Manavalan Satyanarayanan, Hilda Joao, Virsen Gaikwad, P. B. Ramamurty

{"title":"Geochemistry of volcanic glass from Mahanadi offshore region, eastern continental margin of India: Constraints on the contribution of latest Toba super-eruption","authors":"Muralidhar Kocherla, Durbar Ray, Manavalan Satyanarayanan, Hilda Joao, Virsen Gaikwad, P. B. Ramamurty","doi":"10.1007/s13131-023-2195-5","DOIUrl":"https://doi.org/10.1007/s13131-023-2195-5","url":null,"abstract":"The tephra layers in multiple sediment cores from the offshore region of the Mahanadi basin in the northern Bay of Bengal were investigated for possible volcanic sources. The glass shards from those tephra layers were studied for size distribution, texture, and elemental geochemistry to establish chronostratigraphic markers for regional and global Quaternary correlation. The textural features of fine-grained (silty) volcanic glasses suggest the distal source of these tephra deposits. Major element composition with elevated SiO2 contents ranging between 75%–76% and dominance of K2O (> 4.5%) over CaO (< 0.9%) suggest ashes have originated from siliceous rhyolitic melts, similar to the petrographic composition of tephra from the Toba volcano. The bulk trace element compositions of the same glass shards were comparable with those reported in the youngest Toba tephra reported elsewhere. Likewise, the LREE-dominated chondrite normalized REE profiles of tephra from the Mahanadi basin closely resemble the characteristic REE patterns in Toba ash from other parts of the Indian Ocean and thus confirmed the contribution of the youngest Toba super-eruption for this ash layers.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"203 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140812799","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}

引用次数: 0

U-Pb zircon ages and petrogeochemistry and tectonic implications of gabbro and granite in southwest Lahad Datu area of Sabah, Malaysia 马来西亚沙巴州拉哈达图西南地区辉长岩和花岗岩的U-Pb锆石年龄、岩石地球化学及其构造影响

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-27 DOI: 10.1007/s13131-023-2218-2

Zhigang Zhao, Wu Tang, Shixiang Liu, Huafeng Tang, Pujun Wang, Zhiwen Tian

{"title":"U-Pb zircon ages and petrogeochemistry and tectonic implications of gabbro and granite in southwest Lahad Datu area of Sabah, Malaysia","authors":"Zhigang Zhao, Wu Tang, Shixiang Liu, Huafeng Tang, Pujun Wang, Zhiwen Tian","doi":"10.1007/s13131-023-2218-2","DOIUrl":"https://doi.org/10.1007/s13131-023-2218-2","url":null,"abstract":"The southwest Lahad Datu felsic rocks were previously thought to have formed in the late Triassic as part of the microcontinental crystalline basement. Based on U-Pb ages, geochemistry, and the Hf isotopes of zircon from the southeastern Sabah gabbro and granite, in this study, the tectonic properties of the Sabah area during the Triassic were investigated. The weighted average U-Pb zircon ages of the gabbro and granite samples were determined to be (230.9 ± 2.5)Ma and (207.1 ± 3.3)Ma, respectively. The granite had SiO2 contents of 66.54%–79.47%, low TiO2 contents of 0.08%−0.3%, Al2O3 contents of 10.97%–16.22%, Na2O contents of 5.91%–6.39%, and low K2O contents of 0.15%–0.65%. The chondrite-normalized rare earth element (REE) patterns exhibit light REE enrichment, with right-sloping curves. The primitive mantle-normalized trace element spider diagrams exhibit Th, U, La, Sr, and Zr enrichment and Nb, Ta, P and Ti depletions, i.e., the geochemical characteristics of typical island arc igneous rocks. The tectonic discriminant diagram indicates that the granite is a volcanic arc granite. The Hf isotopic analysis of gabbro zircon revealed that the zircons have εHf(t) values of 12.08–16.24 (mean of 14.32) and two-stage model ages (tDM2) of 223–491 Ma (mean of 347 Ma). This indicates that the diagenetic magma of the gabbro was mainly derived from melting of newly formed crustal materials. The ophiolite in southeast Sabah has existed since the early Late Triassic. The crystalline basement granite in southeastern Sabah was emplaced lasted from late Triassic to early Cretaceous. Based on previous studies and global plate reconstruction models, it is speculated that the southeastern Sabah granite may have been formed in an island arc setting, i.e., where the oceanic crust of the Paleo-Tethys Ocean collided with the oceanic crust of the Panthalassa Ocean.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"103 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140799468","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}

