Collision of the North China and Yangtse Blocks and formation of coesite-bearing eclogites: Timing and processes☆

A synopsis of events related to the assembly of eastern Gondwana

A hypothesis for a late Precambrian fit of western North America with the Australia-Antarctic shield region permits the extension of many features through Antarctica and into other parts of Gondwana. Specifically, the Grenville orogen may extend around the coast of East Antarctica into India and Australia. The Wopmay orogen of northwest Canada may extend through eastern Australia into Antarctica and thence beneath the ice to connect with the Yavapai-Mazatzal orogens of the southwestern United States. The ophiolitic belt of the latter may extend into East Antarctica. Counterparts of the Precambrian-Paleozoic sedimentary rocks along the U.S. Cordilleran miogeocline may be present in the Transantarctic Mountains. Orogenic belt boundaries provide useful piercing points for Precambrian continental reconstructions. The model implies that Gondwana and Laurentia rifted away from each other on one margin and collided some 300 m.y. later on their opposite margins to form the Appalachians.

Southwest U.S.-East Antarctic (SWEAT) connection: A hypothesis

High-P/T metamorphic belts were classified into types A and B according to their protoliths. The A-type (collision-type) blueschists possess passive-margin protoliths characterized by platform-type carbonates, bimodal volcanics, and peraluminous sediments. B-type (Cordilleran-type) blueschists consist of active continental-margin protoliths in an accretionary complex characterized by bedded chert, MORB and ocean-island basalts, reef limestones, and graywackes. The spatiotemporal distribution of blueschists and eclogites of the world was compiled; among 250 recognized high-P/T belts, about 20% belong to the A type and the rest to the B type. Most A-type zones lie in Europe and the Tethyan domain, include ultrahigh-pressure metamorphic terranes, and have metamorphic pressure up to 45 kbar. B-type zones occur mainly in the circum-Pacific orogenic belts and intracontinental orogens in Asia, and were recrystallized at P <12 kbar. Associated peridotites include garnet peridotite in the A type and strongly serpe...

Blueschists and Eclogites of the World and Their Exhumation

https://cyberleninka.org/article/n/966601.pdf

Orogen styles in the East African Orogen: A review of the Neoproterozoic to Cambrian tectonic evolution.

Ion microprobe U-Pb dating of zircons from the Lutzow-Holm Complex (LHC) and the Yamato-Belgica Complex (YBC), East Antarctica indicate high-grade regional metamorphism and associated folding of LHC occurred between $$521 \pm 9$$ and $$553 \pm 6 Ma$$. This shows, for the first time, the existence of a Cambrian orogenic belt within the East Antarctic Shield. Many zircons from the LHC contain cores that record inherited ages from ~2900 to ~1500 Ma. Components of ~1000 Ma zircon have been identified in three locations. This may indicate the maximum age of the deposition of LHC. One metasedimentary gneiss from the YBC records a well-defined age at about 600 Ma, whereas another yields a dispersion of ages interpreted as the result of varied radiogenic Pb loss in ~1000 Ma zircons at about 500-600 Ma. These gneisses have inherited ages of up to ~2500 Ma. Our work enables an improved fit to the once contiguous fragments of Gondwana. The Highland/Southwestern Complex (HSWC) of Sri Lanka has remarkable petrological...

Cambrian Orogenic Belt in East Antarctica and Sri Lanka: Implications for Gondwana Assembly

Evidence for prograde metamorphic evolution of Sri Lankan pelitic granulites, and implications for the development of continental crust

Phase petrology of eclogites and related rocks from the Motalafjella high-pressure metamorphic complex in Spitsbergen (Arctic Ocean) and its significance

The Cretaceous Abukuma metamorphic terrane consists of the oceanic Gosaisyo Series overthrust onto the terrigenous Takanuki Series. Although the dominant mineralogy defines one of the classic areas of andalusite–sillimanite type progressive metamorphism, there are several lines of evidence suggesting an earlier higher-pressure (up to c. 12 kbar) history of the Takanuki Series and the nearby Gosaisyo Series. These are: (1) the occurrence of rare although widespread relic kyanite in sillimanite+K-feldspar zone-grade pelitic rocks; (2) the high grossular content of garnet interiors (up to c. 30 mol %) overgrown by Ca-poor rims (c. 2 mol % grossular) in pelitic rocks containing Al2SiO5 minerals (sillimanite±relic kyanite±retrograde andalusite), plagioclase and quartz; (3) the occurrence of rutile as inclusions in garnet in pelitic rocks; and (4) the occurrence of relic corundum+almandine association in silica-poor and Al–Fe-rich rocks. Garnet in the Takanuki Series pelitic rocks commonly shows textural sector zoning and preserves growth zoning despite the high metamorphic grade, suggesting rapid changes in P–T  conditions and a relatively short duration of high-temperature conditions. Combined with radiometric dating, these observations suggest that the Abukuma sillimanite+K-feldspar zone-grade rocks underwent a clockwise P–T  path with very fast (>4 mm y−1) average burial and exhumation rates.

Cretaceous high-temperature rapid loading and unloading in the Abukuma metamorphic terrane, Japan

Geological correlations of East Antarctica with adjoining continents have been puzzling geologists ever since the concept of a Gondwana supercontinent surfaced. Despite the paucity of outcrops because of ice cover, difficulty of access and extreme weather, the past 50 years of Japanese Antarctic Research Expeditions (JARE) has successfully revealed vital elements of the geology of East Antarctica. This volume presents reviews and new research from localities across East Antarctica, especially from Dronning Maud Land to Enderby Land, where the geological record preserves a history that spans the Archaean and Proterozoic. The reviews include extensive bibliographies of results obtained by geologists who participated in the JARE. Comprehensive geological, petrological and geochemical studies, form a platform for future research on the formation and dispersion of Rodinia in the Mesoproterozoic and subsequent assembly of Gondwana in the Neoproterozoic to Early Palaeozoic.

Yoshikuni Hiroi

Papers

Cambrian Orogenic Belt in East Antarctica and Sri Lanka: Implications for Gondwana Assembly

Evidence for prograde metamorphic evolution of Sri Lankan pelitic granulites, and implications for the development of continental crust

Phase petrology of eclogites and related rocks from the Motalafjella high-pressure metamorphic complex in Spitsbergen (Arctic Ocean) and its significance

Cretaceous high-temperature rapid loading and unloading in the Abukuma metamorphic terrane, Japan

Geodynamic evolution of East Antarctica : a key to the East-West Gondwana connection