科研之友
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摘要
Roundness reflects the transport history of gravels, but methods of determining roundness in the field have had little progress over decades. In this study, we introduce a new method to quantify the roundness of gravels on outcrops by combining field digital photographs and laboratory image processing. The Chihsia Formation in northern Chaohu City, Anhui Province, South China deposited different types of calcirudites that were formed in carbonate slope environment, including light-color limestones gravels originated from platform and dark-color limestones matrix. Using this method, we calculate the roundness of gravels from different kinds of calcirudites and characterize the geometry of the carbonate slope of the Permian-aged Chihsia Formation in Chaohu area and conclude that the gravels in calcirudites are primarily sub-angular (0.11-0.28), sub-angular to rounded (0.21-0.43), and sub-rounded to rounded (0.36-0.58) in the upper, middle and lower slopes which have dip angles of 15-25 degrees, 30-35 degrees and 1-10 degrees, respectively. These results show that this method not only can be used for quantitative studies of the roundness of gravel-size particles in carbonate slope environments, but may also has broad applications for investigations of the roundness of gravels in other settings.
- 出版日期2018-12
- 单位合肥工业大学
