Ordovician convergent-margin volcanism and tectonism in the Lachlan sector of east Gondwana

Different styles of modern and ancient non-collisional orogens and implications for crustal growth: a Gondwanaland perspective

“…Several authors (e.g., Foster and Gray 2000;Collins and Hobbs 2001;Fergusson 2003Fergusson , 2014Gray and Foster 2004) regarded the Lachlan Orogen as the site of multiple coeval subduction zones from the Ordovician to the Silurian, an interpretation not favoured by Glen (2013) or Packham and Hubble (2016). Glen et al (1998) argued for Ordovician subduction in the Lachlan Orogen to account for the calcalkaline signature of Early to Late Ordovician volcanics (Macquarie Volcanic Province) that we now regard as inherited (Quinn et al 2014). The New England Orogen is the most outboard of orogens in the Tasmanides (Figs.…”

“…6, 9). These volcanics evolved from >482 to ϳ437 Ma in four phases originally thought to have formed above a west-dipping subduction zone (Glen et al 1998, but now it is believed to be rift-related, splitting the eastern Ordovician turbidite sub-basin into two parts (Figs. 6A, 6B; Fig.…”

120 to 0 Ma tectonic evolution of the southwest Pacific and analogous geological evolution of the 600 to 220 Ma Tasman Fold Belt System

“…Following the Delamerian deformation in the Late Cambrian, the subduction zone is believed to have jumped outboard, east of the Selwyn Block microcontinent, to form the Early Ordovician to Late Ordovician Macquarie Arc (Glen et al 1998). Arc-type lavas as old as 480 Ma are recorded from the Ordovician volcanic Parkes-Narromine belt (Butera et al 2001), which trends southward into northeastern Victoria around the headwaters of the Murray River.…”

Terrane processes at the margins of Gondwana: introduction

“…It consists of several orogenic belts whose age of deformation and accretion decreases from west to east (Murray et al 1987;Coney et al 1990;F16ttmann et al 1993;Glen et al 1998;Ireland et al 1998;Fergusson 2003;McElhinny et al 2003). The Early Palaeozoic Delamerian orogeny formed as Neoproterozoic and Cambrian sedimentary and volcanic arc terranes were accreted along the formerly passive margin of the western Australian Precambrian continental core.…”

“…Improved geochemical analytical methods for analysing trace and rare earth elements in volcanic rocks (especially ICP-MS) and greater understanding of their compositional variations has led to growing confidence in assigning tectonic settings to the volcanic arcs that are key elements in the orogenic belt for palaeotectonic reconstructions (e.g. Glen et al 1998;Spandler et aL 2004;Wang et al 2004). 4.…”