Open AccessImaging links between lithospheric architecture and surface geology in the Proterozoic Curnamona Province, Australia
Author(s) -
Williams H. A.,
Betts P. G.
Publication year - 2007
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jb004966
Subject(s) - geology , proterozoic , felsic , lithosphere , igneous rock , outcrop , tectonics , seismology , shear zone , paleontology , geophysics , lineament
Potential field (magnetic and gravity) analysis is an effective method to investigate crustal‐scale architecture and provides a means of linking continental‐scale geophysical data sets (e.g., seismic tomography) with detailed geological and geophysical studies. Here, we image deep‐crustal structure of the Proterozoic Curnamona Province, Australia, in aeromagnetic and gravity data sets and establish spatial and temporal links between deep structures and near surface geological features by superimposing first vertical derivative responses on upward continued images. Upward continued gravity and aeromagnetic data show NW–SE, NE–SW, E–W, and N–S oriented long‐wavelength discontinuities and boundaries to anomalies, which we interpret as deep‐seated structures. These structures predate the oldest known tectonic events recorded in outcropping rocks and appear to have been long‐lived, thereby influencing the tectonic history of the province. For example, outcropping Cambrian shear zones, evident in vertical derivative data, appear to have nucleated off displaced segments of a once continuous deep‐seated structure of Proterozoic origin that has been imaged in upward continued data. Long‐wavelength gradients defining E–W and NW–SE structures in upward continued aeromagnetic data intersect beneath the dominantly felsic Benagerie igneous province in the central province and are coincident with a large negative gravity anomaly interpreted as felsic igneous rocks that are coeval to the volcanic pile. Tectonic implications of this study include (1) deep‐seated structures in the Curnamona Province have protracted histories; (2) these structures appear to have controlled the location and distribution of younger shear zones, igneous activity, and possibly basin subsidence in the upper crust; (3) geophysical lineaments are likely to have evolved and propagated during multiple tectonic cycles and hence record the protracted evolution of a geological province.