scholarly journals Depositional conditions on an alluvial fan at the turn of the Weichselian to the Holocene – a case study in the Żmigród Basin, southwest Poland

Geologos ◽  
2016 ◽  
Vol 22 (2) ◽  
pp. 105-120 ◽  
Author(s):  
Paweł Zieliński ◽  
Robert J. Sokołowski ◽  
Stanisław Fedorowicz ◽  
Barbara Woronko ◽  
Beata Hołub ◽  
...  
Keyword(s):  
Alluvial Fan ◽  
Luminescence Dating ◽  
Braided River ◽  
Gis Analysis ◽  
The Holocene ◽  
Sedimentary Succession ◽  
Late Weichselian ◽  
Stratigraphic Succession

Abstract Presented are the results of research into the fluvio-aeolian sedimentary succession at the site of Postolin in the Żmigród Basin, southwest Poland. Based on lithofacies analysis, textural analysis, Thermoluminescence and Infrared-Optical Stimulated Luminescence dating and GIS analysis, three lithofacies units were recognised and their stratigraphic succession identified: 1) the lower unit was deposited during the Pleni-Weichselian within a sand-bed braided river functioning under permafrost conditions within the central part of the alluvial fan; 2) the middle unit is the result of aeolian deposition and fluvial redeposition on the surface of the fan during long-term permafrost and progressive decrease of humidity of the climate at the turn of the Pleni- to the Late Weichselian; 3) the upper unit accumulated following the development of longitudinal dunes at the turn of the Late Weichselian to the Holocene; the development of dunes was interrupted twice by the form being stabilised by vegetation and soil development.

LONG-TERM RATES OF FAULTING DERIVED FROM COSMOGENIC NUCLIDES AND SHORT-TERM VARIATIONS CAUSED BY GLACIAL-INTERGLACIAL VOLUME CHANGES OF GLACIERS AND LAKES

2006 ◽  
Vol 20 (03) ◽  
pp. 261-276 ◽  
Author(s):  
RALF HETZEL ◽  
ANDREA HAMPEL
Keyword(s):  
Slip Rate ◽  
Alluvial Fan ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Slip Rates ◽  
The Holocene ◽  
Last Glacial ◽  
River Terraces ◽  
The Last Glacial

Seismic hazard evaluations on major faults in Earth's crust are based on their slip histories, which reflect the frequency of earthquakes that ruptured a fault in the past. On a 100 000-year timescale, the slip rate of a fault can be determined by dating geomorphic surfaces that are offset by a fault. Application of this method to alluvial fan surfaces and river terraces offset by thrust faults in Tibet yields long-term slip rates of less than 1mm/a. Slip rates on a 10 000-year timescale are derived from paleoseismologic data and document that faults experience considerable slip rate variations on timescales of 100 to 1000 years. In particular, slip rates are often considerable higher in the present interglacial, the Holocene, than during the last glacial period, the Late Pleistocene. The causes of this behavior have remained enigmatic but their assessment is essential for an accurate evaluation of a fault's past and future seismicity. Numerical experiments show that the retreat of lakes and glaciers at the end of the last glacial period can cause an increase in the Holocene slip rate of a fault. Such a correlation between enhanced seismicity and climate-driven mass fluctuations on Earth's surface is best documented for the Wasatch Fault, Utah.

scholarly journals QUATERNARY SOIL-GEOLOGICAL STRATIGRAPHY IN GREECE

2018 ◽  
Vol 36 (2) ◽  
pp. 856 ◽  
Author(s):  
R. Paepe ◽  
I. Mariolakos ◽  
E. Van Overloop ◽  
S. Nassopoulou ◽  
J. Hus ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Ice Age ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Middle Term ◽  
Tropical Regions ◽  
The Holocene ◽  
Of Greece

