The evolution of the Pine Creek Geosyncline and its relation to the structural framework of north-western Australia

Abstract

This Thesis presents an account of the geology of the Lower Proterozoic rocks which occupy the Pine Creek Geosyncline, and attempts to trace the evolution of the geosyncline by a reconstruction of the sequence of deposition of the sediments; by relating different facies assemblages to structural units developed in the geosynolinal tract; and by a brief consideration of the igneous rocks, which, together with the sediments, make up the geosynclinal pile. The geosyncline is discussed as a unit within the structural framework of North-western Australia, which, for the purpose of this Thesis, is taken as the area shown on Plate 6. The thesis is divided into three parts: Part 1 is descriptive and deals with the stratigraphy of the Lower Proterozoic rocks of the geosyncline, with brief descriptions of the igneous rocks. Rock units of other ages in the area are noted but not described. Part 2 is interpretative and traces the evolution of the geosyncline. Some repetition of material presented in the first section has been found necessary here in order to maintain the continuity of the discussion. Part 3 offers a new reconstruction of the Precambrian framework of North-western Australia in order to explain further the tectonic style and sedimentation pattern of the Pine Creek Geosyncline