A prolonged crustal history from Archean through Proterozoic to Cambrian, spanning more than half of the Earth’s evolution through time is preserved in the rock record in East Antarctica. Geological field studies have been conducted in Dronning Maud Land and Enderby Land of East Antarctica as part of the scientific program of Japanese Antarctic Research Expedition (JARE). Late Neoproterozoic to Cambrian (>600-520 Ma) high-grade metamorphic terranes, developed as major orogenic belts during the Gondwana supercontinent formation, are recognized in central Dronning Maud Land, Sør Rondane Mountains, Belgica and Yamato Mountains (Yamato-Belgica Complex), Lützow-Holm Bay-Prince Olav Coast region (Lützow-Holm Complex) to western Enderby Land (Western Rayner Complex) over 2000 km from west to east along the coast-inland of the Antarctic continent. Relatively narrow and sporadic Meso-Neoproterozoic (1000-900 Ma) high-grade blocks (Hinode Block and Niban-nishi Rock - granulite-facies; Akebono Rock - amphibolite-facies) are identified in Prince Olav Coast geographically within the Lützow-Holm Complex. Archean high-grade-UHT granulites and gneisses of the Napier Complex represent the largest regional terrain covering 400 × 200 km² area in Enderby Land, along with widespread Meso-Neoproterozoic granulite-facies zone of Rayner Complex from Enderby Land through Kemp Land, McRobertson Land toward east to Prydz Bay region. Thus, the continental crustal domain investigated by the Japanese Antarctic expeditions is key in understanding the Archean-Proterozoic-Cambrian deep crustal history and processes. In this special issue we summarize the recent progress in the mineralogical, petrological, geochemical, and geochronological studies carried out in East Antarctica.

Blue-green potassic-ferro-chloro-pargasite containing up to 0.3 wt% BaO and 4.6 wt% Cl occurs together with Cl-poor cummingtonite in a mafic granulite composed mainly of olive-brown potassic-ferro-pargasite with subordinate orthopyroxene, Ba- and Cl-bearing biotite, calcic plagioclase, quartz, ilmenite, zircon, and Cl-rich fluorapatite. The mafic granulite is characterized by high bulk rock contents of large-ion lithophile elements such as K, Ba, Pb, and Rb. Mineral assemblages, compositions and textures suggest four stages of recrystallization to form and modify the potassic-ferro-pargasite. Stage 1 is the main granulite-facies metamorphism, whereas stages 2-4 correspond to local phenomena most probably caused by fluid infiltration along a fracture during cooling. Stage 2 includes biotite formation with concomitant compositional change of orthopyroxene and potassic-ferro-pargasite to more Fe-rich. Fluorapatite partially changed composition from Cl-rich to Cl-poor. Stage 3 was a more localized event including (1) increase of K, Cl, Al, and Fe and decrease of Si, Ti, and Mg in the potassic-ferro-pargasite, accompanied by the color change from olive-brown to blue-green, and (2) formation of Cl-poor cummingtonite and sodic plagioclase by replacement of preexisting potassic-ferro-pargasite. Stage 4 was a more localized phenomenon within blue-green potassic-ferro-pargasite. It may be expressed as a volatile-conserving reaction such as Cl-bearing potassic-ferro-pargasite → potassic-ferro-chloro-pargasite + Cl-poor cummingtonite. The mafic granulite appears not to have undergone partial melting even at stage 1 most probably because of the high Cl content of the dominant potassic-ferro-pargasite.