Peloponnesus and Crete are probably offering the best possible standard sections for Eastern Mediterranean Pleistocene Series. Complete Pleistocene Standard Lithostratigraphic Sections from Sparta (Peloponnesus) and Kandanos (Crete) reveal continuous Pleistocene Land Sequences composed of cyclic palaeosol levels interfering with clastic fluvial, eolian (loess) and gravel deposits comparable with analogues found elswhere over the earth. Most suitable for correlation are: a) the standard Idfess area of Northern Europe, Russia and China, and b) the subtropical and tropical regions of Africa and Asia. The standard Greek Pleistocene Lithostratigraphic Sequence independently recorded at both sites (and partially from sites in other regions of Greece) reveal a number of 103 palaeosols of both interglacial and interstadial stages, indicating the extreme warm to relative warm phases of the Pleistocene ice age. This number suits surprisingly well to the 103 levels of the equally warm odd numbered oxygen isotopie stages (OIS) of the Pleistocene deep sea record which equally encompass the warm phases of the Pleistocene. Special attention is given to the Upper Pleistocene of Koroni (Southern Peloponnesus) as a case study for the Last Interglacial - Last Glacial Cycle, i.e. the middle term cycle extending in time from 127 Ka (thousand years) till 10 Ka or beginning of the Holocene. It stands as a model for the recurrent 100 Ka cycles of the long term overall Pleistocene record. Finally, in addition to the Pleistocene, the twenty wet - dry cycles of the Holocene are reviewed.

scholarly journals Kame or Moraine? A Sedimentological Study of a Glaciomarginal Landform at Niedźwiedziny (Great Polish Lowland)

Geologos ◽  
2014 ◽  
Vol 20 (3) ◽  
pp. 167-181
Author(s):  
Aleksandra Ewert-Krzemieniewska
Keyword(s):  
Marginal Zone ◽  
High Energy ◽  
Alluvial Fan ◽  
Braided River ◽  
Gravel Pit ◽  
Facies Associations ◽  
Sedimentary Succession

Abstract A sedimentary succession in a gravel pit at Niedźwiedziny was investigated in order to determine its origin: kame or moraine. The gravel pit is located in an isolated hill of approx. 600 m long and 250–400 m wide. The succession is built of glaciofuvial deposits: a sandy/gravelly unit in the lower and middle parts, overlain by diam-icton. Five lithofacies have been distinguished, which represent two facies associations: (1) a fuvial association evolving from a high-energy to a transitional to a shallow braided river on an alluvial fan, and (2) an association of cohesive deposits representing a glacigenic mass fow. The interpretation is based mainly on palaeocurrent data and differs from conclusions by earlier investigators. The ice-marginal zone is characterised by a large variety of glaciomarginal forms. Their sedimentology, morphology and palaeogeography are determined by successive phases of deglaciation. The results of the present study show that the character of the deglaciation in the study area changed with time from frontal to areal deglaciation.

Coupled controls of climate, geology, and biota on late Pleistocene alluvial fan morphodynamics along the coast of the hyperarid Atacama Desert

2020 ◽  
Author(s):  
Janek Walk ◽  
Melanie Bartz ◽  
Georg Stauch ◽  
Mark Reyers ◽  
Steven A. Binnie ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Atacama Desert ◽  
Source Area ◽  
Alluvial Fan ◽  
Sediment Supply ◽  
Luminescence Dating ◽  
Alluvial Fans ◽  
Functional Relationships ◽  
Marine Terraces

<p>In the hyperarid environment of the Atacama Desert, alluvial fans are the principle fluvial geo-archive reflecting variations in climate and tectonics in their architecture. While they have been studied in the core of the desert to reconstruct long-term palaeoenvironmental changes from the Oligocene to the Quaternary and, in particular, to constrain the onset of hyperaridity, alluvial fans along the coast (20.5°S – 25.5°S) are younger and show a much higher activity; thus, they can serve as archives during the Pleistocene to Holocene evolution. However, past and recent morphodynamics of the coastal alluvial fans (CAF) are yet poorly reconstructed so that the understanding of an interplay between climatic, geologic, and biotic controls is still challenging.</p><p>We related climatic, lithologic, and tectonic source-area characteristics to geomorphometric parameters of the CAF and their catchments. Geomorphometric analyses were conducted based on the 12.5 m TanDEM‑X WorldDEM™, lithological and tectonic data were extracted from regional geological maps, and the frequency of heavy rainfall events derived from a regional Weather Research and Forecasting (WRF) model was used as a climate parameter. We further combined luminescence dating, cosmogenic nuclide exposure dating, and existing chronological data to constrain the timing of Pleistocene alluvial fan deposition as well as the ages of interbedded marine terraces.</p><p>Results indicate a primary climatic control on CAF dynamics shown in the functional relationships with catchment hydromorphometrics that mirror a high susceptibility to debris-flows as well as in the temporal pattern of CAF activity. Distinct phases of CAF activity occurred during the late Pleistocene (95–80 ka, 60–45 ka, and 35-20 ka) and the Holocene – driven by atmospheric changes from the Pacific Ocean. The primary source of precipitation is reflected along the latitudinal gradient: frontal systems and cut-off lows mainly originating from the extratropics. Towards the south, an increasing density of Loma vegetation can be observed so that also possible feedback mechanisms of biota on sediment supply need to be considered. While source-area lithology is of negligible relevance for CAF morphodynamics, an important long-term influence of tectonics can be seen in the regional uplift, which in turn controls the catchment shape and relief. From the numerical dating of the marine terraces, uplift rates ranging between ~0.06 and ~0.57 m/ka were derived for the late Pleistocene period.</p><p>Acknowledgement: TanDEM-X WorldDEM™ data is provided by a DLR Science grant, 2017.</p><p>References: <br>Bartz, M., Walk, J., Binnie, S.A., Brill, D., Stauch, G., Lehmkuhl, F., Hoffmeister, D., Brückner, H., in press. Late Pleistocene alluvial fan evolution along the coastal Atacama Desert (N Chile). Global and Planetary Change, 103091. https://doi.org/10.1016/j.gloplacha.2019.103091</p><p>Walk, J., Stauch, G., Reyers, M., Vásquez, P., Sepúlveda, F.A., Bartz, M., Hoffmeister, D., Brückner, H., Lehmkuhl, F., 2020. Gradients in climate, geology, and topography affecting coastal alluvial fan morphodynamics in hyperarid regions – The Atacama perspective. Global and Planetary Change 185, 102994. https://doi.org/10.1016/j.gloplacha.2019.102994</p>

