[The Journal of Geology, 2000, volume 108, p. 199–218]  2000 by The University of Chicago. All rights reserved. 0022-1376/2000/10802-0005$01.00 199 Actualistic Ophiolite Provenance: The Cyprus Case Eduardo Garzanti, 1 Sergio Ando ` , and Maria Scutella ` Dipartimento di Scienze della Terra, Universita ` di Milano, Via Mangiagalli 34, 20133 Milano, Italy (e-mail: eduardo.garzanti@unimi.it) ABSTRACT The island of Cyprus represents an excellent site to assess quantitatively petrologic clastic response to actively obducting oceanic sources in order to define an actualistic reference for ophiolite provenance, in terms of framework composition and heavy mineral suites. An improved methodology, an extension of the classic ternary QFL logic to include a wider spectrum of key indexes and ratios, provides an accurate synthesis of modal data and allows differ- entiation of three main petrographic provinces and at least seven subprovinces. Diagnostic signatures of detritus from various levels of an oceanic lithospheric source, and criteria for distinguishing provenance from suprasubduction versus mid-oceanic ophiolites are also outlined. Modern sands derived from the Troodos Ophiolite contain variable proportions of largely pelagic carbonate to chert, boninite to basalt, diabase to metabasite, plagiogranite to gabbroic, and cumulate grains supplied from progressively deeper-seated levels of the multilayered oceanic crust. Dense minerals are mainly clinopyroxenes (diopside), prevailing over orthopyroxenes (enstatite, hypersthene, clinoenstatite), horn- blende, tremolite/actinolite, and epidote. Where serpentinized mantle harzburgites have been unroofed, detritus is markedly enriched in cellular serpentinite grains and enstatite, with still negligible olivine and spinel. Sedimenta- clastic sands dominated by chert (Mamonia Province) or carbonate grains (Kyrenia Province) are deposited along the southern and northern shores of the island, respectively. Compositions of Cyprus sands are virtually unaffected by climatic, sedimentary, or anthropic processes; recycling of sandstones from foreign sources is a major process only in the Karpaz Peninsula. Petrographic analysis also provides an independent mean to identify prevalent directions of longshore sand transport. Introduction Clastic petrography is a fundamental tool for un- raveling geologic evolution of ancient sedimentary basins associated with the development of orogenic belts. Although analysis of modern sediments pro- vides crucial quantitative information (Ingersoll 1990; Ingersoll et al. 1993), studies of actualistic petrofacies are still sparse and limited (e.g., Potter 1978, 1994; DeCelles and Hertel 1989; Johnsson et al. 1991; Graham et al. 1993; Le Pera and Critelli 1997). Models of orogenic provenance based on solid actualistic data sets are as a consequence still largely incomplete and mainly focused on mag- matic arc settings (Dickinson and Valloni 1980; Valloni 1985; Marsaglia and Ingersoll 1992). Partic- ularly scarce is quantitative mineralogical and pet- rographic information on modern sands derived Manuscript received June 2, 1999; accepted September 28, 1999. 1 Dipartimento di Scienze Geologiche e Geotecnologie, Universita ` di Milano-Bicocca, Via Emanueli 14, 20126 Milano, Italy. from ophiolitic sequences (e.g., McBride and Picard 1987; Garzanti et al. 1998), even though identifi- cation of ophiolitic detritus is of paramount im- portance in paleogeodynamic reconstructions. The first arrival of ophiolitic grains in a collisional basin allows recognition and dating of the onset of ob- duction processes and the final closure of an oce- anic seaway (e.g., Garzanti et al. 1996), whereas their changing abundance through time provides fundamental clues to reconstructing the subse- quent evolution of suture belts. The island of Cyprus, claimed to be a fragment of ocean floor now exposed on land and actually in the process of emplacement (Gass et al. 1994; Rob- ertson 1998a), is a very suitable natural laboratory for studying modern provenance to define a refer- ence for ophiolite provenance. The Troodos Massif is one of the most studied, best-preserved, most coherent, and most structurally intact ophiolites known, widely accepted as the type ophiolite. Var- ious levels of virtually unmodified oceanic litho-