This book will broaden readers' understanding of pegmatites in a special
geodynamic setting, dealing with the emplacement of the
Hagendorf-Pleystein Pegmatite Province (HPPP) in the Central European
Variscides. This treatise illustrates the complex processes leading to
the formation and partial destruction of the pegmatites, documenting the
geochronological, chemical, mineralogical, geological and
geomorphological / sedimentological data set. The book starts with a
detailed account of the economic geology of the various pegmatites,
explaining why these deposits are a major resource of ceramic raw
materials. In its concluding section, a model of the pegmatite evolution
in an ensialic orogen provides meaningful insights into the genetic
aspects of pegmatite generation.
The Late Paleozoic rare-element pegmatites of the HPPP, Oberpfalz-SE,
Germany, rank among the largest concentrations in Europe. The biggest
pegmatite of this mining district totals 4.4 million tons of ore
(Hagendorf-South). The mining history of the HPPP is restricted to the
20th century, when local entrepreneurs started mining operations in
search of ceramic raw materials, feldspar and quartz. Today the
"Silbergrube Aplite" is still worked for feldspar. The traditional
mining of pegmatitic and aplitic rocks in Central Europe, such as the
Bohemian Massif, which is shared by Germany, the Czech Republic, Poland
and Austria, has been focused on these industrial minerals. In addition
to these major commodities, lithium was mined for a period of time. But
even today many of these pegmatites of calc-alkaline affiliation have
not lost their appeal to mineralogists and mineral enthusiasts for their
wealth of minerals that contain P, Nb, Ta, Li, Be, B, U, Th, Sc, Ti and
Sn. The most favorable crustal section to bring about pegmatitic rocks
of this type, encompassing pegmatoids, metapegmatites, reactivated
pseudopegmatites and pegmatites sensu stricto is the ensialic orogen,
exemplified by the Variscan (Hercynian) Orogen, which geodynamically
connects the Paleozoic pegmatite provinces in North America and Europe.
The geological history of the HPPP, however, goes much further than the
Carboniferous-Permian magmatic activity, when the last structural
disturbances of the Variscan orogeny affected the NE-Bavarian Basement
between 450 and 330 Ma. During this time mafic magmatic rocks together
with calcareous and arenaceous sediments were converted into
paragneisses, calcsilicate rocks, and amphibolites. It is the period of
time when tectonic shortening led to over thrusting and when the
emplacement of nappes and the architectural elements of the ensialic
orogen began taking shape. During the Late Permian, the Mesozoic and the
Cenozoic, the HPPP did not lie idle in geological terms; hypogene and
supergene alteration continued and found its most recent expression in
alluvial-fluvial "nigrine" placer deposits, which resulted from the
unroofing of the pegmatites and aplites in the HPPP and can be used even
outside HPPP as an ore guide to pegmatites.
