太平洋CC区西部沉积物地球化学特征及其成因  

Geochemical Characteristics and Genetic Mechanisms of Sediments from Western Clarion-Clipperton Zone,Pacific Ocean

作　　者：姜柳青 汪卫国 梁积伟[1] 戴霜 蒋敏 陶文星 马晓军 JIANG LiuQing;WANG WeiGuo;LIANG JiWei;DAI Shuang;JIANG Min;TAO WenXing;MA XiaoJun(School of Earth Sciences and Resources,Chang’an University,Xi’an 710054,China;Third Institute of Oceanography,MNR,Xiamen,Fujian 361005,China;School of Earth Sciences,Lanzhou University,Lanzhou 730000,China)

机构地区：[1]长安大学地球科学与资源学院,西安710054 [2]自然资源部第三海洋研究所,福建厦门361005 [3]兰州大学地质科学与矿产资源学院,兰州730000

出　　处：《沉积学报》2021年第5期1185-1197,共13页Acta Sedimentologica Sinica

基　　金：大洋协会项目(DY-135-E2-5-02);自然资源部第三海洋研究所基本科研业务费项目(2018006)。

摘　　要：对太平洋CC区西部7根沉积物短柱样的常微量元素进行浓度测试,以了解沉积物元素时空分布特征及其来源和控制因素。与上地壳元素平均值(UCC)相比,研究区沉积物中MnO、P2O5、Co、Ni、Cu、Mo、Ba明显富集,Al2O3、K2O、Fe2O3、CaO、Sr等亏损。聚类和因子分析表明研究区沉积物元素有4种来源,其中Al2O3、Fe2O3、K2O、MgO、TiO2、V、Cr、Co、Rb、Zr、Nb、Cs、Hf、Ta、Pb、Th、U为陆源黏土成因;CaO和Sr为钙质生物成因;MnO、P2O5、B、Ni、Cu、Zn、Mo、Ba为海水自生成因;Na2O为火山—热液成因。10.2°N以北沉积物元素为陆源黏土、海水自生和钙质生物成因,而10.2°N以南沉积物元素为陆源黏土、海水自生和火山—热液成因。沉积物中陆源物质主要来自亚洲高空气流携带的风尘物质。沉积物中海水自生成因的金属元素富集,与富氧的南极底流有关。柱样中CaO、Sr含量的时空变化,与柱样所处水深、冰期生产力和碳酸钙补偿深度变化有关。柱样中Ba/Ti指示的火山—热液活动在地质时期呈减弱的趋势,其对沉积物的影响也向北减弱。The major and trace elements of sediments in seven short cores collected from the western Clarion-Clipperton Zone in the Pacific Ocean were measured,with an attempt to understand their spatial and temporal distributions and genetic mechanism.Compared to the Upper Continental Crust(UCC),the sediments in the study area are significantly enriched in MnO,P_(2)O_(5),Co,Ni,Cu and Mo.They are depleted in Al_(2)O_(3),K_(2)O,Fe_(2)O_(3),CaO and Sr.Cluster and factor analysis show that the elements of the sediments are derived from four sources:1)Al_(2)O_(3),Fe_(2)O_(3),K_(2)O,MgO,TiO_(2),V,Cr,Co,Rb,Zr,Nb,Cs,Hf,Ta,Pb,Th and U from terrestrial clay;2)CaO and Sr from calcareous biogenous sediments;3)MnO,P_(2)O_(5),B,Ni,Cu,Zn,Mo,Ba are hydrogenous;and 4)Na_(2)O is of volcanic-hydrothermal origin.Sediments sampled to the north of latitude 10.2°N were terrigenous,hydrogenous and calcareous biogenous;sediments to the south were terrigenous,hydrogenous and volcano-hydrothermal genesis.The terrestrial material mainly comes from aeolian material carried by upper air currents from Asia.Hydrogenous enrichment of metal elements in the sediments is related to oxygen-rich Antarctic Bottom Water(AABW).The spatial and temporal variation of biogenous CaO and Sr is related to the ocean depths of the cores,and the changes of carbonate compensation depth(CCD)responding to falling sea levels and productivity change during the glacial period.The volcanic-hydrothermal activity indicated by the Ba/Ti ratio in the cores weakened over geological time,and its impact on the sediments also weakened northward.

关 键 词：太平洋 CC区 沉积物 地球化学 成因机制 

分 类 号：P534.63[天文地球—第四纪地质学]