In addition, we are imaging the interpreted mantle source region for Erebus magmas and investigating the role that the Terror Rift system plays in generating and focusing magmatism. A primary goal of this work is to constrain the distribution of melt within and beneath the volcanic edifice. A pool of 11 Phoenix Geophysics V5 systems coupled with Numeric Resources high impedance preamplifiers were used. Measurements were made at 129 locations on Ross Island and vicinity. Data collection occurred over three field seasons from 2014-2017. In addition, we mapping the rifted crustal structure and examining the mantle source of the magma and the role that the Terror Rift system plays in the active volcanism. We are using magnetotelluric ( MT) methods and instrumentation, especially developed for use in Antarctica, to image the resistivity structure (magmatic system) of Erebus and the older volcanoes forming Ross Island. Petrologic models suggest that Erebus is undergoing fractional crystallisation of deep mantle-derived parental basanite magma in one or more crustal magma chambers. Phonolite magmas like those at Erebus have been responsible for devastating eruptions (e.g. Erebus has the world's only persistent phonolite lava lake in its summit crater, and thus provides a window into the heart of a degassing volcano's magmatic system. F.Įrebus volcano, on Ross Island, Antarctica, in the south west Ross Sea, offers a unique opportunity to understand the magmatic system of an active alkaline volcano, and rifting within the West Antarctica Rift System. Imaging the Magmatic System of Erebus Volcano, Antarctica using the Magnetotelluric Method A number of phyla whose members are known to oxidize Mn(II) or Fe The phototroph-containing phyla Cyanobacteria, Chloroflexi, and Chlorophyta (latter eukaryotic) were only seen in Harry's Dream. Acidobacteria was the only phylum detected in all three caves, and was a major component of each library. The three cave soils displayed very low (Warren, Warren West) or moderate division-level diversity, with distinct communities in each environment. The latter results are presented by Anitori et al. The composition of the resident microbial communities was assessed using 16S rRNA and ITS libraries, while metabolic and functional characteristics were analyzed by culturing. Both Warren caves were completely dark, while Harry's Dream received continuous indirect light during the Austral summer, and offered a control to the two dark caves. The fumaroles were studied in three caves, Warren, Warren West and Harry's Dream these displayed, respectively, temperatures of 18Â☌, 2Â☌ and 11Â☌ at our sampling sites. Fumarole gases forming these caves are mostly atmospheric, enriched with water vapor and CO2. Most of the ice caves on Mt Erebus are relatively shallow and illuminated by natural light, but some are deep enough to afford complete darkness. We studied terrestrial DOVEs in fumarolic ice caves on the summit plateau of Mt Erebus, an active volcano on Ross Island, Antarctica (). When compared to other crustal oligotrophic environments, DOVEs are particularly relevant due to their considerable reductive potential, high permeability and the substantial chemical exchange facilitated by their hydrothermal systems. It may serve as the base of the foodweb at the surface via hydrothermal circulation, venting pore fluids, cold seeps or gases, and offer a means for primary carbon fixation. M.ĭark Oligotrophic Volcanic Ecosystems (DOVEs) in the earth's crust may host substantial biomass sustained by chemolithoautotrophic metabolic reactions. ĭark Oligotrophic Volcanic Ecosystems (DOVEs) in Fumarolic Ice Caves of Mt. The image was acquired December 31, 2013, covers an area of 63 x 73 km, and is located at 77.5 degrees south, 167.1 degrees east. Continuous lava-lake activity with minor explosions, punctuated by occasional larger strombolian explosions that eject bombs onto the crater rim, has been documented since 1972, but has probably been occurring for much of the volcano's recent history. The glacier-covered volcano was erupting when first sighted by Captain James Ross in 1841. An elliptical 500 x 600 m wide, 110-m-deep crater truncates the summit and contains an active lava lake within a 250-m-wide, 100-m-deep inner crater. The 3794-m-high Erebus is the largest of three major volcanoes forming the crudely triangular Ross Island. This image from NASA Terra spacecraft shows Mount Erebus, the world southernmost historically active volcano, overlooking the McMurdo research station on Ross Island.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |