Horizon - Life On Mars 火星生命 - 7

Rice had seen the same thing in Iceland, one of the few places on Earth with similarities to Mars. It too is extremely cold, and most of the water is frozen into glaciers². And also like Mars, buried underground, are massive volcanoes. This powerful combination has shaped the entire landscape. When a volcano erupts, lakes of steaming melt water form high up on top of the glacier¹ until the enormous weight of water forces its way down, bursting out from the base of the glacier. These are the biggest floods on Earth, a surging wall of water stretching for kilometers. In their wake they leave vast planes littered with boulders⁴. To a geologist⁵ these boulder³ fields contain unmistakable evidence of the floodwaters that ripped through here.

Okay, well this is really a classic textbook example, these two large boulders here. The size of them indicates this was an enormous flood that deposited these features, but also if you look at their geometry, these boulders are kind of dipping back in this direction. This has given us information about the path that floodwaters took that deposited these boulders. The floodwaters were going in this direction when these rocks were deposited. Now there is other interesting things in the scene here. For instance, notice some of these smaller rocks are very well rounded, and these little nicked corners of these boulders here, these are kind of percussion⁶ marks and these are produced in a water, highly turbulent water column when the boulders and rocks are basically slamming into one another, knocking the corners off. These things all grouped together just tell you there’s no doubt this was a catastrophic flood deposit.

The pictures from Mars showed the rocks in exactly the same pattern as on Iceland. Here were the slanting⁷ boulders lined up by the floodwaters. And the cameras on the rover provided detailed⁸ views of the individual rocks, with their telltale chipped edges. It seemed that the vast Martian channels had been carved by enormous floods. It was final confirmation⁹ that Mars had once been warm and wet like the Earth, and that meant that there really was every chance for life to have evolved there.

deposit:(动词)to lay down or leave behind by a natural process
(名词)Something deposited, especially by a natural process, as:
a: Geology. A concentration of mineral matter or sediment¹⁰ in a layer, vein¹¹, or pocket
b: Physiology¹². An accumulation of organic or inorganic¹³ material, such as a lipid or mineral, in a body tissue, structure, or fluid.
c: A sediment or precipitate¹⁴ that has settled out of a solution.

1 glacier   

n.冰川，冰河

参考例句：

• The glacier calved a large iceberg.冰河崩解而形成一个大冰山。
• The upper surface of glacier is riven by crevasses.冰川的上表面已裂成冰隙。

2 glaciers   

冰河，冰川( glacier的名词复数 )

参考例句：

• Glaciers gouged out valleys from the hills. 冰川把丘陵地带冲出一条条山谷。
• It has ice and snow glaciers, rainforests and beautiful mountains. 既有冰川，又有雨林和秀丽的山峰。 来自英语晨读30分（高一）

3 boulder   

n.巨砾；卵石，圆石

参考例句：

• We all heaved together and removed the boulder.大家一齐用劲，把大石头搬开了。
• He stepped clear of the boulder.他从大石头后面走了出来。

4 boulders   

n.卵石( boulder的名词复数 )；巨砾；（受水或天气侵蚀而成的）巨石；漂砾

参考例句：

• Seals basked on boulders in a flat calm. 海面风平浪静，海豹在巨石上晒太阳。 来自《简明英汉词典》
• The river takes a headlong plunge into a maelstrom of rocks and boulders. 河水急流而下，入一个漂砾的漩涡中。 来自《简明英汉词典》

5 geologist   

n.地质学家

参考例句：

• The geologist found many uncovered fossils in the valley.在那山谷里，地质学家发现了许多裸露的化石。
• He was a geologist,rated by his cronies as the best in the business.他是一位地质学家，被他的老朋友们看做是这门行当中最好的一位。

6 percussion   

n.打击乐器；冲突，撞击；震动，音响

参考例句：

• In an orchestra,people who play percussion instruments sit at the back.在管弦乐队中，演奏打击乐器的人会坐在后面。
• Percussion of the abdomen is often omitted.腹部叩诊常被省略。

7 slanting   

倾斜的，歪斜的

参考例句：

• The rain is driving [slanting] in from the south. 南边潲雨。
• The line is slanting to the left. 这根线向左斜了。

8 detailed   

adj.详细的，详尽的，极注意细节的，完全的

参考例句：

• He had made a detailed study of the terrain.他对地形作了缜密的研究。
• A detailed list of our publications is available on request.我们的出版物有一份详细的目录备索。

9 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

10 sediment   

n.沉淀，沉渣，沉积(物)

参考例句：

• The sediment settled and the water was clear.杂质沉淀后，水变清了。
• Sediment begins to choke the channel's opening.沉积物开始淤塞河道口。

11 vein   

n.血管，静脉；叶脉，纹理；情绪；vt.使成脉络

参考例句：

• The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
• The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。

12 physiology   

n.生理学，生理机能

参考例句：

• He bought a book about physiology.他买了一本生理学方面的书。
• He was awarded the Nobel Prize for achievements in physiology.他因生理学方面的建树而被授予诺贝尔奖。

13 inorganic   

adj.无生物的；无机的

参考例句：

• The fundamentals of inorganic chemistry are very important.无机化学的基础很重要。
• This chemical plant recently bought a large quantity of inorganic salt.这家化工厂又买进了大量的无机盐。

14 precipitate   

adj.突如其来的；vt.使突然发生；n.沉淀物

参考例句：

• I don't think we should make precipitate decisions.我认为我们不应该贸然作出决定。
• The king was too precipitate in declaring war.国王在宣战一事上过于轻率。