scholarly journals Pleistocene Deposits in the Southern Egyptian Sahara: Lithostratigraphic Relationships of Sediments and Landscape Dynamics at Bir Tarfawi

2017 ◽  
Vol 34 (1) ◽  
pp. 23-38
Author(s):  
Christopher L. Hill ◽  
Romuald Schild
Keyword(s):  
Groundwater Table ◽  
Middle Pleistocene ◽  
Middle Paleolithic ◽  
Stratigraphic Sequence ◽  
Climate Conditions ◽  
Green Lake ◽  
Wet Climate ◽  
Topographic Depressions ◽  
Hydrologic Conditions ◽  
Basin Fill

Abstract The sedimentological and lithostratigraphic record from north-central Bir Tarfawi documents the presence of Pleistocene basin-fill deposits. Three topographic basins were created as a result of deflation during climate episodes associated with lowering of the local groundwater table. In each case, the three deflational basins or topographic depressions were subsequently filled with sediments; these basin aggradations coincided with changes from arid climate conditions to wetter conditions and a rise in the groundwater table. The oldest and highest sedimentary remnant is associated with Acheulian artifacts and may reflect spring-fed pond and marsh conditions during a Middle Pleistocene wet climate episode. Lithofacies for a lower stratigraphic sequence (the “White Lake”) documents deposition in a perennial lake that varied in extent and depth and is associated with Middle Paleolithic artifacts. A third episode of deflation created a topographic low that has been filled with Late Pleistocene sediments that are associated with Middle Paleolithic artifacts and fossil remains. Lateral and vertical variations in the lithofacies of this basin-fill sequence and the sediments of the “grey-green” lake phases provide a record of changing hydrologic conditions. These hydrologic conditions appear to reflect variations in water-table levels related to groundwater recharge and, at times, local rains.

scholarly journals Slope Failure in a Period of Increased Landslide Activity: Sennwald Rock Avalanche, Switzerland

Geosciences ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 331
Author(s):  
Selçuk Aksay ◽  
Susan Ivy-Ochs ◽  
Kristina Hippe ◽  
Lorenz Grämiger ◽  
Christof Vockenhuber
Keyword(s):  
Slope Failure ◽  
Rock Avalanche ◽  
Eastern Alps ◽  
Rock Failure ◽  
Rhine River ◽  
Stratigraphic Sequence ◽  
Exposure Age ◽  
Wet Climate ◽  
Cosmogenic Nuclide Dating ◽  
Additional Support

The Säntis nappe is a complex fold-and-thrust structure in eastern Switzerland, consisting of numerous tectonic discontinuities and a range of hillslopes prone to landsliding and large slope failures that modify the topography irreversibly. A slope failure, namely the Sennwald rock avalanche, occurred in the southeast wall of this fold-and-thrust structure due to the rock failure of Lower Cretaceous Helvetic limestones along the Rhine River valley. In this research, this palaeolandslide is examined in a multidisciplinary approach for the first time with detection and mapping of avalanche deposits, dynamic run-out modelling and cosmogenic nuclide dating. During the rock failure, the avalanche deposits were transported down the hillslope in a spreading-deck fashion, roughly preserving the original stratigraphic sequence. The distribution of landslide deposits and surface exposure age of the rock failure support the hypothesis that the landslide was a single catastrophic event. The 36Cl surface exposure age of avalanche deposits indicates an age of 4.3 ± 0.5 ka. This time coincides with a notably wet climate period, noted as a conditioning factor for landslides across the Alps in the mid-Holocene. The contemporaneity of our event at its location in the Eastern Alps provide additional support for the contention of increased regional seismic activity in mid-Holocene.

