Premium
Geophysical modelling of the Ebersbrunn diatreme, western Saxony, Germany
Author(s) -
Matthes Heidrun,
Kroner Corinna,
Jahr Thomas,
Kämpf Horst
Publication year - 2010
Publication title -
near surface geophysics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.639
H-Index - 39
eISSN - 1873-0604
pISSN - 1569-4445
DOI - 10.3997/1873-0604.2010020
Subject(s) - diatreme , geology , impact crater , maar , phreatomagmatic eruption , volcano , lapilli , breccia , bouguer anomaly , geophysics , seismology , pyroclastic rock , kimberlite , gravity anomaly , physics , paleontology , astronomy , mantle (geology) , oil field
The Ebersbrunn diatreme near Ebersbrunn, western Saxony, Germany, causes an elliptical Bouguer anomaly of about –2.5 m Gal, which covers an area of approximately 2.2 km × 2 km and an elliptical magnetic anomaly with values between –250 nT and 1000 nT about half a kilometre smaller in diameter and situated within the southern part of the Bouguer anomaly. Considering magnetic susceptibility and density values determined from core samples of the diatreme, a symmetrical, cone‐shaped body with an oval surface outcrop of 2 km × 1.5 km and a dip angle of the slopes of about 82° is modelled. It comprises a central structure with a diameter of 800–900 m and susceptibility values up to 9000*10 −6 SI higher and densities up to 220 kg/m 3 lower than the surrounding chimney. Additionally, susceptibility within the body increases with depth and decreases with the degree of weathering. The geometry can clearly be associated with the diatreme of a maar‐diatreme‐volcano. Regarding the petrographic information (the occurrence of pelletal lapilli as juvenile phase, the basaltoid character of the occurring ground mass of magmatic origin and 80% wall rock content) and the final geophysical model, the Ebersbrunn structure can definitely be regarded as the partially eroded remnant (diatreme and root zone) of a maar‐diatreme‐volcano. The association of earthquake swarms in intraplate regions of intersecting fractures and volcanism has led to renewed interest in the eroded maar‐diatreme‐volcano.