Phosphatized discontinuity surfaces in the limestone of the Kunda Regional Stage (Middle Ordovician) in northwest Russia
Abstract
Phosphatized discontinuity surfaces are widely distributed in Lower – Middle Ordovician
condensed carbonate sections of Baltoscandia. However, it is difficult to diagnose them and therefore
they are poorly studied as compared to other impregnated surfaces. Morphological typification
and genetic interpretation of the phosphatized discontinuities are given using material from the
Endoceras limestone of the Kunda Regional Stage. The distribution of the discontinuity surfaces on
the paleofacies profile is shown. The discontinuity surfaces with fine, usually eroded impregnation
and phosphate-filled shells which are relics of full-eroded surfaces are common in the most shallowwater
and high-energy lithofacies (bioclastic grain- and packstones, proximal wackestones). In the
deeper-water wackestones, the discontinuity surfaces with deeper phosphate impregnation, varying
from hardground (strongly phosphatized, not bioturbated) to softground (weakly phosphatized,
bioturbated) are common.
About the Author
G. S. Iskyul
A. P. Karpinsky Russian Geological Research Institute (VSEGEI)
Russian Federation
Russian Federation
Candidate of Geological and Mineralogical Sciences, Researcher
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Review
For citations:
Iskyul G.S. Phosphatized discontinuity surfaces in the limestone of the Kunda Regional Stage (Middle Ordovician) in northwest Russia. Regional Geology and Metallogeny. 2019;(78):5–20. (In Russ.)
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