Geology of the northern Convoy Range, Victoria Land, Antarctica

Abstract

In this paper, we supply a geological map of the area between 76°-76°30 ′ S and 159°-163°E, that was the only missing portion to complete an entire coverage of Victoria Land, filling the gap between the GIGAMAP program (to the north) and the maps by the New Zealand Antarctic program (to the south). The mapped area encompasses an early Paleozoic basement, and a flat-lying cover of sedimentary and igneous rocks, Permo-Triassic to Jurassic in age. The basement consists of large bodies of the Granite Harbour Igneous Complex, a granitic complex linked to the Ross Orogeny. After the early Paleozoic Ross Orogeny, the area was uplifted and eroded, and the sandstones of the Beacon Supergroup were deposited on the resulting erosion surface. The Beacon Supergroup sandstones were in turn covered and in most cases incorporated into the volcanic and sub-volcanic rocks of the Jurassic Ferrar Group.

A comprehensive 1:250,000 scale geological map of the Convoy Range and Franklin Island quadrangles (Victoria Land, Antarctica)

“…Both at Mt Murray and at the eastern slopes of Mt Endeavour, such tectonic foliation is steeply dipping to the ENE (Fig. 10A), but the folds exposed in the southern slopes of Mt Murray clearly indicate a structural control on the attitudes of the Wilson rocks (Capponi et al, 2020). In the Mt Murray outcrop, a mineral lineation lies on the foliation and is steeply plunging to the ENE.…”

“…Evidence of contact metamorphism, due to the emplacement of the Granite Harbour granitoids, occurs locally, e.g. in the Walker Rocks area (Molzahn et al, 1996;Capponi et al, 2020).…”

“…A suite of gabbro-diorite rocks (GHt) occurs in the western cliffs of Mt Smith and belong to the Granite Harbour Intrusive Complex (Capponi et al, 2020). These rocks are unfoliated to weakly-foliated and crop out beneath the light-grey granite.…”

“…In the northern part of the mapped area, the outcrops of Beacon sandstone are quite limited, and only at Mt Smith small bodies of sandstone rest above the erosion surface (Fig. 3C), sandwiched between the granitic basement and the overlying dolerite (Capponi et al, 2020). In a cliff south of Mt Chetwynd, a level of Beacon sandstone, which is continuous for about 1 km, overlies the Granite Harbour granitoid, but the erosion surface itself is not visible; the upper part of the cliff consists of Ferrar Dolerite.…”

Zircon U-Pb Dating of the Irizar Granite in the Central Victoria Land, Antarctica: Insights into the Tectonic Evolution along the Ross Orogen

“…The Central Victoria Land, bounded by the Reeves and Fry Glaciers, is located within the Wilson terrane [57] (Figures 1B and 2). Based on field relationships, and the petrological, mineralogical and geochemical compositions, the GHI rocks in this area can be subdivided into three main units: the Larsen granodiorite, Irizar granite, and Vegetation lamprophyre [11,58,59] (Figure 2).…”