首页
登录
职称英语
Scattered around the globe are more than 100 small regions of isolated volca
Scattered around the globe are more than 100 small regions of isolated volca
游客
2023-08-18
23
管理
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). [br] The author believes that _____.
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 true
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
文章第2段的开头指出That the plates are moving is now beyond dispute。beyond dispute意为“毋庸置疑”,故答案选B项。从第2段第4句的“但是一个板块相对于另外一个板块的运动不能被顺理成章地解释成板块与它相对于地球内部的运动”,可排除A项。
转载请注明原文地址:https://tihaiku.com/zcyy/2937744.html
相关试题推荐
TheAmericaneconomicsystemisorganizedaroundabasicallyprivateenterpr
TheAmericaneconomicsystemisorganizedaroundabasicallyprivateenterpr
TheAmericaneconomicsystemisorganizedaroundabasicallyprivateenterpr
TheAmericaneconomicsystemisorganizedaroundabasicallyprivateenterpr
TheAmericaneconomicsystemisorganizedaroundabasicallyprivateenterpr
Believeitornot,bluejeanshavebeenaroundforover130years.LeviStra
Believeitornot,bluejeanshavebeenaroundforover130years.LeviStra
Believeitornot,bluejeanshavebeenaroundforover130years.LeviStra
Believeitornot,bluejeanshavebeenaroundforover130years.LeviStra
Believeitornot,bluejeanshavebeenaroundforover130years.LeviStra
随机试题
[audioFiles]2017m5s/audio_ezfj_131_201705[/audioFiles]TheOxfordandCambri
员工个人绩效的基本特征不包括( )A.绩效必须是可衡量的或可评估的 B.绩效
在一个媒介发达的时代,不少人觉得,图片才是传播的王道。髙速的时代应有高速的传播,
《义务教育数学课程标准(2011年版)》中有两类行为动词:一类描述结果目标的行为
(2016年真题)关于远期利率,以下说法错误的是()。A.是利率衍生品的定
关于药物基因组学说法正确的是A:药物基因组学研究人类基因变异和药物剂量关系的科学
根据以下资料。回答。 2006年全国共有生产力促进中心1331家,比上年增
在制订方案的环节,限定目标尤为重要。限定目标可以使用SMART方法,即具体性(
下列哪项不是动脉粥样硬化的高危因素? a.血浆总胆固醇增高b.血浆hdl增高
进行建设项目财务现金流量分析时,若采用的折现率提高,则()。A.净现金流量
最新回复
(
0
)