Tertiary uplift history of the Troodos massif, Cyprus A.H.F. ROBERTSON* Department of Geology, University of Cambridge, Sedgwick Museum, Downing Street, Cambridge CB2 3EQ, England ABSTRACT INTRODUCTION Troodos massif that he took as an indica- tion of possible subaerial exposure. The detailed uplift history of a portion of In the recent debate about the mech- Subsequently, in Maastrichtian time, the Late Cretaceous Tethyan oceanic litho- anisms of formation and subsequent de- open oceanic stage in the evolution of the sphère is documented by in situ sedimentary formation of the Troodos massif of Cyprus, Troodos massif was terminated by major sequences around the Troodos massif of little account has been taken of the various tectonic movements that simultaneously af- Cyprus. The pre-uplift tectonic setting first in situ Upper Cretaceous and Tertiary fected the whole belt stretching from Greece involved genesis of the Troodos massif at a sedimentary sequences that are exposed through Cyprus to Oman and beyond spreading ocean ridge of Late Cretaceous around the perimeter of the Troodos mas- (Smith, 1971). In the south and southwest age, followed by deformation in Maas- sif. This paper has two main objectives. of Cyprus, substantial thrust sheets and trichtian time. Then, after a brief period of First, it outlines the sedimentary develop- mélange were emplaced directly over the latest Cretaceous deep-water pelagic ment of southern Cyprus in the Tertiary Troodos ocean floor. This deformation is sedimentation, much of the area was blan- Period, of interest to many working in the suggestive of subduction and a trench envi- keted in early Tertiary time by a wedge of East Mediterranean. Secondly, on a more ronment, as will be discussed elsewhere. pelagic carbonates derived from the north- general level, it documents the uplift of the When these tectonic movements came to an east. Gradual uplift to the middle Miocene Troodos oceanic lithosphere from near end later during Maastrichtian time, the is documented by shallowing-upward car- oceanic depths in the Early Cretaceous to entire south margin of the Troodos massif bonate sequences culminating in lagoons the present altitude of Mount Olympos, was left tectonically sliced, tilted en masse and localized reefs that were adjacent to more than 2,000 m. It emerges that this to the southwest, and under a deep cover of emergent areas of vegetated and deeply final uplift is the antecedent of a long his- sea water, as indicated by the pelagic nature weathered Troodos rocks. tory of episodic uplift, subsidence, erosion, of the marls and chalks that began to ac- A pulse of vastly accelerated middle and peneplanation. The dominant driving cumulate soon afterward. With this re- Miocene uplift is recorded by slumping, force here is believed to involve periodic gional tectonic setting as a background, I widespread erosion, and folding of the serpentinization of parts of Troodos ultra- now pass on to a more detailed discussion south Troodos sedimentary sequences. This mafic rocks during periods of regional of the later uplift history of the Troodos uplift was associated with rapid deposition tectonic instability. This represents one im- massif. of both clastic and carbonate sediments in portant general mechanism of uplifting subsiding basins to the south. The Miocene oceanic lithosphere to the relatively high Late Maastrichtian: Deep-Water uplift culminated in localized reef develop- structural levels needed to facilitate the Calcareous Sedimentation ment and gypsum deposition, then perva- emplacement of ophiolites. sive peneplanation of the Troodos massif. Immediately after emplacement of the In contrast, much of the Troodos massif Stratigraphy of the Cyprus Sedimentary allochthonous rocks, calcareous pelagic remained low-lying and tectonically stable Deposits sediments began to accumulate over the during Pliocene time, whereas to the north, Throughout this paper reference is made whole area as if nothing had happened. sedimentary basins developed along high- to the provisional stratigraphic nomencla- Where the Troodos massif had escaped the angle faults initiated during the late ture as set out by Mantis (1970; Table 1). earlier deformation, as around the east and Miocene emplacement of the adjacent This stratigraphy is still under review by north of the massif, the basal marls and Kyrenia Range. Major uplifts during the members of the Cyprus Geological Survey chalks of the Lower Lefkara Formation (see Pleistocene epoch were renewed, as shown Department. Mantis, 1970, and Robertson and Hudson, by thick deposits of marine and continental 1974, for stratigraphic details, also Table 1) fanglomerates. Late Cretaceous Tectonic Setting were ponded into broad hollows inherited The uplift of