首页
登录
职称英语
For all their great diversity of shapes and sizes, glaciers can be divided
For all their great diversity of shapes and sizes, glaciers can be divided
游客
2024-05-14
3
管理
问题
For all their great diversity of shapes and sizes, glaciers can be divided into two essential types: valley glaciers, which flow downhill from mountains and are shaped by the constraints of topography (地貌), and ice sheets, which flow outward in all directions from dome--like centers of accumulated ice to cover vast expanse of terrain. Whatever their type, most glaciers are remnants of great shrouds of ice that covered the earth years ago. In a few of these glaciers the oldest ice is very ancient indeed; the age of parts of the Antarctic sheet may exceed 500,000 years.
Glaciers are born in rocky womb above the snow line, where there is sufficient winter snowfall and summer cold for snow to survive the annual melting. The long gestation period of a glacier begins with the accumulation and gradual transformation of snow flakes. Soon after they reach the ground, complex snowflakes are reduced to compact, roughly spherical ice crystals, and the basic components of a glacier. As new layers of snow and firm, snow that survives the melting of the previous summer, accumulate, they squeeze out most of the air bubbles trapped within and between the crystals below. This process of recrystallization continues throughout the life of the glacier.
The length of time required for the creation of glacier ice depends mainly upon the temperature and the rate of snowfall. In Iceland, where snowfall is heavy and summer temperatures are high enough to produce plenty of melt--water, glacier ice may come into being in a relatively short time--say, ten years. In parts of Antarctica, where snowfall is scant and the ice remains well below its melting temperature year round, the process may require hundreds of years.
The ice does not become a glacier until it moves under its own weight, and it cannot move significantly until it reaches a critical thickness--the point at which the weight of the piled-up layers overcomes the internal strength of the ice and the friction between the ice and the ground. This critica} thickness is about 60 feet. The fastest moving glaciers have been gauged at not much more than two and a half miles per year, and some cover less than 1/100 inch in that same amount of time. But no matter how infinitesimal the flow, movement is what distinguishes a glacier from a mere mass of ice. [br] Which of the following is NOT true about glaciers?
选项
A、Glaciers are diversified in shapes and sizes.
B、Glaciers can be divided into valley glaciers and ice sheets.
C、Glaciers are remnants of great shrouds of ice that covered the earth years ago.
D、Few glaciers have a long history.
答案
D
解析
根据题干关键词glaciers定位到原文第一段。文中指出:In a few of these glaciers the oldest ice is very ancient indeed;the age of parts of the Antarctic sheet may exceed 500,000 years.可见,有的冰川的冰年龄可能超过50万年,故D项表述有误。
转载请注明原文地址:https://tihaiku.com/zcyy/3598745.html
相关试题推荐
Plato,anancientGreekphilosopher,believedthatmenaredividedintothre
Plato,anancientGreekphilosopher,believedthatmenaredividedintothre
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
Humanity’sprimal(原始的)effortstosystematizetheconceptsofsize,shapes,
随机试题
HowtoBeEffectiveReaders?I.Introductionofreadingand
在数据库设计过程中,设计用户外模式属于( );数据的物理独立性和数据的逻辑独立
呕吐反应多见于下列哪些情况麻醉()A.氯胺酮麻醉 B.丙泊酚麻醉 C.依
下列不属于肾动脉造影检查适应证的是A.原因不明的高血压,听诊脐周有血管杂音者
心室发生期前收缩之后出现代偿间歇的原因是:A.窦房结的节律性兴奋延迟发放 B
天王补心丹主治证候的病因病机是()A.心脾两虚,气血不足 B.心阴不
下列哪种蛋白不是由肝细胞合成的?()A.白蛋白 B.凝血酶原 C.前白蛋白
《中华人民共和国药品管理法》规定的管理范围中不包括A.药品经营 B.药品质量控
数千年以来,人们对满月之夜总是心存偏见,因为在一些传说中,有人会在满月之夜变成狼
主动脉瓣中度狭窄时瓣口面积为A.<0.75cm B.0.75~1..cm C
最新回复
(
0
)