Formation phases of carbonate cements and sedimentary environments in lower Jurassic sandstones of the Lenghu V tectonic belt, North Qaidam Basin, China
文献类型：期刊论文
| 作者 | Guo, Jiajia1,2; Sun, Guoqiang2; Liu, Weiming1,2 |
| 刊名 | CARBONATES AND EVAPORITES
 |
| 出版日期 | 2019-12-01 |
| 卷号 | 34期号:4页码:1367-1379 |
| 关键词 | Carbon isotope Oxygen isotope Carbonate cements Sedimentary environment Qaidam Basin |
| ISSN号 | 0891-2556 |
| DOI | 10.1007/s13146-018-0439-9 |
| 英文摘要 | Based on petrography and geochemistry, formation phases of carbonate cements and their sedimentary-diagenetic environments in Jurassic clastic rocks from the Lenghu V tectonic belt are determined. The results demonstrate that studied successions are mainly dark gray or black mudstone with interbedded thin gray siltstone and a few greywacke layers. Sandstones are lithic and feldspathic lithic greywacke with high kaolinite content. Calcite and ferrocalcite are the main carbonate cements. The carbon isotope values(delta C-13) of the carbonate cements range from - 15.6 to 9.2 parts per thousand (average - 3.2 parts per thousand) with a bimodal distribution. One peak is 4 parts per thousand, which includes samples from the upper Xiaomeigou Formation (Fm) and the other one is - 12 parts per thousand, which mainly represents the lower section. The oxygen isotope values(delta O-18) have a wide range from - 18.5 to - 8.3 parts per thousand (average - 13.31 parts per thousand). Combined with microscopic observations, two phases of carbonate cements are distinguished according to their isotopic characteristics. The earlier carbonate cements are mainly calcite and ferrocalcite, and they were precipitated in eodiagenesis stage. The carbon source of calcite was inorganic, and ferrocalcite was mixed with carbon from methanogenesis. This mixture led to a positive bias in the delta C-13 curve, which artificially inflated the paleosalinity. The later carbonate cements, formed in mesodiagenesis stage, were ferrocalcite. Decarboxylation of organic matters led to lower delta C-13 values. The major and trace elements data show that Sr, Ba, Fe and Mn have weak correlation with Al, Ti. So, they are effective to interpret the sedimentary environment. The Sr/Ba ratio < 1 indicates fresh water environment, Sr/Ca, Sr/Cu and Fe/Mn ratios suggest humid climate, and V/(V + Ni) ratio shows suboxic-anoxic environment. The carbon and oxygen isotopes, together with elemental geochemistry, show that the climate during the Early Jurassic was warm and wet and the studied successions were deposited in fresh water. The variations in elemental ratio curves indicate that climate became wetter and warmer later in the Early Jurassic. |
| WOS关键词 | ISOTOPIC COMPOSITION ; GEOCHEMISTRY ; MINNESOTA ; ULM |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000496621400013 |
| 出版者 | SPRINGER |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/95835]  |
| 专题 | 地质与地球物理研究所_兰州油气中心 |
| 通讯作者 | Sun, Guoqiang |
| 作者单位 | 1.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 2.Chinese Acad Sci, Inst Geol & Geophys, Gansu Prov Key Lab Petr Resources Res, Key Lab Petr Resources, Lanzhou 730000, Gansu, Peoples R China |
| 推荐引用方式 GB/T 7714 | Guo, Jiajia,Sun, Guoqiang,Liu, Weiming. Formation phases of carbonate cements and sedimentary environments in lower Jurassic sandstones of the Lenghu V tectonic belt, North Qaidam Basin, China[J]. CARBONATES AND EVAPORITES,2019,34(4):1367-1379. |
| APA | Guo, Jiajia,Sun, Guoqiang,&Liu, Weiming.(2019).Formation phases of carbonate cements and sedimentary environments in lower Jurassic sandstones of the Lenghu V tectonic belt, North Qaidam Basin, China.CARBONATES AND EVAPORITES,34(4),1367-1379. |
| MLA | Guo, Jiajia,et al."Formation phases of carbonate cements and sedimentary environments in lower Jurassic sandstones of the Lenghu V tectonic belt, North Qaidam Basin, China".CARBONATES AND EVAPORITES 34.4(2019):1367-1379. |
入库方式： OAI收割
来源：地质与地球物理研究所
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