Chapter 17 Multivariate Analysis of Heavy Mineral Assemblages of Sediments from the Marginal Seas of the Western Pacific
2007; Elsevier BV; Linguagem: Inglês
10.1016/s0070-4571(07)58017-9
ISSN2352-2844
AutoresAlexander Derkachev, Natalia Nikolaeva,
Tópico(s)Geological and Geochemical Analysis
ResumoHeavy mineral data of sediments from the marginal seas of the Western Pacific (Bering, Okhotsk, Japan, East China, Philippine, Banda, etc.), from the Tonga and Vanuatu Trenches and from adjacent areas have been evaluated using multivariate statistics and correlation, factor, cluster and discriminant analyses. The overall characteristics of heavy mineral assemblages and the regional variability of mineral associations are described and interpreted. Despite the large latitudinal and environmental range of the study basins, the complexity of source rocks and volcanic signatures are clearly reflected in the distribution of heavy mineral assemblages. Results allowed identification of several mineralogical provinces, linked to distinct hinterland complexes and associated tectonic controls. Q-mode factor analysis differentiated four major groups of assemblages of distinctive provenance. R-mode factors helped to define representative mineral associations, which best characterise the mineral composition of the sediments of the individual marginal seas, and led to the delineation of eight provinces. Lithogeodynamic discriminant diagrams, based on average values of heavy mineral compositions, identify assemblages which are most typical of differing types of magmatic and metamorphic rocks, and discriminate between them and those associated with other crustal lithologies. Changing compositions of the heavy mineral assemblages indicate a clear trend from simple geodynamic environments to composite ones, including oceanic uplifts, young island arcs, evolved and mature island arcs, marginal-continental volcanic ranges, fold belts, ancient cratons and platforms.
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