Belgian-Japanese search for Antarctic meteorites during the 2010.2011 field season.

第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月17日（木） 国立国語研究所 2階講

Visible and Near-Infrared Spectral Survey of Select HED Meteorite Samples Stored at the National Institute of Polar Research.

第2回極域科学シンポジウム/第34回南極隕石シンポジウム 11月18日（金） 国立国語研究所 2階講

Diversity in the Visible-NIR Absorption Band Characteristics of Lunar and Asteroidal Plagioclase

Studying the visible and near-infrared (VNIR) spectral properties of plagioclase has been challenging because of the difficulty in obtaining good plagioclase separates from pristine planetary materials such as meteorites and returned lunar samples. After an early study indicated that the 1.25 m band position of plagioclase spectrum might be correlated with the molar percentage of anorthite (An#) [1], there have been few studies which dealt with the band center behavior. In this study, the VNIR absorption band parameters of plagioclase samples have been derived using the modified Gaussian model (MGM) [2] following a pioneering study by [3]

Stenian A-type granitoids in the Namaqua-Natal Belt, southern Africa, Maud Belt, Antarctica and Nampula Terrane, Mozambique: Rodinia and Gondwana amalgamation implications

We carried out SHRIMP zircon U-Pb dating on A-type granitic intrusions from the Namaqua-Natal Province, South Africa, Sverdrupfjella, western Dronning Maud Land, Antarctica and the Nampula Province of northern Mozambique. Zircon grains in these granitic rocks are typically elongated and oscillatory zoned, suggesting magmatic origins. Zircons from the granitoid intrusions analyzed in this study suggest w1025e1100 Ma ages, which confirm widespread Mesoproterozoic A-type granitic magmatism in the Namaqua-Natal (South Africa), Maud (Antarctica) and Mozambique metamorphic terrains. No older inherited (e.g., w2500 Ma Achean basement or w1200 Ma island arc magmatism in northern Natal) zircon grains were seen. Four plutons from the Natal Belt (Mvoti Pluton, Glendale Pluton, Kwalembe Pluton, Ntimbankulu Pluton) display 1050e1040 Ma ages, whereas the Nthlimbitwa Pluton in northern Natal indicates older 1090e1080 Ma ages. A sample from Sverdrupfjella, Antarctica has w1091 Ma old zircons along with w530 Ma metamorphic rims. Similarly, four samples analysed from the Nampula Province of Mozambique suggest crystallization ages of w1060e1090 Ma but also show significant discordance with two samples showing younger w550 Ma overgrowths. None of the Natal samples show any younger overgrowths. A single sample from southwestern Namaqualand yielded an age of w1033 Ma. Currently available chronological data suggest magmatism took place in the Namaqua-Natal-MaudMozambique (NNMM) belt between w1025 Ma and w1100 Ma with two broad phases between w1060e1020 Ma and 1100e1070 Ma respectively, with peaks at between w1030e1040 Ma and w1070 e1090 Ma. The age data from the granitic intrusions from Namaqualand, combined with those from Natal, Antarctica and Mozambique suggest a crude spatial-age relationship with the older >1070 Ma ages being largely restricted close to the eastern and western margins of the Kalahari Craton in northern Natal, Mozambique, Namaqualand and WDML Antarctica whereas the younger <1060 Ma ages dominate in southern Natal and western Namaqualand and are largely restricted to the southern and possibly the western margins of the Kalahari Craton. The older ages of magmatism partially overlap with or are marginally younger than the intracratonic Mkondo Large Igneous Province intruded into or extruded onto the Kalahari Craton, suggesting a tectonic relationship with the Maud Belt. Similar ages from granitic augen gneisses in Sri Lanka suggest a continuous belt stretching from Namaqualand to Sri Lanka in a reconstituted Gondwana, formed during the terminal stages of amalgamation of Rodinia and predating the East African Orogen. This contiguity contributes to defining the extent of Rodinia-age crustal blocks, subsequently fragmented by the dispersal of Rodinia and Gondwana.This study was supported by a Grant-in-Aid for Scientific Research from the Japan Society for the Promotion of Science to K.S. (Nos. 09041116 and 13440151) and a Grant-in-Aid for the Young Scientists from JSPS to T.H. Antarctic Research funding to GHG from the NRF, South Africa, Grant ID. 110739, is gratefully acknowledged. The Council for Geoscience Pretoria, South Africa are thanked for the opportunities provided in Namaqualand (GHG) and Mozambique (GHG, KS). Discussion of the plate tectonic setting of these rocks from Bill Collins is acknowledge