| The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere is divided into a few dozen plates of various sizes and shapes, in general the plates are in motion with respect to one another. A mid-ocean ridge is a boundary between plates where new lithospheric material is injected from below. As the plates diverge from a mid-ocean ridge they slide on a more yielding layer at the base of the lithosphere. Since the size of the Earth is essentially constant, new lithosphere can be created at the mid-ocean ridges only if an equal amount of lithospheric material is consumed elsewhere. The site of this destruction is another kind of plate boundary: a subduction zone. There one plate dives under the edge of another and is reincorporated into the mantle. Both kinds of plate boundary are associated with fault systems, earthquakes and volcanism, but the kinds of geologic activity observed at the two boundaries are quite different. The idea of sea-floor spreading actually preceded the theory of plate tectonics. In its original version, in the early 1960’s, it described the creation and destruction of the ocean floor, but it did not specify rigid lithospheric plates. The hypothesis was substantiated soon afterward by the discovery that periodic reversals of the Earth’s magnetic field are recorded in the oceanic crust. As magma rises under the mid-ocean ridge, ferromagnetic minerals in the magma become magnetized in the direction of the magma become magnetized in the direction of the geomagnetic field. When the magma cools and solidifies, the direction and the polarity of the field are preserved in the magnetized volcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallel to the axis of the rift. The oceanic crust thus serves as a magnetic tape recording of the history of the geomagnetic field that can be dated independently; the width of the stripes indicates the rate of the sea-floor spreading. | |
| 板块结构理论描述岩石圈的运动。岩石圈是相对坚硬的地球外层，包括全部地壳和部分地幔。岩石圈被划分为几十个大小不同形状各异的板块，一般而言这些板块都 处于相对运动之中。一道中海脊是板块之间的边界，在那里新的岩石圈的物质从下部注入。当板块从中海脊脱离时，它们滑向在岩石圈基部较易变形的地层上。 因为地球的大小本质上是不变的，只有同等数量的岩石圈物质在其它地方被吞没，新的岩石圈才能生成。销毁旧岩石圈的地方形成另外一种板块边界：一块潜没的区 域。在这里，一块板块潜没到另一板块的边缘之下并结合入地幔之中。两种板块边界均与地层系统、地震以及火山活动有关，但在两种边界处观察到的诸般地质活动 却迥然不同。 海床扩展说实际上早于板块结构理论。在20世纪60年代它的理论雏形中，描述了海底的生成和毁灭，但没有详细介绍坚硬的岩石圈板块。这个假定不久之后为发现所证实。 该发现表明地球磁场周期性的逆转被记录在海洋地壳中。当岩浆从中海脊下涌起的时候，岩浆中的磁铁矿物质按地磁场的方向被磁化。岩浆冷却并凝固下来后，地磁 场的方向和磁极被保留在磁化了的火山岩中。磁场的逆转形成一系列与断层轴线平行的条形磁区。这样海洋壳就扮演了磁带的角色，记录下可以鉴定时间的地磁场的 历史。条形磁区的宽度表明了海底扩展的速度。 |
| The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere is divided into a few dozen plates of various sizes and shapes, in general the plates are in motion with respect to one another. A midocean ridge is a boundary between plates where new lithospheric material is injected from below. As the plates diverge from a midocean ridge they slide on a more yielding layer at the base of the lithosphere. Since the size of the Earth is essentially constant, new lithosphere can be created at the midocean ridges only if an equal amount of lithospheric material is consumed elsewhere. The site of this destruction is another kind of plate boundary: a subduction zone. There one plate dives under the edge of another and is reincorporated into the mantle. Both kinds of plate boundary are associated with fault systems, earthquakes and volcanism, but the kinds of geologic activity observed at the two boundaries are quite different. The idea of seafloor spreading actually preceded the theory of plate tectonics. In its original version, in the early 1960' s, it described the creation and destruction