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
Scattered around the globe are more than 100 small regions of isolated volcanic activity known to geologists as hot spots. Unlik
Scattered around the globe are more than 100 small regions of isolated volcanic activity known to geologists as hot spots. Unlik
admin
2019-06-23
38
问题
Scattered around the globe are more than 100 small regions of isolated volcanic activity known to geologists as hot spots. Unlike most of the world’s volcanoes, they are not always found at the boundaries of the great drifting plates that make up the earth’s surface; on the contrary, many of them lie deep in the interior of a plate. Most of the hot spots move only slowly, and in some cases the movement of the plates past them has left trails of dead volcanoes. The hot spots and their volcanic trails are milestones that mark the passage of the plates.
That the plates are moving is now beyond dispute. Africa and South America, for example, are moving away from each other as new material is injected into the sea floor between them. The complementary coastlines and certain geological features that seem to span the ocean are reminders of where the two continents were once joined. The relative motion of the plates carrying these continents has been constructed in detail, but the motion of one plate with respect to another cannot readily be translated into motion with respect to the earth’s interior. It is not possible to determine whether both continents are moving in opposite directions or whether one continent is stationary and the other is drifting away from it. Hot spots, anchored in the deeper layers of the earth, provide the measuring instruments needed to resolve the question. From an analysis of the hot-spot population it appears that the African plate is stationary and that it has not moved during the past 30 million years.
The significance of hot spots is not confined to their role as a frame of reference. It now appears that they also have an important influence on the geophysical processes that propel the plates across the globe. When a continental plate comes to rest over a hot spot, the material rising from deeper layer creates a broad dome. As the dome grows, it develops deep fissures(cracks); in at least a few cases the continent may break entirely along some of these fissures, so that the hot spot initiates the formation of a new ocean. Thus just as earlier theories have explained the mobility of the continents, so hot spots may explain their mutability(inconstancy).
The hot spot theory may prove useful in explaining _____.
选项
A、the structure of the African plates
B、the revival of dead volcanoes
C、the mobility of the continents
D、the formation of new oceans
答案
D
解析
关于hot spot theory的作用,除了第2段提到的参照作用外,第3段论及的另一个重要作用在于它能够推动板块在地球表面漂移(propel the plates across the globe),从而引发了新海洋的形成(initiates the formation of a new ocean).故答案选D项。
转载请注明原文地址:https://kaotiyun.com/show/nJX7777K
0
大学英语六级
相关试题推荐
A、Atouraroundthecity.B、Acruisealongtheriver.C、Avisitaroundthecampus.D、Discussionandsomeseminars.B男士在说到对代表团的活动
A、All-arounddevelopmentB、Creativityforthefuture.C、Basicsocialskills.D、Academiccapability.D演讲者提到现在我们的教育体制建立在学术能力的概念上,学
A、Theyrefertotransgenicorganisms.B、Theyareharmfultotheenvironment.C、Theyaregrowningreenandcleanways.D、Theyar
A、Stayinginaglassboxfor44daysjustwithwater.B、ThrowingcheeseburgersonaplanearoundLondon.C、Havinghisresearchp
A、Studyinginaforeignenvironment.B、Livingfarawayfromfamily.C、Returningbacktohomecountry.D、Fittingintoaforeignc
ThebesttimetoviewtheMonaLisa,accordingtoanewbookonthebesttimestodothings,isaroundnineo’clockonaSunday
ThebesttimetoviewtheMonaLisa,accordingtoanewbookonthebesttimestodothings,isaroundnineo’clockonaSunday
ThebesttimetoviewtheMonaLisa,accordingtoanewbookonthebesttimestodothings,isaroundnineo’clockonaSunday
ThebesttimetoviewtheMonaLisa,accordingtoanewbookonthebesttimestodothings,isaroundnineo’clockonaSunday
Theconceptofobtainingfreshwaterfromicebergsthataretowedtopopulatedareasandaridregionsoftheworldwasoncetrea
随机试题
为防止和减少因订购期间需求率增长或到货延误所引起的缺货而设置的库存,称为()。
治疗弓形体病:治疗鼠疫:
造成阑尾管腔阻塞从而诱发急性阑尾炎的最常见原因是
制订会计电算化发展规划并组织实施是财政部门管理会计电算化的基本任务之一。()
根据下面材料,回答以下问题:某公司当前支付的红利为1元/股,第一年和第二年的盈利增长率和红利增长率均为20%,第三年盈利增长率和红利增长率下降到15%,从第四年开始,盈利增长率和红利增长率下降到6%,并一直维持这个水平。接上题,如果该客户一年之后卖出
现代商业银行的基本管理制度是()。
【2011.江西】人本主义心理学家马斯洛把求知、审美、创造的需要归入()之中。
A.BuildYourKid’sWorkSkillsB.PlaceTimeLimitsonLeisureActivitiesC.TalkabouttheFutureonaRegularBasisD.HelpK
Whatdepartmentdoesthespeakermostlikelyworkin?
WritingaResearchPaperI.ResearchPaperandOrdinaryEssayA.Similarityin【T1】________:
最新回复
(
0
)