Japan Geoscience Union Meeting 2024

Presentation information

[J] Poster

S (Solid Earth Sciences ) » S-MP Mineralogy & Petrology

[S-MP24] Deformed rocks, Metamorphic rocks and Tectonics

Thu. May 30, 2024 5:15 PM - 6:45 PM Poster Hall (Exhibition Hall 6, Makuhari Messe)

convener:Yoshihiro Nakamura(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology), Takayoshi Nagaya(Tokyo Gakugei University), Yumiko Harigane(Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST)), Ken Yamaoka(National Institute of Advanced Industrial Science and Technology)

5:15 PM - 6:45 PM

[SMP24-P04] Olivine fabric development during ductile deformation of peridotite samples from the mid-Jurassic Vourinos ophiolite, Greece

*Yumiko Harigane1, Tomoaki Morishita2, Akihiro Tamura2, Kenichiro Tani3, Osamu Ishizuka1,4, Annie Rassios5 (1.Geological Survey of Japan, National Institute of Advanced Industrial Science and Technology (AIST), 2.Kanazawa University, 3.National Museum of Nature and Science, 4.Japan Agency for Marine-Earth Science and Technology, 5.Hellenic Survey of Geology and Mineral Exploration)

Keywords:olivine fabric, ductile deformation, the mid-Jurassic Vourinos ophiolite, supra-subduction zone (SSZ) setting

The Vourinos ophiolite is one of Sub-Pelagian ophiolites (Pindos, Vourinos, Othris ophiolites in Greece and Albanian ophiolites in Albania) and is located on the eastern margin of the Eocene-Miocene Mesohellenic Trough, where is separated from the synchronous Pindos ophiolite along the western margin. Two ophiolites are thought to be connected beneath the postorogenic Mesohellenic Trough of the Sub-Pelagonian zone (Makris,1977; Jones et al.,1991).
The Vourinos ophiolite consists of a 12 km thick section with intact pseudo-stratigraphy from mantle rocks across the 'petrological Moho' and basal crustal cumulate section, into transitions of ultramafic to mafic magma chambers, dioritic cumulates and plagiogranites, and an intact transition to a sheeted dyke swarm (Moores 1969; Jackson et al. 1975; Rassios l98l; Rassios et al. 1983b). Dilek (2003) suggested that the Vourinos ophiolite is a typical Mediterranean-type supra-subduction zone (SSZ) ophiolite based on such crust-mantle stratigraphy. Almost of all exposed area in the Vourinos ophiolite is depleted mantle lithosphere (mainly harzburgite) with inclusions of dunite, that this mantle section preserves deformation structure from ductile (high-temperature and low-temperature) to brittle deformation, suggesting that such ductile deformation could occur under ocean spreading setting (Rassios et al., 1994; Rassios and Moores, 2006).
To investigate the olivine fabric development during ductile deformation of peridotites on SSZ setting, we collected sixteen peridotites (harzburgite and dunite) from the Vourinos ophiolite in the Western Hellenides of Greece. The collected peridotites consist of harzburgite and dunite, and display the microstructure of high-temperature deformation and mylonitic deformation. Here, we present the field information, detailed rock descriptions, analyses of mineral fabrics, and geochemical analyses of the minerals in the sixteen peridotite samples sampled from four areas (Voidolakkos, Rizo, Aetoraches and Chromio) on the Vourinos ophiolite.