Terrane

About: Terrane is a research topic. Over the lifetime, 11025 publications have been published within this topic receiving 442596 citations. The topic is also known as: tectonostratigraphic terrane.

The Geology of New Guinea - The Cordilleran Margin of the Australian Continent

Abstract: The island of New Guinea is the mountainous margin of the Australian continent. Paleozoic and Proterozoic Australian craton extends northward beneath the shallow waters of the Arafura Sea to underlie the southern plains of New Guinea and, with overlying sediments, to form the dramatically sculpted southern slopes of the central range in a great fold and thrust belt. The fold and thrust belt marks the outer limit of the autochthon. Beyond, to the N, E and W, is an aggregation of terranes that have accreted since the Late Cretaceous, driven by oblique convergence between the Pacific and Indo-Australian plates. The terranes comprise continental fragments and blocks of oceanic volcanic arc and of oceanic crust and mantle origin, and include two great ophiolites. The plate boundary itself is a complex system of microplates, each with separate motion, and marked by every kind of plate boundary. In the E the opening of the Manus Basin is associated with rapid clockwise rotation of New Britain, and the opening of the Woodlark Basin causes extension of continental crust in the Papuan peninsula and islands. This has resulted in the development of low-angle extensional faults and domal structures in metamorphic rocks and the exhumation of Pliocene eclogite. Remarkably similar extensional structures and the exhumation of Pliocene eclogite are seen in the Bird's Head area of western New Guinea (Wandamen Peninsula). Flat and shallow oblique subduction at the New Guinea Trench has caused the deformation of Plio-Quaternary sediments in the Mamberamo Basin, deformation and Pliocene igneous activity in the central range, and the southwestward motion of the Bird's Head. The island has significant resources of economic minerals and hydrocarbons.

Involvement of the Argentine Precordillera terrane in the Famatinian mobile belt: U-Pb SHRIMP and metamorphic evidence from the Sierra de Pie de Palo

Abstract: New data suggest that the eastern margin of the Argentine Precordillera terrane comprises Grenvillian basement and a sedimentary cover derived from it that were together affected by Middle Ordovician deformation and metamorphism during accretion to the Gondwana margin. The basement first underwent low pressure/temperature (P/T) type metamorphism, reaching high-grade migmatitic conditions in places (686 6 40 MPa, 790 6 17 8C), comparable to the Grenvillian M2 metamorphism of the supposed Laurentian counterpart of the terrane. The second metamorphism, recognized in the cover sequence, is of Famatinian age and took place under higher P/T conditions, following a clockwise P-T path (baric peak: 1300 6 100 Mpa, 600 6 50 8C). Low-U zircon overgrew detrital Grenvillian cores as pressure fell from its peak, and yields U-Pb SHRIMP ages of ca. 460 Ma. This is interpreted as the age of ductile thrusting coincident with early uplift; initial accretion to Gondwana must have occurred before this. The absence of late Neoproterozoic detrital zircons is consistent with a Laurentian origin of the Argentine Precordillera terrane.