Publication details
Structural Geology Research of the Sudoměřice Tunnel – the Paleostress Analysis (Moldanubicum, South Bohemia)
| Authors | |
|---|---|
| Year of publication | 2015 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | The study area is located in the central part of the Moldanubicum, in the Variegated Unit. It is bordered by the Mid-Bohemian Plutonic complex in the west. Data were collected from new Sudoměřice tunnel excavation, recently excavated outcrops and natural outcrops tunnel construction surroundings. Double track Sudoměřice tunnel is part of the Tábor – Sudoměřice u Tábora railway track section of 4th railway transit corridor Praha – České Budějovice. The tunnel excavation proceeded through biotite-sillimanit paragneiss and migmatite with sporadic fine-grained aplite intrusions. Paragneiss and migmatite are medium to fine-grained with distinctive W-E foliation dipping 10–30° to the north. Rock was variously altered along faults and joints. Similar geology was documented in other studied localities (old track cuts, recently excavated cuts for new track, excavated outcrop for new underpass to Sudoměřice station, outcrops west of Prudice, near D3 motorway, and Moraveč). Outcrops situated near Borotín are formed in granitiod intrusion. Most of outcrops showed slight variations in measured foliation. Faults, striations orientation and kinematics from the tunnel and outcrops were processed by updated version of MARK 2011 software (Kernstocková, 2011). Results of paleostress analysis showed heterogenouse origin of dip-slip faults and three dominant phases. Phase one main compression axis (sigma 1) plunges 24° to the NE whereas relative extension axis (sigma 3) moderately plunging to the west. Characteristics of phase two are sigma 1 plunging 29° to the ESE and sub-vertical sigma 3 trending to the NW. Phase three has distinctive subhorizontal sigma 1 trending to the NNW while sigma 3 is moderately plunging to the WSW. Faults corresponding to determined stress axis were separated using MIM Package (Yamaji & Sato, 2005). On the basis of Anderson’s theory, normal and reverse faults fitted to phase one and phase three while phase two matched only normal faults. |