scholarly journals Re-evaluating Pleistocene–Holocene occupation of cave sites in north-west Thailand: new radiocarbon and luminescence dating

Antiquity ◽  
2021 ◽  
pp. 1-18
Author(s):  
Cyler Conrad ◽  
Rasmi Shoocongdej ◽  
Ben Marwick ◽  
Joyce C. White ◽  
Cholawit Thongcharoenchaikit ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Luminescence Dating ◽  
Socioeconomic Change ◽  
Hunter Gatherers ◽  
The Holocene ◽  
North West ◽  
Highland Region ◽  
Terminal Pleistocene ◽  
Mainland Southeast Asia

Established chronologies indicate a long-term ‘Hoabinhian’ hunter-gatherer occupation of Mainland Southeast Asia during the Terminal Pleistocene to Mid-Holocene (45 000–3000 years ago). Here, the authors re-examine the ‘Hoabinhian’ sequence from north-west Thailand using new radiocarbon and luminescence data from Spirit Cave, Steep Cliff Cave and Banyan Valley Cave. The results indicate that hunter-gatherers exploited this ecologically diverse region throughout the Terminal Pleistocene and the Pleistocene–Holocene transition, and into the period during which agricultural lifeways emerged in the Holocene. Hunter-gatherers did not abandon this highland region of Thailand during periods of environmental and socioeconomic change.

Caregivers' Perceptions of Speech-Language Pathologist Talk About Child Language and Literacy Disorders

2020 ◽  
Vol 29 (4) ◽  
pp. 2049-2067
Author(s):  
Karmen L. Porter ◽  
Janna B. Oetting ◽  
Loretta Pecchioni
Keyword(s):  
Language And Literacy ◽  
Collective Case Study ◽  
Study Approach ◽  
School Aged Children ◽  
Speech Language Pathologist ◽  
Therapy Goals ◽  
Semistructured Interviews ◽  
Types Of Information

Purpose This study examined caregiver perceptions of their child's language and literacy disorder as influenced by communications with their speech-language pathologist. Method The participants were 12 caregivers of 10 school-aged children with language and literacy disorders. Employing qualitative methods, a collective case study approach was utilized in which the caregiver(s) of each child represented one case. The data came from semistructured interviews, codes emerged directly from the caregivers' responses during the interviews, and multiple coding passes using ATLAS.ti software were made until themes were evident. These themes were then further validated by conducting clinical file reviews and follow-up interviews with the caregivers. Results Caregivers' comments focused on the types of information received or not received, as well as the clarity of the information. This included information regarding their child's diagnosis, the long-term consequences of their child's disorder, and the connection between language and reading. Although caregivers were adept at describing their child's difficulties and therapy goals/objectives, their comments indicated that they struggled to understand their child's disorder in a way that was meaningful to them and their child. Conclusions The findings showed the value caregivers place on receiving clear and timely diagnostic information, as well as the complexity associated with caregivers' understanding of language and literacy disorders. The findings are discussed in terms of changes that could be made in clinical practice to better support children with language and literacy disorders and their families.

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