引用次数: 0

Gene characterization and phylogenetic analysis of four mitochondrial genomes in Caenogastropoda Caenogastropoda 四种线粒体基因组的基因特征和系统发育分析

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-27 DOI: 10.1007/s13131-023-2258-7

Jiangyong Qu, Wanqi Yang, Xindong Teng, Li Xu, Dachuan Zhang, Zhikai Xing, Shuang Wang, Xiumei Liu, Lijun Wang, Xumin Wang

{"title":"Gene characterization and phylogenetic analysis of four mitochondrial genomes in Caenogastropoda","authors":"Jiangyong Qu, Wanqi Yang, Xindong Teng, Li Xu, Dachuan Zhang, Zhikai Xing, Shuang Wang, Xiumei Liu, Lijun Wang, Xumin Wang","doi":"10.1007/s13131-023-2258-7","DOIUrl":"https://doi.org/10.1007/s13131-023-2258-7","url":null,"abstract":"Caenogastropoda is a highly diverse group, containing ∼60% of all existing gastropods. Species in this subclass predominantly inhabit marine environments and have a high ecological and economic value. Owing to the increase in relevant phylogenetic studies, our understanding of between species relatedness in Caenogastropoda has improved. However, the biodiversity, taxonomic status, and phylogenetic relationships of this group remain unclear. In the present study, we performed next-generation sequencing of four complete mitochondrial genomes from three families (Buccinidae, Columbellidae, and Cypraeidae) and the four mitogenomes were classical circular structures, with a length of 16 177 bp in Volutharpa ampullacea, 16 244 bp in Mitrella albuginosa, 16 926 bp in Mauritia arabica asiatica and 15 422 bp in Erronea errones. Base composition analysis indicated that whole sequences were biased toward A and T. Then compared them with 171 complete mitochondrial genomes of Caenogastropoda. The phylogenetic relationship of Caenogastropoda derived from Maximum Likelihood (ML) and Bayesian Inference (BI) trees constructed based on CDS sequences was consistent with the results of traditional morphological analysis, with all three families showing close relationships. This study supported Caenogastropoda at the molecular level as a separate clade of Mollusca. According to our divergence time estimations, Caenogastropoda was formed during the middle Triassic period (∼247.2–237 Ma). Our novel mitochondrial genomes provide evidence for the speciation of Caenogastropoda in addition to elucidating the mitochondrial genomic evolution of this subclass.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"9 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140801553","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}

引用次数: 0

Seasonal variation of mesoscale eddy intensity in the global ocean 全球海洋中尺度涡旋强度的季节性变化

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-27 DOI: 10.1007/s13131-023-2278-3

Yongcan Zu, Yue Fang, Shuangwen Sun, Libao Gao, Yang Yang, Guijun Guo

{"title":"Seasonal variation of mesoscale eddy intensity in the global ocean","authors":"Yongcan Zu, Yue Fang, Shuangwen Sun, Libao Gao, Yang Yang, Guijun Guo","doi":"10.1007/s13131-023-2278-3","DOIUrl":"https://doi.org/10.1007/s13131-023-2278-3","url":null,"abstract":"Mesoscale eddies are a prominent oceanic phenomenon that plays an important role in oceanic mass transport and energy conversion. Characterizing by rotational speed, the eddy intensity is one of the most fundamental properties of an eddy. However, the seasonal spatiotemporal variation in eddy intensity has not been examined from a global ocean perspective. In this study, we unveil the seasonal spatiotemporal characteristics of eddy intensity in the global ocean by using the latest satellite-altimetry-derived eddy trajectory data set. The results suggest that the eddy intensity has a distinct seasonal variation, reaching a peak in spring while attaining a minimum in autumn in the Northern Hemisphere and the opposite in the Southern Hemisphere. The seasonal variation of eddy intensity is more intense in the tropical-subtropical transition zones within latitudinal bands between 15° and 30° in the western Pacific Ocean, the northwestern Atlantic Ocean, and the eastern Indian Ocean because baroclinic instability in these areas changes sharply. Further analysis found that the seasonal variation of baroclinic instability precedes the eddy intensity by a phase of 2–3 months due to the initial perturbations needing time to grow into mesoscale eddies.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"1 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140799463","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}

引用次数: 0

Catch organism assemblages along artificial reefs area and adjacent waters in Haizhou Bay 海州湾人工鱼礁区及邻近海域的渔获生物群落

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-27 DOI: 10.1007/s13131-023-2226-2

Shike Gao, Bin Xie, Chengyu Huang, Xiao Zhang, Shuo Zhang, Wenwen Yu

{"title":"Catch organism assemblages along artificial reefs area and adjacent waters in Haizhou Bay","authors":"Shike Gao, Bin Xie, Chengyu Huang, Xiao Zhang, Shuo Zhang, Wenwen Yu","doi":"10.1007/s13131-023-2226-2","DOIUrl":"https://doi.org/10.1007/s13131-023-2226-2","url":null,"abstract":"To better understand the community patterns mediated by connectivity in artificial reefs of coastal areas, it is necessary to understand the distribution and coexistence of organisms with artificial reefs area and adjacent waters. This study was conducted to examine main catches assemblages collected by trawls in Haizhou Bay, which included five habitats: the artificial reef area (AR), aquaculture area (AA), natural area (NA), estuary area (EA) and comprehensive effect area (CEA). The result shows that the total abundances of species in the five habitats were highly different (univariate PERMANOVA: P = 0.001, n = 24), but some species were also unique in their habitat (e.g. Scapharca subcrenata and Glossaulax didyma in AA). The body size distribution of specific species between habitats are different. For Collichthys lucidus, their body size in AR (14.63 cm ± 1.64 cm) and EA (14.3 cm ± 0.85 cm) is higher than that in NA (10.65 cm ± 1.64 cm), CEA (11.28 cm ± 1.85 cm) and AA (12.1 cm ± 0.43 cm), which indicates the potential connection from AR to EA mediated by their adult population. We concluded that artificial reefs in AR can be considered key components that have the ability to support species assemblages in adjacent habitats. This study has implications for the conservation and monitoring of species assemblages in coastal areas in terms of that artificial reefs can be applied in different stages of habitat protection implementation and in different combinations of scenarios.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"25 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140801554","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}

引用次数: 0

Effects of shore-normal coastal structure on medium- to long-term embayed shoreline evolution 海岸--正常海岸结构对中长期堤岸演变的影响

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-16 DOI: 10.1007/s13131-023-2222-6

Jitao Yu, Yuanting Ding, Pei Liu, Renfu Fan, Lin Zhang

{"title":"Effects of shore-normal coastal structure on medium- to long-term embayed shoreline evolution","authors":"Jitao Yu, Yuanting Ding, Pei Liu, Renfu Fan, Lin Zhang","doi":"10.1007/s13131-023-2222-6","DOIUrl":"https://doi.org/10.1007/s13131-023-2222-6","url":null,"abstract":"Based on high-tide shoreline data extracted from 87 Landsat satellite images from 1986 to 2019 as well as using the linear regression rate and performing a Mann-Kendall (M–K) trend test, this study analyzes the linear characteristics and nonlinear behavior of the medium- to long-term shoreline evolution of Jinghai Bay, eastern Guangdong Province. In particular, shoreline rotation caused by a shore-normal coastal structure is emphasized. The results show that the overall shoreline evolution over the past 30 years is characterized by erosion on the southwest beach, with an average erosion rate of 3.1 m/a, and significant accretion on the northeast beach, with an average accretion rate of 5.6 m/a. Results of the M–K trend test indicate that significant shoreline changes occurred in early 2006, which can be attributed to shore-normal engineering. Prior to that engineering construction, the shorelines are slightly eroded, where the average erosion rate is 0.7 m/a. However, after shore-normal engineering is performed, the shoreline is characterized by significant erosion (3.2 m/a) on the southwest beach and significant accretion (8.5 m/a) on the northeast beach, thus indicating that the shore-normal engineering at the updrift headland contributes to clockwise shoreline rotation. Further analysis shows that the clockwise shoreline rotation is promoted not only by longshore sediment transport processes from southwest to northeast, but also by cross-shore sediment transport processes. These findings are crucial for beach erosion risk management, coastal disaster zoning, regional sediment budget assessments, and further observations and predictions of beach morphodynamics.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"26 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140612479","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}

