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  3. A Scientific Debate: Neptunism vs. Plutonism 1. For modern geologists, the question of how rocks are formed has been answered

A Scientific Debate: Neptunism vs. Plutonism 1. For modern geologists, the question of how rocks are formed has been answered

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问题                 A Scientific Debate: Neptunism vs. Plutonism
   1. For modern geologists, the question of how rocks are formed has been answered. The processes by which sediments are cemented together to form sedimentary rocks, subterranean magma shoots to the surface to form igneous rocks, and intense heat and pressure transform both of these into metamorphic rocks are well understood. But in the days when geology was just beginning to develop as a separate scientific discipline, the origin of Earth’s rocks was the subject of an intense debate. Among the theories circulating around the late eighteenth and early nineteenth centuries were two primary contenders: Neptunism, posited by the German Abraham Werner, and Plutonism, a theory of James Hutton, a Scottish geologist.
   2. To fully understand the debate between Neptunism and Plutonism, it is essential to first examine the broader scientific context in place at the time. Before the nineteenth century, the accepted view of Earth’s history was defined by a concept known as Catastrophism. Its basic tenets were that the planet was of a young age and that its past was marked by a series of distinct and catastrophic events. In England in particular, this theory was influenced by the belief that a worldwide flood had occurred as described in the Christian Bible.
   3. Werner’s theory of Neptunism relied on some of the assumptions inherent in Catastrophism. The word Neptunism comes from the name of the Roman god of the sea, Neptune, as Werner suggested that all of Earth had once been covered by a vast, hot ocean.The waters of this ocean, he said, contained small amounts of diluted minerals. Over time, these ancient waters evaporated and sank lower, and as they disappeared, the minerals remained and fused into crystals to produce the rocks and landmasses visible on Earth’s surface. A series of later catastrophic floods, such as the one reported in the Bible, added more rocks and explained the different rock layers that geologists were beginning to discover around this time.
   4. Concurrently, there were many other geologists who were starting to reject the notion of Catastrophism. A Much of the contemporary evidence being collected regarding fossils and the complexity and diversity of geologic formations suggested that the planet was much older than anyone had previously thought,B As a result, the theory of Uniformitarianism was introduced, which stated that Earth’s geologic processes were gradual and unfolding at an incredibly slow rate over an immense timeframe.C Even more important for the field of geology, Uniformitarianism held that those same processes were still occurring. D
   5. James Hutton was among the earliest proponents of Uniformitarianism, and it greatly informed his theory of Plutonism. Named for the Roman god of the underworld, Pluto, it stated that Earth’s rocks were created through the tremendous heat and force of volcanic activity. Hutton described a continuous cycle by which heat deep within Earth pushed up the land above, creating mountains and volcanoes, and deposited rocks on the surface. Erosion over time would break down the rocks and transport their sediments to the bottom of the oceans, where they were heated and turned into solid rock once more, and again lifted to the surface by volcanic activity.This concept of a long, continuous cycle was a clear expression of Uniformitarianism and provided a better explanation for how the geologic complexities of Earth had taken shape.
   6. During the first half of the nineteenth century, increasing numbers of scientists adopted Hutton’s views, and today he is often referred to as the "father of geology" Werner’s theory of Neptunism, on the other hand, was dismissed, and Uniformitarianism replaced Catastrophism as the guiding principle of geologic study. Even though Plutonism was later shown to contain many inaccuracies, some of its concepts turned out to be close to the truth. For instance, its descriptions of the volcanic uplift of the crust and the continuous recycling of rock fit well with the modern theory of plate tectonics. Moreover, Hutton’s ideas encouraged the development of more accurate methods for determining the age of rocks, such as radiocarbon dating, by which geologists have been able to confirm that Earth’s history stretches back billions of years.
The word tenets in the passage is closest in meaning to
选项 A、opinions.
B、principles.
C、examinations.
D、entitlements.
答案B
解析
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