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
考研
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
2008-12-26
39
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 mil lion 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 deed 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).
选项
A、the motion of the plates corresponds to that of the earth’s interior
B、the geological theory about drifting plates has been proved to be truse
C、the hot spots and the plates move slowly in opposite directions
D、the movement of hot spots proves the continents are moving apart
答案
B
解析
短文第二段段首句告诉我们:对于板块漂移这一理论现已无人质疑,及随后列举的有关非洲及南美洲板块的实例,我们可以判断选项"关于板块漂移这一理论现已被证实是正确的"为正确答案。
转载请注明原文地址:https://jikaoti.com/ti/FwjRFFFM
0
考研英语一
相关试题推荐
Themainideaofthefirstparagraphisthat______.Whatdoestheword"disruptive"(Paragraph3)mostprobablymean?
ThemajordifferencebetweennarrativesalesandsuggestivesalesisthatWhichofthefollowingisthebesttitleforthepass
Amajorreasonforconflictintheanimalworldisterritory.Themaleanimal(21)anarea.Thesizeoftheareaissufficientt
Nameshavegainedincreasingimportanceinthecompetitiveworldofhighereducation.Ascollegesstriveformarketshare,they
Thecellphone,adevicewehavelivedwithformorethanadecade,offersagoodexampleofapopulartechnology’sunforeseensi
Scienceisanenterpriseconcernedwithgaininginformationaboutcausality,ortherelationshipbetweencauseandeffect.Asim
Accordingtoarecentsurveyonmoneyandrelationships,36percentofpeoplearekeepingabankaccountfromtheirpartner.Whi
Manyadultsmaythinkthey’regettingenoughshut-eye,butinamajorsleepstudyalmost80percentofrespondentsadmittedton
Shortlybeforehediedoflymphoma,thegreatwriterandphysicianLewisThomas,whosebooksturnedscienceintoawayofapprec
[A]financialaidshouldbeprovidedtopoorcountriesthatarewithawidevarietyofplantsandanimals.[B]everyonewillsin
随机试题
卫星:飞船:航天()。
The1983report"ANationAtRiskcitedasexamplesofthedeclineofeducationalstandards?()
试论述双因素理论对我国现代企业管理具有哪些借鉴意义?
怀疑半月板损伤时最精确、理想的辅助检查方法是
实验中常用枸橼酸钠抗凝血,其机制是
我国现行税收体系中,涉及土地税收的课税项目主要有()。
在预测声级前需根据声源与预测点之间的空间分布形式将声源简化成()几类。
会计法律制度是指国家权力机关和行政机关制定的各种会计规范性文件的总称。下列各中,属于会计法律制度的是()。
概念学习的主要方式有()。
()是教学活动的出发点和归宿。
最新回复
(
0
)