Nove poznatky o geologicke stavbe melechovskeho masivu

Six 150-200 m long fully cored boreholes were realized in the Melechov granite pluton during the period 2004-2006. These boreholes provided the first information about internal structure of the pluton, namely about the contact between individual intrusions, and about the contact between the granite and the enclosing Moldanubian gneiss. Pair of boreholes Mel-1 and Mel-2 (200 m deep, in the distance of 20 m from one another, situated on the western slope of the Melechov hill) reveals a high degree of internal inhomogenities and post magmatic alteration, mainly chloritization, in the coarse-grained two-mica Melechov-type granite. Pair of boreholes Mel-3 and Mel-4 (180 and 194 m deep, in the distance of 150 m from one another, situated to the north of the village of Kaliště) was situated in an intensively tectonised area along the contact between the fine-grained two-mica Lipnice-type and Kouty-type granites. These boreholes confirmed a generally flat shape of the contact and finger-like penetration of the Kouty-type granite into the Lipnice-type granite. The inclined 150 m long borehole Mel-5 located in an abandoned quarry near the village of Lipnice was used especially to compare tectonic structures on the surface and in the borehole. The aim of inclined borehole Mel-6 (150 m long, situated near the village of Žebrákov) was to confirm an exact location of the contact between the Kouty-type granite and gneiss, indicated here by geophysical methods. Detailed chemical, petrological and mineralogical investigation of all borehole cores has been performed.