Paleozoic–Mesozoic Geology of South Island, New Zealand: Subduction-related Processes Adjacent to SE Gondwana
CONTAINS OPEN ACCESS
This volume presents a set of research papers that provide new data and interpretations of the Permian–Triassic terranes of SE Gondwana, now exposed in South Island, New Zealand. Following an introduction for general readers, a historical summary and a review of biostratigraphy, the individual papers primarily focus on the Permian magmatic arc of the Brook Street Terrane, the classic Permian Dun Mountain ophiolite and the Permian–Triassic Maitai Group sedimentary succession. The new results emphasize the role of subduction and terrane displacement adjacent to the Permo-Triassic Gondwana margin, and present fundamental insights into three crustal processes: subduction initiation, supra-subduction zone oceanic crust genesis and forearc basin evolution. The volume concludes with a wide-ranging summary and synthesis of the regional Cambrian to Early Cretaceous tectonostratigraphy of New Zealand's South Island in relation to the wider areas of Zealandia, East Australia and West Antarctica. The volume will interest geoscientists, including stratigraphers, sedimentologists, palaeontologists, igneous petrologists, geochemists, geochronologists and economic geologists, and is aimed at professional geologists and advanced students of geology.
Chapter 11: Geochemistry used to infer source characteristics and provenance of mudrocks of the Permian–Triassic Maitai Group and the associated Patuki Melange, South Island, New Zealand
-
Published:May 08, 2019
-
CiteCitation
Romesh Palamakumbura, Alastair H. F. Robertson, 2019. "Geochemistry used to infer source characteristics and provenance of mudrocks of the Permian–Triassic Maitai Group and the associated Patuki Melange, South Island, New Zealand", Paleozoic–Mesozoic Geology of South Island, New Zealand: Subduction-related Processes Adjacent to SE Gondwana, A. H. F. Robertson
Download citation file:
- Share
Abstract
Chemical and mineralogical evidence is reported, first for mudrocks from the Mid-Permian–Mid-Triassic Maitai Group and, secondly, for Late Permian(?) mudrocks from the structurally underlying Patuki Melange. Weathering and alteration indices indicate increased source weathering and aluminosilicate input stratigraphically upwards in the Maitai Group. The Maitai Group exhibits an upward change from a relatively enriched continental magmatic arc source (and related country rocks) during the Late Permian, to a relatively depleted continental magmatic arc source (and related country rocks) during the Triassic. The melange mudrocks have a similar provenance to the Late Permian mudrocks of the Maitai Group. The melange mudrocks are, however, generally less altered, probably because of additional, local, ophiolite-related input. Red iron-rich mudrocks accumulated widely in two Triassic Maitai Group formations and also locally in the Patuki Melange. The iron oxide was derived by continental weathering under warm conditions, and then accumulated relatively slowly under oxidizing seafloor conditions. The chemical evidence, as a whole, indicates sources for all of the mudrocks similar to the Median Batholith and associated country rocks, or non-exposed equivalents along the SE Gondwana active continental margin. Accumulation took place during a change from an icehouse to a hothouse world.
- age
- alteration
- Australasia
- chemical composition
- chemical fractionation
- clastic rocks
- climate change
- continental crust
- crust
- ferruginous composition
- geochemistry
- igneous rocks
- iron-rich composition
- Lower Triassic
- major elements
- Mesozoic
- mineral composition
- mudstone
- New Zealand
- Paleozoic
- Permian
- Permian-Triassic boundary
- provenance
- sedimentary rocks
- sedimentology
- sediments
- source rocks
- South Island
- stratigraphic boundary
- stratigraphy
- thickness
- trace elements
- Triassic
- Upper Permian
- X-ray diffraction data
- Maitai Group
- Patuki Melange