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  3. In 1831 when Smith was finally recognized by the Geological Society of Londo

In 1831 when Smith was finally recognized by the Geological Society of Londo

游客2024-01-03  29
问题     In 1831 when Smith was finally recognized by the Geological Society of London as the "father of English geology," it was not only for his maps but also for something even more important. Ever since people had begun to catalog the strata in particular outcrops, there had been the hope that these could somehow be used to calculate geological time. But as more and more accumulations of strata were cataloged in more and more places, it became clear that the sequences of rocks sometimes differed from region to region and that no rock type was ever going to become a reliable time marker throughout the world. Even without the problem of regional differences, rocks present a difficulty as unique time markers. Quartz is quartz—a silicon ion surrounded by four oxygen ions—there’s no difference at all between two-million-year-old Pleistocene quartz and Cambrian quartz created over 500 million years ago. [br] Which of the sentences below best expresses the essential information in the highlighted sentence in paragraph 3? Incorrect choices change the meaning in important ways or leave out essential information.
选项 A、The discovery of regional differences in the sequences of rocks led geologists to believe that rock types could some day become reliable time markers.
B、Careful analysis of strata revealed that rocks cannot establish geological time because the pattern of rock layers varies from place to place.
C、Smith’s catalogs of rock strata indicated that the sequences of rocks are different from place to place and from region to region.
D、Because people did not catalog regional differences in sequences of rocks, it was believed that rocks could never be reliable time markers.
答案 B
解析
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