申友GMAT教学辅导中心强悍解析：
According to a recent theory（注意，提出最新理论，后一般展开理论具体内容）, Archean-age gold-quartz vein systems were formed more than two billion years ago from magmatic fluids that originated from molten granite-like bodies deep beneath the surface of the Earth. //（第一层：介绍最新的关于太古代年龄黄金石英脉系统的形成理论）This theory is contrary to （与...相反）the widely held view （注意，提出被广泛认可的理论，后一般展开理论具体内容）that the systems were deposited from metamorphic fluids, that is, from fluids that formed during the dehydration of wet sedimentary tocks.（此句修饰metamorphic fluids，第一遍读文时可略读）//（第二层：介绍与最新理论相悖的被广泛认可的理论）
The recently developed theory has considerable practical importance（正评价词）. Most of the gold deposits discovered during the original gold rushes were exposed at the Earth’s surface and were found because they had shed trails of alluvial gold that were easily traced by simple prospecting methods. Although（结构词，表让步）these same methods still lead to an occasional discovery, most deposits not yet discovered have gone undetected because they are buried and have no surface expression.//（第一层：最新理论的重大实践意义：最初发现金矿只需简单地根据砂金痕迹探测，而现在由于大多数金矿埋于地下，不易被发现）
The challenge in exploration is therefore（结构词，表因果联系）to unravel the subsurface geology of an area and pinpoint the position of buried minerals. Methods widely used today include（后提出三种现今使用的方法）（①analysis of aerial images that yield a broad geological overview;）（ ②geophysical techniques that provide data on the magnetic, electrical, and mineralogical properties of the rocks being investigated;） and （③sensitive chemical tests that are able to detect the subtle chemical halos that often envelop mineralization.）//（第一层：金矿勘测的难点以及目前广泛使用的三种探测方法）However（结构词，表转折关系）, none of these high-technology methods are of any value（负评价词）if the sites to which they are applied have never mineralized, and to maximize the chances of discovery the explorer must therefore（结构词，表因果） pay particular attention to selecting the ground formations most likely to be mineralized. //（第二层：如果勘察的地点从来没有矿化，那么目前被广泛使用的高科技方法就没有一个有价值）Such ground selection （指代selecting the ground formations most likely to be mineralized）relies to varying degrees on conceptual models, which take into account theoretical studies of relevant factors.//（第三层：地层选择依赖于概念模型的程度变化，而概念模型要考虑相关因素的理论研究）
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