Proposed Title 1: - Queen's University

epresented by the 1884±3 Ma Gerowie Tuff (Pietsch and Stuart-Smith, 1987) and the
overlying 1877±11 Ma Mount Bonnie Formation (Needham et al., 1988). These rocks are
uncomformably overlain by the ca. 1863 Ma Finniss Group (Walpole et al., 1968).
Following deposition of the Pine Creek Orogen sequence, the 1870±6 Ma Zamu
Dolerite sills (Page et al., 1980) were intruded, folded, and metamorphosed with the host
rocks by the 1860–1840 Ma Nimbuwah event of the Top End Orogen (Ferguson and
Needham, 1978; Lally and Worden 2004). In the SAVMF, the regional metamorphic grade
is greenschist facies (Needham et al., 1988a). Deformation and metamorphism were
accompanied and followed by emplacement of granitic rocks (Stuart-Smith et al., 1993;
Ferenczi and Sweet, 2005; Rasmussen et al., 2006; Neumann and Fraser, 2007).
Following exhumation of the final stages of the Nimbuwah event, minor deformation
and rift-related sedimentation occurred during the ca. 1825 Ma Cullen Event (Wyborn et
al., 1997), resulting in deposition of the El Sherana Group (Needham et al., 1988a). The El
Sherana Group consists of the Coronation sandstone and associated felsic volcanics, the Pul
Pul Rhyolite at 1829±5 Ma (Jagodzinski, 1991). Following folding, faulting and erosion of
the El Sherana Group, the Edith River Group (Kurrundie Sandstone) overlain by the Plum
Tree Creek volcanics at 1822±6 Ma (Jagodzinski, 1992) were deposited. Ahmad et al.,
(2006) interpreted the initial deposition of the El Sherana Group at 1865 Ma associated
with graben formation centred on the South Alligator River valley and followed later by
rifting and deposition of the Edith River Group at 1850 Ma. A regional low-grade
metamorphism, the ca. 1780 Ma Shoobridge event, may represent a thermal stage
137