Magnetostratigraphy of the Apalós Formation (early Pleistocene): Evidence for pulsed uplift of Cyprus

Abstract

[1] Landscape formation on Cyprus is controlled by processes directly linked to the uplift and unroofing of the Troodos ophiolite complex since mainly early Miocene times. Understanding the island's geology and dating individual tectonic events will help in differentiating between tectonically controlled uplift and eustatic sea level or climatic changes. In order to improve the timing of these events, a magnetostratigraphic study was carried out on two terraces in the Mesaoria Basin of central Cyprus. At Vlokkariá, southwest of Nicosia, an artificial cliff exposes the sedimentary Apalós Formation of early Pleistocene age. A nearby section situated on a terrace, probably postdating the Vlokkariá section, was sampled at Kókkinos. Remanence-carrying minerals are end-member magnetite and maghemite formed by exsolution and oxidation from ophiolitic titanomagnetite. Hematite as a late alteration product is also present. Alternating field demagnetized paleomagnetic samples yield predominantly reversed polarities interpreted to have been acquired as early detrital remanent magnetization during the Matuyama chron. Two zones of normal polarity within the Apalós Formation are interpreted to correlate to the Olduvai and Jaramillo subchrons. Pre-Apalós marine sediments at the bottom of the Vlokkariá section show transitional polarity behavior and therefore might correlate with the onset of the Reunion event. Results from the Kókkinos section are exclusively of normal polarity, which has been acquired during the Brunhes chron. Sedimentation rates derived from these magnetostratigraphic results are in the order of 3-6 cm/kyr with a marked increase to 50 cm/kyr just below the MatuyamaJaramillo polarity transition, which is interpreted to reflect increased uplift of the source area and supports the hypothesis of pulsed uplift of the Troodos ophiolite complex.

Pliocene–Pleistocene sedimentary development of the syntectonic Polis graben, NW Cyprus: evidence from facies analysis, nannofossil biochronology and strontium isotope dating

“…Comparison with the Mesaoria Basin indicates that the calcareous mudstones making up the lower part of the succession in the Polis graben are lithologically similar to the Nicosia Formation. However, additional minor lithologies in the Mesaoria Basin, including conglomerates of the Kakkaristra and Apalos formations, are not known to occur in the Polis graben (Henson, Browne & McGinty, 1949; Baroz, 1979; McCallum & Robertson, 1990, 1995 b ; Schirmer et al 2010; Kinnaird, Robertson & Morris, 2011; Weber et al 2011; Palamakumbura & Robertson, 2016). The Nicosia Formation in the Mesaoria Basin is dated as Pliocene in age based on planktonic foraminifera (Lord, Panayides & Xenophontos, 2000; Harrison et al 2004).…”

“…In recent years, information on the age of the Nicosia Formation in the Mesaoria Basin has increased considerably based on micropalaeontology (e.g. Lord, Panayides & Xenophontos, 2000; Harrison et al 2004, 2008, 2013) and magnetostratigraphy (Kinnaird, Robertson & Morris, 2011; Weber et al 2011). In addition, the sedimentology and palaeoenvironments of both the Nicosia Formation (McCallum & Robertson, 1990, 1995 b ; Schirmer et al 2010) and the Athalassa Formation (McCallum & Robertson, 1995 a ; Palamakumbura & Robertson, 2016) have been investigated in some detail, although there is still scope for improved micropalaeontological dating in particular.…”

Quantitative dating of Pleistocene deposits of the Kyrenia Range, northern Cyprus: implications for timing, rates of uplift and driving mechanisms

“…The presence of non-marine, fluvial deposits (Apalos Formation) around the periphery of the Troodos Massif indicates that this area was above sea level by the Late Pliocene (McCallum & Robertson 1995a;Schirmer et al 2010;Kinnaird et al 2011;Weber et al 2011). Throughout the Mesaoria (Mesarya) Basin, the mudstone and marl facies of the Nicosia (Lefkosa) Formation pass transitionally upwards into bioclastic calcarenites of the Athalassa (Gürpınar) Formation.…”

“…Palaeomagnetic dating has previously been used to help constrain the age of Pliocene and Pleistocene shallow-marine sediments around the southern and eastern margins of the Troodos Massif (Kinnaird et al 2011;Weber et al 2011). A similar approach was adopted for the sedimentary rocks exposed within and adjacent to the Kyrenia Range during this study.…”

“…Other macrofossils including bivalves rarely provide reliable results (Van Calsteren & Thomas 2006). Magnetostratigraphy has obvious potential, following successful studies of similar deposits in the south of Cyprus (Kinnaird et al 2011;Weber et al 2011), but is dependent on the sediments preserving measurable stable magnetic remanence that is indicative of magnetic polarity (Kodama 2012). Strontium isotopic analysis is also useful but only for the dating of suitable, well-preserved fossils from an openmarine setting (Beets & De Ruig 1992;Müller 1993).…”