当前位置: X-MOL 学术Palaeogeogr. Palaeoclimatol. Palaeoecol. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Sedimentology and geochemistry of Carboniferous-Permian marine-continental transitional shales in the eastern Ordos Basin, North China
Palaeogeography, Palaeoclimatology, Palaeoecology ( IF 3 ) Pub Date : 2021-04-06 , DOI: 10.1016/j.palaeo.2021.110389
Leifu Zhang , Dazhong Dong , Zhen Qiu , Chenjun Wu , Qin Zhang , Yuman Wang , Dexun Liu , Ze Deng , Shangwen Zhou , Songqi Pan

A continuously cored well covering the Carboniferous-Permian Benxi, Taiyuan, and Shanxi formations in the eastern Ordos Basin provides a rare window into environmental conditions of the marine-continental transitional strata. Integration of petrographic, mineralogical, and high-resolution geochemical data allows marine-continental investigating the depositional environment, organic abundance, detrital influx, paleoclimate, paleo-water salinity, and paleoredox conditions of transitional facies. The marine-continental transitional strata in the Upper Carboniferous to Lower Permian consist of complex interbedding of sandstone, shale, coal and limestone. TOC contents display a considerable change in the vertical direction, with high TOC content in coal, moderate TOC in shale, low TOC content in limestone and no noticeable TOC enrichment in sandstone. The Upper Carboniferous Benxi Formation is dominated by marine facies then changing into transitional facies. The Lower Permian Taiyuan Formation is characterized by multiple alternation of marine and transitional facies. Marine limestones are characterized by low detrital influx proxies, whereas transitional shales show high detrital influx input and oxic environment. The Lower Permian Shanxi Formation is a typical marine-continental transitional depositional system, which is characterized by complex interbedding of shales, sandstones and coals. Sandy intervals were deposited in deltaic and tidal flat environment and characterized by high Ti and Al content, low TOC (0.09–0.97%, avg. 0.31%), relatively low U/Th (0.11–0.32, avg. 0.17), showing limited influence of seawater. Shale intervals were deposited in a lagoonal environment with high TOC (0.94–40.64%, avg. 5.43%), Sr/Ba and trace elemental proxies values (U/Th, 0.18–3.27%, avg. 0.44%; MoEF, 0.95–32.3, avg. 8.56; UEF, 0.67–15.17, avg. 2.53). This study shows that high-resolution geochemical characteristics of elements could be reliable indicators for sedimentary facies analysis, and hence could provide broader implications for utilizing trace element geochemistry from marine-continental transitional periods in which sedimentary environment changes frequently and organic-rich sediment accumulated under varied conditions.



中文翻译:

华北鄂尔多斯盆地东部石炭纪-二叠纪海陆陆相过渡页岩的沉积学和地球化学

覆盖鄂尔多斯盆地东部石炭纪-二叠系本溪,太原和山西地层的连续取芯井为海洋-陆相过渡层的环境条件提供了一个难得的窗口。整合了岩石学,矿物学和高分辨率地球化学数据,可以进行海洋大陆调查沉积环境,有机质丰度,碎屑涌入,古气候,古水盐度和过渡相的古陆条件。上石炭统到下二叠统的海陆过渡层由砂岩,页岩,煤和石灰岩的复杂层合组成。TOC含量在垂直方向上显示出很大的变化,煤中的TOC含量高,页岩中的TOC含量适中,石灰石中的TOC含量低,而砂岩中的TOC含量却不明显。上石炭统本溪组以海相为主,然后转变为过渡相。下二叠纪太原组的特征是海洋相和过渡相的多重交替。海洋石灰石的特征是碎屑涌入量低,而过渡页岩显示出大量碎屑涌入量和含氧环境。下二叠统山西组是典型的海陆陆过渡沉积体系,其特征是页岩,砂岩和煤层错复杂。砂质层段沉积在三角洲和潮汐平坦的环境中,其特征在于高的Ti和Al含量,低的TOC(0.09-0.97%,平均0.31%),相对较低的U / Th(0.11-0.32,平均0.17),显示出有限海水的影响。页岩层段沉积在高TOC(0。94–40.64%,平均。5.43%),Sr / Ba和痕量元素代理值(U / Th,0.18-3.27%,平均0.44%; MoEF,0.95–32.3,平均。8.56; ü EF,0.67-15.17,AVG。2.53)。这项研究表明,元素的高分辨率地球化学特征可能是沉积相分析的可靠指标,因此可以为利用海洋-陆相过渡时期的痕量元素地球化学提供更广泛的意义,在海洋-过渡时期,沉积环境经常变化,富含有机物的沉积物在条件各不相同。

更新日期:2021-04-06
down
wechat
bug