of the ocean floor, but it did not specify rigid lithospheric plates. The hypothesis was substantiated soon afterward by the discovery that periodic reversals of the Earth' s magnetic field are recorded in the oceanic crust. As magma rises under the midocean ridge, ferromagnetic minerals in the magma become magnetized in the direction of the magma become magnetized in the direction of the geomagnetic field. When the magma cools and solidifies, the direction and the polarity of the field are preserved in the magnetized volcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallel to the axis of the rift. The oceanic crust thus serves as a magnetic tape recording of the history of the geomagnetic field that can be dated independently the width of the stripes indicates the rate of the seafloor spreading. | |
| ban kuai jie gou li lun miao shu yan shi quan de yun dong. yan shi quan shi xiang dui jian ying de di qiu wai ceng, bao kuo quan bu di qiao he bu fen di man. yan shi quan bei hua fen wei ji shi ge da xiao bu tong xing zhuang ge yi de ban kuai, yi ban er yan zhei xie ban kuai dou chu yu xiang dui yun dong zhi zhong. yi dao zhong hai ji shi ban kuai zhi jian de bian jie, zai na li xin de yan shi quan de wu zhi cong xia bu zhu ru. dang ban kuai cong zhong hai ji tuo li shi, ta men hua xiang zai yan shi quan ji bu jiao yi bian xing de di ceng shang. yin wei di qiu de da xiao ben zhi shang shi bu bian de, zhi you tong deng shu liang de yan shi quan wu zhi zai qi ta di fang bei tun mo, xin de yan shi quan cai neng sheng cheng. xiao hui jiu yan shi quan de di fang xing cheng ling wai yi zhong ban kuai bian jie: yi kuai qian mo de qu yu. zai zhe li, yi kuai ban kuai qian mo dao ling yi ban kuai de bian yuan zhi xia bing jie he ru di man zhi zhong. liang zhong ban kuai bian jie jun yu di ceng xi tong di zhen yi ji huo shan huo dong you guan, dan zai liang zhong bian jie chu guan cha dao de zhu ban di zhi huo dong que jiong ran bu tong. hai chuang kuo zhan shuo shi ji shang zao yu ban kuai jie gou li lun. zai 20 shi ji 60 nian dai ta de li lun chu xing zhong, miao shu le hai di de sheng cheng he hui mie, dan mei you xiang xi jie shao jian ying de yan shi quan ban kuai. zhe ge jia ding bu jiu zhi hou wei fa xian suo zheng shi. gai fa xian biao ming di qiu ci chang zhou qi xing de ni zhuan bei ji lu zai hai yang di qiao zhong. dang yan jiang cong zhong hai ji xia yong qi de shi hou, yan jiang zhong de ci tie kuang wu zhi an di ci chang de fang xiang bei ci hua. yan jiang leng que bing ning gu xia lai hou, di ci chang de fang xiang he ci ji bei bao liu zai ci hua le de huo shan yan zhong. ci chang de ni zhuan xing cheng yi xi lie yu duan ceng zhou xian ping xing de tiao xing ci qu. zhe yang hai yang qiao jiu ban yan le ci dai de jue se, ji lu xia ke yi jian ding shi jian de di ci chang de li shi. tiao xing ci qu de kuan du biao ming liao hai di kuo zhan de su du. |
| The theory of plate tectonics describes the motions of the lithosphere, the comparatively rigid outer layer of the Earth that includes all the crust and part of the underlying mantle. The lithosphere is divided into a few dozen plates of various sizes and shapes, in general the plates are in motion with respect to one another. A midocean ridge is a boundary between plates where new lithospheric material is injected from below. As the plates diverge from a midocean ridge they slide on a more yielding layer at the base of the lithosphere. Since the size of the Earth is essentially constant, new lithosphere can be created at the midocean ridges only if an equal amount of lithospheric material is consumed elsewhere. The site of this destruction is another kind of plate boundary: a subduction zone. There one plate dives under the edge of another and is reincorporated into the mantle. Both kinds of plate boundary are associated with fault systems, earthquakes and volcanism, but the kinds of geologic activity observed at the two boundaries are quite different. The idea of seafloor spreading actually preceded the theory of plate tectonics. In its original version, in the early 1960' s, it described the creation and destruction of the ocean floor, but it did not specify rigid lithospheric plates. The hypothesis was substantiated soon afterward by the discovery that periodic reversals of the Earth' s magnetic field are recorded in the oceanic crust. As magma rises under the midocean ridge, ferromagnetic minerals in the magma become magnetized in the direction of the magma become magnetized in the direction of the geomagnetic field. When the magma cools and solidifies, the direction and the polarity of the field are preserved in the magnetized volcanic rock. Reversals of the field give rise to a series of magnetic stripes running parallel to the axis of the rift. The oceanic crust thus serves as a magnetic tape recording of the history of the geomagnetic field that can be dated independently the width of the stripes indicates the rate of the seafloor spreading. | |
| bǎn kuài jié gòu lǐ lùn miáo shù yán shí quān de yùn dòng. yán shí quān shì xiāng duì jiān yìng de dì qiú wài céng, bāo kuò quán bù dì qiào hé bù fèn dì màn. yán shí quān bèi huà fēn wéi jǐ shí gè dà xiǎo bù tóng xíng zhuàng gè yì de bǎn kuài, yì bān ér yán zhèi xiē bǎn kuài dōu chǔ yú xiāng duì yùn dòng zhī zhōng. yī dào zhōng hǎi jí shì bǎn kuài zhī jiān de biān jiè, zài nà li xīn de yán shí quān de wù zhì cóng xià bù zhù rù. dāng bǎn kuài cóng zhōng hǎi jí tuō lí shí, tā men huá xiàng zài yán shí quān jī bù jiào yì biàn xíng de dì céng shàng. yīn wèi dì qiú de dà xiǎo běn zhì shàng shì bù biàn de, zhǐ yǒu tóng děng shù liàng de yán shí quān wù zhì zài qí tā dì fāng bèi tūn mò, xīn de yán shí quān cái néng shēng chéng. xiāo huǐ jiù yán shí quān de dì fāng xíng chéng lìng wài yī zhǒng bǎn kuài biān jiè: yí kuài qián mò de qū yù. zài zhè lǐ, yí kuài bǎn kuài qián mò dào lìng yī bǎn kuài de biān yuán zhī xià bìng jié hé rù dì màn zhī zhōng. liǎng zhǒng bǎn kuài biān jiè jūn yǔ dì céng xì tǒng dì zhèn yǐ jí huǒ shān huó dòng yǒu guān, dàn zài liǎng zhǒng biān jiè chù guān chá dào de zhū bān dì zhì huó dòng què jiǒng rán bù tóng. hǎi chuáng kuò zhǎn shuō shí jì shang zǎo yú bǎn kuài jié gòu lǐ lùn. zài 20 shì jì 60 nián dài tā de lǐ lùn chú xíng zhōng, miáo shù le hǎi dǐ de shēng chéng hé huǐ miè, dàn méi yǒu xiáng xì jiè shào jiān yìng de yán shí quān bǎn kuài. zhè gè jiǎ dìng bù jiǔ zhī hòu wèi fā xiàn suǒ zhèng shí. gāi fā xiàn biǎo míng dì qiú cí chǎng zhōu qī xìng de nì zhuǎn bèi jì lù zài hǎi yáng dì qiào zhōng. dāng yán jiāng cóng zhōng hǎi jí xià yǒng qǐ de shí hòu, yán jiāng zhōng de cí tiě kuàng wù zhì àn dì cí chǎng de fāng xiàng bèi cí huà. yán jiāng lěng què bìng níng gù xià lái hòu, dì cí chǎng de fāng xiàng hé cí jí bèi bǎo liú zài cí huà le de huǒ shān yán zhōng. cí chǎng de nì zhuǎn xíng chéng yī xì liè yǔ duàn céng zhóu xiàn píng xíng de tiáo xíng cí qū. zhè yàng hǎi yáng qiào jiù bàn yǎn le cí dài de jué sè, jì lù xià kě yǐ jiàn dìng shí jiān de dì cí chǎng de lì shǐ. tiáo xíng cí qū de kuān dù biǎo míng liǎo hǎi dǐ kuò zhǎn de sù dù. |
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