Journal of Petroleum Geology, vol.27 (4), October
Copyright 2004 by Scientific Press Ltd. All rights reserved.
MIDDLE MIOCENE DASHAVA FORMATION
SANDSTONES, CARPATHIAN FOREDEEP, UKRAINE
T. M. Peryt
Minerals, National Academy of Sciences of Ukraine,
Naukova 3A, Lviv 79053, Ukraine.
**Panstwowy Instytut Geologiczny, Rakowiecka 4, 00-75 Warszawa,
*Institute of Geology and Geochemistry of Combustible
+ author for correspondence, email: [email protected]
Middle Miocene (Sarmatian) sandstones in the Ukrainian Carpathian Foredeep are important
exploration targets for natural gas. In this paper, we report on petrophysical studies on core
samples of these sandstones with which we integrate wireline log data from 42 boreholes. Sarmatian
siltstones and sandstones in the study area are assigned to the lower part of the Dashava Formation.
Seventeen units (LD17 to LD1: 0.05 to 5m thick) are recognized in this formation on the basis of
lithostratigraphy and log response. Sandstone content is highest within three lithostratigraphic
complexes corresponding to units LD17-LD14, LD9-LD8 and LD5-LD3.
During the Sarmatian, the Carpathian Foredeep was characterized by two depositional systems:
a basinal turbidite system, and a second, more mixed system. Important controls on sedimentation
included basin configuration and water depth, the occurrence of turbidity and other currents, and
the location of provenance areas. Clastic material was delivered to the basin by rivers and ephemeral
streams mostly from the Carpathian foldbelt. The content of sandy material within the Sarmatian
succession increases from NW to SE, and from the central portion of the Krukenychy depression
to the margins of the basin.