They found a unique layer of sediment worldwide.
他们在世界各地发现了一层独特的沉积物。
Sediment sorting and compaction influence permeability and porosity.
沉积物的分选和压实作用影响渗透率和孔隙度。
They are found wherever fast rivers carrying loads of coarse sediment once flowed.
在携带大量粗泥沙的湍急河流流经的任何地方，都能找到它们。
The organic matter may partially decompose, using up the dissolved oxygen in the sediment.
有机物可能会进行部分分解，并耗尽沉积物中的溶解氧。
The crater, now deeply buried in sediment, was originally about 200 kilometers in diameter.
这个陨石坑现在深埋在沉积物中，最初直径约200公里。
They had found a prehistoric boat, preserved by the type of sediment in which it was buried.
他们发现了一艘史前的船，这艘船依靠埋藏它的沉积物保存了下来。
Thus a proportion of the total volume of any sediment, loose or cemented, consists of empty space.
因此，无论是疏松或胶结，沉积物总体积都有一部分是由空隙组成的。
So sediment is transported and then deposited and it forms layers on the Earth's surface over time.
所以沉积物被运输，然后沉积，随着时间的推移，它在地球表面形成了层。
Most desert streambeds are normally dry, but they occasionally receive large flows of water and sediment.
大多数沙漠河床通常是干燥的，但它们偶尔也会有大量的水流和沉积物。
Sediment above and below the gypsum layer contained tiny marine fossils, indicating open-ocean conditions.
在石膏层上方和下方的沉积物中含有许多小型海洋生物化石，这表明这里的海洋环境很开放。
The more poorly sorted or the more tightly compacted a sediment is, the lower its porosity and permeability.
沉积物分选越差或压实越紧，其孔隙度和渗透率就越低。
These seas have a typical oceanic floor, except that the floor is overlaid by several kilometers of sediment.
这些海洋有一个典型的海底，只不过这个海底被几公里厚的沉积物覆盖。
Petroleum, consisting of crude oil and natural gas, seems to originate from organic matter in marine sediment.
石油由原油和天然气组成，它们似乎来源于海洋沉积物中的有机物质。
The plant functions as a stabilizer and a sediment trap and as a nursery area for estuarine fish and shellfish.
该植物可作为稳定剂和沉积物捕集器，并可以作为培育河口鱼类和贝类的地方。
When snorkeling, do not touch the coral or stir up sediment, as these actions can damage the reef's fragile ecosystem.
潜泳的时候，不要碰珊瑚礁或者搅动沉淀物，因为这样做可能会破坏珊瑚脆弱的生态系统。
Others point out that decreased sediment loads will likely lead to erosion of downstream riverbanks and the Mekong Delta.
其他人指出，泥沙负荷的减少可能会导致下游河岸和湄公河三角洲的侵蚀。
Both oil and gas are less dense than water, so they generally tend to rise upward through water-saturated rock and sediment.
石油和天然气的密度都比水小，所以二者通常会浮在被水浸泡的岩石和沉积物的表层。
As geologists, we examine layers of sediment on the Earth' s surface to approximate the dates of past geologic time periods.
作为地质学家，我们研究地球表面的沉积层以估算过去地质时期的年代。
Much of the water in a sample of water-saturated sediment or rock will drain from it if the sample is put in a suitable dry place.
如果把水饱和的沉积物或岩石样品放在合适的干燥的地方，样品中的大部分水将从中流出。
Recent studies of sediment in the North Atlantic's deep waters reveal possible cyclical patterns in the history of Earth's climate.
最近对北大西洋深海沉积物的研究揭示了地球气候历史上可能的循环模式。
It was apparent that the glaciation occurred in the relatively recent past because the drift was soft, like freshly deposited sediment.
很明显冰川作用就发生在相对不远的过去，因为漂流物很软，像新鲜的沉积物。
Samples recovered from the expedition revealed important differences in chemical composition and fossil distribution among the sediment layers.
探险队采集的样品揭示了沉积物层之间化学成分及化石分布上的重大差异。
The sample consisted of pebbles of hardened sediment that had once been soft, deep-sea mud, as well as granules of gypsum and fragments of volcanic rock.
这一样本包括曾经柔软的的硬化沉积物的卵石、深海淤泥以及石膏颗粒和火山岩碎片。
The relative amount of these two kinds of water varies greatly from one kind of rock or sediment to another, even though their porosities may be the same.
这两种水的相对含量在不同的岩石或沉积物之间差异很大，尽管它们的孔隙率可能是相同的。
An iridium-enriched sediment layer and a large impact crater in the Yucatn provide evidence that a large meteorite struck Earth about 65 million years ago.
尤卡坦半岛上富含铱的沉积层和一个巨大的陨石坑提供了证据，证明了约6500万年前，一颗大型陨石撞击了地球。
This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth.
这一沉积层富含稀有金属铱，以及其他在陨石中较丰富而在地壳中十分罕见的元素。
Sediment as you know, is material like sand, gravel, fossil fragments that is transported by natural processes like wind, water flow or the movement of glaciers.
如你所知，沉积物是通过风、水流或冰川运动等自然过程输送的物质，如沙子、砾石、化石碎片等。
Also, things like the damming of rivers has caused increased sediment production, not to mention the addition of more carbon dioxide and methane in the atmosphere.
此外，河流筑坝等工程也增加了沉积物的产量，更不用说大气中二氧化碳和甲烷的增加。
This idea was modified in the late twentieth century, when geologists and oceanographers examining oceanic sediment found fossil evidence of warming and cooling of the oceans.
在20世纪后期，地质学家和海洋学家在研究海洋沉积物时发现了能够证明海洋变暖和变冷的化石，并修正了这一观点。
At certain times, apparently, more icebergs from the Arctic Ocean in the far north were traveling south well into the North Atlantic before melting and shedding their sediment.
显然，在某些时候，来自北冰洋最北端的更多冰山赶在融化沉积前向南漂入北大西洋。
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