Episodicity of Mesozoic terrane accretion along the Pacific margin of Gondwana: implications for superplume-plate interactions

Abstract

A review of evidence for deformation and terrane accretion on the Late Triassic-Early Jurassic margins of Pangaea and the mid-Cretaceous margins of the palaeo-Pacific ocean shows that deformation was global and synchronous with probable superplume events. Late Triassic-Early Jurassic deformation appears to be concentrated in the period 202–197 Ma and was coeval with eruption of the Central Atlantic Magmatic Province, onset of Pangaea break-up, a period of extended normal magnetic polarity and a major mass extinction event, all possible expressions of a superplume event. Mid-Cretaceous deformation occurred in two brief periods, the first from approximately 116 Ma to 110 Ma in the west palaeo-Pacific and the second from roughly 105 Ma to 99 Ma in the east palaeo-Pacific, with both events possibly represented in northeast Siberia. This deformation was coeval with eruption of major oceanic plateaux, core-complex formation and rifting of New Zealand from Gondwana, the Cretaceous normal polarity epoch, and a major radiation of flowering plants and several animal groups, all linked with the mid-Cretaceous superplume event. A simple unifying mechanism is presented suggesting that large continental or oceanic plates, when impacted by a superplume, tend to break-up/reorganize, associated with gravitational spreading away from a broad, thermally generated topographic high and with a resulting short-lived pulse of plate-marginal deformation and terrane accretion.

Thermochronologic constraints on the tectonic evolution of the western Antarctic Peninsula in late Mesozoic and Cenozoic times

“…The data indicate a uniform episode of regional denudation and post-metamorphic cooling from temperatures in excess of 250-300°C in the Late Cretaceous, which is -on a regional scale -concomittant with the Palmer Land event on the Antarctic Peninsula (Vaughan et al, 2002) and the accretion of the Scotia Metamorphic Complex (Feraud et al, 2000). On a larger scale, it is consistent with a period of deformation affecting the whole eastern Pacific domain (Vaughan & Livermore, 2005). The observations preclude any significant later thermal overprint, as should be expected in the case of subduction of ridge segments beneath the Antarctic Peninsula.…”

Permo-Carboniferous conglomerates in the Trinity Peninsula Group at View Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana

“…Episodic convergence and compression on the Pacific margin has been identified by Vaughan & Livermore (2005). A pattern of alternating extension and convergence along an active margin resembles that seen in the Palaeozoic rocks of eastern Australia (e.g.…”

“…Intercalations of red chert up to several metres thick in Trinity Peninsula Group rocks of the South Orkney Islands indicate the presence of a deep-water starved basin and possibly an entrapped piece of older oceanic crust. The outliers of the Botany Bay Group suggest that both the View Point and Hope Bay areas were deformed by Early Jurassic times but evidence that the very similar Trinity Peninsula type rocks of the Miers Bluff Formation of the South Shetland Islands are of Jurassic age (Hervé et al 2006) suggest a second younger belt of sedimentation and deformation that post-dates Late Triassic deformation (Vaughan & Livermore, 2005) in the Antarctic Peninsula. The Trinity Peninsula Group may thus comprise two or more discrete sedimentary-tectonic tracts that amalgamated during the Mesozoic and collectively accreted to the magmatic Central Domain of Vaughan & Storey (2000) in Cretaceous times.…”

“…Map of localities mentioned in the text and outcrop distribution of the Trinity Peninsula Group (dark grey) in the northern Antarctic Peninsula (after Paciullo et al 2002). current location (Vaughan & Livermore, 2005). Age control for the Trinity Peninsula Group is not strong.…”

New Rb-Sr mineral ages temporally link plume events with accretion at the margin of Gondwana

“…Tectonic erosion during subduction (Hervé and Fanning 2003) or the subsequent removal of accreted material during transpression (Vaughan and Livermore 2005), could explain the volumetrically small proportion of preserved accreted material. Moreover, Vaughan and Livermore (2005) proposed that short-lived stress increases at plate boundaries, caused by the arrival of mantle plumes at the base of the lithosphere, may have controlled accretion, e.g., spanning the TriassicJurassic boundary and in the mid-Cretaceous.…”