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
This view may be correct: it has the advantage that the currents are driven by temperature differences that themselves depend on
This view may be correct: it has the advantage that the currents are driven by temperature differences that themselves depend on
admin
2011-02-10
69
问题
This view may be correct: it has the advantage that the currents are driven by temperature differences that themselves depend on the position of the continents. Such a back-coupling, in which the position of the moving plate has an impact on the forces that move it, could produce complicated and varying motions.
On the other hand, the theory is implausible because convection does not normally occur along lines, and it certainly does not occur along lines broken by frequent offsets or changes in direction, as the ridge is. Also it is difficult to see how the theory applies to the plate between the Mid-Atlantic Ridge and the ridge in the Indian Ocean. This plate is growing on both sides, and since there is no intermediate trench, the two ridges must be moving apart. It would be odd if the rising convection currents kept exact pace with them. An alternative theory is that the sinking part of the plate, which is denser than the hotter surrounding mantle, pulls the rest of the plate after it. Again it is difficult to see how this applies to the ridge in the South Atlantic, where neither the African nor the American plate has a sinking part.
Another possibility is that the sinking plate cools the neighboring mantle and produces convection currents that move the plates. This last theory is attractive because it gives some hope of explaining the enclosed seas, such as the Sea of Japan. These seas have a typical oceanic floor, except that the floor is overlaid by several kilometers of sediment. Their floors have probably been sinking for long periods.
It seems possible that a sinking current of cooled mantle material on the upper side of the plate might be the cause of such deep basins. The enclosed seas are an important feature of the earth’s surface and seriously require explanation because, in addition to the enclosed seas that are developing at present behind island arcs, there are a number of older ones of possibly similar origin, such as the Gulf of Mexico, the Black Sea, and perhaps the North Sea.
It can be inferred from the passage that, of the following, the deepest sediments would be found in the ______.
选项
A、Black Sea
B、Indian Ocean
C、South Atlantic
D、Pacific
答案
A
解析
转载请注明原文地址:https://www.kaotiyun.com/show/UycO777K
本试题收录于:
NAETI中级口译笔试题库外语翻译证书(NAETI)分类
0
NAETI中级口译笔试
外语翻译证书(NAETI)
相关试题推荐
Securitymenbelievethetit-for-tatmurdersweretheresultofthebombingwhichhadoccurredinthecitycenter.
Americanswhoconsiderthemselves______inthetraditionalsensedonotusuallyhesitatetoheapcriticismindomesticmattersov
Yourusualteacherhaslosthisvoiceand________Iamtakinghisplacetoday.
OurGuiltySecretNexttimeyoupickupalunchtimesandwich,takeamomenttothinkaboutwhereithascomefrom.Thinkoft
Jerryshouldn’thavefinishedtheproject,orhewouldhavereportedtothepresident.
Computersareplayingamoreandmoreimportantfunctioninourdailylife,whichshouldnotbebelittled.
Allmothersareofthesamenatureasamother,andifyourMumwillbeatycoonlikeGates,shewillbeabletobuyyouthesam
Someartistsimmodestlyidealizeorexaggeratethesignificanceoftheirwork,yetothers,disdainingtoexalttheroleofthea
EarlyinSeptembereachyear,thepopulationofAnnArbor,Michigan,suddenlyincreasesbyabout25,000asstudentsarrivefort
Noticingthatshewasn’thappywiththearrangements,Itriedtobookadifferenthotel.
随机试题
WhatisrequiredinmanydifferentsituationsinAmericanculture?Anexpressionof_________________________________________
HSE管理小组职责是负责审定(),作出HSE重大决策。
宜用灸法的有()。
肝气乘脾型泄泻选用肾阳虚衰型泄泻选用
现金流量与利润的主要区别是,前者的计算以现金制为基础,后者的计算以应计制为基础。()
下列关于应付账款的表述正确的有()。
有关老年期记忆力下降的机制的解释包括()。
柜房、飞钱
A、 B、 C、 A
CharacteristicsqfAmericanCultureI.PunctualityA.Goingtothetheater:be【T1】______twentyminutesprior【T1】______B.
最新回复
(
0
)