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Flow characteristics of Metresa: an Oligocene seismoturbidite in the Dukla Unit, Polish Carpathians
Author(s) -
SLACZKA A.,
WALTON E. K.
Publication year - 1992
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1992.tb02123.x
Subject(s) - lamination , geology , turbidity current , turbidite , deposition (geology) , sedimentary structures , stratification (seeds) , geomorphology , grain size , sediment , erosion , current (fluid) , paleontology , geochemistry , sedimentary depositional environment , oceanography , structural basin , seed dormancy , chemistry , botany , germination , organic chemistry , layer (electronics) , dormancy , biology
Metresa is a thick, distinctive turburdite within the Menilite Shales in the Carpathians of south‐east Poland. It was deposited by a SE‐flowing turbidity current derived from the Silesian cordillera and can be traced for 55 km downcurrent; it has a width of at least 15 km. The current contained roughly 3 km 3 of sediment and conforms to the definition of a seismoturbidite. Grain‐size analyses of samples from the nine localities where Metresa is exposed indicate average velocities decreasing from 2 m s −1 to less than 1 m s −1 over the 55 km. Massive divisions are poorly developed; instead, the turbidite, although graded, tends to be laminated throughout. Flat lamination predominates with intercalated cross‐lamination and erosion structures at various levels. Small‐scale cross‐lamination, presumably associated with ripples, occurs at some upper levels. An exceptional feature is a large‐scale wave‐like structure somewhat resembling hummocky cross‐stratification. The structures are not consistent with the inferred velocities. It is suggested that the stability fields relating structures to stream power (herein called the ‘Allen fields’) are displaced in respect to deposition from waning turbidity currents.