Layered Jurassic intrusions in Antarctica

The Magmatic Architecture of Continental Flood Basalts I: Observations From the Deccan Traps

“…Although there are layered mafic intrusions associated with recent CFBs such as the Doros Complex (∼20 km 3 , Parana–Etendeka CFB, T. Owen‐Smith & Ashwal, 2015), NAIP associated central complexes such as Rum, Mull, Skye ($$< $$100 km 3 , Namur et al., 2010; O'Driscoll, 2007; O'Driscoll et al., 2006), the Skaergaard intrusion (∼280 km 3 , NAIP, Nielsen, 2004), La Balma‐Monte Capio intrusion (CAMP, Denyszyn et al., 2018), and the Graveyard Point Intrusion (Snake River Plain Basalt, $$< $$10 km 3 C. M. White, 2007), they are much much smaller than RLS and the required size for the large magma reservoir model (see Smith & Maier, 2021 for a full catalog of layered mafic intrusions). The one exception to this are the large layered mafic intrusions in the Karoo‐Ferrar province e.g., Dufek‐Forrestal intrusions (10,200–11,880 km 3 , Ferris et al., 1998; Semenov et al., 2014, though could be $$ > $$50,000 km 3 ) as well as other layered intrusion in the region (Elliot & Fleming, 2021; Jordan & Becker, 2018; Semenov et al., 2014). At present, there is no similar high resolution stratigrpahic U‐Pb datasets for the Dufek intrusion to assess its formation history.…”

Investigating the distribution of magmatism at the onset of Gondwana breakup with novel strapdown gravity and aeromagnetic data

“…Unfortunately, deeper level mafic intrusions associated with the Karoo-Ferrar LIP in Antarctica are only exposed in two areas (Fig. 1) (Semenov et al, 2014). Firstly Vestfjella in Dronning Maud land where two separate layered Gabbro intrusions up to 25 km 2 and 3 km thick are seen cross cutting the CFB sequences (Vuori and Luttinen, 2003).Secondly the Dufek Intrusion ~1000 km further south, suggested from geological observations to cover an area of 24,000-34,000 km 2 with an estimated thickness of 8-9km (Ford and Himmelberg, 1991), although aeromagnetic data suggests an area of closer to 6600 km 2 (Ferris et al, 1998).…”

“…The sub-ice extent of individual Antarctic intrusions has been investigated using aerogeophysical data, although precise determination of intrusion size has been controversial (Behrendt et al, 1981;Ferris et al, 1998;Semenov et al, 2014). A number of additional magnetic anomalies of high to moderate amplitudes associated with magmatism during Gondwana break up are inferred within the continental crust from regional aeromagnetic compilations (Corner, 1994;Golynsky and Aleshkova, 1997;Leitchenkov et al, 1996), regional aerogravity data (Aleshkova et al, 1997) and ground based surveys (Ruotoistenmäki and Lehtimäki, 1997).…”

The geotectonic setting, age and mineral deposit inventory of global layered intrusions

“…Only few layered intrusions have been reported in Antarctica, the largest of which being the ~ 1.8 Ga Dufek intrusion (> 6,600 km 2 ) of the Ferrar Province (Ford 1983;Kistler et al 2000;Ferris et al 2003). Discovered in 1957, the ~ 7-8-km-thick Dufek intrusion consists of sub-horizontal and alternating layers (~ few mm to 10s of metres in thickness) of gabbro, gabbronorite, anorthosite, titanomagnetite gabbronorite, gabbroanorthosite, and pyroxenite (Semenov et al 2014). Despite its size, no economic Ni, Cu, PGE, Ti, V, and Cr concentrations are known (Ford 1983).…”