Influence of palaeoclimate and the green house effect on Hettangian clay mineral as sem blages (Holy Cross Mts. area, Polish Basin)

Hettangian clay mineral assemblages from the Holy Cross Mts. margin (south eastern part of the epicontinental Polish Basin) were mostly controlled by climaticcon ditions and weathering regime. Hettangian claystones and mudstones were deposited in continental and marine-margin palaeoenvironments in a warm climate, mostly with year-round humidity. The pronounced, long-term green house conditions intensified chemical weathering in the hinterland. Reworking and redeposition of ancient sediments caused by tectonics and/or by sea-level changes and early diagenesis may have modified the clay mineral content in the earliest Hettangian. Burial diagenesis and telodiagenesis changed the clay mineral composition only locally.