Geneza rowu Nysy na tle badań wykonanych w okolicy Idzikowa

Abstract

NOTES ON THE ORlGIN OF THE NYSA GRABEN

The presence of a distinct brachysyncline has been ascertained by the writers in Cretaceous rocks of the NE portion of the Nysa Graben near Idzików and Waliszów in the Kłodzko (Glatz) region. On every side it is surrounded by faults along which flexures have formed emphasizing the brachysynclinal structure of this unit. The evolution of the brachysyncline has gone on during a long period of time. The subsiding movements commenced towards the close of the Turonian continuing through the Senonian. Their intensity was probably strongest during the Upper Coniacian. Sedimentation associated with these movements built up a 900 m. thick series of Upper Cretaceous beds. This is the maximum, thus far ascertained, thickness of Cretaceous sediments in the Kłodzko region where the average thickness is 500 m. The beginning of the brachysynclinal subsiding movements coincides with the evolution of the Nysa graben. It subsided by gravity forces along the axis of the widespread rising anticlinal structure consisting of the Orlickie and Bystrzyckie Mountains and the Śnieżnik Massif. The elevation of this structure preceded the evolution of the Nysa graben, having begun during the Middle Turonian. After the formation of the graben through gravity force the growing compression caused the steepening of slopes or the overturning of marginal flexures and local overthrusting of Cretaceous strata by metamorphic rocks.