Bedrock is the solid rock that is exposed at the surface or immediately underlies soil and loose surface debris. Regolith is the relatively thin covering of soil and unconsolidated rock waste that hides the bedrock in most are-as. Bedrock is continuous and may consist of any kind of rock, whereas regolith is discontinuous, although generally present②.Regolith tends to be a few tens of feet thick or less, but may be much thicker. It may develop in place by the decay and disintegration of bedrock or consist of transported materials. Soil refers to the upper portion of the regolith which has been so altered by physical, chemical, and biological processes that it can support rooted vegetation. However, soil may be absent from an area.
基巖是出露于地表或直接位于土壤和松散的地表巖屑之下的堅(jiān)硬巖石。浮土是由土壤和未固結(jié)巖屑組成的比較薄的覆蓋層， 在許多地方掩蓋著基巖?；鶐r是延續(xù)不斷的，可由任何一種巖石 構(gòu)成。而浮土雖普遍存在，但不是延續(xù)不斷的。浮土一般厚幾十英尺或更少，但也有厚得多的。它可能是通過基巖的腐蝕和崩解 就地生成的，或者由搬運(yùn)來的物質(zhì)所組成。土壤指的是浮土的上 部，它受到物理的、化學(xué)的和生物的作用而發(fā)生變化，以致能使 植物根系繁生。但是，有的地區(qū)可能缺失土壤。
By direct observation, man has access to only a very thin outer part of the crust ； the deepest mines penetrate less than 2 miles (3 km) beneath the surface, and the deepest wells about 5 miles (8 km). However, certain rocks now exposed at the surface may once have been buried several miles below it.
人們直接觀察只能接觸到地殼很薄的表層：最深的礦井深入 地下不到2英里（3公里），最深的鉆井約為5英里（8公里）。 但是，某些現(xiàn)在出露于地表的巖石，可能一度埋在地面以下數(shù)英 里的地方。
Chemical analyses have been made for rocks of various types, and the proportions of the elements in the outer 10-mile (16 km) zone of the lithosphere have been estimated. Eight elements apparently constitute more than 98% by weight of this zone: oxygen (most abundant), silicon, aluminum, iron, calcium, sodium, potassium, and magnesium (least abundant). The following mnemonic expression arranges these eight elements in the order of their relative abundances: “Only Silly Artists In College Study Past Midnight. If the materials in the atmosphere and hydrosphere are added to those of the 10-mile zone, percentages are changed only slightly.
對(duì)各種類型的巖石已做過化學(xué)分析，并估算了巖石圈外部10 英里（16公里）巖帶中各種元素的比例。有八種元素明顯地占此 巖帶重量的98%以上：氧（最多）、硅、鋁、鐵、鈣，鈉、鉀和鎂（最 少）。下面這句有助于記憶的話編排了這八種元素相對(duì)豐度的順序：“Only Silly Artists In College Study Past Midnight.” （“唯藝院之癡者乃讀以待旦。”）如果把大氣圈和水圈中的物質(zhì)加進(jìn)這10英里巖帶的物質(zhì)中，上述百分比只有很小的變化。
Of these eight elements oxygen and silicon combined as silica (SiO2) make up about three-fourths of the total. Thus the silicate minerals are the most abundant in the crust, especially the feldspars, pyroxenes, amphiboles, micas, and quartz.
在這八種元素申，化合成氧化硅（SiO2）的氧和硅，約占總 量的四分之三。因此，地殼中最豐富的是硅酸鹽礦物，特別是長(zhǎng)石、輝石、角閃石、云母和石英。
