Geologia Croatica (Sep 2009)
Discriminant Function Analysis of Upper Miocene and Pliocene Sands from the Southwestern Part of the Pannonian Basin System, Croatia
Abstract
Multiple discriminant analysis (MDA) of Upper Miocene and Pliocene sands of SW portion of Pannonian Basin System is performed in order to find out optimum criteria of separating previously defined informal lithostratigraphic units - Ozalj, Andraševec, Hum Zabočki, Cernik and Pluska. Heavy mineral association is employed as independent variables, or descriptors, in the process of discrimination and results of analysis established a clear and strong bond between characteristic heavy mineral assemblages in the Upper Miocene and Pliocene sands their affinity to particular lithostratigraphic units. In this respect, Pluska unit is especially highlighted, followed by Ozalj and Hum Zabočki units. Close heavy mineral/lithostratigraphic unit relationship was found very useful in unraveling the basic sedimentologic meaning hidden under specific discriminant functions in the mathematical model. The most prominent is DF1 accounting for almost three fourth of the total variance of the investigated sedimentary system. In accordance with its “key” mineral it is labeled kyanite function which indicates the (metamorphic) provenance of the siliciclastic mineral detritus. The second most important, DF2, is labeled garnet-zircon function and, being bipolar, it points at both provenance of siliciclastic material (older sedimentary rocks) and hydraulic conditions during the detritus transport and sedimentation. Finally, DF3 is of minor importance indicating stability of heavy mineral association in sandy sediments. Three lithostratigraphic units, namely Ozalj, Pluska and Hum Zabočki are clearly separated by the functions labeled after their distinctive (“key”) heavy minerals.
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