Sedimentary response to volcanic activity in the Okinawa Trough since the last deglaciation

来源 :Chinese Journal of Oceanology and Limnology | 被引量 : 0次 | 上传用户:abmabc
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
To investigate the relationship between volcanic activity and sediment record on regional and temporal scales,158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT),and two cores recovered in the northern and southern OT,respectively.Mineralogy,grain-size,and geochemical analyses of those samples show that:1) volcanic glass,volcanic-type pyroxene,hypersthenes,and magnetite increase in sediment influenced by volcanic activity;2) sediment grain sizes (and also silt content) increase in ash layers;and 3) the contents of Na2O and Zr are higher,while terrigenous elements,e.g.,TFe2O3 and K2O,and biogenous compositions,e.g.,CaO and Sr,are relatively lower in ash layers than those of non-ash layers.The distribution of volcanic ash has three distinguishing characteristics:1) volcanic ash is more abundant in the northern and central OT than the southern OT;2) volcanic ash increases from continental shelf to the trough;3) the sediment during the last 12 000 a suggests stronger volcanic events than during 15 000-12 000 a.The eruptive locations,frequency,and volume of calderas are among the most important factors controlling the distributions of volcanic ash.In addition,the main Kuroshio warm current that extends northward probably impeded the diffusion of volcanic ash to the west and south in the OT.However,a southward current probably carried some volcanic ash toward southern OT. To investigate the relationship between volcanic activity and sediment record on regional and temporal scales, 158 surface sediment samples were collected from the East China Sea Shelf to the northern Okinawa Trough (OT), and two cores recovered in the northern and southern OT, respectively. Mineralogy, grain-size, and geochemical analyzes of those samples show that: 1) volcanic glass, volcanic-type pyroxene, hypersthenes, and magnetite increase in sediment influenced by volcanic activity; 2) sediment grain sizes (and also silt content) increase in ash layers; and 3) the contents of Na2O and Zr are higher, while terrigenous elements, eg, TFe2O3 and K2O, and biogenous compositions, eg, CaO and Sr, are relatively lower in ash layers than those of non-ash layers. volcanic ash has three distinguishing characteristics: 1) volcanic ash is more abundant in the northern and central OT than the southern OT; 2) volcanic ash increases from continental shelf to the trough; 3) the sediment during the last 12 000 a suggests stronger volcanic events than during 15 000-12 000 a. The eruptive locations, frequency, and volume of calderas are among the most important factors controlling the distributions of volcanic ash. In addition, the main Kuroshio warm current that extends northward probably impeded the diffusion of volcanic ash to the west and south in the OT. However, a southward current probably carried some volcanic ash toward southern OT.
其他文献
辅酶Q(CoQ)或泛醌,是由表示氧化还原活性的苯醌骨架和类异戊二烯单位为n组成的同族体的总称。本稿中,氧化型用CoQn表示,含有2个电子的还原型用CoQnH_2表示。天然中存在着n=1
热烈祝贺《照相机》杂志出版100期1996年改版大16开本会年是机械工业网《照相机》杂志创刊16周年,本用是《照相机》杂志出版的第100期,自1996年起,《照相机》杂志改版16开本。值此纪急的日子,诚示衷地
上海当代艺术馆Museum of Contemporary Art Shanghai藏身于有上海浦西城市“心脏”之称的人民公园的绿荫之中,在这喧嚣都市的一隅宁谧中又新增了一个特有的艺术化生活空间三
“贫困设计”是邱志杰和中国美术学院贫困设计课题组在2006年提出的一个概念,指的是日常生活中底层人民为解决生活需求,随机进行的设计和制作行为。2006年上海双年展期间,邱
为了避免“办公室政治”降低效率、形成宗派,我们有这样一个不成文的制度:在一个部门里,当第一把手和第二把手发生无原则纠纷时,如果这个部门的绩效是中等以上的话,我们会毫
抒情作为表达方式之一,应当是不成问题的。因为文中不可能没有情感,有情感要表达,就需要抒情。关于抒情的表达,叶圣陶在《作文论》中说:“情感譬如彩光的灯,而叙述、议论是被
女性的安全感天生比男性要差,健康、婚姻、金钱、爱人、控制感等等各种因素都会让女人产生不安全感,许多时候,女性会因为这种不安全感令自己生活变得焦虑不安,缺乏快乐……然
老板欣赏不欣赏自己?会不会在好机会来临的时候将它作为礼物送给自己?红包里塞的钱会不会比别人多?怎样才能让老板喜欢自己?这些问题总是让办公室一族费思量。但老板会怎么
George Cairns告诉大家如何按照图库网站所需的风格处理自己的照片。也许你有将自己满意的作品打印装裱挂在墙上,或分享到Flickr等在线画廊网站的经验,但你的大多数照片也许
企鹅unique35相机介绍企鹅(PENGUN)taluue35tgNLtl!deffe2:司在今年第六届中国照相机械产品博览会上展示的超薄迷你型微电脑控制、液晶显示的全自动照相机。为使读者能详细地了解,现就封面企鹅hoqde35相机——:删:全自动... P