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Facies Models and Modern Sedimentary Environments |
Department of Geology and Physical Sciences, Oxford Polytechnic, Headington, Oxford OX3 0BP
A number of problems are encountered in the study and interpretation of sequences of volcaniclastics (sediments or sedimentary rocks composed predominantly of volcanic particles). These problems include the lack of modern analogues, the complex interaction of volcanic and sedimentary processes, and extensive diagenetic alteration. Volcaniclastic sediments are produced and emplaced by autoclastic (mechanical breakage during magma movement), hydroclastic (water/magma interaction), pyroclastic (magmatic explosion) and epiclastic (sedimentary erosion, transport and deposition) processes, or by any combination of these. The systematic study of lithology, texture and primary structure sequences, and their lateral and vertical variations, is leading to the erection of facies models for recent volcaniclastics. These models are likely to have important applications in the interpretation of ancient sequences of volcaniclastic sedimentary rocks, as well as practical applications in mineral and petroleum exploration and volcano prediction.
