(Table 1) Age determinations of basement rocks of DSDP Leg 31

The origin and development of the Phillipine Sea have been central issues in tectonic studies of a marginal sea: the deep-sea drilling project (DSDP), Leg 31, was primarily intended to resolve the question. Unfortunately, at only two of the Leg 31 sites (292 and 296) were microfossils indicating the age of the basement recovered, so the age of the ocean basin, had to be deduced by dating the drilled basement rocks.

Sm-Nd isotopic investigation for rocks of Prince Charles Mountains, East Antarctica

The Prince Charles Mountains have been subject to extensive geological and geophysical investigations by former Soviet, Russian and Australian scientists from the early 1970s. In this paper we summarise, and review available geological and isotopic data, and report results of new isotopic studies (Sm-Nd, Pb-Pb, and U-Pb SHRIMP analyses); field geological data obtained during the PCMEGA 2002/2003 are utilised. The structure of the region is described in terms of four tectonic terranes. Those include Archaean Ruker, Palaeoproterozoic Lambert, Mesoproterozoic Fisher, and Meso- to Neoproterozoic Beaver Terranes. Pan-African activities (granite emplacement and probably tectonics) in the Lambert Terrane are reported. We present a summary of the composition of these terranes, discuss their origin and relationships. We also outline the most striking geological features, and problems, and try to draw attention to those rocks and regional geological features which are important in understanding the composition and evolution of the PCM and might suggest targets for further investigations.