On the issues related to the discoid cores

2017 ◽  
Vol 17 (1) ◽  
pp. 174-178
Author(s):  
Youcheng Chen ◽  
Tongli Qu
Keyword(s):  
Middle Stone Age ◽  
Middle Pleistocene ◽  
Middle Paleolithic ◽  
Stone Age ◽  
The West ◽  
Upper Pleistocene ◽  
Old World ◽  
Insight Into

AbstractThe discoid core and the Levallois core are important symbols of the Middle Paleolithic Age in the west of the Old World. The two types of artifacts show not only technical relationships but also differences. The discoid core can be classified into two sub-types, namely the unifacial and the bifacial classes. In China, discoid cores may have appeared in the upper Middle Pleistocene, and prevailed in the lower and middle Upper Pleistocene, which corresponded to the middle Paleolithic Age in Europe and to the Middle Stone Age in Africa. The discovery and study of discoid cores provide significant insight into the culture of the Middle Paleolithic Age in China.

Holocene palaeoenvironmental records from the high-altitude Wular Lake, Western Himalayas

The Holocene ◽  
2020 ◽  
Vol 30 (5) ◽  
pp. 733-743 ◽  
Author(s):  
Rayees Ahmad Shah ◽  
Hema Achyuthan ◽  
Aasif Mohmad Lone ◽  
Sanjeev Kumar ◽  
Pankaj Kumar ◽  
...  
Keyword(s):  
High Altitude ◽  
North Atlantic ◽  
Sedimentation Rate ◽  
Lake Level ◽  
Western Himalayas ◽  
Kashmir Valley ◽  
Climate Conditions ◽  
Wular Lake ◽  
Wet Climate ◽  
Lake Margin

We present a comprehensive record of Holocene (11,590–628 cal. yr BP) climate and hydrographic changes around the Wular Lake located in Kashmir Valley, India. Based on the multi-proxy investigations, we have identified three phases of wet climate conditions that prevailed from the commencement of the Holocene Epoch – 9000 cal. yr BP, 8100–6650 cal. yr BP and 6350–5000 cal. yr BP, whereas periods of dry climate were observed during 9000–8100 cal. yr BP, 6650–6350 cal. yr BP and ~5000 to 4000 cal. yr BP. The results also suggested that the lake widened and deepened significantly around 6350–5000 cal. yr BP. The results indicated desiccation and the exposure of the lake margin around 5000–4500 cal. yr BP. The sedimentation rate since 4500–628 cal. yr BP was quite low for detailed paleoclimate interpretations. Oscillations in lake extension and deepening appear to be due to changing intensity of westerly moisture in the region, and we correlate several of the low lake-level phases to the Bond events caused by North Atlantic ice rafting events.

scholarly journals Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice

2019 ◽  
Vol 13 (7) ◽  
pp. 2023-2041 ◽  
Author(s):  
Johannes Sutter ◽  
Hubertus Fischer ◽  
Klaus Grosfeld ◽  
Nanna B. Karlsson ◽  
Thomas Kleiner ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Sheet ◽  
Middle Pleistocene ◽  
Climate Modelling ◽  
Geothermal Heat ◽  
Antarctic Ice Sheet ◽  
West Antarctic Ice Sheet ◽  
Climate Conditions ◽  
West Antarctic ◽  
Pleistocene Climate

Abstract. The international endeavour to retrieve a continuous ice core, which spans the middle Pleistocene climate transition ca. 1.2–0.9 Myr ago, encompasses a multitude of field and model-based pre-site surveys. We expand on the current efforts to locate a suitable drilling site for the oldest Antarctic ice core by means of 3-D continental ice-sheet modelling. To this end, we present an ensemble of ice-sheet simulations spanning the last 2 Myr, employing transient boundary conditions derived from climate modelling and climate proxy records. We discuss the imprint of changing climate conditions, sea level and geothermal heat flux on the ice thickness, and basal conditions around previously identified sites with continuous records of old ice. Our modelling results show a range of configurational ice-sheet changes across the middle Pleistocene transition, suggesting a potential shift of the West Antarctic Ice Sheet to a marine-based configuration. Despite the middle Pleistocene climate reorganisation and associated ice-dynamic changes, we identify several regions conducive to conditions maintaining 1.5 Myr (million years) old ice, particularly around Dome Fuji, Dome C and Ridge B, which is in agreement with previous studies. This finding strengthens the notion that continuous records with such old ice do exist in previously identified regions, while we are also providing a dynamic continental ice-sheet context.

