Indicators of recent geodynamic activity in the Ksi?? Castle area (?wiebodzice Unit, Sudetes) in the light of structural analysis and geodetic measurements

摘要

Abstract. Indicators of recent geodynamic activity in the Ksi?? Castle area are registered by the measuring instruments of the SRC PAS (Space Research Centre of Polish Academy of Sciences) Geodynamic Laboratory at Ksi??. Over 40 years of continuous observations from quartz horizontal pendulums (since 1974) and over 10 years of observations from water-tube tiltmeters (since 2002) have documented irregularly repeatable strong signals related to the relative displacement of blocks in the rock substrate, on which Ksi?? Castle is located. These signals have dip (rotational) and vertical strike-slip components. Also, the presence of a horizontal strike-slip component is evidenced by geometric anomalies (deformations) of the shape of the Pelcznica river valley, which directly correspond to the orientation of the main faults in the area. Recent geodynamic activity is documented by destruction of (the construction elements in the castle complex. Instrumental indicators of movement, geodetic measurements and structural analysis of the rock massif have allowed for constructing a model showing the main unconformity surfaces in the analysed rock massif. Sinistral, NE–SW and ENE–WSW-oriented strike-slip faults prevail in the laboratory corridors, along with perpendicular WNW–ESE and NW–SSE-oriented clextral and normal faults. Most dislocations are accompanied by zones of intense cataclasys, secondary silification, and Fe and Mn mineralization. Generally, the faults were formed due to reactivation of joint fractures cutting the steeply N-and S-dipping (at 75-90°) deposits of the Ksi?? Conglomerate Formation.