Akiko Takeo (Earthquake Research Institute of Tokyo University) received an IR best poster award for her work entitled: “Seismic anisotropy in the uppermost mantle beneath oceanic regions from data of broadband OBSs”. She is interested in the seismic velocity structure in the uppermost mantle, as it is one of the keys to understanding plate tectonics. Takeo analyses data from broadband ocean bottom seismometers deployed in oceanic regions such as the Shikoku Basin, south of Japan. 1D radially anisotropic structures beneath the Shikoku Basin can be obtained by measuring phase velocities of surface waves, indicating deformation at depths greater than 50 km.
Of the Mantle Imaging workshop, she said: “It was a good experience for me to attend the workshop because I could discuss both methods and results with seismologists, geomagnetists and petrologists. Also I learnt from other presentations about structure and processes in the mid ocean ridges and subduction zones. The field trip was also a good chance to study the composition and deformation of peridotite by seeing real rocks”.
Shusaku Yamazaki (Niigata University, Japan, working with Prof. Sumio Miyashita), was also awarded an IR student poster prize for his poster: “Formation of incipient oceanic island arc crust: geology and geochemistry of the late intrusive rocks in the Oman Ophiolite”. Oman ophiolite is considered as an analogue for fast-spreading oceanic crust and upper mantle sequences. Yamazaki’s interest in the Oman ophiolite is the petrogenesis of late intrusive rocks with island arc type characteristics in the
lower gabbroic crust. New mapping in the lower oceanic crustal sequence allows recognition of the detailed distribution of late intrusive plutonics and boninitic dike swarms. In the poster, it is argued that their petrogenesis is based on petrography and geochemistry, and proposes that the complex of late intrusive plutonics in the mapped area can be regarded as a good example for early stage evolution of an intra-oceanic island arc crust.