scholarly journals Excavations in the Acheulean Levels at the Earlier Stone Age Site of Canteen Koppie, Northern Province, South Africa

2012 ◽  
Vol 78 ◽  
pp. 51-71 ◽  
Author(s):  
John McNabb ◽  
Peter Beaumont
Keyword(s):  
South Africa ◽  
Middle Pleistocene ◽  
Stone Age ◽  
Considerable Time ◽  
Stratigraphic Sequence ◽  
Open Cast Mining ◽  
Core Technology ◽  
Open Cast

The fluvial gravels of the river Vaal in South Africa have long been known as a source for Earlier Stone Age (ESA) artefacts. Most were discovered through the open cast mining for diamonds that has left very littlein situfluvial sediment remaining today. The site of Canteen Koppie is an internationally famous location with a reputation for prolific Acheulean artefacts, especially handaxes and the enigmatic prepared core and Levallois-like technology known as Victoria West. Our understanding of this site, and most other Vaal locations, is almost solely based on highly selected artefact collections. Here, we report on the first controlled excavations ever to be conducted at Canteen Koppie. The deposits are likely to date to the Early and Middle Pleistocene, and our excavations sample the full depth of the stratigraphic sequence. The lower units, first identified in these excavations, add a considerable time depth to the Acheulean occupation of the site, making this the longest chrono-stratigraphic sequence in South Africa to our knowledge. Given the current international interest in the origins of Levallois/prepared core technology (PCT), its occurrence in Unit 2b Upper, and its presence alongside Victoria West technology in Unit 2a has significant implications for debates on the role of Victoria West in the origins of PCT. From the Canteen Koppie evidence, Levallois and Victoria West are clearly rooted in the Acheulean.

scholarly journals Dispersion of tongka langit banana in Buru and Seram, Maluku Province, Indonesia, based on topographic and climate factors

2020 ◽  
Vol 21 (5) ◽  
Author(s):  
HALVINA GRASELA SAIYA ◽  
Adriana Hiariej ◽  
ANNEKE PESIK ◽  
ELIZABETH KAYA ◽  
MEITTY LOUISE HEHANUSSA ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Environmental Factors ◽  
Remote Sensing And Gis ◽  
Climate Factors ◽  
Climate Data ◽  
Climate Condition ◽  
Climate Conditions ◽  
Shuttle Radar Topographic Mission ◽  
Wet Climate ◽  
Gis Methods

Abstract. Saiya HG, Hiariej A, Pesik A, Kaya E, Hehanussa ML, Puturuhu F. 2020. Dispersion of tongka langit banana in Buru and Seram, Maluku Province, Indonesia, based on topographic and climate factors. Biodiversitas 21: 2035-2046. The aim of this research is to understand the dispersion of tongka langit banana as one of the important endemic species in Maluku and also to know the topographic and climate factors hypothetically influencing the dispersion of tongka langit banana. The associated environmental factors are an initial approach that can be used to assess why the species only exists in certain locations. The data of coordinates were collected from survey activity; meanwhile, the slope and contour data were from the Shuttle Radar Topographic Mission (SRTM); and the climate data were from Meteorology, Climatology, and Geophysical Agency through statistic data publication. Then, all data were analyzed using Remote Sensing and GIS methods. The results showed that in Buru Island, tongka langit bananas were found in four locations, with climate condition was rather wet and found on slope grade of 0-8% and 8-15%. Whereas in Seram Island, tongka langit bananas were found in fifteen locations, with wet climate conditions, and on the same condition of slope as those found in Buru island.

scholarly journals Northern Mediterranean climate since the Middle Pleistocene: a 637 ka stable isotope record from Lake Ohrid (Albania/Macedonia)

