Late Pliocene‐early Pleistocene Athalassa Formation, north central Cyprus: carbonate sand bodies in a shallow seaway between two emerging landmasses

Abstract

The late Pliocene‐early Pleistocene Athalassa Formation accumulated within the Neogene Mesaoria basin of northern Cyprus, bordered by two subdued, but rising, landmasses, the Kyrenia Range to the north and the Troodos ophiolitic massif to the south. In the eastern part of the basin, the formation is dominated by cross‐stratified bioclastic‐rich sandstones interpreted as shallow‐marine, carbonate sand bodies. The sediments are described in terms of six calcarenite facies and subfacies and one sandstone fades. Palaeocurrent analysis indicates that the carbonate sand bodies formed near the southern margin of the Kyrenia landmass and then migrated southwards across a shallow‐marine platform. The driving force is believed to have been storms, generated by strong winds. Such winds during the late Pliocene‐early Quaternary were probably stronger than today in this area. Other factors influencing deposition of the formation include minor tectonic instability, and probable eustatic sea‐level changes. Study of the Athalassa Formation thus provides insights into late Pliocene‐Pleistocene palaeoenvironments in the easternmost Mediterranean.

Pleistocene fanglomerate deposition related to uplift of the Troodos Ophiolite, Cyprus

“…Olympos is focused within an Upper Cretaceous ocean floor graben system where intrusive ophiolitic rocks were initially exhumed to high structural level in the Upper Cretaceous (Varga and Moores, 1985). Third, some erosion already took place during the late Miocene-mid-Pliocene when relatively minor uplift took place (McCallum and Robertson, 1990). Thus, rapid uplift in the upper Pliocene soon unroofed ultramafic rocks that were channeled northward by the paleo-Karyotis River, without wider dispersal.…”

“…It is overlain by a Late Cretaceous to Miocene, predominantly deep-water, pelagic carbonate succession (Lefkara Formation), deep to shallow-marine sequences (Pakhna Formation;Robertson, 1976;Eaton and Robertson, 1993). Pliocene deposition was ini- tially fine-grained marine (Nicosia Formation), then shallow-marine (Kakkaristra Formation), to fluvial (Apalos Formation) in the upper Pliocene (McCallum, 1989;McCallum andRobertson, 1990, 1995a; Table 1). Shallow-marine carbonates of late Pliocene to early Pleistocene age (Athalassa Formation) are present in some areas (McCallum and Robertson, 1995b).…”

“…Pliocene deposition was ini- tially fine-grained marine (Nicosia Formation), then shallow-marine (Kakkaristra Formation), to fluvial (Apalos Formation) in the upper Pliocene (McCallum, 1989;McCallum andRobertson, 1990, 1995a; Table 1). Shallow-marine carbonates of late Pliocene to early Pleistocene age (Athalassa Formation) are present in some areas (McCallum and Robertson, 1995b). A shallowing-upward succession of late Pliocene age records an early stage of surface uplift of the Troodos ophiolite.…”

“…The Troodos Massif underwent partial uplift and emergence prior to the late Pliocene (Robertson, 1977;McCallum and Robertson, 1990;Robertson et al, 1991). However, intense tectonic uplift began in the late Pliocene marked, in southern Cyprus, by a sudden switch from quiet open-marine Pliocene muds and silts, to alluvial conglomerates and sands of the F1 unit (McCallum, 1989;Poole, 1992), with localized incision and channel downcutting (Houghton et al, 1990).…”

“…Recent studies of coarse alluvial deposition have particularly focused on extensional faulting and graben development (e.g., Leeder, 1993;Postma and Drinia, 1993;Collier et al, 1993), but here we focus on conglomerates shed radially from a rising point source. Previous studies of the Pleistocene of southern Cyprus, including evidence from shallow-marine and continental sediments and geomorphic erosion surfaces, have indicated that strong surface uplift of the Troodos ophiolite took place, beginning in the upper Pliocene (Robertson, 1977;McCallum and Robertson, 1990;Houghton et al, 1990;Poole and Robertson, 1991). The results of Leg 160, following geophysical surveys (Limonov et al, 1994;Robertson et al, 1995a), suggest that the overall driving force of the uplift of the Troodos ophiolite was the collision of a continental fragment, the Eratosthenes Seamount, with the active boundary of the Eurasian and African plates (i.e., the Cyprus active margin) located directly south of Cyprus (Robertson et al, 1995a, b;Emeis, Robertson, Richter, et al, 1996;Fig.…”