Автор(ы):Олюнин В.Н.
Редактор(ы):Думитрашко Н.В.
Издание:Наука, Москва, 1978 г., 268 стр., УДК: 551.4
Язык(и)Русский
Происхождение рельефа возрожденных гор

Рассматриваются вопросы о происхождении и формировании рельефа эпиплатформенных возрожденных гор и развитии гидрографической сети северного горного обрамления Центрально-Азиатского орогенного пояса, а также связанные с ними вопросы о роли пликативных и дизъюнктивных дислокаций при формировании рельефа, о происхождении кайнозойских песчаных и супесчаных отложений и возможности существования неоген-четвертичных озер-гигантов. Особое внимание уделяется развитию новейших морфоструктур байкальской рифтовой подзоны и Забайкалья под действием глубинных процессов и экзогенных факторов

Выпуск 23
Автор(ы):Buslov M.M., Frank Vanhaecke, J. De Grave, Marina Elburg, Peter Van den Haute, Stijn Glorie, Zhimulev F.I.
Издание:Terra Nova, 2011 г., 9 стр.
Язык(и)Английский
Emplacement and exhumation of the Kuznetsk-Alatau basement (Siberia): implications for the tectonic evolution of the Central Asian Orogenic Belt and sediment supply to the Kuznetsk, Minusa and West Siberian Basins

New geochronological data [zircon U ⁄Pb, titanite fission-track (TFT) and apatite fission-track (AFT) dating and apatite (U-Th-Sm)/He thermochronology] and thermal history modelling yield constraints on the development of the granitoid basement of the Kuznetsk-Alatau Mountains, southern Siberia. The final stages of magmatism in the Kuznetsk-Alatau palaeo-island-arc are Late Cambrian, and collision of the arc with Siberia occurred in the Early Ordovician. The basement was exhumed by the Early Devonian. Continuous Devonian–Early Triassic sedimenta-

tion filled the adjoining Kuznetsk and Minusa basins and buried (and re-heated) the Kuznetsk-Alatau basement. After initial Pangaea break-up and Siberian flood-basalt magmatism, the basement reached TFT and AFT retention-temperatures in the Middle Triassic and Early Cretaceous, respectively, during denudation-induced cooling.


Автор(ы):Alfred Krönera, Dondov Tomurhuue, Dunyi Liua, Fuqin Zhangd, Laicheng Miaod, Ping Jian, Wei Zhanga, Windley B.F., Yurao Shia
Издание:Elsevier, 2010 г., 19 стр.
Язык(и)Английский
Zircon ages of the Bayankhongor ophiolite mélange and associated rocks: Time constraints on Neoproterozoic to Cambrian accretionary and collisional orogenesis in Central Mongolia

Central Mongolia is geologically characterized by close juxtaposition of an accreted oceanic terrane with an arc-microcontinent collision zone. We present new U–Pb zircon ages and geochemical data for the Bayankhongor ophiolite mélange from the oceanic terrane and for a syenite porphyry pluton from the arc-microcontinent zone, providing critical constraints on the regional evolution in late Neoproterozoic to early Cambrian times. An anorthosite (655±4 Ma) associated with layered gabbro, a rodingite (metasomatized layered gabbro) (647±6 Ma), and a high-level isotropic amphibole gabbro (647±7 Ma) yielded the oldest zircon ages for the plutonic part of the ophiolite. A plagiogranite dike in the amphibole gabbro yielded an age of 636±6 Ma, which is the youngest date obtained for the ophiolitic rocks. We suggest that the long duration (ca. 20 Ma) for formation of this plutonic sequence characterizes the sea-floor spreading evolution, and the Nd–Sr isotopic composition (εNd(t) = +7.6 to +4.7; initial 87Sr/86Sr ratio = 0.70279–0.70327) points to a mid-ocean-ridge origin. The syenite porphyry, dated at 523±2 Ma, records the terminal or post-collisional phase of orogeny. The Bayankhongor oceanic lithosphere experienced at least 92Ma of drift between its formation and accretion.

ТематикаРегиональная геология
Ленты новостей
1540.57