Geometric characteristics of pull-apart basins

Pull-apart basins are depressions bounded on their sides by two or more strike-slip faults and on their ends by diagonal transfer faults. As proposed by theoretical, experimental, and numerical studies in the literature, there are angular and scale relationships between these faults. Here, I compiled the major results on geometries of pull-apart basins of previous workers and then examined the geometric characteristics of pull-apart basins along the North Anatolian fault zone for a comparison of current data in two and three dimensions. According to the results of my compilation from the literature and measurements of pull-apart examples from northern Turkey, the acute angles of this type of strike-slip basin are clustered at 30 degrees-35 degrees. In metric scale, the consistency in their two-dimensional (2-D) geometry is well known as an aspect ratio of 3:1 between length and width. Basin length is a function of stretching associated with strike-slip displacement, and increased displacement causes the width of the fault zone to increase, resulting in wider pull-apart basins. However, the depth of a pull-apart basin is a function of stretching associated with strike-slip displacement. In this study, comparison of data related to pull-apart basin scales from the literature suggests that the depth is related to the length and width.