Beginning Of Late Pleistocene Research Articles

New volcanological and palethnological data from Avetrana site (Southern Italy)

This work describes the Mousterian lithic artifacts found in the Avetrana karst filling (Apulia), among the oldest of southern Italy. A volcanoclastic layer found at the base of Bed 8, in the highest part of the stratigraphic succession, is also described. The compositional characteristics of the glasses of this volcanoclastic layer indicate a possible area of origin in the Mount Vulture volcano, and allow us to suggest that it is an aeolian fallout that occurred during or immediately after a late eruption of the Mount Vulture, probably within the 132 ± 10 ka time span. The chronological result relating to the volcanoclastic sediments would place the underlying beds in the last Interglacial, MIS 5e, and the overlying Bed 8 at the onset of last Glacial period, MIS 5d. Moreover, it is in agreement with the paleoclimatic considerations based on the ecological and biogeographical features of mammal assemblages and it has a very important significance also for the biochronology of the Pleistocene. In fact, it allows us to confirm that some taxa found in the Avetrana succession, such as Crocidura gr. suaveolens, Arvicola italicus, the evolved form of Microtus (Terricola) gr. savii, and the modern form of Dama dama, occur for first time in Italy at the beginning of Late Pleistocene.

Geomorphological features of Marmara Sea Islands

The Sea of Marmara is located on a continental crust. The Sea of Marmara, which is a remnant of the Sarmasien period of the Miocene Sea, is an inland sea (Okay, 2007). It opens to the Black Sea with the Bosphorus and the Aegean Sea with the Dardanelles. Its surface area is 11 111 km2 (Gazioğlu, et al., 2002) and its average depth ranges from -200 to -500 m (Doğanay, 1997). At the end of the third time, and at the beginning of the fourth time, there were crumbs and crashes arising from the earth crust movements in and around, where this sea lies today (İzbırak, 1996).In the Marmara Sea, the oldest sediments were deposited as a result of the transformation of the Marmara Sea from a lacustrine environment to a marine environment with the Mediterranean Tyrenian transgression at the end of Middle Pleistocene. When the sea level in the Sea of Marmara is at the same or higher than the present day, water passage from the Black Sea has occurred. At the beginning of Late Pleistocene, as a result of a sudden drop in world sea level, the water passage from the Marmara Sea to the Mediterranean was cut and the marine sedimentation environment was replaced by lacustrine sedimentation. At the beginning of Late Pleistocene (between 64.000-59.000 BC), Mediterranean waters entered the Sea of Marmara and the Black Sea with the sudden rise of sea level (Algan, et al., 2011 ). After the transgression, the gulfs and islands in the Sea of Marmara were formed.

HADJOH-2: A MIDDLE PALEOLITHIC WORKSHOP-CAMP IN NORTHWESTERN CAUCASUS

This article outlines the results of a multidisciplinary study of a stratifi ed Middle Paleolithic site Hadjoh-2, northwestern Caucasus, situated at the outcrop of high-quality Shahan fl int. During fi ve fi eld seasons, more than 6-meter deep deposits were excavated over an area of ca 33 sq. m. Ten lithological strata and four habitation horizons were identifi ed. Excavations focused on the bottom layers 6 and 7. During their accumulation, the site occupied a fl oodplain terrace on the right bank of the Sredniy Hadjoh River, a right tributary of the Belaya. Because the terrace dates to the Middle/Late Pleistocene boundary, the site is no earlier than the beginning of Late Pleistocene, 130–120 ka BP. Results of pollen analysis suggest that the climate was cold and dry, and subalpine and alpine meadows prevailed around the site at that time. The study of lithic assemblages shows that the bottom layers accumulated when the site was a workshop near the fl int outcrops. In both layers, knapping debris such as cores, chips, and small fragments predominate. Most tools are unfi nished bifacial forms. These assemblages are paralleled by the Eastern Micoquian industries of Mezmaiskaya, Barakaevskaya, Monasheskaya, and Ilskaya.

