USING A DISCRIMINANT FUNCTION FOR DETERMINING A RELATIONSHIP BETWEEN DETRITAL MODES AND TECTONIC SETTINGS: AN APPROACH TOWARD UNVEILING SOME SOURCE-TO-SINK FACTORS

The final composition from siliciclastic rocks is highly connected with the nature of source-areas (provenance types), with the processes of weathering, erosion, transport, and diagenesis that are interrelated in deposit with the type of basin and tectonic environment in which they were deposited (Source-to-Sink). Source-to-sink analyses imply provenance analysis and tectonic analysis as its final product.

Under this conception this work develops a statistical bivariable analysis and a discriminant analysis in 1411 sandstones deposited within nine types of sedimentary basins, to obtain an optimal relative variation of principal components and partitioning of ternary compositional data, given by the sense of perception of the natural scale, into a discriminant basin-type compositional signature.

The statistical bivariable analysis indicates that basins that present mayor source-area rejuvenance, are basins linked to island arcs and continental arcs (Ilr-P, Ilr-F. Ilr-Lv; subduction related basins). Other basins are influenced by processes of selection, textural maturity, and the exhumation/unroofing of the sedimentary carapace, this are rift, foreland, and accretionary settings. Finally, basins controlled by transcurrent systems or strike-slip present a mixed characteristic in processes lately described, but whit a considerable mayor input from crystalline and metamorphic rocks (Ilr-Lm ).

To preclude the application the exploratory methodology is applied to a case study of samples Late Triassic–Early Cretaceous sandstones from the NE of Mexico, which belong to four different formations, and are derived from ~eleven source areas of the Sierra Madre Oriental. This method is restricted by the lack of compiled variables from the many available tectonic settings, and the interpretative manipulation caused by those quartz-rich sedimentary environments.

To improve source-to-sink provenance models, the use of ternary subcompositions should be replaced by discriminant analyses of the full (Qm, Qp, P, K, Lv, Ls, Lm) sedimentary framework petrography indices (Sedimentary Recycling Index; SeReIn), and their covariance structure could be employed to unmix samples into compositional basin analysis. These interpretations have a more general tool–meaning to estimate contrasting sink histories.