Radiolarian evidence for the age of chert blocks from the Upper Cretaceous ophiolitic melange unit of the Erakh area, Armenia

Danelian, T., Asatryan, G., Sahakyan, L., Avagyan, A. and Galoyan, G. (2015) Radiolarian evidence for the age of chert blocks from the Upper Cretaceous ophiolitic melange unit of the Erakh area, Armenia. Geological Society London Special Publications, 428 . doi:10.1144/SP428.7


Author Danelian, T.
Asatryan, G.
Sahakyan, L.
Avagyan, A.
Galoyan, G.
Title Radiolarian evidence for the age of chert blocks from the Upper Cretaceous ophiolitic melange unit of the Erakh area, Armenia
Journal name Geological Society London Special Publications   Check publisher's open access policy
ISSN 0305-8719
2041-4927
Publication date 2015
Year available 2015
Sub-type Article (original research)
DOI 10.1144/SP428.7
Open Access Status Not Open Access
Volume 428
Total pages 12
Place of publication Bath, Avon United Kingdom
Publisher Geological Society Publishing House
Collection year 2016
Language eng
Formatted abstract
Two new and relatively well-preserved radiolarian faunas were extracted from blocks included in the Cretaceous ophiolitic mélange unit that crops out in the Erakh area south of Yerevan, Armenia. One of these radiolarian assemblages was extracted from cherts that are in stratigraphic contact with variolitic lavas. This radiolarian assemblage suggests a late Aalenian to middle Bajocian age (Unitary Association Zones 2–3) based on the co-occurrence of the species Parasaturnalis diplocyclis (Yao) and Transhsuum hisuikyoense (Isozaki & Matsuda). A second radiolarian assemblage was obtained from a block, several metres thick, of alternating pelagic limestones and cherts. It was characterized by the co-occurrence of the species Hemicryptocapsa capita Tan and Dicerosaturnalis dicranacanthos (Squinabol). The presence of these two species within the same assemblage correlates with Unitary Association Zone 17 and these samples are therefore assigned to the late Valanginian. These results suggest that submarine volcanic activity took place during the late Aalenian–middle Bajocian interval and that mixed carbonate and siliceous ooze accumulated during the late Valanginian. Previous biochronological data on Radiolaria from the Erakh mélange and the Vedi ophiolite are reviewed and their implications for the geodynamic and palaeoenvironmental evolution of the Tethyan ocean in Armenia are discussed.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Geography, Planning and Environmental Management Publications
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Created: Fri, 01 Apr 2016, 13:32:23 EST by Gayane Asatryan on behalf of School of Geography, Planning & Env Management