Geomorphic disequilibrium in the Eastern Korean Peninsula: Possible evidence for reactivation of a rift-flank margin

Tectonically inactive since the middle Miocene, the Korean Peninsula is generally considered a typical passive continental margin with asymmetric relief with only low levels of seismic activity. Recent reports of uplift rates as high as 150–350mmka−1 from geomorphic markers using numerical dating methods (e.g. radiocarbon, optically stimulated luminescence (OSL), and cosmogenic nuclides), however, cast doubt on the tectonic quiescence of Korea. Thus, we evaluate the geomorphic status of eastern Korea using denudation rates at geomorphic timescales of 103–106years, which are equivalent to the rates previously reported at local points. To infer regional denudation rates, we measured catchment-wide denudation rates (CWDR) in 13 watersheds using in situ cosmogenic 10Be and 14C analyses of riverine sediment samples in eastern Korea. These CWDR data suggest that the mean denudation rate during the past 5–14ka centers around ~74.7±25.4mm·ka−1, which is consistent with the long-term, geologic exhumation rate we derive of ~74±10.1mm·ka−1 since the middle Miocene. However, our CWDR data are ~2–3 times lower than rates of coastal uplift and river incision of 150–350mm·ka−1 derived from data on marine and fluvial terraces, respectively. In addition to isotopic analyses, we quantified topographic indices such as elevation, relief, and slope, and then compared these indices with CWDRs to examine morphological changes that might be related to tectonic disturbances since the beginning of late Pleistocene. The relationship between CWDRs and topographic indices indicates that most of the study area rests in a near steady-state condition. However, in contrast to the smooth concave longitudinal profile expected for a steady-state landscape, topographic analyses reveal the presence of major knickzones (confirmed by field reconnaissance). These knickzones may have been produced by changes in base level caused by tectonic events, lithologic variations or sea-level changes. Our 1-D modeling of knickpoint propagation suggests that tectonic disturbance is the factor most likely to produce knickzones in the study area, raising the possibility that erosional signals caused by late-Pleistocene tectonic disturbance affected channel gradients, but that the knickpoints have not yet propagated through the entire catchment area. Our results suggest that the eastern part of the Korean Peninsula is approaching, but has not completely reached, a geomorphic steady-state, and that transient conditions have been induced by reactivation of the rift-flank margin no later than the late Pleistocene, causing tilting of the central Korean Peninsula to the west at a rate of 7.0×10−10m/m per year over the past ~125ka.

The roles of rivers and Pleistocene refugia in shaping genetic diversity in Praomys misonnei in tropical Africa

Aim This study aims to elucidate the phylogeography of the murid rodent Praomys misonnei and to document whether or not rain forest refugia and rivers structure patterns of diversity within this species. Location Tropical Africa, from Ghana to Kenya. Methods Patterns of genetic structure and signatures of population history (cytochrome b gene) were assessed in a survey of 229 individuals from 54 localities. Using maximum likelihood, Bayesian, network and genetic structure analyses, we inferred intra-specific relationships and tested hypotheses for historical patterns of gene flow within P. misonnei. Results Our phylogenetic analyses reveal a strong phylogeographical structure. We identified four major geographical clades within P. misonnei: one clade in Ghana and Benin, a Nigerian clade, a West Central African clade and a Central and East African clade. Several subclades were identified within these four major clades. A signal of population expansion was detected in most clades or subclades. Coalescence within all of the major clades of P. misonnei occurred during the Middle Pleistocene and/or the beginning of Late Pleistocene. Main conclusions Our results suggest a role for both Pleistocene refugia and rivers in structuring genetic diversity in P. misonnei. This forest-dwelling rodent may have been isolated in a number of forest fragments during arid periods and expanded its range during wetter periods. Potential forest refugia may have been localized in Benin-Ghana, south-western Cameroon, southern Gabon, northern Gabon and eastern Democratic Republic of Congo-western Uganda. The Niger and/or the Cross Rivers, the Oubangui-Congo, Sanaga, Ogooue and/or Ivindo Rivers probably stopped the re-expansion of the species from relict areas.