Quaternary history of Mount Olympus, Greece (original) (raw)
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Quaternary glacial history of Mount Olympus, Greece
Geological Society of America Bulletin, 1997
Erosional and depositional evidence on Mount Olympus, Greece, and across the adjacent piedmont provides clear indication that the mountain was more extensively glaciated over a longer period of time than has been previously reported. The stratigraphic record of Pleistocene-Holocene events on Mount Olympus is most clearly documented on the eastern piedmont, where three discrete sedimentary packages (units 1-3), each capped by a distinctive soil, reflect glacial and nonglacial activity in the Mount Olympus region. A working stratigraphic framework for sediments and soils is proposed and is tentatively correlated with a dated alluvial succession south of Mount Olympus. We suggest that the oldest sedimentary package (unit 1) predates 200 ka (isotope stage 8?). Lithologic and pedologic equivalents of the piedmont stratigraphy are found within major valleys draining Mount Olympus, as well as within cirque basins and on the summit plateau surface. These deposits can be clearly tied to three stages of cirque development on the upland and at valley heads. Taken together, upland and piedmont glacial features and deposits indicate the following general scenario: (1) earliest glaciation (isotope stage 8?) produced upland ice and valley glaciers that extended as piedmont lobes east, north, and west of Mount Olympus; (2) nonglacial (interglacial) conditions (isotope stage 7?) were accompanied by extensive erosion and subsequent pedogenesis; (3) a second glaciation (isotope stage 6?) involved production of upland ice and valley glaciers that did not reach the piedmont; (4) interglacial (interstadial) conditions (isotope stage 5?) provided time for stream erosion and substantial pedogenesis; (5) final(?) glaciation (isotope stages 4-2?) was restricted to valley heads (no upland ice) and glaciers that extended to mid-valley positions; (6) nonglacial conditions (isotope stage 1?) were associated with additional pedogenesis and stream incision. The largest cirque on the mountain (Megali Kazania) may contain depositional evidence for neoglaciation. Study of the neotectonic history of the Mount Olympus region indicates that uplift has persisted throughout the mid-Pleistocene and Holocene at a rate of about 1.6 m/k.y.; the total uplift since deposition of unit 2 is approximately 200 m.
Postcollisional Tectonics and Magmatism in the Eastern Mediterranean Region edited by Y. Dilek and S. Pavlides. , 2006
Evidence of former equilibrium line elevations on Mount Olympus, Greece, coupled with estimates of uplift rate, point to more extensive Pleistocene glaciation and far colder climates than previous studies have indicated. These findings are supported by the record of glacial deposition both on the mountain and across the adjacent pied-mont. The data not only provide evidence of significant equilibrium line altitude depression from a present-day elevation as much as 600 m above the mountain's summit (2917 m), but also show that Mount Olympus was glaciated on several occasions, and that the first episode of glaciation significantly predated the late Pleistocene. Piedmont sediments east and west of Mount Olympus record three discrete stages of deposition, each of which can be related to glacial activity on the mountain. Soils that separate these sedimentary units correspond to nonglacial intervals and can be correlated to a dated soil succession south of Olympus. This correlation suggests that the oldest soils correspond to the isotope stage 7 (Mindel/Riss) interglacial event (ca. 210,000 yr before present; U/Th disequilibrium) and that the oldest Pleistocene sediments record isotope stage 8 (Mindel) glaciation in the Olympus region. Subsequent stages of deposition are interpreted to record glaciation on the mountain during the isotope stage 6 (Riss) and isotope stages 4–2 (Würm) glacial events. Sedimentary units defined on the piedmont are also recognized on the Olympus upland and within valley-head cirques, where they correspond to three stages of cirque development. The distribution of these materials, as well as the occurrence of glacial erosional and depositional landforms, indicates that Mount Olympus supported up-land ice during the first and second episodes of glaciation and that the first glaciation was sufficiently extensive to produce piedmont ice lobes that covered parts of the eastern , northern, and western piedmont of the mountain.
