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对全球寒武系-奥陶系界线精确划分对比问题的思考 被引量:1
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作者 汪啸风 svend stouge +3 位作者 王传尚 Jorg Maletz 闫春波 Gabriella Bagnoli 《地层学杂志》 CSCD 北大核心 2023年第2期201-224,共24页
基于吉林白山大阳岔小阳桥剖面高精度多学科交叉研究,综合高分辨率生物、层序、化学和磁性地层学的再研究成果,国际奥陶系分会于2019年5月表决通过了中国北方小阳桥剖面为奥陶系底界的全球辅助层型剖面和点(ASSP),即新修的标准辅助界线... 基于吉林白山大阳岔小阳桥剖面高精度多学科交叉研究,综合高分辨率生物、层序、化学和磁性地层学的再研究成果,国际奥陶系分会于2019年5月表决通过了中国北方小阳桥剖面为奥陶系底界的全球辅助层型剖面和点(ASSP),即新修的标准辅助界线层型(SABS)(Martinetal.,2022a,2022b),从而为国内外其他区块寒武系-奥陶系界线的精确划分和对比提供了新依据。据此,本文讨论了以下剖面的寒武系-奥陶系界线精确划分与对比问题:位于华夏地块大陆边缘岛弧或弧后盆地相的广东台山新厂阶命名剖面,分别位于扬子地块台地、陆棚-斜坡和斜坡-盆地相的湖北宜昌黄花场两河口剖面、江西修水武宁剖面和湖南常德瓦尔岗剖面,分别位于中朝地块台地和台缘的河北唐山赵阁庄剖面和山东青州饶王山剖面,位于新疆塔里木地块巴楚—西边大板塔格一带寒武系-奥陶系界线所在剖面,位于加拿大纽芬兰绿岬GSSP剖面,以及位于美国犹他州劳森湾的ASSP剖面。值得注意的是,新建立的小阳桥ASSP剖面位于陆棚-斜坡过渡地带,在古地理位置上正好处于浅水碳酸盐台地(如美国劳森湾ASSP)与深水下斜坡(如加拿大绿岬GSSP)和深水下斜坡-盆地(如中国湖南瓦尔岗(Wargang或Wa’ergan))剖面之间的关键位置,从而成为连接他们之间的纽带和对比标志,并据此提高国内外相关界线划分与对比的准确性。此外,小阳桥ASSP详细的生物、沉积、化学和磁性地层分析揭示了绿岬GSSP剖面所指定的GSSP生物和地球化学标志,说明绿岬GSSP剖面的寒武系-奥陶系界线应对比于小阳桥ASSP剖面的标志性块状叠层石石灰岩(0m)之上的第24层(BD24)底部(19.9±0.2m);生物地层学上,该界线位于牙形石Cordylodusintermedius带上部(Cordyloduslindstromi带底界之下1.5m),在最早的浮游笔石(Rhabdinoporaproparabola)首现(FAD)层位(BD26)之下1 m处。层序地层、海平面变化、事件地层和化学地层研究表明,奥陶系底界位于全球弓头虫(Acerocare)低水位事件之下、稀土元素地球化学异常(REE)之上,继之出现最大碳同位素(δ^(13)Ccarb)正偏移(no.3)。这些物理和化学变化为破解全球寒武系-奥陶系界线的精确划分与对比问题,特别是为解决不同大陆和相区间的寒武系-奥陶系界线的精确划分和对比问题,增添了额外的依据。 展开更多
关键词 小阳桥剖面 全球辅助界线层型剖面和点 寒武系-奥陶系界线 高分辨率地层学 牙形石 笔石
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Conodont diversification during the Ordovician:A perspective from North China and Tarim(Northwestern China) 被引量:2
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作者 WU RongChang Ian G. PERCIVAL +1 位作者 svend stouge ZHAN RenBin 《Science China Earth Sciences》 SCIE EI CAS 2014年第3期397-407,共11页
Review of the literature on Ordovician conodont diversification in palaeoplates of North and Western China reveals that four diversity peaks are present in North China,occurring in the middle Tremadocian,early Floian,... Review of the literature on Ordovician conodont diversification in palaeoplates of North and Western China reveals that four diversity peaks are present in North China,occurring in the middle Tremadocian,early Floian,late Floian,and late Darriwilian,with three of these peaks(excepting that in the late Floian)also being recorded in Tarim.Three diversification intervals are present in North China,during the Tremadocian,late Floian,early and middle Darriwilian;comparable intervals are observed in the early and late Tremadocian,early Floian,and the Middle Ordovician in Tarim.The main conodont diversification episode in both palaeoplates took place in the Darriwilian,at the time of the Great Ordovician Biodiversification Event.A comparison of conodont diversity patterns in different palaeoplates(North China,Tarim,and South China)demonstrates that conodont radiation events mainly occurred within the Tremadocian,Floian,and Darriwilian.Conodont diversifications in these paleoplates also display some differences.In contrasting with Tarim and South China,North China witnessed a rapid conodont diversification during late Floian time.Conodont diversity in North China and Tarim increased continually and reached a peak in the late Darriwilian,concurrent with a prominent decreasing trend in South China.Differences of conodont diversification in these three palaeoplates may be related to their palaeogeography and tectonic history.When conodont diversifications in North China and Tarim are analysed on the background of palaeoenvironments,the main episodes are seen to be partly coincident with second order sea-level changes,particularly in North China.In general,conodont radiation correlates with large scale transgressions. 展开更多
关键词 conodont diversification ORDOVICIAN North China TARIM
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