1. NEW TYPE OF BRITTLE DEFORMATIONS: TWO-AXIAL TURN STRUCTURE OF FRACTURES IN THE KOVDOR CARBONATITE INTRUSION (NW RUSSIA).
- Author
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Zhirov, Dmitry
- Subjects
- *
BRITTLE materials , *DEFORMATIONS (Mechanics) , *FRACTURE mechanics , *CARBONATITES , *IGNEOUS intrusions - Abstract
The investigation of the fault tectonics in the Kovdor carbonatite intrusion (NW Russia) has resulted in the identification of a new brittle deformations type. It is formed due to the simultaneous turn of fissure planes at discrete angles around two orthogonal guiding lines (axes), where one is represented by a vertical massif symmetry axis (L1), and the other axis (L2) lies horizontally in the fracture plane. Nonetheless, the rotation along the both axes is codirectional, i.e., when moving counterclockwise around the L1 axis, the L2 rotation is also counterclockwise. If we very tentatively consider a fissure as an ellipse, and take into account the whole assemblage of long and short axes, the overall picture of their spatial distribution generates a screw conoid or ordinary helicoid type structure. It will be shown as an S-shaped plane poles chain in the stereogram. A sequence of large scale fissures (longer than 100 meters), which are 25 to 100 meters apart from each other and regularly vary in strike and dip angle, is mapped in the open pit of the Kovdor apatite-magnetite deposit. This is a new type of brittle deformations, which is of significance for the interpretation of evolutional features and modern state of the stress field in the Kovdor central-type carbonatite intrusion. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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