外国黄片网站黄色片一级视屏|国产视频-日美不卡在线视频|看欧美1级1级1级生活片儿|青青草人人插青青操干日AV|青青操在线免费观看av|一级成年国产中文字幕av一|美女黄黄视频骚货网站在线观看|欧美一级做一级a做片|少妇高潮一区二区三区99|丁香五月蜜桃久久久亚洲精品成人

Chinese scientists recreate Earth's first mass extinction

Source: Xinhua| 2019-04-24 20:24:24|Editor: Shi Yinglun
Video PlayerClose

NANJING, April 24 (Xinhua) -- Chinese scientists have recreated the process of Earth's first mass extinction with high accuracy, which will contribute to the study of biological evolution.

Scientists in east China's Nanjing Institute of Geology and Palaeontology under the Chinese Academy of Sciences said they made the achievement under a comprehensive stratigraphic framework about three times more accurate than before.

They summarized the evolutionary features of benthonic animals in the late Ordovician period, the time when the extinction took place and combined them with biological and carbon isotope stratigraphic data, to improve the preciseness of geological and palaeontological research in the period.

About 85 percent of marine life was wiped out during the first mass extinction, with the marine ecosystem severely damaged.

However, due to limited references and low data precision, no final conclusion has been made so far concerning the cause and process of the extinction.

"We found that the exact time of the extinction was 445 million years ago, which is also the time when the Antarctic Gondwana ice sheet was formed," said Wang Guangxu, leader of the research team.

"Climate change and the formation of the ice sheet are probably the main causes of the large marine life extinction," he added.

The results have been published on the world's top journal Earth-Sciences Reviews.

TOP STORIES
EDITOR’S CHOICE
MOST VIEWED
EXPLORE XINHUANET
010020070750000000000000011100001380057261