2016 ◽  
Vol 13 (6) ◽  
pp. 1801-1820 ◽  
Author(s):  
Jack H. Lacey ◽  
Melanie J. Leng ◽  
Alexander Francke ◽  
Hilary J. Sloane ◽  
Antoni Milodowski ◽  
...  
Keyword(s):  
Climate Change ◽  
Isotope Composition ◽  
Biological Evolution ◽  
Winter Precipitation ◽  
Middle Pleistocene ◽  
Lake Ohrid ◽  
Climate Conditions ◽  
Glacial Sediments ◽  
Core Profile ◽  
Environmental Events

Abstract. Lake Ohrid (Macedonia/Albania) is an ancient lake with unique biodiversity and a site of global significance for investigating the influence of climate, geological, and tectonic events on the generation of endemic populations. Here, we present oxygen (δ18O) and carbon (δ13C) isotope data from carbonate over the upper 243 m of a composite core profile recovered as part of the Scientific Collaboration on Past Speciation Conditions in Lake Ohrid (SCOPSCO) project. The investigated sediment succession covers the past ca. 637 ka. Previous studies on short cores from the lake (up to 15 m, < 140 ka) have indicated the total inorganic carbon (TIC) content of sediments to be highly sensitive to climate change over the last glacial–interglacial cycle. Sediments corresponding to warmer periods contain abundant endogenic calcite; however, an overall low TIC content in glacial sediments is punctuated by discrete bands of early diagenetic authigenic siderite. Isotope measurements on endogenic calcite (δ18Oc and δ13Cc) reveal variations both between and within interglacials that suggest the lake has been subject to palaeoenvironmental change on orbital and millennial timescales. We also measured isotope ratios from authigenic siderite (δ18Os and δ13Cs) and, with the oxygen isotope composition of calcite and siderite, reconstruct δ18O of lake water (δ18Olw) over the last 637 ka. Interglacials have higher δ18Olw values when compared to glacial periods most likely due to changes in evaporation, summer temperature, the proportion of winter precipitation (snowfall), and inflow from adjacent Lake Prespa. The isotope stratigraphy suggests Lake Ohrid experienced a period of general stability from marine isotope stage (MIS) 15 to MIS 13, highlighting MIS 14 as a particularly warm glacial. Climate conditions became progressively wetter during MIS 11 and MIS 9. Interglacial periods after MIS 9 are characterised by increasingly evaporated and drier conditions through MIS 7, MIS 5, and the Holocene. Our results provide new evidence for long-term climate change in the northern Mediterranean region, which will form the basis to better understand the influence of major environmental events on biological evolution within Lake Ohrid.

scholarly journals Earliest occupation of the Central Aegean (Naxos), Greece: Implications for hominin and Homo sapiens’ behavior and dispersals

2019 ◽  
Vol 5 (10) ◽  
pp. eaax0997 ◽  
Author(s):  
Tristan Carter ◽  
Daniel A. Contreras ◽  
Justin Holcomb ◽  
Danica D. Mihailović ◽  
Panagiotis Karkanas ◽  
...  
Keyword(s):  
Homo Sapiens ◽  
Upper Paleolithic ◽  
Luminescence Dating ◽  
Middle Pleistocene ◽  
Southeast Europe ◽  
Stratigraphic Sequence ◽  
Early Upper Paleolithic ◽  
History Of ◽  
Alternative Routes ◽  
Early Upper

We present evidence of Middle Pleistocene activity in the central Aegean Basin at the chert extraction and reduction complex of Stelida (Naxos, Greece). Luminescence dating places ~9000 artifacts in a stratigraphic sequence from ~13 to 200 thousand years ago (ka ago). These artifacts include Mousterian products, which arguably provide first evidence for Neanderthals in the region. This dated material attests to a much earlier history of regional exploration than previously believed, opening the possibility of alternative routes into Southeast Europe from Anatolia (and Africa) for (i) hominins, potentially during sea level lowstands (e.g., Marine Isotope Stage 8) permitting terrestrial crossings across the Aegean, and (ii) Homo sapiens of the Early Upper Paleolithic (Aurignacian), conceivably by sea.

Sign in / Sign up

Export Citation Format

Share Document