Uwagi o spękaniach w skałach północnej osłony granitoidów karkonosko-izerskich w rejonie Szklarskiej Poręby

Abstract

REMAKRS ON FRACTURES IN ROCKS OF NORTHERN COVER OF THE KARKONOSZE-IZERA GRANITAIDS IN THE SZKLARSKA PORĘBA REGION Summary The paper present results of analysis of fractures in rocks of the Szklarska Poręba schist belt in eastern part of the Wysoki Grzbiet (Izerskie Mts), that is in area of direct contact of these rocks and those of the Karkonosze-Izera Massif. The question of age and mutual relations of sets of joints found at opposite sides of the contact zone is discussed. Low-angle dislocations are shown to be the oldest fractures in this schist belt. Their origin is explained by the Author as related to tensional conditions in cover of rising Karkonosze-Izera granitoid intrusion. After solidification of outer parts of the granitoid massif, younger discontinuities became overprinted on the above mentioned. The discontinuities represent continuations of joint formed in the granite and they include marginal fissures, low angle normai faults, low angle fractures (L), and transversal (Q) and longitudinal (S) fractures as identified by Closs.