Other symbols include Southern Victoria Land basin (SVL) and Discovery accommodation zone (D-A-Z). The lower right inset shows regional structural setting 15, 16, 17, including the Ross Fault (green) in the accommodation zone of the terminus of the Terror Rift (TR) and Discovery graben (DG). Hypothesized Erebus fault zone contains principal low-resistivity structure resolved through the crust. Note the warm-colored ellipse region southwest of Mount Erebus indicating conductive volumes in the 0–7 km depth range approximately (Supplementary Information). Coordinate ticks denote both UTM Zone 58S (singles) and latitude–longitude (doubles). Site map showing impedance phase-tensor ellipses at the MT sounding locations over Mount Erebus and Ross Island during three field seasons see text for color and shape designations. Erebus offers a unique opportunity to investigate magmatic system processes from the mantle source to the surface and the enigmatic tectonic-structural controls of extensional magmatism and volatile release. However, they also provide important resources such as rare earth elements and precious metals and thus are important to understand 6, 7. ![]() Phonolite magmas in other settings have been explosively destructive 5. Compositionally uniform phonolitic lavas have dominated Erebus volcano eruptions for the last 17 ka 4 (Fig. Mount Erebus is the only phonolitic volcano with a persistent summit lava lake 3. Phonolitic-series magma is alkali-rich and highly evolved from its parental basanite. Rift settings and alkalic magmas contribute enormous amounts of CO 2 to the global exosphere budget, with climate-forcing level increases of atmospheric concentrations documented several times during Earth’s history 2. Basaltic alkalic magmas are CO 2-rich because they result from low degrees of partial melting of a mantle source often showing signs of being complexly metasomatized 1. Arc magmas typically have volatiles dominated by H 2O from dehydration of subducted oceanic crust. Unlike H 2O-rich subduction arc volcanoes, CO 2-dominated Erebus geophysically shows continuous magmatic structure to shallow crustal depths of < 1 km, as the melt does not experience decompression-related volatile supersaturation and viscous stalling.Īlkalic volcanoes in rift settings stand in stark contrast to calc-alkaline volcanoes in arcs, such as the ring of fire around the Pacific Ocean. This magmatic valve lies within an inferred, east-west structural trend forming part of an accommodation zone across the southern termination of the Terror Rift, providing a dilatant magma pathway. The lateral turn represents a structural fault-valve controlling episodic flow of magma and CO 2 vapour, which replenish and heat the high level phonolite differentiation zone. Here we show using magnetotelluric data that a steep, melt-related conduit of low electrical resistivity originating in the upper mantle undergoes pronounced lateral re-orientation in the deep crust before reaching shallower magmatic storage and the summit lava lake. Seismic studies provide limited images of the magmatic system. Links may default to another scale - there may be only one scale available for some places.Erebus volcano, Antarctica, with its persistent phonolite lava lake, is a classic example of an evolved, CO 2-rich rift volcano. Not all map scales listed below may be available for every location, in some cases The scale as they may appear on your screen. Map Scales: The maps scales shown below may be the scales of the original map data (eg 1:50000 Landranger Maps) and NOT Map Location Accuracy: The coordinates listed for many locations are general regional coordinates (not accurate) and should not be relied upon for locating localities (eg with a GPS). ![]() Visit any sites listed in without first ensuring that you have the permission of the land and/or mineral rights holdersįor access and that you are aware of all safety precautions necessary. Important Disclaimer: This locality information is for reference purposes only. These map resources refer to external websites, and as such links are outside of the control of they mayįrom time to time fail to work, some may also not be as accurate as we would wish.
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