The Characteristics of Storm Deposits in The Lower Huanglong Formatiom of Majiaoba Area, Northwestern Sichuan Provine
详细信息
- 责任者：Xu Jinlong (School of Resources and Environmental Engineering ; Hefei University of Technology ; Hefei ; China) ; Hong Tianqiu
- 刊名：Chinese Journal of Geology
- 出版年：2012
- 卷期：47(2)
- 关键词：风暴沉积 ; tempestite deposit ; 四川 ; Sichuan Province
- 页码：p.422-439
- 图表：illus., 2 plates, 39 refs.
- 分类号：0803
- issnNo：ISSN0563-5020
- isbnNo：CN11-1937/P
摘要
There are many depositional characteristics of storm deposits in the lower Huanglong Formation around Majiaoba area, Jiangyou County, including storm shell limestone, storm calcirudite,storm nodular limestone, storm calcarenite, scouring structures, graded beddings, similar knotty structures, scale beddings, horizontal beddings, current beddings, bioturbate structures and so on. Through detailed field observation and laboratory study, four storm layers have been recognized in each of the two sections and a total of five combinations of stormdeposits systems have been divided. Combination Ⅰ ,which is deposited in normal weather wave base nearby open platform facies, is characterized by scouring structures, coarse gravel beddings, scale beddings, horizontal beddings, current beddings, bioturbate structures and dragonfly fossil concentration. Combination Ⅱ , formed by above normal wave base nearby restricted platform faicies, is represented by bioclastic limestone with similar knotty structures, graded beddings and massive beddings. Combination Ⅲ, which is deposited above normal weather wave base nearby winnowed open platform edge facies, is characterized by coarse gravel beddings, graded beddings and massive beddings. Combination Ⅳ located on combination Ⅲ, is characterized by graded beddings, hummocky cross stratifications and massive beddings. It is proven that the combination IV begins to deposit before storm flow Ⅲ completely ended and deposits in normal weather wave base nearby the storm fluid. Combination V ,which is formed at the place sunny weather wave base nearby open platform facies, is characterized by scouring structures, coarse gravel beddings and mudstone. These tempestite are wholly proximal storms rocks. The research of tempestite is useful in stratigraphic correlation, paleoclimate, lithofacies paleogeography, sedimentary evolution and oil-gas exploration.