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Tectonic sedimentology: sediment systems deciphering global to local tectonics



Tectonic sedimentology has broad appeal because it can be applied at many time and length scales, such as sedimentary consequences of: changing rates of plate creation at mid-ocean ridges, continent–continent collisions, plateaux uplift, active plate margins, extensional rift tectonics and the birth, growth and death of individual folds and faults. Tectonic sedimentology deals with the direct influence of neotectonics on sedimentation and basin development, and with the inverse problem of reconstructing the order and development of palaeotectonic structures. This review attempts to show how the scope and importance of the subject has developed over the last decade and is divided into five themes: (i) At the largest tectonic scale, constraints on mid-ocean ridge activity and continent–continent collisions come from: (a) precise chemical analyses of fluid inclusions in marine halite deposits dating back to ca 550 Ma; (b) Sr-isotopic ratios of marine Phanerozoic calcitic fossils; and (c) chemical composition of Archaean and Proterozoic banded iron formations. (ii) At regional scales, constraints on the timing and extent of continental plateau uplift/incision and cratonic tilting are given by: (a) palaeoaltimetry estimates from oxygen isotope depletion in carbonate palaeosols; (b) radiometric dating of palaeowater-table speleothems; and (c) preferential river migration. (iii) At basin scales, catchment processes are emphasized as key controls on sediment flux from tectonic uplands to sedimentary basins. The inadequacy of sediment transport algorithms based on tractive stress and flow power to describe erosion, incision and sediment transport during the most formative catchment hydrological events is emphasized. (iv) Rates of basin-scale fault and fold growth, displacement, death and basement uplift are provided by application of facies analysis and sequence stratigraphy to accurately-dated sediments in sedimentary basins. (v) The effects of changing climate and varying basin base-level in modifying tectonic influences on erosion and sedimentation are examined. In such cases, experimental and numerical modelling using multi-variate parameters of subsidence rate, sediment supply and sea-level change can shed light on the problem. Future developments will undoubtedly improve such models, hopefully establishing full linkage and feedback between sediment/water supply and changing climate within an overall tectonic framework that may itself be changing.