Troodos oceanic crust is at- from the earlier ocean-ridge setting. These tributed to the progressive serpentinization The scene initially was set for the Tertiary sediments were deposited as finely lami- of ultramafic rocks of the oceanic layer 4. uplift of Troodos by the ocean-floor genesis nated nannoplankton and planktonic These rocks, which were first deformed and of the Troodos massif (Gass and Masson- foraminiferal and radiolarian oozes, free of partly serpentinized in Late Cretaceous Smith, 1963; Moores and Vine, 1971; Vine macrofossils except fish teeth. Sedimentary time, were subsequently remobilized during and others, 1973). As early as the Campan- features point to deep-water deposition periods of regional tectonic instability, ian, lateral facies variations of in situ se- close to the carbonate compensation depth especially during the middle Miocene and quences of pelagic (Perapedhi Formation) (Robertson and Hudson, 1974). Pleistocene. The dominant driving force and volcanogenic sediments (Kannaviou In contrast, in the south of Cyprus, the may have involved the liberation of water Formation, Table 1) show that parts of the Maastrichtian marl-chalk sequences locally from a subduction zone dipping northward present Troodos massif were already topo- reach very much greater thicknesses, partly beneath Cyprus. graphically elevated relative to the sur- owing to an addition from erosion of the rounding areas. Indeed, de Vaumas (1959) newly emplaced allochthonous rocks. For described peneplaned surfaces of pre- example, north of Monagroulli, Limassol * Present address: Grant Institute of Geology, Tertiary age in the Akamas Peninsula and District (Fig. 1), the basal several hundred West Mains Road, Edinburgh EH93JW, Scotland. around the northern margins of the metres of the Lefkara sequence consist of Geological Society of America Bulletin, v. 88, p. 1763-1772, 4 figs., 1 table, December 1977, Doc. no. 71208. 1763 Downloaded from http://pubs.geoscienceworld.org/gsa/gsabulletin/article-pdf/88/12/1763/3418490/i0016-7606-88-12-1763.pdf by guest on 29 September 2021 1764 A.H.F. ROBERTSON TABLE 1. BASIC STRATIGRAPHIC alternations of massive silty chalks and Eocene sedimentary deposits appear to be NOMENCLATURE OF IN SITU finely laminated argillaceous marls. These thin or absent. For example, near Aredhiou, SEDIMENTARY COVER OF sediments contain abundant silt-sized Paleocene and lower Eocene chalks are quartz, chert, and clasts of low-grade overlain disconformably by Oligocene TROODOS MASSIF metamorphic rocks, all presumably derived marls of the Upper Lefkara Formation. - O FANGLOM- Y from erosion of the Moni Mélange, an ad- In general, throughout the middle E ERATE & jacent body which was emplaced earlier in Eocene, the south margin of the Troodos CEN BeachDeoosits UATER MAR Û-LEIST the Maastrichtian. massif still remained under relatively deep but gradually shallowing seas, whereas at. Paleocene and Early Eocene: Gradually areas to the north were already relatively 0. < z a. t/> Shallowing Seas elevated, undergoing only minimal LU 3 sedimentation, possibly some submarine o 8 < CU z S In Cyprus, as in many other areas of the erosion. o LLf Oä ad < Mediterranean, Danian sediments have not < been recognized (Mantis, 1975, personal Oligocene to Early Miocene: Localized UJ O. 1 s! 14 commun.), presumably owing to non- Subaerial Exposure Q£ Í deposition (see Worsley, 1971). In some a. areas, as in the Troulli inlier, Nicosia Dis- From Oligocene to early Miocene time, in a. 2 3 trict, several laterally continuous chert beds many areas there was continued accumula- occur near the top of the Maastrichtian se- tion of marls and chalks in seas that prog- quence in otherwise unsilicified chalks and ressively retreated until some areas were LU UJ marls. These cherts may represent either exposed subaerially. The disappearance of •7/ enhanced radiolarian productivity or the Radiolaria, which are abundant in the UJ M preferential dissolution of CaC03, possibly Eocene chalks, may have been due to a re- z < owing to a period of relatively elevated car- striction of the seas around Cyprus from E « z - bonate compensation depth. open oceanic circulation farther east. Three L GYPSU O E During Paleocene and early Eocene time, main areas of sedimentation that can be z LU X CONGLOMER calcareous pelagic sedimentation was suc- recognized are (1) south and east of * «o E ceeded by the accumulation of a thick se- Troodos: shallow seas and lagoons; (2) Od quence of calciturbidites and possible con- north margin of Troodos: unrestricted DD O u l < tourites along the southeastern margins of carbonate-depositing seas; and (3) north- O the Troodos massif (Fig. 2). In general, the west of Troodos: emergence, erosion, and a. CALCARENIT M SANDSTON