SEDIMENTARY PROVENANCE AND PALEOFLOOD HISTORY OF THE MOHAWK RIVER AS RECORDED IN COLLINS POND, SCOTIA, NY
The bedrock underlying the Mohawk River drainage basin varies considerably: the northern part of the Mohawk River drainage basin is underlain mainly of gneiss, the central part by calcareous shale and dolostone, and the southern part by carbonates and Paleozoic red beds of the Catskill Mountains. Modern Mohawk River alluvium was sampled throughout the drainage basin to elucidate geochemical fingerprints of different sectors of the catchment. Major element geochemistry of the <63 µm fraction indicate that K2O ranges from 2.79% in the north (the headwaters of East and West Canada Creek) to 2.03% in the southern Schoharie region; likewise, samples from the northern part of the drainage basin have a higher percentage of Nb, ~50.5%, whereas the Central Mohawk and Schoharie Valley sectors yield 32% and 36%, respectively. Finally, Al2O3 is higher in samples from the southern sector (10.9% ) relative to samples from the northern part of the drainage basin (8.8%). Samples from an ~7.5-meter long sediment core from Collins Pond indicate that the majority of clastic sediment that has entered the pond was derived from the central Mohawk and southern Schoharie Valley regions.