首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at
admin
2017-11-17
46
问题
The Earth comprises three principal layers: the dense, iron-rich core, the mantle made of silicate (硅酸盐) that are semi-molten at depth, and the thin, solid-surface crust. There are two kinds of crust, a lower and denser oceanic crust and an upper, lighter continental crust found over only about 40 percent of the Earth’s surface. The rocks of the crust are of very different ages. Some continental rocks are over 3,000 million years old, while those of the ocean floor are less than 200 million years old. The crusts and the top, solid part of the mantle, totaling about 70 to 100 kilometers in thickness, at present appear to consist of about 15 rigid plates, 7 of which are very large. These plates move over the semi-molten lower mantle to produce all of the major topographical (地形学的) features of the Earth. Active zones where intense deformation occurs are confined to the narrow, interconnecting boundaries of contact of the plates.
There are three main types of zones of contact: spreading contacts where plates move apart, converging contacts where plates move towards each other, and transform contacts where plates slide past each other. New oceanic crust is formed along one or more margins of each plate by material issuing from deeper layers of the Earth’s crust, for example, by volcanic eruptions (爆发) of lava (火山 熔岩) at mid-ocean ridges. If at such a spreading contact the two plates support continents, a rift (裂缝 ) is formed that will gradually widen and become flooded by the sea The Atlantic Ocean formed like this as the American and Afro-European plates moved in opposite directions. When two plates carrying continents collide, the continental blocks, too light to be drawn down, continue to float and therefore buckle (起褶皱) to form a mountain chain along the length of the margin of the plates.
According to the second paragraph, the formation of the Atlantic Ocean is the example of_____.
选项
A、spreading contacts
B、the influence of volcanic eruptions
C、converging contacts
D、transform contacts
答案
A
解析
事实细节题。第2段主要分成两部分:第一部分谈板块活动的三种形式,第二部分分别举例说明。其中在说明spreading contacts时,引用了大西洋的例子:“The Atlantic Ocean formed like this…”,所以答案为A。
转载请注明原文地址:https://kaotiyun.com/show/yJa7777K
0
大学英语四级
相关试题推荐
WhichAttributesofaFoodProductareMostImportanttoConsumersA)TheAustralianstateofVictoriaisinvestinginapro
WhichAttributesofaFoodProductareMostImportanttoConsumersA)TheAustralianstateofVictoriaisinvestinginapro
WorkingtoImprovetheConditionsofEvergladesNationalParkA)WhenmanypeoplethinkofFlorida,imagesofsandycoastlin
Thereisnodenyingthatstudentsshouldlearnsomethingabouthowcomputerswork,justasweexpectthematleasttounderstand
"Youneedanapartmentaloneevenifit’soveragarage",declaredHelenGurleyBrowninher1962bestsellerSexandtheSingle
A、Thegirl’stwothighsarefusedtogether.B、Thegirl’slegsfusedtogetherfromherthighstoherankles.C、Thegirl’stwokne
Theownershipofpetsbringsavarietyofbenefitsthattheuninitiatedwouldneverbelieve.Foreverytaleofshreddedcushion,
A、Crossthetips.B、Stopleaningforward.C、Pointthetipstogether.D、Movetoagentleplace.C
2013年10月30日,中国第一所网络文学大学(onlineliteratureuniversity)成立。诺贝尔文学奖得主(NobelLiteraturePrizeLaureate)莫言担任名誉校长(honoraryprincipal).该大
随机试题
简述问卷设计的步骤。
简述如何评价习近平经济思想。
常用葛根而不用升麻治疗的病证是
某法院院长发现经本院终审的一个合同纠纷案件确有错误,应当再审,下述处理方法中正确的是()。
在下列外商投资企业中,不能够享受“两免三减半”税收优惠的有()。
教师辱骂学生侵犯了学生的()
治理通货膨胀需要采取紧缩性货币政策、加强需求和供给管理等措施,但从根本上看,则要加快经济结构调整。其中非常重要的一点是,应通过减税等措施减轻企业的负担。因为企业负担过重,就没有能力提高职工工资;为获得必要的利润,企业还要提高其产品价格。如果企业的负担减轻了
下列关于自然现象的说法错误的是()。
下面不属于需求分析阶段任务的是
Whatisthefocusofthepassage?
最新回复
(
0
)