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The Influence of Lithospheric Flexure Induced by Volcano Loading on Neogene Basin Evolution in McMurdo Sound, West Antarctica

Chen, Jie
http://rave.ohiolink.edu/etdc/view?acc_num=osu1448967436

Abstract Details

2015, Master of Science, Ohio State University, Geological Sciences.
The marine Erebus Basin surrounds the volcanic Ross Island in McMurdo Sound, Antarctica. This basin has evolved under the influence of flexure driven by loading by the three volcanoes that make up Ross Island. Seismic reflection data west of Ross Island are used to document the seismic stratigraphic framework of the flexural basin. Five seismic units are mapped within the sedimentary infill of the basin. Seismic facies are documented within each unit, ranging from chaotic facies interpreted as volcanic mass flows and ice-proximal glacial deposits, to laminated units interpreted as alternating pelagic, hemipelagic and glaciomarine deposits. The volcanogenic units form part of the aprons around the volcano slopes and the glaciomarine units fill the axial basin. Two seismic sequences are defined based on patterns of surface depth and unit thickness. Seismic Sequence 1 is bounded by the Rj and Rk seismic surfaces, showing thickening and deepening toward Mount Bird volcano. Seismic Sequence 2 includes units from the Rk seismic surface up to the seafloor, and thickens and deepens toward Mount Erebus volcano. Seismic mapping thus shows evidence of two discrete sub-basins formed by Mt. Bird loading since 3.8-4.6 Ma and Mt. Erebus loading since ~1.31 Ma. Both units also show thickening in a zone northwest of Ross Island where accommodation space was formed by Terror Rift faulting, indicating that Terror Rift was still active when the Ross Island volcano loading occurred. The Bird-Erebus flexural basin has an overall wedge-shaped fill that thickens toward the volcanoes of Ross Island, typical of the geometry of other basins formed by volcano loads in ocean basins. The Erebus Basin is underfilled, with only ~325 m of infill, compared with >2000 m of fill typically found in moats around ocean island volcanic chains. Like stratal sequences of other flexural basins, the Bird-Erebus flexural basin fill shows onlap geometries in cross-moat profiles. However, unlike stratal sequences of other flexural basins, no offlap pattern is observed in either cross-moat or along moat profiles. Gravity flows related to mass wasting of Ross Island volcanoes are a significant component of the Bird-Erebus basin fill but, unlike other basins formed by volcano loads, is not the dominant fill. Instead, seismic facies mapping and AND-1B core show that a significant component of glaciomarine deposits occurs in the flexural basin. Glacial erosion removed some of the flexural basin fill, particularly along the regional Rk seismic surface. A 3D thin elastic plate model was used to simulate flexural basin evolution induced by Ross Island volcano loading, and to evaluate regional lithospheric strength. Using the dip angle of seismically mapped reflector surfaces as the constraint, the best fit lithospheric strength is represented by effective elastic thickness of 4-5 km. This weak lithosphere in the Ross Island region can be explained by faulting, thin crust, and high heat flow in this rift tectonic setting.
Terry Wilson (Advisor)
170 p.
Geology

Recommended Citations

Citations

  • Chen, J. (2015). The Influence of Lithospheric Flexure Induced by Volcano Loading on Neogene Basin Evolution in McMurdo Sound, West Antarctica [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448967436

    APA Style (7th edition)

  • Chen, Jie. The Influence of Lithospheric Flexure Induced by Volcano Loading on Neogene Basin Evolution in McMurdo Sound, West Antarctica. 2015. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1448967436.

    MLA Style (8th edition)

  • Chen, Jie. "The Influence of Lithospheric Flexure Induced by Volcano Loading on Neogene Basin Evolution in McMurdo Sound, West Antarctica." Master's thesis, Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1448967436

    Chicago Manual of Style (17th edition)

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