5.11发散的板块边界
Section outline
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What can we see in Western North America?
::我们在西北美能看见什么?Many locations in western North America are being rifted apart. One such is the Rio Grande Rift in Texas. At this location, hot mantle rises up beneath the crust to cause the divergence.
::北美西部的许多地方正在分裂。 其中一个是德克萨斯的里奥格兰德裂谷。 在这个地方,热层地壳在地壳下上升,造成裂痕。Tectonic Features of Western North America
::北美西部构造特征Western North America has all three of the different types of plate boundaries and the features that are seen at them. A divergent plate boundary runs through the Gulf of California in Mexico. The divergence is pulling Baja California and mainland Mexico apart. Just north of there, around the US-Mexico border, in California, there is a transform boundary. Plates on both sides of the plate boundary are sliding past each other. Still further north, in the Pacific Northwest, a subduction zone just offshore is part of a convergent plate boundary .
::西北美有三种不同的板块边界和特征。墨西哥加利福尼亚湾有不同的板块边界。分歧将下加利福尼亚州和墨西哥大陆分开。就在北面,美国-墨西哥边界附近,加利福尼亚州有一个变形边界。板块边界两侧的板块相互滑过。更北端,太平洋西北,一个离岸的下潜区是聚在一起的板块边界的一部分。This map shows the three major plate boundaries in or near California.
::该地图显示加利福尼亚州或附近三大板块的边界。In the Figure a red bar where seafloor spreading is taking place. A long black line is a transform fault and a black line with hatch marks is a trench where subduction is taking place. Notice how one type of plate boundary transitions into another.
::在图中,红条是海底扩散的发生地。长黑条是变形断层,黑条是有舱盖标记的黑条是进行潜入的战壕。注意一种类型的板块边界如何向另一种交错。Plate Divergence on Land
::陆地上的热差异A divergent plate boundary on land rips apart continents ( Figure ).
::陆地上不同的板块边界撕裂了各大洲(图)。When plate divergence occurs on land, the continental crust rifts, or splits. This effectively creates a new ocean basin as the pieces of the continent move apart.
::当板块在陆地上出现裂痕时,大陆地壳裂痕或裂痕。 随着大陆块的分离,这实际上创造了一个新的海洋盆地。In continental rifting , magma rises beneath the continent , causing it to become thinner, break, and ultimately split apart. New ocean crust erupts in the void, ultimately creating an ocean between continents. On either side of the ocean are now two different lithospheric plates. This is how continents split apart.
::在大陆裂缝中,岩浆在大陆下上升,导致大陆变薄、分裂并最终分裂。 新的海洋地壳在真空中爆发,最终在大陆之间形成海洋。 在海洋的两侧,现在都是两个不同的地平层板块。这就是大陆分裂的方式。These features are well displayed in the East African Rift, where rifting has begun, and in the Red Sea, where water is filling up the basin created by seafloor spreading. The Atlantic Ocean is the final stage, where rifting is now separating two plates of oceanic crust .
::这些特征在东部非洲裂谷和红海都得到了很好的展示,前者的裂痕已经开始,后者的水正在填充海底扩张所创造的盆地。 大西洋是最后阶段,裂痕正在分离海洋地壳的两个板块。Baja California
::下加利福尼亚州Baja California is rifting apart from mainland Mexico, as seen in this satellite image.
::下加利福尼亚州与墨西哥大陆相隔裂,这从卫星图像中可见一斑。Baja California is a state in Mexico just south of California. In the Figure , Baja California is the long, skinny land mass on the left. You can see that the Pacific Ocean is growing in between Baja California and mainland Mexico. This body of water is called the Gulf of California or, more romantically, the Sea of Cortez. Baja is on the Pacific Plate and the rest of Mexico is on the North American Plate. Extension is causing the two plates to move apart and will eventually break Baja and the westernmost part of California off of North America. The Gulf of California will expand into a larger sea.
::下加利福尼亚州是墨西哥加利福尼亚州以南的一个州。 在图中, 下加利福尼亚州是左边的漫长、 瘦小的陆地质量。 您可以看到太平洋在下加利福尼亚州和墨西哥大陆之间正在增长。 这块水域被称为加利福尼亚湾, 或更浪漫的科特斯海。 下加利福尼亚州在太平洋板块上, 墨西哥的其余部分在北美板块上。 扩展导致两个板块分开, 并最终将巴哈州和加利福尼亚州最西部地区从北美分割开来。 加利福尼亚州湾将扩大为更大的海洋 。Volcanism in Baja California is evidence of rifting.
::下加利福尼亚火山是裂开的证据Rifting has caused volcanic activity on the Baja California peninsula as seen in the Figure .
::从图中可以看出,断裂导致下加利福尼亚半岛火山活动。Can you relate what is happening at this plate boundary to what happened when Pangaea broke apart?
::你能把板块边界发生的事 和潘加亚分裂时发生的事联系起来吗?Summary
::摘要- Where continental rifting takes place, continents are split apart and an ocean may grow or be created between the two new plates.
::在出现大陆裂痕的地方,大陆被分割,海洋可能在两个新板块之间生长或形成。
- Baja California is rifting apart from mainland Mexico.
::下加利福尼亚州与墨西哥大陆分离裂开
- Continental rifting can create major ocean basins, like the Atlantic.
::大陆裂开可以形成大型海洋盆地,如大西洋。
Review
::回顾- How is a divergent plate boundary on land different from one in the ocean?
::陆地上不同的板块边界与海洋的边界有何不同?
- What is happening to the Baja California peninsula?
::下加利福尼亚半岛发生什么了?
- How did continental rifting play into the breakup of Pangaea?
::大陆裂开如何影响潘加埃亚的分裂?
- Where continental rifting takes place, continents are split apart and an ocean may grow or be created between the two new plates.
