Isotopic anomalies at the Precambrian-Cambrian boundary

前寒武纪-寒武纪边界的同位素异常

• 批准号: 07041094
• 负责人: MATSUMOTO Ryo
• 金额: $ 5.95万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07041094/
• 关键词: Precambrian; Cambrian boundary; Cambrian explosion; F; F boundary; Carbon isotope; Rare earth elements; Cerium anomaly; Redox potential; P; T境界; アバデ-; ジョルファ; 炭素同位体層序; イラン; 中国; 炭素同位体; カンブリア; 絶滅事変; 地球環境; 二畳-三畳境界; エルブールズ; 先カンブリア系; 先カンブ

This project was originaly intended to elucidate the nature of the Precambrian/Cambrian boundary event. However, the actual field work plans were reorganized and expanded towards the entire Paleozoic sections in the course of the joint study with the Iranian geologist group. Because the P/C boundary event was believed to be characterized only through the comparison with the other Paleozoic boundary events such as F/F boundary and P/T boundary. We have obtained the following major results concerning the chemo-stratigraphy and environmental changes of the Paleozoic world.1. Negative and positive carbon isotopic anomaly have been recognized just below and bove the P/C boundary. The formaer and the latter are interpreted to correspond to mass extinction of Precambrian fauna and explosive diversification of the Paleozoic type fauna. Moreover, strong positive anomaly was observed in the late Cambrian strata.2. Moderate negative carbon anomaly in the upper Devonian is probably attributed to the Famenian/Frasnian boundary events.3. Cyclic changes in carbon isotopic composition recognized in the Carboniferous-Permian may reflect the glacier-interglacier cycles.4. Chondrite-normalized REEs patterns show interesting secular variations. Strong negative Ce anomaly occurs in the Cambrian explosion intervals whereas the remaining Paleozoic sections show normal pattern, suggesting that the Cambrian explosion was associated with oxygenated ocean while the entire Paleozoic ocean was characrerized by reducing environment.

该项目是原始的，旨在阐明前寒武纪/寒武纪边界事件的性质。但是，在与伊朗地质学家集团的联合研究过程中，实际的现场工作计划重组并扩展到整个古生代部分。因为据信P/C边界事件仅通过与其他古生代边界事件（例如F/F边界和P/T边界）进行比较来表征。我们已经获得了以下有关古生代世界的化学间学和环境变化的主要结果。1。负同位素异位异常的负和阳性碳在下方已经识别出来，并在P/C边界下进行了识别。形式和后者被解释为对应于前寒武纪动物群的质量灭绝以及古生代型动物群的爆炸性多样化。此外，在寒武纪晚期的地层中观察到了强烈的阳性异常。2。上泥盆纪的中度负碳异常可能归因于Famenian/Frasnian边界事件3。石炭纪 - permian中识别的碳同位素组合物的循环变化可能反映冰川交流循环4。软骨归一化的REES模式显示出有趣的世俗变化。强烈的CE异常发生在寒武纪爆炸的间隔中，而其余的古生代则显示出正常的模式，这表明寒武纪爆炸与氧化海洋有关，而整个古生物学海洋的特征是通过还原环境来表征。

项目成果

Watanabe,D.,and Matsumoto,R.: "REE′s of Carbmates from Devonian to Triassic" Geochemical Journal. (発表予定). (1997)

Watanabe, D. 和 Matsumoto, R.：“从泥盆纪到三叠纪的稀土元素”地球化学杂志（即将出版）。

Kimura, H., Matsumoto, R., Hamdi, B., and Kakuwa, Y.: "The Vendian-Cambrian delta 13 C record" North Iran.E.P.S.L.147. 1-7 (1997)

Kimura, H.、Matsumoto, R.、Hamdi, B. 和 Kakuwa, Y.：“旺迪安-寒武纪三角洲 13 C 记录”北伊朗.E.P.S.L.147。

松本 良: "炭酸塩のS^<13>C異常の要因と新しいパラダイム「ガスハイドレート仮説」" 地質雑. 101. 902-924 (1995)

Ryo Matsumoto：“碳酸盐中S^ 13 C异常的原因和新范式‘天然气水合物假说’”地质杂志101. 902-924 (1995)。

Matsumoto, r., Zhong Zheng, Kakuwa, Y., Hamdi, B., and Kimura, H.: "Preliminary results of paleomagnetic study on the Cambrian to the Triassic rocks of the Alborz, Northeaast Iran" Jour.Fac.Sci., Univ.of Tokyo, Sec.II. 22. 233-249 (1995)

Matsumoto, r.、Zhong Cheng、Kakuwa, Y.、Hamdi, B. 和 Kimura, H.：“伊朗东北部厄尔布尔士河寒武纪至三叠纪岩石古地磁研究的初步结果”Jour.Fac.Sci。

Matsumoto, R and Paull, C.: "ODP Initial Reports, Vol. 164" Ocean Drilling Program, College Station, TX., 620 (1997)

Matsumoto, R 和 Paull, C.：“ODP 初始报告，第 164 卷”海洋钻探计划，德克萨斯州大学城，620 (1997)