引用次数: 0

Diagenetic evolution and reservoir quality of the Oligocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea 南海珠江口盆地白云沙洲渐新世砂岩的成因演化与储层质量

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-16 DOI: 10.1007/s13131-023-2262-y

Bing Tian, Shanshan Zuo, Youwei Zheng, Jie Zhang, Jiayu Du, Jun Tang

{"title":"Diagenetic evolution and reservoir quality of the Oligocene sandstones in the Baiyun Sag, Pearl River Mouth Basin, South China Sea","authors":"Bing Tian, Shanshan Zuo, Youwei Zheng, Jie Zhang, Jiayu Du, Jun Tang","doi":"10.1007/s13131-023-2262-y","DOIUrl":"https://doi.org/10.1007/s13131-023-2262-y","url":null,"abstract":"The Oligocene Zhuhai sandstones are significant reservoirs for hydrocarbons in the Baiyun Sag, South China Sea. For effective appraisal, exploration and exploitation of such a deep-water hydrocarbon sandstone, samples of five wells from depths of 850 m to 3 000 m were studied. A series of comprehensive petrographic and geochemical analyses were performed to unravel the diagenetic features and their impact on the reservoir quality. Petrographically, the sandstones are dominated by feldspathic litharenites and lithic arenites with fine to medium grain sizes and moderate to good sorting. The reservoir quality varies greatly with a range of porosity from 0.2% to 36.1% and permeability from 0.016 × 10−3 µm2 to 4 301 × 10−3 µm2, which is attributed to complex diagenetic evolution related to sedimentary facies; these include compaction, cementation of calcite, dolomite, siderite and framboidal pyrite in eogenetic stage; further compaction, feldspar dissolution, precipitation of ferrocalcite and ankerite, quartz cements, formation of kaolinite and its illitization, precipitation of albite and nodular pyrite, as well as hydrocarbon charge in mesogenetic stage. The dissolution of feldspar and illitization of kaolinite provide internal sources for the precipitation of quartz cement, while carbonate cements are derived from external sources related to interbedded mudstones and deep fluid. Compaction is the predominant factor in reducing the total porosity, followed by carbonate cementation that leads to strong heterogeneity. Feldspar dissolution and concomitant quartz and clay cementation barely changes the porosity but significantly reduces the permeability. The high-quality reservoirs can be concluded as medium-grained sandstones lying in the central parts of thick underwater distributary channel sandbodies (>2 m) with a high content of detrital quartz but low cement.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"182 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140612303","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}

引用次数: 0

Development of SNP parentage assignment techniques in the yellowfin seabream Acanthopagrus latus 黄鳍鲷SNP亲子鉴定技术的开发

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-15 DOI: 10.1007/s13131-023-2221-7

Hongbo Zhao, Liangmin Huang, Jing Zhang, Songyuan You, Qingmin Zeng, Xiande Liu

{"title":"Development of SNP parentage assignment techniques in the yellowfin seabream Acanthopagrus latus","authors":"Hongbo Zhao, Liangmin Huang, Jing Zhang, Songyuan You, Qingmin Zeng, Xiande Liu","doi":"10.1007/s13131-023-2221-7","DOIUrl":"https://doi.org/10.1007/s13131-023-2221-7","url":null,"abstract":"Acanthopagrus latus is an essential aquaculture species on the south coast of China. However, there is a lack of systematic breeding of A. latus, which considerably limits the sustainable development of A. latus. As a result, genetic improvements are urgently needed to breed new strains of A. latus with rapid growth and strong resistance to disease. During selective breeding, it is necessary to estimate the genetic parameters of the target trait, which in turn depends on an accurate disentangled pedigree for the selective population. Therefore, it is necessary to establish the parentage assignment technique for A. latus. In this study, 95 individuals selected from their parents and their 14 families were used as experimental material. SNPs were developed by genome re-sequencing, and highly polymorphic SNPs were screened on the basis of optimized filtering parameters. A total of 14 392 738 SNPs were discovered and 205 SNPs were selected for parentage assignment using the CERVUS software. In the model where the gender of the parents is known, the assignment success rate is 98.61% for the male parent, 97.22% for the female parent, and 95.83% for the parent pair. In the model where the gender of the parents is unknown, the assignment success rate is 100% for a single parent and 90.28% for the parent pair. The results of this study were expected to serve as a reference for the breeding of new varieties of A.latus.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"270 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578916","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}