Geomorphologic and paleoclimatic evidence of Holocene glaciation on Mount Olympus, Greece
This study investigates the possibility of Holocene glaciation on Mount Olympus (Greece) with a respective local temperature–precipitation equilibrium line altitude (TP-ELA) at c. 2200 m a.s.l., based on geomorphologic and paleoclimatic evidence. At present, the local TP-ELA is situated above the mountain’s summit (c. 2918 m a.s.l.), but permanent snowfields and ice bodies survive within Megala Kazania cirque between c. 2400 and c. 2300 m a.s.l., because of the cirque’s maritime setting that results from its close proximity (c. 18 km) to the Aegean Sea and of the local topographical controls. The snow and ice bodies occupied a considerably larger area and attained a stabilization phase between AD 1960 and 1980, also manifested from aerial photographs, a period characterized by increased winter precipitation (Pw) with subsequent TP-ELA depression to c. 2410 m a.s.l. Mid- to late-20thcentury Pw and TP-ELA variations exhibit negative correlations with the winter North Atlantic Oscillation index (NAOw) at annual and multidecadal (30 years) timescales. Late Holocene (AD 1680–1860) reconstructed summer mean temperatures were lower by Ts < 1.1°C in relation to the reference period between AD 1960 and 1980 and were also superimposed to negative NAOw phases, thus bracketing this time interval as a favorable one to glacial formation and/or advance. Millennial-scale annual precipitation reconstructions at the hypothesized TP-ELA (c. 2200 m a.s.l.) point the period between 8 and 4 kyr BP as another glacier-friendly candidate. The mid-Holocene rather simplistic sequence of potential glacial advance phase was disturbed by short-lived cold climatic deteriorations, well-documented over the northern Aegean region that may partly explain the multicrested shape of the highest (c. 2200 m a.s.l.) morainic complex of Megala Kazania cirque.
Pleistocene glacial and lacustrine activity in the southern part of Mount Olympus (central Greece)
Area, 2016
Glacial activity affects landscape evolution in some parts of mountainous Greece. This paper deals with the southern part of Mount Olympus where the geomorphological impacts of Pleistocene glaciations are well presented. It is a preliminary study to demonstrate the landscape that has evolved as a result of glacial activity in these uplands. For this purpose, detailed field work and large-scale geomorphological mapping were performed. A 25-m sediment core was retrieved from the study area on which preliminary lithological and micropalaeontological-palaeobotanical analyses were performed. The intense glacial activity of the southern Mount Olympus area produced a number of landscape changes. Three cirques were identified in the uplands whose evolution has led to the formation of various types of moraines (ground, lateral, medial and terminal) down to an altitude of 1677 m. Intense glacio-fluvial activity caused a major reconfiguration of the drainage network in this area and also caused the formation of a lake. The occurrence of a water body in the area is documented by the presence of aquatic vegetation in parts of a 25-m core retrieved from this former lake basin. In recent times, the lake overtopped the fluvial deposits that bounded it, incising them and leading to the emptying of the lake.
Neogene–Recent extension on the eastern flank of Mount Olympus, Greece
2010
The Olympus massif of NE Greece comprises metamorphosed and deformed Triassic and Cretaceous–Eocene carbonates considered to represent part of the passive southwestern margin of Neotethys, which separated the Apulia plate of mainland Greece from southern Europe in the Mesozoic. Ocean closure in the Early Tertiary led to subduction of this passive margin, as a result of which the Olympus carbonates were tectonically overridden in the Eocene by a series of thrust sheets consisting of locally high P/T (blueschist) metamorphosed continental margin sediments, basement granitoid gneisses, and ophiolitic rocks. Following collision, uplift of the Olympus carbonates by ~ 