Magnetotelluric survey for undercover structural mapping, Central Victoria

A geological interpretation of the Echuca magnetotelluric survey, Victoria

“…The new MT08 (Echuca) dataset presented here supports the structural trends found along the southern MT07 (Bendigo) line (Dennis et al 2011) and shows that the MT07 results previously obtained can be extrapolated north. Following the application of high-frequency statics corrections, a 2-D inversion of the data was completed.…”

“…The Paleozoic geology of the northern region has been interpreted by Moore (2004Moore ( , 2005Moore ( , 2006 from airborne magnetic and gravity data, constrained by several hundred boreholes and geological mapping. In contrast, a previous MT survey on the Bendigo seismic line (MT07; Dennis et al 2011), was located approximately 50 km to the south where the basement is much closer to the surface, and several exposed areas of the western Lachlan Orogen can still be observed (VandenBerg et al 2000). The available correlations indicate that geophysical signatures of the obscured geology in the Echuca survey region are very similar to those observed on the southern margins of the Murray Basin, and suggest a northern extrapolation of the Bendigo Zone as a whole (Lisitsin et al 2007).…”

“…Models suggesting that the geometry and distribution of the groups of goldfields are the surface expressions of fluid flows related to the major faults (Cox et al 1991;Willman 2007;Willman et al 2010) may encourage the use of MT methods as a tool for further exploration. Previous comparisons with deep seismic data (Dennis et al 2011) also demonstrate the merits of the MT method for the mapping of major faults.…”

Magnetotelluric imaging zone in western Victoria of a Palaeozoic Andean margin subduction

“…MT response over the easterly Lachlan portion of the seismic transect did not find significant conductive anomalies within the crust (Dennis et al, 2011a, Dennis et al 2011b. Small, thin conductors in the mid-crust coincided with the top of ancient seafloor basalts and the anomalies were interpreted as being cause by graphitic black shales known from this level.…”

Transient electromagnetic surveys for the measurement of near-surface electrical anisotropy

“…1 for conceptual geology), including the Heathcote Fault on its western margin and the Mount William Fault defining its eastern lower margin (Edwards et al, 1998). Maintaining their reference numbers from the previous regional TEM survey (Dennis et al, 2010), sites 38 and 39 (site 39 situated within the 4 km wide greenstone belt and site 38 located~3 km further east) were selected following an analysis of the site coincident MT data (Dennis et al, 2011), indicating a near-surface anisotropic response (MT apparent resistivity curves presented by Fig. 3).…”