Petrochemistry of mafic and ultramafic rocks of CY-4 drill-hole, Cyprus crustal study project

Abstract EN

This paper is a result of study and investigation of 45 samples collected, at 50 meter intervals , from CY-4 drill hole of the Cyprus Crustal Study Project, to confirm , on basis of petrographic studies and chemical analysis, the classification of the Troodos Ophiolite suite and the terminology of the rock units .

Troodos complex comprises a Cretaceous ideal ophiolite suite.

Drill hole CY-4, located in the southeastern part of the complex , penetrates through sheeted dikes, gabbroic rocks, and ultramafic cumulates.

The rock sequence of the drill hole could be broadly classified into : 1) a diabasie zone representing the sheeted dikes, (9.85m-483.5Om), 2) a zone of mixture of sheeted dikes and gabbros, (483.50m-837.45m), 3) massive gabbro zone, (837.4Sm-1346.80m), 4) cumulate gabbro zone, (1346.80m-1754.IOm), and 5) ultramafic zone consisting essentially of clinopyroxcnite, websterite and dunitc , (1754.lOm-226Jm) .

The studied samples can be divided chemically into mafic and ultramafic groups which correspond closely to the petrographic classification.

Mafic magmatic rocks are generally oversaturated tholeiites.

Trace element contents arc similar to those expected from such rock suites .

Chemical characteristic s of the ultramafic rocks indicate a cumulate origin consistent with previous investigations.