6–8 km was accomplished by Early Neogene ductile and Late Neogene–Recent brittle normal faulting, which exposed the carbonates in the form of a structural window through the overriding thrust stack. The focus of this exhumation occurred on the eastern flank of the massif where a thick calc–mylonite with down-to-the-east sense-of-shear indicators and a prominent zone of NNW-to NW-trending brittle normal faults separate the carbonates from telescoped structurally overlying units. Published 40 Ar/ 39 Ar microcline ages that indicate a thermal perturbation close to the contact zone in excess of 100–150 °C at 16–23 Ma (Early Miocene) are taken to date the onset of ductile extension, and imply long-term uplift rates of ~ 0.4 to 1 km/m.y. Degradation of Pleistocene glacial features on the Olympus massif and the presence on its eastern piedmont of deeply incised streams, erosional terraces, and fault scarps that offset the sedimentary deposits of three cycles of Pleistocene glacial deposition (Units 1–3), testify to its continuing uplift. A prominent frontal fault offsets Unit 2 by > 150 m and several subsidiary NW-trending normal faults with a cumulative displacement of ~ 130 m offset a paleosol developed on Unit 1. Kinematic indicators indicate normal dip-slip movement. Cumulative fault displacement for Unit 1 exceeds 277 m, yielding a minimum uplift rate of ~ 1.3 mm/yr, given the oxygen isotope stage 7 (Mindel/Riss) age of 210 ka proposed for the Unit 1 paleosol. Cumulative offset of > 196 m for the paleosol developed on Unit 2 yields an uplift rate of ~ 1.6 mm/yr, given its proposed isotope stage 5e (Riss/Würm) age of 125 ka. This estimate is supported by longitudinal valley profile data that document ~ 200 m of stream incision since Unit 2 deposition and show the offset as reflecting uplift of the Olympus massif rather than subsidence of the adjacent Gulf of Thermaikos. Assuming 1.8 Ma for the base of the Pleistocene, these rates yield a total uplift range for the Quaternary of 2.3–4.1 km, consistent with the present 2.6 km height of Olympus above the exposed frontal fault. Neogene uplift of Olympus was likely facilitated by extension accompanying the opening of the Aegean back-arc basin during the Miocene as a result of the southward retreat of the Hellenic subduction zone. For the Pliocene–Recent, uplift was likely facilitated by extension linked to the termination of dextral motion at the western end of the North Anatolian Fault associated with the westward tectonic escape of Anatolia.
Last glacial geomorphologic records in Mt Chelmos, North Peloponnesus, Greece
Journal of Mountain Science, 2018
This study deals with the analysis of the glacial processes that have affected the relief of Mt Chelmos in northern Peloponnesus, Greece during middle and Late Pleistocene. The goal was to compile a combined geomorphological-geological map of the study area which would enable the chronological stratification of the glacial landforms cropping up on Mt. Chelmos. Chronological stratification was further aided by optically stimulated luminescence (OSL) dating. The map served as the basis upon which the reconstruction and discussion on the phases of the Middle-Late Quaternary paleoclimatic history of Mt. Chelmos have been made. A sophisticated semi-automated method was first used to analyze the Digital Elevation Model (DEM), combined with Aster, Quickbird and ALOS imagery in order to identify glacial and periglacial, as well as karstic features. Then, these features along with other nonrecognizable features from the remote-sensing images were documented in the field. In this way, several glacial landforms were identified, such as moraines and cirques, indicating extended glaciation phases during the middle and Late Pleistocene. Additionally, a ground moraine located at an altitude of 1900-2050 m, within the Spanolakos glacial valley, was dated using the OSL-dating method. The resulting ages indicate a phase of glacier advance/stabilization during MIS-5b (89-86 ka), which is in consistence with pollenrecord evidence from Greece and the Mediterranean.
