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Orbicular granite near Jelenia Góra in southwestern Poland: the first outcrops?


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In 1802, Leopold von Buch described some outcrops of orbicular granite in the Karkonosze granite, Lower Silesia, Poland. In that publication, Abraham Gottlieb Werner wrote a foreword dated 1800. The Silesian discovery predates that of the well-known orbicular diorite (Napoleonite) in outcrop on Corsica and, thus, may be the first ever record of this distinctive rock type in its geological context. The characterizing, closely-packed, simple orbs comprise K-feldspar cores surrounded by rims of radiating K-feldspar and quartz. Rapid growth from a hydrous, pegmatitic melt is indicated. The Karkonosze outcrop, in the timing of its discovery, is a unique part of the geological heritage.

eISSN:
1899-8526
ISSN:
1899-8291
Language:
English
Publication timeframe:
Volume Open
Journal Subjects:
Geosciences, Geophysics, other