STRATIGRAPHY OF THE PRE-JURASSIC BLOCKY SEDIMENTARY ROCKS TO THE SOUTH OF BURSA, NW Turkey

Year 1989, Volume: 109 Issue: 109, 15 - 24, 01.02.1989

Orhan Kaya Orhan Özkoçak Alvis Lısenbee

Abstract

Two of the major pre-Jurassic units of northwest Turkey consist of blocky sedimentary rocks (Dışkaya formation in this report) and low-grade metamorphic rocks (glaucophanitic) greenschist facies . In the study area, the Dışkaya formation is divisible into laterally continuous stratigraphic units of olistostromes and shale-lithic sandstone sequences. The blocks include variably recrystallized limestones, some with Late Paleozoic faunal elements, marble-like recrystallized limestones, submarine mafic volcanic rocks, quartzo-feldspathic sandstones, gray and red bedded chert. The complex internal structure, which is characterized by large sandstone pseudo-boudins up to several meters across, is the product of soft-sediment deformation. The basal olistostrome unit of the Dışkaya formation rests with a slightly deformed contact on the metamorphic rocks and contains at its base blocks derived from the immediately underlying metatuff unit. The Dışkaya formation has slope characteristics. It appears to have been deposited on an older structural system comprising primarily low-grade metamorphic rocks, which has also constituted source area. The field data is not directly indicative of an accretionary wedge origin for the pre- Jurassic blocky sedimentary rocks (the Dışkaya formation) which is suggested in all recent tectonic syntheses. 

Keywords

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