TITLE:
Shallow Reflection Surveys of the East Ongul Island, the Lützow-Holm Complex, East Antarctica
AUTHORS:
Masaki Kanao, Tetsuya Takemoto, Akira Fujiwara, Kiyoshi Ito, Takeshi Ikawa
KEYWORDS:
Shallow Reflection Surveys, Metamorphic Layering, Crustal Structure, Continental Evolution, East Antarctica
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.9,
August
28,
2014
ABSTRACT: The
shallow reflection surveys were carried out in 2007 and 2010 austral summers in
East Ongul Island, the Lützow-Holm Complex (LHC), East Antarctica. LHC is
identified by geologically as one of the Pan-African terrains of Eastern
Dronning Maud Land. The multi-channel reflection surveys targeted to achieve
the image of laminated layering of metamorphic rocks near the surface (the
depths down to a few hundreds of meters) of the crystalline crust. Two surveys
were conducted in total length of the profiles about 500 m along a main traffic
load across the East Ongul Island. The multi-channel acquisition systems were
utilized with combining the dense geophones along the profiles. Seismic sources
were adopted by combining the boom of a power shovel, a weight drop and hammer
shots with their intervals in a few tens of meters. The obtained data include
clear first P-arrivals in far offset distance. The energy of P-S converted
waves was enhanced because of the characteristics of the seismic sources. Pre-stacked
images could be expected to the information on metamorphic layering for several
lithological structure composed by hornblende gneiss, garnet gneiss and
pyroxene gneiss appearing as the surface bedrocks. The conducted shallow
reflection surveys would give rise to one step for understanding tectonic
formation of LHC, as one of the Pan-African mobile belts in Gondwana
super-continent.