蜜臀av性久久久久|国产免费久久精品99|国产99久久久久久免费|成人精品一区二区三区在线|日韩精品一区二区av在线|国产亚洲欧美在线观看四区|色噜噜综合亚洲av中文无码|99久久久国产精品免费播放器

<cite id="ygcks"><center id="ygcks"></center></cite>
  • 
    
  • <rt id="ygcks"></rt>
    <cite id="ygcks"></cite>
  • <li id="ygcks"><source id="ygcks"></source></li> <button id="ygcks"></button>
  • <button id="ygcks"></button>
    <button id="ygcks"><input id="ygcks"></input></button>
    
    
    <abbr id="ygcks"><source id="ygcks"></source></abbr>
    
    
    
     
    
    

    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
    莲花县| 福鼎市| 呼和浩特市| 泰州市| 楚雄市| 桓仁| 广昌县| 永康市| 洪雅县| 萨嘎县| 资溪县| 永顺县| 屯昌县| 高雄县| 曲阳县| 阿城市| 报价| 游戏| 汽车| 东源县| 蕲春县| 炎陵县| 桑植县| 九江县| 竹北市| 新宾| 山丹县| 咸宁市| 营山县| 称多县| 姜堰市| 沈丘县| 潞西市| 故城县| 孟津县| 安新县| 宁晋县| 罗甸县| 肇源县| 淮北市| 五原县|