ACT科学Session3地球学（考古学-例题解析）
考古学 Archaeology
例题练习 2
(OG3-Passage V)
科学家讨论了两种导致2.5亿年前90%海洋生物灭绝的原因。
Scientist 1
这些海洋生物灭绝的原因是大陆溢流的火山作用，这种作用导致火山喷发持续了100万年，产生了200万立方千米的熔岩。 火山喷发导致大量的含硫气体(四氧化硫)进入空气之中。这些气体与空气中的水蒸气结合，从而产生了酸雨，之后酸雨在全球范围降落，毒害了水中的许多生物。四氧化硫也损坏了大气中的臭氧，使高强度的紫外线射向地球表面。
火山爆发也向大气中释放了大量的二氧化碳。 大气中二氧化碳等级的升高提高了海洋表面海水二氧化碳的含量，使二氧化碳达到了可以使许多海洋生物中毒的等级。二氧化碳含量的增加也引起了气候变暖，减少了地球两极和赤道之间的温度差，因此海洋环流减少，海水变得缺少氧气。
Scientist 2
这些海洋生物灭绝的原因是富有二氧化碳的深海水的翻转。
2.5亿年前，地球上上没有大陆冰盖。现如今，大陆冰盖促进降低海水表面的温度，冰盖下降，驱使海洋进行垂直环流。2.5亿年前，因为海洋没有这样的环流形成，所以海水停滞不前且缺乏氧气。
生活在海水表面的光合生物移除大气中的二氧化碳，将其转换为有机物质。这种有机物质沉入海底，之后通过氧化想成二氧化碳。因此，深海里二氧化碳含量的等级急剧提升，而大气中二氧化碳含量继续下降，这种现象导致了气候变冷。 冰川和冰盖快速形成，从而降低了海水表面的温度，海洋开始垂直环流。 深海中的海水升到了海表面， 释放了积累已久的二氧化碳，明显地增加了大气和海表面中的二氧化碳浓度。 过量的二氧化碳毒害了许多海洋生物。
例题练习 2.1
Which of the following statements best explains why Scientist 1 mentioned ultraviolet light?
A. High levels of ultraviolet light are beneficial to many living things.
B. High levels of ultraviolet light are harmful to many living things.
C. Ultraviolet fight helps create ozone in the atmosphere.
D. Ultraviolet light helps create CO2 in the atmosphere.
【考点分析】
l 观点冲突类文章，此题为单一观点题。
l 抓住定位词 Scientist 1，直接定位到种观点，题目考察ultraviolet light 提到原因。
l 根据“SO4 - containing aerosols also helped break down ozone in the atmosphere, permitting high levels of ultraviolet light to reach the surface.”可以直接排除C&D选项，同时结合“The extinctions were caused by continental flood volcanism, a massive volcanic eruption lasting 1 million years that produced 2 million km3 of lava. The eruption sent large amounts of sulfate-containing (SO4 ) aerosols into the air. ”直接比较得出正确答案为B。
例题练习 2.2
Large amounts of SO4 - containing aerosols in the atmosphere are known to reflect some of the incoming solar radiation back into space, which results in a lowering of the surface temperature. Based on the information provided, this finding would most likely weaken the viewpoint(s) of:
F. Scientist 1 only.
G. Scientist 2 only.
H. both Scientist 1 and Scientist 2.
J. neither Scientist 1 nor Scientist 2.
【考点分析】
l 观点冲突类文章，此题为综合观点题。
l 抓住定位词 SO4 - containing aerosols ，题目给出信息SO4 - containing aerosols会降低温度。
l 先看科学家1的观点，“The eruption sent large amounts of sulfate-containing (SO4 ) aerosols into the air. ….The increased levels of also caused climatic warming that decreased the temperature difference between the poles and the equator, thus slowing ocean circulation and causing ocean water to become oxygen-poor.”，结合起来必然削弱科学家1的观点，而科学家2根本未提到SO4，故而不受影响，直接得出正确答案为F。
例题练习 2.3
Scientist 2 would most likely state that the vertical circulation that is present in most of the oceans today is maintained, at least in part, by the presence of:
A. high levels of CO2 in the air.
B. active volcanoes around the Pacific Ocean rim.
C. ice sheets in Earth’s polar regions.
D. marine organisms in deep ocean waters.
【考点分析】
l 观点冲突类文章，此题为单一观点题。
l 抓住定位词 Scientist 2 & vertical circulation 。
l 根据“Glaciers and ice sheets grew rapidly, cooling the ocean surface waters such that vertical circulation of the ocean began.”，推断得出正确答案为C。
例题练习 2.4
Both scientists would most likely agree that the ocean water was, or became, oxygen-poor when which of the following events occurred?
