1.60 Ga felsic volcanic blocks in the moraines of the Terre Adélie Craton, Antarctica: Comparisons with the Gawler Range Volcanics, South Australia

Abstract

Rhyodacite and rhyolite blocks found in numerous moraines on the Terre Adélie Craton in Antarctica are samples of a high-temperature high-K calc-alkaline to alkali-calcic igneous suite emplaced at ca 1.60 Ga. They comprise lavas and pyroclastic rocks, including ignimbritic varieties, chemically representative of anorogenic and post-orogenic igneous suites. The eruptive centres are probably close to the coast according to radar satellite images that show the trace of the ice streams. The volcanic suite is similar in age, petrography and chemical composition (major and trace elements as well as Nd isotopes) to the Gawler Range Volcanics from the Gawler Craton of South Australia. These similarities strengthen correlations previously established between the Gawler Craton and the Terre Adélie Craton (Mawson Continent). Moreover, the present petrological, geochemical and geochronological data give a new insight into the last major thermal event affecting the Mawson Continent. The results also highlight the useful contribution of moraines to our knowledge of Antarctic geology.

Crustal heat production and estimate of terrestrial heat flow in central East Antarctica, with implications for thermal input to the East Antarctic ice sheet

“…Likewise, they are different from igneous and metamorphic rocks exposed at the Adélie Land coast (ages of ca. 2.4 and 1.7 Ga; Oliver and Fanning, 1997), although one population is similar in age to ∼ 1.6 Ga glacial clasts sampled by Peucat et al (2002). As shown in Fig.…”

“…The major ice drainages in East Antarctica are marked by nearly radial flow away from central ice divides and domes toward the continental margin (Fig. 2), providing natural proxy samples of the continental interior by bedrock erosion during glacial flow (Peucat et al, 2002;Goodge et al, 2008Goodge et al, , 2017. Unique among the major drainages, glacial ice in Byrd Glacier and related smaller drainages moves nonradially from the main ice divides because it is obstructed by the high-standing Transantarctic Mountains (peak elevations > 4000 m).…”

Scouting Craton’s Edge in Paleo-Pacific Gondwana

“…1), the ~1.7 Ga Gawler signature appears to extend from southern Australia into the Wilkes Land region of East Antarctica (Oliver and Fanning, 1997). It is unknown, however, where this basement province extends beyond the narrow coastal exposures of the Commonwealth Bay region (Peucat et al, 2002), due to a lack of aeromagnetic data. Southeast (in rotated coordinates), over the western edge of Victoria Land, longwavelength (~100-300 km) 200-500 nT highs are linked to Precambrian shield rocks (e.g.…”

“…1) (Goodge et al, 2001) Range at ~1.7 Ga (Goodge et al 2001) may correspond to igneous and metamorphic events of this age in the Commonwealth Bay region in Antarctica (CB, Fig. 1) (Oliver and Fanning, 1997;Peucat et al, 2002) and in the Gawler craton of Australia (GC, Fig. 1) (Daly et al, 1998).…”

“…In particular, geological connections between exposures along the coast (Fanning et al, 1995;Fitzsimons, 2000;Peucat et al, 2002;Tingey, 1991) with those ~1800 km south in the Miller Range area (MR, Fig. 1) (Goodge et al, 2001) Range at ~1.7 Ga (Goodge et al 2001) may correspond to igneous and metamorphic events of this age in the Commonwealth Bay region in Antarctica (CB, Fig.…”