Age of picrite and picrodolerite magmatism in western Mongolia

Abstract

The paper presents 39Ar/40Ar and UPb (SHRIMP zircon method) geochronological data on minor picrodolerite intrusions from western Mongolia. Picrodolerite magmatism in western Mongolia took place within different age intervals and in different geodynamic settings: accretionary–collisional Ꞓ1-2, ~510 Ma (Üüreg Nuur association, Hayrhan intrusion), intraplate D1, 410–390 Ma (Tsagaan Shuvuut Range, Mor’t Uula intrusion), intraplate D3–C1, 345–360 Ma (Altan Gadas, Tavtyn Hundiyn, and Hu Tsan Bulak intrusions), island-arc C2, 315–335 Ma (Dzahuy, Yaryn Had, and Javhlant intrusions), and intraplate P1, ~270 Ma (Dzaraa Uula intrusion). Petrographic, mineralogical, and geochemical data permit distinguishing derivates of picrobasaltic (12–14 wt.% MgO) (Üüreg Nuur association, Tsagaan Shuvuut, Javhlant, Yaryn Had) and melabasaltic melts (7–10 wt.% MgO) (Mor’t Uula, Altan Gadas, Dzahuy, Dzaraa Uula) among picrodolerite magmatism in western Mongolia. Picritoids in these associations resulted from early olivine fractionation. The Early Devonian picrites and picrodolerites of the Tsagaan Shuvuut Range and the olivine dolerites of the Mor’t Uula intrusion can be assigned to mafic magmatism in the Devonian large igneous province (LIP) in the North Mongolian megablock. The Late Devonian–Early Carboniferous picrodolerite intrusions in the Baruun Huuray zone (Altan Gadas) and Mongolian Altay (Tavtyn Hundiyn) are related to the Tien Shan LIP. Bimodal volcanism on the southern margin of the Hangayn Mts. (Dzaraa Uula), in the eastern segment of the Hanhöhiy Ridge (Dzagday Nuur, Hara Teg), and in the Argalantu trough (Tegshiyn Gol, Muhur Shurgah, and Deed Shurgah massifs) may be related to the Tarim LIP, where they are part of an Early Permian volcanoplutonic association. Carboniferous picrodolerite intrusions in the South Mongolian megablock and the Trans-Altai Gobi formed in subduction-related settings (Dzahuy, Yaryn Had, Javhlant).

Neoproterozoic‐Early Paleozoic Peri‐Pacific Accretionary Evolution of the Mongolian Collage System: Insights From Geochemical and U‐Pb Zircon Data From the Ordovician Sedimentary Wedge in the Mongolian Altai

“…During the Late Cambrian, a new NE and/or east dipping subduction system developed along the SW and west margins of the Mongolian Precambrian blocks giving rise to the generation of widespread arc magmatism (with maximum activity at circa 510 Ma) variously intruding the Precambrian basement and the accreted Lake Zone (e.g., Izokh et al, ; Mongush et al, ; Rudnev et al, ; Yarmolyuk et al, ), exemplified by the Ikh‐Mongol arc system (see Janoušek et al, Figure ). We propose that formation of this giant arc was connected with the development of an equally giant turbidite basin to the south or west (Figure ).…”

The Early Palaeozoic mega‐thrusting of the Gondwana‐derived Altay–Lake zone in western Mongolia: Implications for the development of the Central Asian Orogenic Belt and Paleo‐Asian Ocean evolution

“…Locations of geochronological age in the Lake and Mongolian Altay. Numbers of each box refer to data from (1) Kovalenko et al, , (2) Gibsher et al, , (3) Jian et al, , (4) Khain et al, , (5) Pfänder et al, , (6) Dijkstra et al, , (7) Izokh et al, , , (8) Lehmann et al, , (9) Stipska et al, 2010, (10) Mongush, Lebedev, Travin, & Yarmolyuk, , (11) Hrdličková et al, , (12) Yarmolyuk et al, , (13) Rudnev et al, , ; Rudnev, Kovach, & Ponomarchuk, , (14) Buriánek et al, , and (15) Jiang et al, [Color figure can be viewed at wileyonlinelibrary.com]…”

Zircon U–Pb geochronology, geochemistry, and Sr–Nd isotopes of the Ural–Alaskan type Tuerkubantao mafic–ultramafic intrusion in southern Altai orogen, China: Petrogenesis and tectonic implications

“…The Altai orogen is located in the western CAOB, which is the world largest accretionary orogen and has been expensively studied during the last 20 years (e.g., Zonenshain et al, 1990;Buslov et al, 2001;Kröner et al, 2007Kröner et al, , 2014Kovalenko et al, 2004;Xiao et al, 2003Xiao et al, , 2010Windley et al, 2007;Polyakov et al, 2008;Izokh et al, 2010Izokh et al, , 2011Safonova et al, 2011;Yarmolyuk et al, 2012). It is situated between the Gorny Altai in Russia to the north and the Western Junggar to the south (Fig.…”