In situ produced cosmogenic 36 Cl Surface exposure dating (SED) Glacial phases Late-glacial Holocene Northeast Mediterranean Mount Olympus Greece a b s t r a c t In this study, we present a new glacial chronology based on 20 in situ-produced 36 Cl-based cosmic ray exposure datings from moraine boulders and bedrock from the Throne of Zeus (TZ) and Megala Kazania (MK) cirques on Mount Olympus. The 36 Cl derived ages of glacial landforms range from 15.6 ± 2.0 to 0.64 ± 0.08 ka, spanning the Late-glacial and the Holocene. The Late-glacial, recorded in both cirques, is partitioned in three distinct phases (LG1-3): an initial phase of moraine stabilization at 15.5 ± 2.0 ka with subsequent deglaciation starting at ~14 ka (LG1), followed by a shift to marginal conditions for glaciation at 13.5 ± 2.0 ka (LG2), sustained by large amounts of wind-blown snow, despite regional warming. Glacial conditions returned at 12.5 ± 1.5 ka (LG3) and were characterized by low air temperatures and glacier shrinking. The Holocene glacial phases (HOL1-3) are recorded only in the MK cirque, likely due to its topographic attributes. An early Holocene glacier stillstand (HOL1) at 9.6 ± 1.1 ka follows the regional temperatures recovery. No glacier activity is observed during the mid-Holocene. The Late Holocene glacier expansions, include a moraine stabilization phase (HOL2) at 2.5 ± 0.3 ka, during wet conditions and solar insolation minima, while (HOL3) corresponds to the early part of the Little Ice Age (0.64 ± 0.08ka). Our glacial chronology is coherent with glacial chronologies from several cirques along the northeast Mediterranean mountains and in pace with numerous proxies from terrestrial and marine systems from the north Aegean Sea.
The Glacial History of the Pindus Mountains, Greece
The Journal of Geology, 2006
Geomorphological evidence for Pleistocene glaciation has been mapped in the Pindus Mountains of northwest Greece, and the chronology of glaciation in this area has been established through soil profile analysis and U-series dating of secondary carbonates (calcite) formed within glacial deposits. Three glacial stages are evident in the sedimentological and geomorphological records. The earliest and most extensive recorded glaciation predates 350,000 yr B.P. and was characterized by extensive valley glaciers and ice fields. A more recent glaciation occurred before the last interglacial and was characterized by glaciers that reached midvalley positions. The last phase of glaciation in Greece is recorded by small cirque glacier moraines and relict periglacial rock glaciers. The glacial and periglacial sequence on Mount Tymphi has been used in conjunction with a reference parastratotype, the long lacustrine sequence at Ioannina, to provide a chronostratigraphical framework for cold-stage deposits in Greece. The three glacial stages are formally defined: the Skamnellian Stage, equivalent to the Elsterian Stage of northern Europe and marine isotope stage (MIS) 12; the Vlasian Stage, equivalent to the late Saalian Stage of northern Europe and MIS 6; and the Tymphian Stage, which is equivalent to the Weichselian/Wü rmian stages of northern Europe and the Alps, respectively, and MIS 5d-2. This is the first formalized chronostratigraphical framework based on the glacial record to be established for cold stages in the Mediterranean and provides a new platform for paleoclimatological investigations in the region.
EarthArXiv (California Digital Library), 2023
Soil formation in Mediterranean periglacial landscapes remains poorly understood as the interplay between erosion and aeolian dust accretion in providing parent materials, and mineral weathering and pedogenesis, as dominant post depositional processes, depends on a variety of local and regional factors. Herein, we investigate the balance between erosion and aeolian dust accretion in the formation of an alpine soil profile along an erosional gradient in the periglacial zone of Mount Olympus in Greece. We applied a wide range of analytical methods to 23 samples, from a soil profile developed in a glaciokarstic plateau, from colluvial sediment horizons interbedded in postglacial scree slopes and from modern Sahara dust samples deposited on the snowpack. Colluvial sediment horizons exhibit high concentrations of calcite rich sand and represent the local erosion products. The soil B horizon developed on a glaciokarstic plateau contains high amounts of fine earth and is rich in quartz, mica, plagioclase, clays, and Fe-Ti oxides. Based on its physical and textural characteristics the soil profile is partitioned in a surficial weathered Bw and a lower illuvial Bt horizon that overlies the local regolith composed of fragmented glacial till and slope wash deposits. Radiogenic isotope systematics, textural and mineralogical analysis show that the contribution of Sahara and locally sourced dust to the development of the soil B horizon ranges between 50 and 65%. Cryoturbation results in fine earth translocation from Bw to the Bt horizon, whereas weak pedogenetic modifications of aeolian and bedrock-derived minerals result in magnetic mineral weathering and secondary clay formation. Our findings reveal that, aeolian dust accretion is the dominant process in providing alpine soil parent material and that cryoturbation, weak pedogenesis, and clay mineral alteration occur within the Mediterranean periglacial zone of Mount Olympus.