科研之友
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摘要
Although the general factors influencing the occurrence and distribution of oolitic systems are well known, details of their landscape-scale patterns and formative processes are less systematically explored. By reviewing published studies and presenting new data and insights, this review systematically examines a suite of Holocene systems from the Bahamas in which patterns and processes are characterized and explicitly linked, with the goal of providing more realistic and accurate models for variability, heterogeneity, and predictability in these systems and their ancient analogs. Sedimentological, geomorphic, and hydrodynamical data document that each ooid shoal is unique in detail, yet shoals share common elements. Within bar forms, systematic trends in grain size, type, and sorting are related to spatial and temporal variability in wave, tide, and current energy. These trends are driven by connections among sedimentology, hydrodynamics, and geomorphic forms, as they shape, and concomitantly are shaped by, each other. Similarly, due to feedbacks, a limited number of bar forms occur among shoals, including tidal sand ridges, parabolic bars, transverse shoulder bars, tidal deltas, and sand flats; the dominant bar form broadly corresponds with flow velocities within and among shoals. Among Bahamian tidal shoals, the mean grain size of ooids, maximum bar heights, and the width of the oolitic facies belts are all positively correlated. Collectively, these results illustrate the mode and magnitude of variability in shapes, orientations, and sedimentology of Holocene oolitic bodies, interpreted to be driven by self-organization and autogenic processes. These perspectives provide testable qualitative and quantitative insights that can be used to understand and predict the character of ancient analogs.
- 出版日期2011-2
