| 黔西南三叠系永宁镇组牙形石研究—兼论下,中三叠统界线 |
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| 引用本文： | 杨守仁,初庆春.黔西南三叠系永宁镇组牙形石研究—兼论下,中三叠统界线[J].北京大学学报(自然科学版),1992,28(6):722-732. |
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| 作者姓名： | 杨守仁 初庆春 |
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| 作者单位： | 北京大学地质学系
(杨守仁)，北京大学地质学系(初庆春) |
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| 摘 要： | 本文首次系统描述了贵州贞丰县龙场、关岭县永宁镇的永宁镇组牙形石5属12种;在永宁镇组中识别出4个牙形石组合带(层)(由下而上):1. Pachycladina obliqua-Parachirognathus delicatulus带,2. Neospathodus homeri-Neospathodus triangularis.带,3. Neogondolella cf. jubata-Neospathodus timorensis带,4. Neogondolella navicula navicula-Neogondolella constricta层;首次将下、中三叠统的界线置于 Neogondolella navicula navicula-Neogondolella constricta层之底,即永宁镇组第4段之底。两统之间为整合接触。
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| 关 键 词： | 永宁镇组 牙形石 三叠纪 贵州 |
Study on Conodonts from Triassic Yongningzhen Formation, Southwestern Guizhou Province with a Discussion on Lower/Middle Triassic Boundary |
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| YANG Shouren,CHU Qingchun.Study on Conodonts from Triassic Yongningzhen Formation, Southwestern Guizhou Province with a Discussion on Lower/Middle Triassic Boundary[J].Acta Scientiarum Naturalium Universitatis Pekinensis,1992,28(6):722-732. |
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| Authors: | YANG Shouren CHU Qingchun |
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| Abstract: | The conodonts (5Genera and 12 Species) first described here were collected from Longchang, Zhenfeng County and Yongningzhen, Guanling County, Southwestern Guiz-hou Province. Four conodont assemblage zones and one bed have been recognized in ascending order: 1. Pachycladina obliqua-Parachirognathus delicatulus Zone, 2. Neospatho-dus homeri-Neospathodus triangularis Zone, 3. Neogondolella cf. jubata-Neogondolella timorensis Zone, 4. Neogondolella navicula navicula-Neogondolella constricta Bed. The boundary between Lower and Middle Triassic was for the first time placed at the base of the Neogondolella navicula navicula-Neogondolella constricta Bed, i. e. the base of the 4th member of the Yongningzhen Formation. The contact between Lower and Middle Triassic is conformable. |
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| Keywords: | Southwestern Cuizhou Province Yongningzhen Formation Conodont zones Lower Triassic Middle Triassic Boundary |
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