First Records of Late Triassic Conodont Fauna and δ13Ccarb from the Dengdengqiao Section, Dangchang County, Gansu Province, Northwestern China
First Records of Late Triassic Conodont Fauna and δ13Ccarb from the Dengdengqiao Section, Dangchang County, Gansu Province, Northwestern China
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DOI：
10.1007/s12583-021-1428-9
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发表时间：
2021-04
影响因子：
3.3
通讯作者：
Hanxiao Li;Miaoyan Wang;Muhui Zhang;P. Wignall;M. Rigo;Yanlong Chen;Xianlang Wu;Z. Ouyang
中科院分区：
文献类型：
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作者：
Hanxiao Li;Miaoyan Wang;Muhui Zhang;P. Wignall;M. Rigo;Yanlong Chen;Xianlang Wu;Z. Ouyang
通过对秦岭盆地上三叠统灯灯桥组49个牙形刺和57个地球化学样品的研究，首次报道了卡尼期牙形刺和碳同位素记录。在87个牙形刺单元中鉴定出2属4种：Mosherella praebudaensis，Mo.龙南种十一月，Mo.sp.，和“Misikella”longidentata。莫的存在。praebudaensis表明，该地层的下部（层2）可归因于朱利安（下卡尼）亚阶段。在以前的研究中发现的放射虫动物群属于卡尼阶晚期，但采样层位尚不清楚。δ 13 C C C C曲线自3层上部开始出现负向偏移，但其地层位置不确定。登登桥组显然至少部分属于卡尼期，但可能包括更年轻的地层。该断面丰富的石灰质藻类可能是由于一些运输，而不是保存在现场。这种罕见的海洋生物生态系统可能反映了登登桥长期的压力和不利条件。
Based on a study of 49 conodont and 57 geochemical samples from the Upper Triassic, carbonate-dominated Dengdengqiao Formation, Qinling Basin, China, the Carnian conodonts and carbon isotope records are first reported. Two genera and four species have been identified amongst 87 conodont elements:Mosherella praebudaensis,Mo. longnanensissp. nov.,Mo.sp., and “Misikella” longidentata. The presence ofMo. praebudaensisindicates that the lower part (bed 2) of the formation is attributable to the Julian (lower Carnian) substage. A radiolarian fauna identified in a previous study belongs to the upper Carnian, but the sampling horizon is unclear. The δ13Ccarbcurve shows a ∼1.8‰ negative excursion beginning from upper part of bed 3, but its stratigraphic location is uncertain. The Dengdengqiao Formation is clearly at least partly of Carnian age but could include younger strata. The abundant calcareous algae at the section is probably due to some transport rather than preserved in site. The unusual ecosystem with rare marine organisms may reflect long-term stressful and unfavorable conditions at Dengdengqiao.