Melbourne Volcanic Province

The K-Ar dates of the volcanic rocks from the Melbourne volcanic province measured by Armstrong (1978) range from 18.5 0.7 Ma (Miocene) for the Nathan Hills to 0.003 0.014 Ma (i.e., 3,000 years) for The Pleiades and 0.01 0.02 Ma (i.e., 10,000 years) for Mt. Melbourne (Kyle 1990c), which suggests that The Pleiades and Mt. Melbourne may be dormant but are not yet extinct. 

The volcanic rocks of the Melbourne volcanic province are alkali-rich like those of the Erebus volcanic province although silica concentrations in the Melbourne province range more widely. The representative chemical analyses compiled by the authors of the book edited by LeMasurier and Thomson (1990) 

---

Fig. 16.5 Whole-rock K-Ar dates of the McMurdo Volcanics of the Erebus, Hallett, and Melbourne volcanic provinces form an unbroken sequence from the Holocene (0 Ma) to the middle Miocene (10 Ma). The oldest date is 18.0 0.7 Ma (early Miocene) followed by 15.4 0.5, 13.8 0.2, and 13.2 0.4 Ma, all of which are in the Miocene. The pattern of variation of K-Ar dates indicates that the volcanic activity started during the early Miocene and continued without interruption to the present. Early-formed volcanic rocks are removed by erosion and may also be covered by younger flows which explains why the frequency of K/Ar dates decreases with the increasing age of the rocks (Data from Armstrong (1978), Forbes et al. (1974), and Fleck etal. (1972))...

Melbourne Volcanic Province of Northern Victoria Land... 

Fig. 16.25 The Melbourne volcanic province of northern Victoria Land forms an arc that extends from Mt. Melbourne in the south to the Vulcan Hills, Mt. Overlord, The Pleiades, and the Malta Plateau in the north. In addition, the Melbourne volcanic province contains numerous small volcanic vents where lava and volcanic ash of basaltic composition have been extruded. The Meander intrusive suite consists of gabbroic rocks whose presence was inferred by an aeromagnetic survey by Bosum et al. (1991) and Behrendt et al. (1991a, b) (Adapted from Kyle (1990f) and from Fig. 2 of Nathan and Schulte (1968))...

Fig. 16.26 The chemical compositions of the McMurdo Volcanics in the Melbourne volcanic province of northern Victoria Land range widely from basanites to phonolites, trachytes, and even rhyolites. Most of the volcanoes in this province include the full range of chemical compositions of lava flows. Bn = basanite, Tp = tephrite, Ftp = phonotephrite, Tpp =...

The Pleiades in Fig. 16.25 consist of a cluster of volcanic cones of late Cenozoic age located on the eastern edge of the Evans Neve and at the head of the Mariner Glacier. This location makes The Pleiades the most northerly volcanoes of the Melbourne volcanic province and places them 140 km west of the coast of northern Victoria Land. The location of The Pleiades... 

Armstrong (1978) reported two K-Ar dates of 5.49 0.12 Ma and 6.6 0.4 Ma (late Miocene) for rocks of the Hallett Peninsula. Three samples of basalt Irom Cape Hallett analyzed by Jones and Walker (1972) have Sr/ Sr ratios that range from 0.7037 to 0.7054 and are consistent with the Sr/ Sr ratios of the volcanic rocks of the Erebus and Melbourne volcanic provinces. 

Mt. Erebus, which still maintains a lava lake in a crater on its summit, is the only active volcano in Antarctica. Mt. Melbourne of the Melbourne volcanic province also continues geothermal activity on its summit, and volcanoes in The Pleiades have erupted in the recent past. All other volcanoes in the Transantarctic Mountains are extinct, although geothermal activity still occurs on a few volcanoes in Mary Byrd Land. 

Worner et al. (1989) reported chemical analyses for 92 samples of volcanic rocks from ten subdivisions of the Melbourne volcanic field. The analyses included major and trace elements and the resulting normative mineral compositions. Without classifying each one of these specimens, it is sufficient to record that their chemical compositions range widely just as they do in the Erebus volcanic province of southern Victoria Land (Fig. 16.4). Worner et al. (1989) also reported isotope... 

The volcanic activity of the Balleny Islands and of Scott Island is related to their location between East Antarctica and Australia (Duncan and McDougall 1989 Lanyon et al. 1993, 1995). Partly for that reason, the Sr/ Sr ratios of the volcanic rocks on these islands are lower than the Sr/ Sr ratios of lavas on the mainland of northern Victoria Land. Hart and Kyle (1993) reported that the volcanic rocks of the Melbourne and Hallett volcanic provinces have higher Sr/ Sr ratios than the lavas on the off-shore islands including Franklin, Coalman, Possession, Scott, and the Balleny islands. 

---