F. Ocean water circulation reversed its usual direction.
G. Ocean water circulation slowed, stopped, or was absent.
H. Oceanic organisms dramatically increased the available oxygen in the ocean water.
J. Oceanic organisms used up all the available CO2 in the ocean water.
【考点分析】
l 观点冲突类文章，此题为综合观点题。
l 抓住定位词 ocean water 。
l 根据“…thus slowing ocean circulation and causing ocean water to become oxygen-poor.”和“Since this circulation was absent 250 Ma, the ocean water was stagnant and oxygen poor.”综合可以得出正确答案为G。
例题练习 2.5
According to the information provided, radioactive dating of volcanic rocks created during the continental flood vulcanism described by Scientist 1 would show the rocks to be about how many million years old?
A. 1
B. 50
C. 100
D. 250
【考点分析】
l 观点冲突类文章，此题为单一观点题。
l 抓住定位词 Scientist 1。
l 根据“an event 250 million years ago (Ma) in which 90% of all marine species became extinct…. The extinctions were caused by continental flood volcanism, a massive volcanic eruption lasting 1 million years that produced 2 million km3 of lava. ”，推断得出正确答案为D。
例题练习 2.6
SO4 — containing aerosols are produced today in large quantities by human activity. Scientist 1 would most likely predict that the climatic effect in an area where large amounts of SO4 — containing aerosols are put into the atmosphere would be a decrease in the:
F. amount of ultraviolet light reaching Earth’s surface in that area.
G. average pH of rainfall in that area.
H. amount of rainfall in that area.
J. average wind speed in that area.
【考点分析】
l 观点冲突类文章，此题为单一观点题。
l 抓住定位词 Scientist 1 。
l 根据“The eruption sent large amounts of sulfate-containing (SO4 ) aerosols into the air. The aerosols combined with water vapor in the air to produce acid rain that fell worldwide and poisoned many bodies of water. ”，结合常识(酸雨有毒，并且PH值低于普通雨水)得出正确答案为G。
例题练习 2.7
Inorganic carbonates are rocks formed from calcium carbonate (CaCO3) that precipitate out of ocean surface waters which have much higher than normal levels of dissolved CO2. If scientists found large deposits of inorganic carbonates that had formed around 250 Ma, this discovery would most likely support the viewpoint(s) of:
A. Scientist 1 only.
B. Scientist 2 only.
C. both Scientist 1 and Scientist 2.
D. neither Scientist i nor Scientist 2.
【考点分析】
l 观点冲突类文章，此题为综合观点题。
l 抓住关键词 CO2。
l 根据全文信息，对于科学家1和2来说CO2含量影响都非常大，所以综合全篇得出正确答案为C。
知识拓展 2
玄武岩
l 化石是存留在岩石中的古生物遗体、遗物或生活痕迹，最常见的是骸骨和贝壳等。
l 化石，古代生物的遗体、遗物或遗迹埋藏在地下变成的跟石头一样的东西。研究化石可以了解生物的演化并能帮助确定地层的年代。保存在地壳的岩石中的古动物或古植物的遗体或表明有遗体存在的证据都谓之化石。从太古宙(34亿年前)至全新世(1万年前)之间都有化石出现。
l 简单地说，化石就是生活在遥远的过去的生物的遗体或遗迹变成的石头。在漫长的地质年代里，地球上曾经生活过无数的生物，这些生物死亡后的遗体或是生活时遗留下来的痕迹，许多都被当时的泥沙掩埋起来。在随后的岁月中，这些生物遗体中的有机质分解殆尽，坚硬的部分如外壳、骨骼、枝叶等与包围在周围的沉积物一起经过石化变成了石头，但是它们原来的形态、结构(甚至一些细微的内部构造)依然保留着;同样，那些生物生活时留下的痕迹也可以这样保留下来。我们把这些石化了的生物遗体、遗迹就称为化石。从化石中可以看到古代动物、植物的样子，从而可以推断出古代动物、植物的生活情况和生活环境，可以推断出埋藏化石的地层形成的年代和经历的变化，可以看到生物从古到今的变化等等。
l 实体化石是由古生物遗体本身的全部或部分(特别是硬体部分)保存下来而形成的化石。在能够避开空气氧化作用和细菌腐蚀作用的特别适宜的情况下，有些生物的遗体能够比较完好地保存而没有显著的变化。如西伯利亚冻土中发现的第四纪猛犸象、波兰发现的迄今所知的最完整的脊椎动物化石——1万年前落入沥青湖的披毛犀、以及树脂化石(参见琥珀)。
ACT科学 Session1地球学相关例题解析可：ACT科学Session3地球学（地质学-例题解析）、ACT科学Session3地球学（气象学-例题解析）
