caa a22 4500 477062326 CHVBK 20180405111404.0 cr unu---uuuuu 170330e19960701xx s 000 0 eng 10.1007/s004450050116 doi (NATIONALLICENCE)springer-10.1007/s004450050116 Microlites and "nanolites" in rhyolitic glass: microstructural and chemical characterization [Elektronische Daten] [Thomas G. Sharp, Richard J. Stevenson, Donald B. Dingwell]  We used transmission electron microscopy (TEM) and scanning electron microscopy (SEM) to study magmatic crystals in the Ben Lomond rhyolite lava dome, Taupo Volcanic Center, New Zealand. Using TEM and SEM to investigate the size distributions of these crystals, we identified three size populations: microphenocrysts (>1.2 μm wide), microlites (>0.6 μm wide), and smaller crystals (<0.6 μm wide) which we term "nanolites". The predominant mineral phases of the microlites and nanolites are augites, pigeonites, and hypersthenes. The compositions and microstructures within these pyroxenes indicate disequilibrium crystallization at approximately 850-900  °C and undercoolings as high as 300  °C from equilibrium crystallization temperatures. Complex microstructures resulting from subsolidus reactions in augite and pigeonite are consistent with moderate cooling rates within the upper obsidian layer of the Ben Lomond rhyolite dome. This study demonstrates the existence of sub-micron magmatic crystals in a rhyolite and illustrates the potential of TEM to provide unique information about the crystallization and cooling histories of glassy volcanic rocks. Springer-Verlag Berlin Heidelberg, 1995 Key words Rhyolite nationallicence Crystallization nationallicence Size distribution nationallicence Microphenocryst nationallicence Microlite nationallicence Nanolite nationallicence Microstructures nationallicence Sharp Thomas G. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut Stevenson Richard J. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut Dingwell Donald B. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut https://doi.org/10.1007/s004450050116 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s004450050116 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sharp Thomas G. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut NATIONALLICENCE 700 1- Stevenson Richard J. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut NATIONALLICENCE 700 1- Dingwell Donald B. Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany, DE aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer