Gravity response of igneous rocks in the northwestern part of the Bohemian Massif
A new cross-border gravity map on the scale of 1:200,000 covering 14,900 km2 of the SE Saxony and NW Bohemia was compiled. It is limited by the sites of Grimma (NW), Karlovy Vary (SW), Neratovice (SE) and Bautzen (NE). Three positive gravity regions - (a) Lusatian Anticline, (b) SE part of the North Saxon Syncline and (c) Teplá-Barrandian Unit were delimited. Separation of the Bouguer anomalies into the regional and residual components together with the Linsser filtering provided three types of derived gravity maps (regional, residual and density boundaries) for geological interpretation. Eighteen negative residual anomalies mostly pertaining to partially buried granite or acid volcanic bodies and ten positive residual anomalies mostly caused by metamorphic complexes were identified. The map of the Linsser indications showing the density boundaries at three depth levels (1, 3 and 6 km) introduces not only numerous disjunctions but also indicates an internal structure of the individual regions. A new cross-border magnetic map covering the same area is also presented.
A “central” circular gravity low (−61 mGal) delineates the Altenberg-Teplice Caldera extending to 10 km depth. Variscan igneous bodies produce only negative gravity anomalies regardless their size. Pre-Variscan igneous bodies cause either weak negative or positive anomalies. A chain of gravity and magnetic anomalies follows the Litoměřice Deep Fault and a large pronounced magnetic anomaly between Doupov volcanic complex (SW) and the Elbe Zone (NE) delineates the Saxothuringian/Teplá-Barrandian Suture Zone.
SNIP (Scopus, 2015): 0.700
IF (ISI, 2015): 1.326
Policy: Open Access