引用次数: 0

The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode 南极半岛西部玛格丽特湾多谷浮游植物生物量与南环流模式的联系

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-15 DOI: 10.1007/s13131-023-2201-y

Ning Jiang, Zhaoru Zhang, Ruifeng Zhang, Chuning Wang, Meng Zhou

{"title":"The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode","authors":"Ning Jiang, Zhaoru Zhang, Ruifeng Zhang, Chuning Wang, Meng Zhou","doi":"10.1007/s13131-023-2201-y","DOIUrl":"https://doi.org/10.1007/s13131-023-2201-y","url":null,"abstract":"Antarctic coastal polynyas are biological hotspots in the Southern Ocean that support the abundance of high-trophic-level predators and are important for carbon cycling in the high-latitude oceans. In this study, we examined the interannual variation of summertime phytoplankton biomass in the Marguerite Bay polynya (MBP) in the western Antarctic Peninsula area, and linked such variability to the Southern Annular Mode (SAM) that dominated the southern hemisphere extratropical climate variability. Combining satellite data, atmosphere reanalysis products and numerical simulations, we found that the interannual variation of summer chlorophyll-a (Chl-a) concentration in the MBP is significantly and negatively correlated with the spring SAM index, and weakly correlated with the summer SAM index. The negative relation between summer Chl-a and spring SAM is due to weaker spring vertical mixing under a more positive SAM condition, which would inhibit the supply of iron from deep layers into the surface euphotic layer. The negative relation between spring mixing and spring SAM results from greater precipitation rate over the MBP region in positive SAM phase, which leads to lower salinity in the ocean surface layer. The coupled physical-biological mechanisms between SAM and phytoplankton biomass revealed in this study is important for us to predict the future variations of phytoplankton biomasses in Antarctic polynyas under climate change.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"44 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140578993","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}

引用次数: 0

U-Pb zircon geochronology of basaltic pyroclastic rocks from the basement beneath the Xisha Islands in the northwestern South China Sea and its geological significance 南海西北部西沙群岛基底玄武质火成岩的U-Pb锆石地质年代及其地质意义

IF 1.4 3区地球科学

Acta Oceanologica Sinica Pub Date : 2024-04-15 DOI: 10.1007/s13131-023-2198-2

Yu Zhang, Kefu Yu, Shiying Li

{"title":"U-Pb zircon geochronology of basaltic pyroclastic rocks from the basement beneath the Xisha Islands in the northwestern South China Sea and its geological significance","authors":"Yu Zhang, Kefu Yu, Shiying Li","doi":"10.1007/s13131-023-2198-2","DOIUrl":"https://doi.org/10.1007/s13131-023-2198-2","url":null,"abstract":"As one of the micro-blocks dispersed in the South China Sea (SCS), the basement of the Xisha Islands has rarely been drilled because of the thick overlying Cenozoic sediments, which has led to a confused understanding of the pre-Cenozoic basement of the Xisha Islands. Well CK-1, a kilometer-scale major scientific drill in the Xisha Islands in the northwestern SCS, penetrated thick reefal limestone (0–888.4 m) and the underlying basement rocks (888.4–901.4 m). In this study, we present the zircon U-Pb ages of basement basaltic pyroclastic rocks from Well CK-1 in the Xisha Islands of the northwestern SCS to investigate the basement nature of the Xisha micro-block. The basement of Well CK-1 consists of basaltic pyroclastic rocks on the seamount. The zircon grains yielded apparent ages ranging from ca. 2 138.9 Ma to ca. 36 Ma. The old group of zircon grains from Well CK-1 was considered to be inherited zircons. Two Cenozoic zircons gave a weighted mean 206pb/238U age of (36.3 ± 1.1) Ma, Mean Squared Weighted Deviations (MSWD) = 1.2, which may represent the maximum age of the volcano eruption. The Yanshanian inherited zircons (116.9–105.7 Ma and 146.1–130.2 Ma) from Well CK-1 are consistent with the zircons from Well XK-1, indicating that the basement of Chenhang Island may be similar to that of Well XK-1. We propose that the Xisha micro-block may have developed on a uniform Late Jurassic metamorphic crystalline basement, intruded by Cretaceous granitic magma.","PeriodicalId":6922,"journal":{"name":"Acta Oceanologica Sinica","volume":"48 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2024-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140579434","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}

引用次数: 0