文章来源:未知 文章作者:meng 发布时间:2010-02-12 01:02 字体: [ ]  进入论坛

Theories about the rates of ice accumulation(积聚,累积) and melting during the Quaternary Period(第四纪) -- the time interval1(时间间隔) ranging from 2.6 million years ago to the present -- may need to be revised, thanks to research findings published by a University of Iowa researcher and his colleagues in the 12 February issue of the journal Science. Jeffrey Dorale, assistant professor of geoscience(地球科学) in the UI College of Liberal Arts and Sciences, writes that global sea level and Earth's climate are closely linked. Data he and colleagues collected on speleothem(洞穴堆积物) encrustations(硬壳,节壳) , a type of mineral deposit, in coastal2 caves on the Mediterranean3 island of Mallorca indicate that sea level was about one meter above present-day levels around 81,000 years ago. The finding challenges other data that indicate sea level was as low as 30 meters -- the ice equivalent of four Greenland ice sheets -- below present-day levels.

He said the sea level high stand of 81,000 years ago was preceded by rapid ice melting, on the order of(相似,近似) 20 meters of sea level change per thousand years and the sea level drop following the high water mark, accompanied by ice formation, was equally rapid.

"Twenty meters per thousand years equates4 to(比拟,相当) one meter of sea level change in a 50-year period," Dorale said. "Today, over one-third of the world's population lives within 60 miles of the coastline. Many of these areas are low-lying and would be significantly altered -- devastated5(毁坏,摧毁) -- by a meter of sea level rise. Our findings demonstrate that changes of this magnitude can happen naturally on the timescale of a human lifetime. Sea level change is a very big deal."

Dorale also noted6 that although their findings disagree with some sea level estimates, such as those from Barbados and New Guinea that come from ancient coral reefs(珊瑚礁) , they are in agreement with data gathered from other sites such as the Bahamas, the U.S. Atlantic coastal plain, Bermuda, the Cayman Islands and California.

"There has been a long-standing debate on this issue, but our data is pretty robust7(强健的,粗野的) ," he said. "The key to our research is two-fold. First, the speleothem approach we employed is novel and extremely precise compared to other methods of sea-level reconstruction8. Second, Mallorca appears to be particularly well suited to the task, because neither tectonics(构造学) nor isostasy -- geological forces of crustal motion -- over-complicate the record. It's really close to the ideal scenario9. It's also a heck of a nice place to do fieldwork."

Dorale's colleagues include Bogdan Onac of the University of South Florida, Tampa; Joan Fornos, Joaquin Gines and Angel Gines, all of the Universitat de les Illes Balears, Mallorca, Spain; Paola Tuccimei of the University of Rome III, Italy; and UI associate professor of geoscience David Peate.

The research was supported by the National Science Foundation(美国国家科学基金会) in a grant(拨款,授予物) to Dorale and Onac.


1 interval 85kxY     
  • The interval between the two trees measures 40 feet.这两棵树的间隔是40英尺。
  • There was a long interval before he anwsered the telephone.隔了好久他才回了电话。
2 coastal WWiyh     
  • The ocean waves are slowly eating away the coastal rocks.大海的波浪慢慢地侵蚀着岸边的岩石。
  • This country will fortify the coastal areas.该国将加强沿海地区的防御。
3 Mediterranean ezuzT     
  • The houses are Mediterranean in character.这些房子都属地中海风格。
  • Gibraltar is the key to the Mediterranean.直布罗陀是地中海的要冲。
4 equates 7b5a7f0640b2cedfd39d5d5473d911d4     
v.认为某事物(与另一事物)相等或相仿( equate的第三人称单数 );相当于;等于;把(一事物) 和(另一事物)等同看待
  • He equates success with material wealth. 他认为成功等同于物质财富。 来自《简明英汉词典》
  • This equates to increased and vigor, better sleep and sharper mental acuity. 也就是说可以起到增强活力,改善睡眠,提高心智的作用。 来自互联网
5 devastated eb3801a3063ef8b9664b1b4d1f6aaada     
v.彻底破坏( devastate的过去式和过去分词);摧毁;毁灭;在感情上(精神上、财务上等)压垮adj.毁坏的;极为震惊的
  • The bomb devastated much of the old part of the city. 这颗炸弹炸毁了旧城的一大片地方。
  • His family is absolutely devastated. 他的一家感到极为震惊。
6 noted 5n4zXc     
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
7 robust FXvx7     
  • She is too tall and robust.她个子太高,身体太壮。
  • China wants to keep growth robust to reduce poverty and avoid job losses,AP commented.美联社评论道,中国希望保持经济强势增长,以减少贫困和失业状况。
8 reconstruction 3U6xb     
  • The country faces a huge task of national reconstruction following the war.战后,该国面临着重建家园的艰巨任务。
  • In the period of reconstruction,technique decides everything.在重建时期,技术决定一切。
9 scenario lZoxm     
  • But the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • This is a totally different scenario.这是完全不同的剧本。
TAG标签: sea research ice