McMurdo Volcanic Group

McMurdo Volcanic Group
Name	McMurdo Volcanic Group
Location	Antarctica
Range	Transantarctic Mountains
Type	Volcanic province
Last eruption	Holocene?

McMurdo Volcanic Group is a dispersed volcanic province on the continent of Antarctica centered in the Ross Sea region and associated with the Transantarctic Mountains and the Ross Ice Shelf. It includes volcanic fields, shield volcanoes, stratovolcanoes, cinder cones, and intrusive complexes that record Cenozoic magmatism linked to continental rifting and polar glaciation. The province is a focus of research by international programs and scientific stations due to its importance for understanding Antarctic tectonics, mantle dynamics, and paleoenvironmental change.

Overview and Geological Setting

The province lies along the margin of the Ross Sea and the Transantarctic Mountains adjacent to the Ross Ice Shelf and encompasses parts of Victoria Land, Ross Island, and the Scott Coast. The volcanic distribution is spatially associated with the West Antarctic Rift System, the Adare Trough, and the Victoria Land Basin, linking magmatism to Cenozoic extension and lithospheric thinning. Research programs from United States Antarctic Program, British Antarctic Survey, Australian Antarctic Division, and New Zealand Antarctic Research Programme have mapped volcanic edifices and sampled rocks to constrain links to regional tectonic events such as the opening of the Southern Ocean and the evolution of the Pacific Plate–Antarctic Plate boundary.

Stratigraphy and Rock Types

Stratigraphic relationships include basaltic lava flows, trachyte, phonolite, and minor andesitic to rhyolitic units that overlie older sedimentary and metamorphic basement of the Beacon Supergroup and the Mawson Group. Surface sequences show stacked pāhoehoe and aʻa flows, pyroclastic deposits, hyaloclastites related to subglacial eruptions, and shallow intrusive dikes and sills cutting Jurassic and Cretaceous strata. Tephra layers correlate with ice-core and marine sediment records recovered during expeditions by USAP and oceanographic cruises by RRS James Clark Ross and RV Polarstern.

Volcanic Centers and Features

Major volcanic centers include Mount Erebus, Mount Terror, Ross Island, Mount Melbourne, Mount Rittmann, and the McMurdo Sound volcanic vents, together with scattered fields such as the Adare Peninsula and Brown Peninsula. Mount Erebus hosts an active lava lake studied by teams from Carnegie Institution, Victoria University of Wellington, and University of Cambridge. Field mapping by researchers from Scripps Institution of Oceanography, Lamont–Doherty Earth Observatory, and Antarctic New Zealand has documented scoria cones, tuyas, and subglacial tuyas like those reported in studies involving the Scott Polar Research Institute.

Age, Eruption History, and Geochronology

Geochronology using K–Ar, Ar–Ar, and U–Pb methods by laboratories at California Institute of Technology, ETH Zurich, and ANU constrains volcanism from the Paleogene through the Quaternary. Eruptive episodes correlate with regional events such as the Paleogene onset of magmatism during Eocene rifting and Neogene pulses potentially synchronous with Antarctic glaciation phases documented by stratigraphers at Ohio State University and Columbia University. Holocene and possibly contemporary activity at Mount Erebus and young tephra deposits imply that parts of the province remain volcanically active in the present epoch investigated by teams from University of Alaska Fairbanks and Smithsonian Institution.

Petrology, Geochemistry, and Mantle Sources

Volcanic rocks range from tholeiitic basalts to alkaline phonolites; geochemical analyses (major, trace, and isotopic) by researchers at University of Cambridge, Pennsylvania State University, and University of Washington indicate lithospheric mantle metasomatism, variable degrees of partial melting, and contributions from enriched mantle components similar to those inferred for other Cenozoic intraplate provinces like the East African Rift and Iceland. Isotope systems (Sr–Nd–Pb–He) analyzed at WHOI and University of Tokyo suggest heterogeneous mantle sources and plume-related versus tectonically induced melt generation debated in literature involving investigators from University of Hawaiʻi and University of Oslo.

Tectonic and Glacial Interactions

Magmatism is intimately tied to rift-related extension in the West Antarctic Rift System and to interactions with the East Antarctic Ice Sheet and local outlet glaciers of the Ross Sea Embayment. Subglacial eruptions produced tuyas and pillow breccias documented during logistic campaigns by Antarctic Logistics & Expeditions and geophysical surveys using ice-penetrating radar from NASA and British Antarctic Survey. Volcanic heat flux has implications for basal melting, subglacial hydrology, and ice-shelf stability discussed in modeling studies at University of Bristol and Lamont–Doherty Earth Observatory.

Biological and Environmental Impacts

Volcanic soils and fumarolic habitats around active centers such as Mount Erebus support microbial and extremophile communities studied by teams from University of Colorado Boulder, Max Planck Institute for Marine Microbiology, and NIWA. Tephra layers serve as chronostratigraphic markers for paleoenvironmental reconstructions used by researchers at Institute of Arctic and Alpine Research and Alfred Wegener Institute. Volcanism also influences local weather patterns observed by Met Office and contributes aerosols affecting atmospheric chemistry monitored by University of Cambridge and Scripps Institution of Oceanography.

Category:Volcanic fields Category:Volcanoes of Antarctica Category:Geology of Antarctica