Unformatted text preview: om the nearby continent. In the days following, samples of solid gypsum were repeatedly brought on deck as drilling operations penetrated the seafloor. Furthermore, the gypsum was found to possess peculiarities of composition and structure that suggested it had formed on desert flats. Sediment above and below the gypsum layer contained tiny marine fossils, indicating openocean conditions. As they drilled into the central and deepest part of the Mediterranean basin, the scientists took solid, shiny, crystalline salt from the core barrel. Interbedded with the salt were thin layers of what appeared to be windblown silt.
3 在 What does the author imply by saying “ Not a single pebble was found that might have indicated that the pebbles came from the nearby continent”? ○The most obvious explanation for the origin of the pebbles was not supported by the evidence.
○The geologists did not find as many pebbles as they expected.
○The geologists were looking for a particular kind of pebble.
○The different pebbles could not have come from only one source.
4在Which of the following can be inferred from paragraph 3 about the solid gypsum layer? ○It did not contain any marine fossil.
○It had formed in openocean conditions.
○It had once been soft, deepsea mud.
○It contained sediment from nearby deserts.
5. Select the TWO answer choice from paragraph 3 that identify materials discovered in the deepest part of the 223
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Mediterranean basin. To receive credit you must select TWO answers. ○Volcanic rock fragments.
○Thin silt layers
○Soft, deepsea mud
6. What is the main purpose of paragraph 3? ○To describe the physical evidence collected by Hsu and Ryan.
○To explain why some of the questions posed earlier in the passage could not be answered by the findings of the Glomar Challenger. ○To evaluate techniques used by Hsu and Ryan to explore the sea floor.
○To describe the most difficult problems faced by the Glomar Challenger expedition.
Paragraph 4: The time had come to formulate a hypothesis. The investigators theorized that about 20 million years ago, the Mediterranean was a broad seaway linked to the Atlantic by two narrow straits. Crustal movements closed the straits, and the landlocked Mediterranean began to evaporate. Increasing salinity caused by the evaporation resulted in the extermination of scores of invertebrate species. Only a few organisms especially tolerant of very salty conditions remained. As evaporation continued, the remaining brine (salt water) became so dense that the calcium sulfate of the hard layer was precipitated. In the central deeper part of the basin, the last of the brine evaporated to precipitate more soluble sodium chloride (salt). Later, under the weight of overlying sediments, this salt flowed plastically upward to form salt domes. Before this happened, however, the Mediterranean was a vast desert 3,000 meters deep. Then, about 5.5 million years ago came the deluge. As a result of crustal a...
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This note was uploaded on 09/17/2013 for the course LANGUAGE 13DL208 taught by Professor Wang during the Fall '13 term at East China Normal University.
- Fall '13