R
Robin Armstrong
Researcher at American Museum of Natural History
Publications - 27
Citations - 1462
Robin Armstrong is an academic researcher from American Museum of Natural History. The author has contributed to research in topics: Volcanic rock & Zircon. The author has an hindex of 13, co-authored 23 publications receiving 1180 citations. Previous affiliations of Robin Armstrong include Natural History Museum.
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Journal ArticleDOI
Reassessment of continental growth during the accretionary history of the Central Asian Orogenic Belt
Alfred Kröner,Victor Kovach,Elena Belousova,Ernst Hegner,Robin Armstrong,Alla Dolgopolova,Reimar Seltmann,D. V. Alexeiev,J.E. Hoffmann,Jean Wong,Min Sun,Keda Cai,Tao Wang,Y. Tong,Simon A. Wilde,Kirill E. Degtyarev,E. Rytsk +16 more
TL;DR: In this article, the authors argue that the production of mantle-derived or juvenile continental crust during the accretionary history of the Central Asian Orogenic Belt (CAOB) has been grossly overestimated.
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The effect of titanite crystallisation on Eu and Ce anomalies in zircon and its implications for the assessment of porphyry Cu deposit fertility
TL;DR: In this article, the trace element chemistry of zircons from titanite-bearing intrusions associated with mineralisation at the world class Oyu Tolgoi porphyry Cu-Au deposit (Mongolia) is reported.
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Trace elements and cathodoluminescence of quartz in stockwork veins of Mongolian porphyry-style deposits
Axel H. E. Müller,Richard Herrington,Robin Armstrong,Reimar Seltmann,Douglas J. Kirwin,Nina G. Stenina,Andreas Kronz +6 more
Abstract: The combination of scanning electron microscope–cathodoluminescence (CL), fluid inclusion analysis and high-resolution electron probe microanalysis of Al, Ti, K and Fe in vein quartz has yielded results permitting a greater understanding of the complex mineralisation of the Central Oyu Tolgoi and Zesen Uul porphyry-style deposits, southern Mongolia. These data demonstrate the relationship between quartz precipitation, dissolution and ore deposition as the mineralising fluid chemistry changed through time. Four major quartz generations are identified in the A-type veins from the stockworks of both the Central Oyu Tolgoi (OTi to OTiv) and Zesen Uul deposits (ZUi to ZUiv). Despite differences in the associated alteration and mineralisation style, the observed CL textures and trace element signatures of the quartz generations are comparable between deposits. The OTi and ZUi stage formed both the primary network of A-type veins and pervasive silicification of the host rock. Using the Ti-in-quartz geothermometer, crystallisation temperatures for OTi and ZUi of between 598°C and 880°C are indicated. The main stage of sulphide mineralisation was accompanied by the dissolution of pre-existing quartz (OTi and ZUi) and precipitation of a weakly luminescent generation of quartz (OTii and ZUii) with a low Ti content, reflected in a calculated temperature drop from approximately 700°C to 340°C in Central Oyu Tolgoi and 445°C in Zesen Uul. OTii and ZUii stage quartzes show high and variable Al concentrations. The next stage of quartz in both deposits (OTiii and ZUiii) forms a fine network of veins in cracks formed in pre-existing quartz. OTiii and ZUiii quartz contain measurable fluid inclusions of moderate salinity (3–17.1 wt.% NaCl eq.), entrapped in the temperature range 256°C to 385°C. OTiii and ZUiii are not related to any sulphide mineralisation. The final OTiv and ZUiv stages are characterised by quartz–calcite micro-breccias that penetrate the A-type veins. Based on the calculated entrapment temperatures, the OTiv/ZUiv stage crystallised between 212°C and 335°C, and the quartz is characterised by elevated but variable Al and Fe contents. The CL and trace element signatures of the OTi to OTiii and ZUi to ZUiii stages of the two Mongolian porphyries show similar features to those observed in porphyry-style deposits from other regions. This suggests that a common sequence of quartz crystallisation occurs during the formation of early veins in many porphyry copper systems.
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Geodynamic evolution of the western Tien Shan, Uzbekistan: Insights from U-Pb SHRIMP geochronology and Sr-Nd-Pb-Hf isotope mapping of granitoids
Alla Dolgopolova,Reimar Seltmann,Dmitry Konopelko,Yu. S. Biske,V. Shatov,Robin Armstrong,Elena Belousova,Robert J. Pankhurst,R. Koneev,F.K. Divaev +9 more
TL;DR: Sr-Nd-Pb-Hf isotope mapping combined with SHRIMP ages of granitoids from four sampling profiles across terrane boundaries in Uzbekistan reveal distinct reservoir types (cratonic and accretionary), witnessed by the diverse nature and origin of the predominant Paleozoic granitic magmatism that provided hosts for major orebodies.
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Late Paleozoic–Mesozoic tectonic evolution of the Trans-Altai and South Gobi Zones in southern Mongolia based on structural and geochronological data
Alexandra Guy,Alexandra Guy,Karel Schulmann,Norbert Clauer,Pavlína Hasalová,Reimar Seltmann,Robin Armstrong,Ondrej Lexa,Antonio Benedicto +8 more
TL;DR: In this article, the Trans-Altai Zone in southern Mongolia is characterized by thrusting of greenschist-facies Silurian oceanic rocks over Devonian and Lower Carboniferous volcano-sedimentary sequences, by E-W directed folding affecting the early carboniferous volcanic rocks and by the development of N-S trending magmatic fabrics in the Devonian-Carboniferous arc plutons.