Geochemistry on rocks from the eastern Weddell Sea

Petrographie and geochemical investigations on ice-rafted debris along the continental margin of the eastern and southern Weddell Sea give additional information for modelling subglacial geology at the continental border region. From northeast to southwest five provinces with different petrographic and geochemical properties could be distinguished:
The northeastern Province I is characterized by volcanic rocks, mainly basalts (>90 %). 0nly a small portion of clastic sedimentary rocks was recognized while metamorphic and plutonic rocks are almost lacking.
Province II is still dominated by basaltic rocks (60 %), but there is a considerable increase in metamorphic (15 %) and clastic seedimentary rocks (25 %).
Province III is typified by a variation in the occurrence of medium to high grade metamorphics (36 %) and a variety of different plutonic rocks (30 %). The portion of volcanic rocks decrease to 20 % whereas sedimentary rocks form a portion of 13 %.
Almost equal portions of intermediate to acidic plutonic rocks, medium- to highgrade metamorphic rocks and clastic sedimentary rocks (28 %) characterize Province IV. Volcanic rocks occcur only in minor portions (15 %).
Finally, Province V is dominated by the occurrence of sedimentary rocks (80 %). Besides clastic sedimentary rocks some calcarous rocks (e.g. trilobite-bearing limestones) have been found. Only minor numbers of volcanic (<10 %), magmatic (<5 %) and metamorphic rocks (<5 %) were observed.
ff