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
In Death Valley, California, one of the hottest, most arid places in North America, there is much salt, and salt can damage rock
In Death Valley, California, one of the hottest, most arid places in North America, there is much salt, and salt can damage rock
admin
2012-08-25
69
问题
In Death Valley, California, one of the hottest, most arid places in North America, there is much salt, and salt can damage rocks impressively. Inhabitants of areas elsewhere, where streets and highways are salted to control ice, are familiar with the resulting rust and deterioration on cars. That attests to the chemically corrosive nature of salt, but it is not the way salt destroys rocks. Salt breaks rocks apart principally by a process called crystal prying and wedging. This happens not by soaking the rocks in salt water, but by moistening their bottoms with salt water. Such conditions exist in many areas along the eastern edge of central Death Valley. There, salty water rises from the groundwater table by capillary action through tiny spaces in sediment until it reaches the surface.
Most stones have capillary passages that suck salt water from the wet ground. Death Valley provides an ultra-dry atmosphere and high daily temperatures, which promote evaporation and the formation of salt crystals along the cracks or other openings within stones. These crystals grow as long as salt water is available. Like tree roots breaking up a sidewalk, the growing crystals exert pressure on the rock and eventually pry the rock apart along planes of weakness, such as banding in metamorphic rocks, bedding in sedimentary rocks, or preexisting or incipient fractions, and along boundaries between individual mineral crystals or grains. Besides crystal growth, the expansion of halite crystals(the same as everyday table salt) by heating and of sulfates and similar salts by hydration can contribute additional stresses. A rock durable enough to have withstood natural conditions for a very long time in other areas could probably be shattered into small pieces by salt weathering within a few generations.
The dominant salt in Death Valley is halite, or sodium chloride, but other salts, mostly carbonates and sulfates, also cause prying and wedging, as does ordinary ice. Weathering by a variety of salts, though often subtle, is a worldwide phenomenon. Not restricted to arid regions, intense salt weathering occurs mostly in salt-rich places like the seashore, near the large saline lakes in the Dry Valleys of Antarctica, and in desert sections of Australia, New Zealand, and central Asia.
Which of the following can be inferred from the passage about rocks that are found in areas where ice is common?
选项
A、They are protected from weathering.
B、They do not allow capillary action of water.
C、They show similar kinds of damage as rocks in Death Valley.
D、They contain more carbonates than sulfates.
答案
C
解析
转载请注明原文地址:https://www.kaotiyun.com/show/3uyO777K
0
托福(TOEFL)
相关试题推荐
Completethesummarybelow.ChooseNOMORETHANTHREEWORDSfromthepassageforeachanswer.Writeyouranswersinboxe
Completethesummarybelow.ChooseNOMORETHANTWOWORDSfromthepassageforeachanswer.Writeyouranswersinboxes
Answerthequestionsbelow.ChooseNOMORETHANTWOWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswersi
TheInnovationofGroceryStoresA.Attheverybeginningofthe20thcentury,theAmericangrocerystoresofferedcomprehen
Completethesentencesbelow.ChooseNOMORETHANTWOWORDSAND/ORANUMBERfromthepassageforeachanswer.Writeyouranswers
Questions14-16Matchthecorrecteventwiththe3placesbelow.A.CaribbeanWeekB.FringeFestivalC.FestivalofLiterature
WritetheappropriatelettersA-CagainstQuestions17-20.WhatarethelocationsofthefollowingplacesinRadford?(A)par
Completetheformbelow.WriteNOMORETHANTHREEWORDSAND/ORANUMBERforeachanswer.ProductIncidentReportExampleAnswer
Completethesentencesbelow.WriteONEWORDAND/ORANUMBERforeachanswer.Atthebeginningofthereport,thehypothesisan
Acardinalrolefor(players)ofthelute,(astringed)instrument,(are)thateverynoteissustainedfor(aslongas)possible
随机试题
心绞痛发生的原因和诱因不包括
队列研究中暴露人群选择有哪些途径
A.中医药管理部门B.工商行政管理部门C.卫生行政部门D.劳动与社会保障部门E.海关对药品生产、经营企业的工商登记、注册,以及监督管理的是()
委托监理服务合同按双方签署的合同协议书上注明的时间终止;自终止日起自然失效。()
造成社会总需求膨胀的因素有()。
()是由外界能激发,是能可靠的引起其后的起爆材料或各种工业炸药爆轰的起爆材料。
康有为第一次上书光绪皇帝,建议变法图强是在()。
设x=x(y,z),y=y(z,x),z=z(x,y)都是方程F(x,y,z)=0所确定的隐函数,并且F(x,y,z)满足隐函数存在定理的条件,则=________.
「日本に留学してよかった」と思っているのは在日留学生の半数しかない、という調査結果が出た。期待と夢に胸をふくらませて日本にやってきた外国からの留学生が、半分は日本に留学したことに失望したり、日本嫌いになったりしていると聞くと①胸が痛む。私は自分の人生が留学
A.whenyourplaneisabouttolandB.whenyouaretakingtabletsC.whenyousufferfromfood-poisoningD.whenyouaretravel
最新回复
(
0
)