| 云南东部上新元古界-下寒武统地层碳同位素变化 |
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| 引用本文： | 蒋志文,木村浩人.云南东部上新元古界-下寒武统地层碳同位素变化[J].云南地质,2004,23(1):1-16. |
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| 作者姓名： | 蒋志文 木村浩人 |
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| 作者单位： | 1. 云南省地质矿产局,云南,昆明,650011
2. 渥太华-卡林顿地质科学中心,加拿大,安大略,KIN,6NS |
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| 摘 要： | 云南东部上新元古界-下寒武统沉积序列中碳酸盐岩较多，本文研究的三条剖面上厚约500m，包括：东龙潭组、渔户村组及筇竹寺组底部，覆于海相冰水沉积之上，反映了从潮上蒸发至浅水相环境。已获得的δ^13C和δ^18O值显示出较大的变化范围，分别是-7．33～ 2．64(‰)和-14．98～ 0．78(‰)。依靠δ^13C测试，结合岩矿鉴定，发现梅树村震旦系．寒武系界线层型剖面岩石成岩作用中有改造现象。显然，δ^13C总的变化范围及变化模式比世界其它地区小，但却包含一个δ^13C负异常，直接位于古生物学上的前寒武系-寒武系界线之下。
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| 关 键 词： | 碳酸盐岩 碳同位素 上新元古界-下寒武统 云南东部 |
The Stratigraphy and Carbon Isotope Variation of Upper Neoproterozoic-Lower Cambrian in East Yunnan, SW Chna |
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| JIANG Zhi-Wen,Hiroto Kimura.The Stratigraphy and Carbon Isotope Variation of Upper Neoproterozoic-Lower Cambrian in East Yunnan, SW Chna[J].Yunnan Geology,2004,23(1):1-16. |
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| Authors: | JIANG Zhi-Wen Hiroto Kimura |
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| Institution: | Jiang Zhi-wen~1Hiroto Kimura~2 |
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| Abstract: | Sedimentary sequences in East Yunnan, Southwest China, record shallow marine carbonate sedimentation through the late Neoproterozoic to the earliest Cambrian. A composite section of approximately 500 m thick has been obtained from three locations in east Yunnan. The sections comprise peritidal flat sediments of the Donglongtan, Yuhucun and basal Qiongzhusi Formations, overlying a glaciogenic unit of the Marinoan ice age, with environments broadly progressing from evaporitic supratidal to shallow subtidal. Measured values of δ13C and δ18O show wide ranges; -7.33～ + 2.64 (‰) and - 14.98～ + 0.79 (‰), respectively.Close examination on the isotope data together with mineralogical and petrographic data confirm that δ13C values from the Sinian-Cambrian boundary strato-type section in Kunyang (Meishucun) are diagenetically modified. Other studied sections appear to retain variation in δ13C, ranging between - 1.40‰ and + 2.64 ‰, whose total range of δ13C variation is smaller than those in other reported locations worldwide, the variation patterns are similar to those from other locations. These include a negative δ13C anomaly immediately beneath the paleontologically determined P∈-∈boundary. |
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| Keywords: | Carbonates Carbon isotopes Upper Neoproterozoic-Lower Cambrian East Yunnan |
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