CAJ | 학술논문

应用露头层序地层学基本原理和方法、结合碳酸盐岩微相、古生物学、成岩作用、沉积相和沉积事件等理论,对江油马角坝地区上石炭统碳酸盐岩地层进行了露头层序地层研究。研究表明,研究区晚石炭世为典型的陆表海沉积,地形平坦,地壳下降相对缓慢,海水较浅,沉积物界面与海平面接近,主体为碳酸盐岩开阔台地和浅滩沉积环境。水体主体深度为0~50m,为低幅高频低速的海平面变化。根据沉积层序界面的露头和镜下标志,共划分出7个三级层序,反映了研究区晚石炭世具有7次相对较大的海平面升降旋回。发育TST和HST,普遍缺失LST,局部CS难以识别。平均每个层序时限约为2．7Ma,并伴随着多次四级、五级乃至高频海平面变化,共同组成了研究区简单而复杂的碳酸盐岩地层格架。动力机制主要源于晚古生代冰川型全球海平面变化,其原因可能为晚古生代冰期(大洋水体积的周期型变化或大陆冰盖的增长和衰减)和风暴事件共同作用的结果,同时受到古地形、物源和沉积物供应量变化的制约。其中,CSQ1、CSQ3和CSQ4对应的海平面变化幅度较大,海平面变化速率主要为突发性的快递上升到缓慢下降或缓慢上升到相对下降的特点。 CSQ2、CSQ5、CSQ6和CSQ7对应的海平面变化幅度不大,为缓慢上升和缓慢下降的特点。
응용로두층서지층학기본원리화방법、결합탄산염암미상、고생물학、성암작용、침적상화침적사건등이론,대강유마각패지구상석탄통탄산염암지층진행료로두층서지층연구。연구표명,연구구만석탄세위전형적륙표해침적,지형평탄,지각하강상대완만,해수교천,침적물계면여해평면접근,주체위탄산염암개활태지화천탄침적배경。수체주체심도위0~50m,위저폭고빈저속적해평면변화。근거침적층서계면적로두화경하표지,공화분출7개삼급층서,반영료연구구만석탄세구유7차상대교대적해평면승강선회。발육TST화HST,보편결실LST,국부CS난이식별。평균매개층서시한약위2．7Ma,병반수착다차사급、오급내지고빈해평면변화,공동조성료연구구간단이복잡적탄산염암지층격가。동력궤제주요원우만고생대빙천형전구해평면변화,기원인가능위만고생대빙기(대양수체적적주기형변화혹대륙빙개적증장화쇠감)화풍폭사건공동작용적결과,동시수도고지형、물원화침적물공응량변화적제약。기중,CSQ1、CSQ3화CSQ4대응적해평면변화폭도교대,해평면변화속솔주요위돌발성적쾌체상승도완만하강혹완만상승도상대하강적특점。 CSQ2、CSQ5、CSQ6화CSQ7대응적해평면변화폭도불대,위완만상승화완만하강적특점。
The Upper Carboniferous strata in the Majiaoba region, Jiangyou, Sichuan are known for well-developed sections and abundant fossils, and thus selected as a classical area for the study of sedimentary characteristics of the Sichuan Basin and even the whole area of the Upper Yangtze area during the Late Carboniferous. Sequence stratigraphy of the Upper Carboniferous strata in the Majiaoba region, Jiangyou, Sichuan is based on the principles and methods of sequence stratigraphy, in integration of carbonate microfacies, palaeontology, diagenesis, sedimentary facies and depositional events. Seven third-order sequences have been distinguished, and represent seven major cycles of sea-level changes in this region. The transgressive and highstand systems tracts are recognized while the low stand systems tract is absent and condensed sections are seldom observed. Each sequence has recorded the time duration of ca. 2. 7 Ma, and may be accompanied by several fourth-to fifth-order high-frequency sea-level changes, which may be constrained by the Late Palaeozoic glacial-type sea-level changes, storm events, palaeotopography, palaeoclimatology, provenance and sediment supply.