Abstract The upper Pennsylvanian Naqing and Narao carbonate successions were deposited in intra‐platform slope‐to‐basinal settings across the Kasimovian–Gzhelian boundary in Guizhou, South China. Conodont faunas consist of a mixture of the endemic taxa of the Idiognathodus luodianensis group and cosmopolitan species of the I. simulator group. The I. luodianensis group includes the new species I. fengtingensis , I. luodianensis , I. naqingensis and I. naraoensis . On platform landmark analysis the species of the I. luodianensis group differ in morphological features from co‐occurring species of the I. simulator group. Both groups display similar increasing asymmetry in P 1 element pairs across the Kasimovian–Gzhelian boundary, as recognized on the basis of the first occurrence of I. simulator . Many Kasimovian Idiognathodus species disappear and several Gzhelian species first appear with I. simulator , including two new species of Streptognathodus : S . nemyrovskae and S . zhihaoi . Just below the base of the Gzhelian, carbonate δ 13 C falls from 4‰ to 2‰ in both sections. The combination of an abrupt faunal turnover immediately above the prominent negative δ 13 C excursion might represent an oceanic event in South China, perhaps recognizable on a global scale. One of these two South China sections may be the best location to place the GSSP for the base of the Gzhelian Stage.

Conodont

Stratotype

Excursion

Magnetostratigraphy

10.1002/spp2.1301

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Citations (13)

Controlling Factors, Accumulation Model and Target Zone Prediction of the Coal‐bed Methane in the Huanghebei Coalfield, North China

Resource Geology (2014)

Dawei Lv Jitao Chen Zengxue Li Guiqiang Zheng Cuiyu Song

Abstract The H uanghebei Coalfield, one of the coal production bases in North C hina, was considered as a coalfield without coal‐bed methane ( CBM ) during past decades. In recent years, however, CBM has been discovered in coal‐bearing successions. In order to understand the CBM geological characteristics and accumulation process in this area, fifteen coal samples were collected and analyzed with respect to coal maceral and reflectance. The result shows that the gas distribution is uneven and the content varies in different areas even for the same coal bed. The storage of CBM is affected by geological factors such as burial depth, geological structures, and magmatic intrusion, among which the former two are more important in the formation of CBM . Deep burial of coal beds with the presence of cap‐rock mudstone can seal CBM . The CBM is also accumulated and preserved at the place where normal faults are distributed. Magmatic intrusion causes contact metamorphism and controls the CBM formation by heating the coal‐bearing successions. The obtained data indicate the geological conditions in northeastern Z haoguan Mine are preferable for CBM formation and conservation; recent exploration estimates the CBM geological reserves up to 282.16 Mm 3 and average of reserve abundance at 0.1662 × 10 8 m 3 km −2 . The C hangqing Mine is a potential prospect in terms of CBM exploration since its geological conditions (structures and burial depth) are similar to the Z haoguan Mine and its cap rock is even better.

Coalbed Methane

10.1111/rge.12044

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Citations (15)