Publication details
Mineralogical and chemical composition of the Hagendorf-North Pegmatite, SE Germany - a monographic study
| Authors | |
|---|---|
| Year of publication | 2013 |
| Type | Article in Periodical |
| Magazine / Source | Neues Jahrbuch fur Mineralogie, Abhandlungen |
| MU Faculty or unit | |
| Citation | |
| Doi | http://dx.doi.org/10.1127/0077-7757/2013/0244 |
| Field | Geology and mineralogy |
| Keywords | Pegmatite; phosphate; feeder channel; supergene alteration; Hagendorf-North; SE Germany |
| Description | Hagendorf-North is a zoned Li-Nb-P-feldspar-quartz pegmatite located W of the village of Hagendorf and about 0.5 km north of the renown Hagendorf-South deposit which once was the largest feldspar pegmatite in Central Europe. Hagendorf-North also known as Meixner Mine was much smaller in size and its minerals assemblage is less variegated than that recorded from its larger "brother". However it was the site where mining began in 1860. But already before the onset of World War II, the pegmatite has no longer been considered an economic target and the mine was shut down. The reason for that small size in the shadow of this huge Hagendorf-South pegmatite is due to its overall role as feeder system to the Hagendorf-type stocklike pegmatites, which was truncated by the Pliocene chemical weathering and Pleistocene erosion, which however was comparatively moderate when compared with the western part of the pegmatite province. Hagendorf-North and South were both emplaced in the central parts of a first order anticline with its hinge line plunging towards the south and thereby providing much better structural, mineralogical and supergene conditions for Hagendorf-South than for Hagendorf-North in terms of accommodation space of the pegmatite body and preservation potential during Cenozoic supergene alteration. Both pegmatites resemble each other as to the temperature of formation spanning the range 500 degrees C to 550 degrees C. The lithogenic process giving rise to the Hagendorf-North pegmatite and its present-day size are as follows: (1) regional metamorphism-structural disturbances, (2) high temperature mobilization, (3) hydrothermal alteration, (4) epithermal mineralization, (5) weathering. The Hagendorf-Pleystein province may be subdivided roughly into two sections. The western section is best described as the Pleystein subzone and the eastern as the Hagendorf subzone. The Hagendorf Zone is marked by a ratio of chemical weathering >> erosion. Newly formed Al-phosphates are widespread and Fe-phosphates indicative of reducing conditions occur to a moderate extent. Chemical weathering was pervasive during the Pliocene, whereas the erosional shaping of the pegmatitic landscape evolved during the Pleistocene. This has also some implications as to the "weathering ruins". The Pleystein-Kreuzberg pegmatite has been depleted of its less resistant feldspar envelope and now morphologically stands out as a "quartz reef", while the Hagendorf-North is a feeder channel system, being deprived of the entire pegmatite body that still was preserved in the Hagendorf-South pegmatite. |