中国地质
中國地質
중국지질
CHINESE GEOLOGY
2015年
1期
192-198
,共7页
牟传龙%葛祥英%周恳恳%王秀平
牟傳龍%葛祥英%週懇懇%王秀平
모전룡%갈상영%주간간%왕수평
川西南%晚奥陶世五峰期%沉积相%岩相古地理
川西南%晚奧陶世五峰期%沉積相%巖相古地理
천서남%만오도세오봉기%침적상%암상고지리
southwestern Sichuan%Late Ordovician Wufeng Age%sedimentary facies%lithofacies palaeogeography
提通过对川西南汉源—马边—雷波地区典型剖面上奥陶统五峰组沉积岩性特征、充填序列、沉积构造及室内分析等研究,并结合研究区晚奥陶世构造特征,将川西南地区五峰期分为2期,划分为潮坪、浅水陆棚和深水陆棚3种沉积相。指出在晚奥陶世五峰早期,受加里东构造运动影响,扬子与华夏陆块发生构造挤压碰撞,川中、黔中等边缘隆起抬升扩大,上扬子地区由克拉通海相盆地转为被隆起围限的隆后盆地,除川中隆起、川西—滇中隆起周缘沉积潮坪相白云质页岩、泥灰岩和白云质灰岩外,川西南绝大部分面积主要发育深水陆棚相炭质页岩和硅质页岩、含炭粉砂质页岩。五峰晚期,伴随着全球性冰期事件的发生,研究区乃至整个上扬子区发生大规模海退,大面积的深水陆棚相转为浅水陆棚沉积,岩性主要为粉砂质页岩、泥灰岩、钙质炭质页岩和硅质灰岩等,较前期钙质成分明显增多。
提通過對川西南漢源—馬邊—雷波地區典型剖麵上奧陶統五峰組沉積巖性特徵、充填序列、沉積構造及室內分析等研究,併結閤研究區晚奧陶世構造特徵,將川西南地區五峰期分為2期,劃分為潮坪、淺水陸棚和深水陸棚3種沉積相。指齣在晚奧陶世五峰早期,受加裏東構造運動影響,颺子與華夏陸塊髮生構造擠壓踫撞,川中、黔中等邊緣隆起抬升擴大,上颺子地區由剋拉通海相盆地轉為被隆起圍限的隆後盆地,除川中隆起、川西—滇中隆起週緣沉積潮坪相白雲質頁巖、泥灰巖和白雲質灰巖外,川西南絕大部分麵積主要髮育深水陸棚相炭質頁巖和硅質頁巖、含炭粉砂質頁巖。五峰晚期,伴隨著全毬性冰期事件的髮生,研究區迺至整箇上颺子區髮生大規模海退,大麵積的深水陸棚相轉為淺水陸棚沉積,巖性主要為粉砂質頁巖、泥灰巖、鈣質炭質頁巖和硅質灰巖等,較前期鈣質成分明顯增多。
제통과대천서남한원—마변—뢰파지구전형부면상오도통오봉조침적암성특정、충전서렬、침적구조급실내분석등연구,병결합연구구만오도세구조특정,장천서남지구오봉기분위2기,화분위조평、천수륙붕화심수륙붕3충침적상。지출재만오도세오봉조기,수가리동구조운동영향,양자여화하륙괴발생구조제압팽당,천중、검중등변연륭기태승확대,상양자지구유극랍통해상분지전위피륭기위한적륭후분지,제천중륭기、천서—전중륭기주연침적조평상백운질혈암、니회암화백운질회암외,천서남절대부분면적주요발육심수륙붕상탄질혈암화규질혈암、함탄분사질혈암。오봉만기,반수착전구성빙기사건적발생,연구구내지정개상양자구발생대규모해퇴,대면적적심수륙붕상전위천수륙붕침적,암성주요위분사질혈암、니회암、개질탄질혈암화규질회암등,교전기개질성분명현증다。
According to the lithological characteristics, filling sequences, sedimentary structures and lab analysis of Late Ordovician Wufeng Formation, combined with the structural features, the authors divided the Wufeng Age in southwestern Sichuan into two periods, and the southwestern Sichuan can be divided into tidal-flat facies and deep shelf and shallow shelf facies. In the Late Ordovician early Wufeng Age, affected by the Caledonian Movement and the continuous extrusion and collision between Yangtze
<br> and Cathaysia blocks, the Central Sichuan and Guizhou were increasingly uplifted, and the Upper Yangtze region was submerged and transformed into carbonate ramp, and finally developed into the back-bulge basin confined by the marginal uplifts. Tidal flat facies were developed around Central Suchuan and Western Sichuan-Central Yunnan uplifts with dolomitic shales, muddy limestones and dolomitic limestones. Large areas of western Sichuan developed deep shelf facies which deposited carbonaceous shales, siliceous and carbonaceous-silty shales. In the late Wufeng Age of Late Ordovician, with the emergence of the worldwide glacial event, large-scale regression started in the study area and even in the whole Upper Yangtze area, shallow shelf facies replaced deep shelf facies with silty shales, muddy limestones, calcareous-carbonaceous shales and siliceous limestones, and they had more calcium in comparison with those in former periods.