听力学科.ppt
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1、听力重点学科概述,By Sandy,课程咨询qq:2880267976答疑qq:2880169563托福千人qq群:200437589,听力重点学科概述,听力重点学科概述,闪,迪,的,科,普,时,间,听力重点学科概述,Part 1.Geology,关键词:layer;plate;topography;technology过去出现过的相关话题:板块运动;岩石圈;地质地貌和气象,听力重点学科概述,Plate tectonics,Key Words:theory of continental drift;sea-floor spreading hypothesis;edge of the plate
2、;volcano and earthquake,听力重点学科概述,听力重点学科概述,Definition:Avolcanois aruptureon thecrust地壳of aplanetary-mass object,such as the Earth,which allows hotlava岩浆,volcanic ash,and gases to escape from amagma岩浆 chamberbelow the surface.On Earth,volcanoes are generally found wheretectonic plates aredivergingorco
3、nverging.,听力重点学科概述,环太平洋火山带,听力重点学科概述,Divergent plate boundaries 分离边界(生长边界)At themid-oceanic ridges,twotectonic platesdiverge from one another as newoceanic crustis formed by the cooling and solidifying of hot molten rock.Because the crust is very thin at these ridges due to the pull of the tectonic p
4、lates,the release of pressure leads toadiabatic隔热的 expansion and the partial melting of themantle,causing volcanism and creating new oceanic crust.Most divergent plate boundariesare at the bottom of the oceans;therefore,most volcanic activity is submarine,forming new seafloor.Black smokers海底黑烟囱(also
5、 known as deep sea vents火山口)are an example of this kind of volcanic activity.Where the mid-oceanic ridge大洋中脊 is above sea-level,volcanic islands are formed,for example,Iceland.著名地貌:红海,大西洋,东非大裂谷(板块内部张裂),听力重点学科概述,Convergent plate boundaries 聚合边界(消亡边界)Subduction zonesare places where two plates,usually
6、 an oceanic plate and a continental plate,collide.In this case,the oceanic plate subducts,or submerges under the continental plate forming a deep ocean trench just offshore(例如太平洋板块俯冲到亚欧板块之下形成马里亚纳海沟).In a process calledflux melting,water released from the subducting plate lowers the melting temperatu
7、re of the overlying mantle地幔 wedge,creatingmagma.This magma tends to be veryviscous due to its highsilica硅content,so often does not reach the surface and cools at depth.When it does reach the surface,a volcano is formed.Typical examples of this kind of volcano areMount Etna埃特纳山and the volcanoes in t
8、hePacific Ring of Fire太平洋火圈带.,听力重点学科概述,Hotspots“Hotspots”is the name given to volcanic areas believed to be formed bymantle plumes(地幔羽),which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting.Because tectonic plates
9、move across them,each volcano becomes dormant and is eventually reformed as the plate advances over the postulated plume.TheHawaiian Islandshave been suggested to have been formed in such a manner,as well as theSnake River Plain,with theYellowstone Calderabeing the part of the North American plate c
10、urrently above the hot spot.This theory is currently under criticism,however.,听力重点学科概述,Classification:活火山 active volcano死火山 extinct volcano休眠火山 dormant volcano全世界有516座活火山,其中69座是海底火山,以太平洋地区最多。活火山主要分布在环太平洋火山带,地中海-喜马拉雅-印度尼西亚火山带、大洋中脊火山带和红海-东非大陆裂谷带,听力重点学科概述,Classification:层状火山(Stratovolcano,又称为成层火山),其外观多
11、为优美、对称的锥形。它们是由无数熔岩流不断堆积形成的。此种火山的熔岩黏滞性较高,通常为安山岩质。因其优美对称的外型,多成为观光胜地。许多著名的山都属此类,例如:日本的富士山、台湾的七星山、菲律宾的马荣火山、意大利的维苏威火山、斯特龙博利火山等,听力重点学科概述,盾状火山盾状火山(Shield Volcano)具有宽广缓和的斜坡,整体看来就像是一个盾牌。此种火山通常由玄武岩岩浆构成,流动性高,故能够分布在很大的区域,才能形成宽广的山形。最著名的例子是夏威夷群岛,这个群岛的每个岛屿都是一座巨大的盾状火山。,冒纳罗亚火山,听力重点学科概述,火山穹丘火山穹丘(lava dome,或称为熔岩穹丘),常见
12、于火山口内或火山的侧翼,是一种圆顶状的突起,看起来类似某些植物的球根。火山穹丘是由高黏度的熔岩形成的,由于其黏度太高,不能从火山口远流,在火山口上及其附近冷却凝固。火山穹丘会成长,这是由于地底岩浆库的空间不足以容纳所有岩浆,导致部分岩浆挤入穹丘下方。如果成长中的穹丘是位于陡峭的山坡上,其成长有可能导致重心的不稳定,最后导致山崩或火山碎屑流。,听力重点学科概述,火山渣锥火山渣锥(Cinder cone)是指由火成岩屑或火山渣(火山的喷出物质)在火山口周围堆积而成的山丘。大多数的火山渣锥都很耐侵蚀,因为落到锥上的降雨渗入到高渗水性的火山渣里,较少对它们的表面进行侵蚀作用。由于火山碎屑物胶结松散,故
13、无法形成较高的堆积,通常都小于500米。,破火山口(Caldera)破火山口通常是由于火山锥顶部(或一群火山锥)因失去地下熔岩的支撑崩塌形成。外形为碗形的凹地,其直径为数百米至数公里不等。著名的例子是美国黄石国家公园的黄石复式破火山口,听力重点学科概述,低平火山口(maar)是由岩浆和水相互作用发生爆炸而形成。在地表下形成了深切到围岩的圆形火山口,并被一个低矮的碎屑环包围。常常会积水而形成火山湖。,听力重点学科概述,Part 2.Biology,关键词:botany,zoology,microbiology过去出现过的相关话题:海洋动物;蝙蝠;生物适应性;动物保护;植物特性,听力重点学科概述,
14、Animal Behavior,觅食行为foraging behavior攻击行为aggressive behavior防御行为defense behavior繁殖行为breeding behavior节律行为Rhythmic behavior社群行为social behavior定向行为orientation behavior通讯行为communication behavior,先天性行为学习行为,听力重点学科概述,觅食行为,听力重点学科概述,防御行为,初级防御:穴居或洞居、保护色、警戒色、拟态等 次级防御:回缩、逃逸、威吓、假死、转移捕食者攻击的部位、反击等。如:竹节虫拟态;乌贼释放墨汁,
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