The Stampede tephra: a middle Pleistocene marker bed in glacial and eolian deposits of central Alaska

1991 ◽  
Vol 28 (7) ◽  
pp. 991-1002 ◽  
Author(s):  
James E. Begét ◽  
Mary Keskinen
Keyword(s):  
River Valley ◽  
Middle Pleistocene ◽  
Alaska Range ◽  
Multiple Fault ◽  
Eolian Sediments ◽  
Eolian Deposits ◽  
Quaternary Glaciations

A deformed block of silt incorporated in a push moraine of the Lignite Creek drift of the Nenana River valley in central Alaska contains the 10 cm thick Stampede tephra. The silt block and tephra are folded, sheared, and cut by multiple fault planes and appear to have been entrained by a glacier and deformed by glaciotectonic processes while frozen. The Stampede tephra is also found in a paleosol preserved within a sequence of eolian sediments near the Tanana River some 175 km to the northeast, allowing direct tephrochronologic correlations between the depositional record of Quaternary glaciations in the Alaska Range and eolian sediments in unglaciated central Alaska. The Lignite Creek drift predates deposits of the late Wisconsin Riley Creek and penultimate Healy glaciations but postdates the Stampede tephra, indicating that it dates to the middle Quaternary, and is not part of the Tertiary Nenana Gravel Formation.

Discovery of Mazama ash in Saskatchewan, Canada

1970 ◽  
Vol 7 (6) ◽  
pp. 1579-1583 ◽  
Author(s):  
Peter P. David
Keyword(s):  
Refractive Index ◽  
Chemical Composition ◽  
Volcanic Glass ◽  
River Valley ◽  
The South ◽  
Sedimentary Environments ◽  
Ash Layer ◽  
South Saskatchewan River ◽  
Eolian Sediments ◽  
Eolian Deposits

The first known Mazama ash occurrence in Saskatchewan was discovered in eolian sediments at the top of the bluffs on the South Saskatchewan River valley 20 miles (~32 km) west of Leader, Saskatchewan. The chemical composition and the refractive index of the volcanic glass serve for the definite identification of the Mazama ash. The ash layer is a useful horizon marker in the eolian sediments, for it represents a time-break at 6 600 years ago. It is suggested that eolian deposits in similar sedimentary environments be examined for other occurrences of the Mazama ash.

scholarly journals Pleistocene horses (genus Equus) in the central Balkans

2003 ◽  
pp. 55-75 ◽  
Author(s):  
Ann Forsten ◽  
Vesna Dimitrijevic
Keyword(s):  
Late Pleistocene ◽  
River Valley ◽  
Middle Pleistocene ◽  
Mountainous Area ◽  
Migration Routes ◽  
Northern Greece ◽  
The North ◽  
Time Period ◽  
Morava River ◽  
River Valleys

A review of the fossil horses of the genus Equus from the central Balkans, a mountainous area comprising Serbia and Montenegro, is presented in this paper. The time period covered by the finds is from the late Early to and including the Late Pleistocene, but the record is not complete: the dated finds are Late Pleistocene in age, while Early and Middle Pleistocene are poorly represented. The horses found resemble those from neighbouring countries from the same time period, probably showing the importance of river valleys as migration routes. The Morava River valley runs in a roughly south-to-north direction, connecting, via the Danube and Tisa River valleys the Hungarian Pannonian Plain in the north with northern Greece in the south, via the Vardar River valley in Macedonia. In Pleistocene, large mammals, including horses, probably used this route for dispersal.

Quaternary glaciations and glacial landform evolution in the Tailan River valley, Tianshan Range, China

2015 ◽  
Vol 358 ◽  
pp. 2-11 ◽  
Author(s):  
Jingdong Zhao ◽  
Jie Wang ◽  
Jonathan M. Harbor ◽  
Shiyin Liu ◽  
Xiufeng Yin ◽  
...  
Keyword(s):  
River Valley ◽  
Landform Evolution ◽  
Glacial Landform ◽  
Quaternary Glaciations

Paleomagnetic Investigation of Lake Lahontan Sediments and Its Application for Dating Pluvial Events in the Northwestern Great Basin

1997 ◽  
Vol 47 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Joseph C. Liddicoat ◽  
Robert S. Coe
Keyword(s):  
Lake Sediment ◽  
Great Basin ◽  
Secular Variation ◽  
Lacustrine Sediments ◽  
River Valley ◽  
Middle Pleistocene ◽  
Truckee River ◽  
Pyramid Lake ◽  
Dating Methods ◽  
Paleomagnetic Secular Variation

AbstractA comparison of paleomagnetic secular variation in sediment of Pleistocene Lake Lahontan in the northwestern Great Basin with secular variation in lake sediment in the Mono Basin, California, indicates that Lake Lahontan was in the valley of the Truckee River between Pyramid Lake and Wadsworth, Nevada, from about 19,000 to 13,000 yr B.P. The secular variation in older Lake Lahontan sediment in the Truckee River valley has the general features of secular variation in middle Pleistocene lacustrine sediments near Rye Patch Dam, Nevada, 125 km to the east. On the basis of field mapping and tephrochronology, the sections of older lacustrine sediments are not coeval. The apparent, but erroneous, correlation of those sediments emphasizes the need for multiple dating methods when paleomagnetic secular variation is used to date stratigraphy.

Late Quaternary Geology and Geochronology of Diring Yuriakh, An Early Paleolithic Site in Central Siberia

1999 ◽  
Vol 51 (2) ◽  
pp. 195-211 ◽  
Author(s):  
Michael R. Waters ◽  
Steven L. Forman ◽  
James M. Pierson
Keyword(s):  
Late Quaternary ◽  
Archaeological Site ◽  
Quaternary Geology ◽  
Paleolithic Site ◽  
Lena River ◽  
Fine Grained ◽  
Early Paleolithic ◽  
Eolian Sediments ◽  
Order Of Magnitude ◽  
Eolian Deposits

AbstractDiring Yuriakh, an archaeological site on the highest terrace of the Lena River in subarctic eastern Siberia, provides evidence for the oldest and northern-most Early Paleolithic occupation in Asia. Stratigraphic and sedimentological studies at the site show that artifacts occur on a single eolian deflation surface that is underlain by fluvial sediments with inset cryogenic sand wedges and overlain by eolian deposits. Thermoluminescence ages on the fine-grained extracts from the eolian sediments and sand wedges that bound the artifact level indicate that the occupation occurred >260,000 yr B.P. and may possibly date between 270,000 and 370,000 yr B.P. This study documents that the artifacts from Diring Yuriakh are an order of magnitude older than artifacts from any previously reported site from Siberia. The antiquity and subarctic location of Diring Yuriakh indicates that people developed a subsistence strategy capable of surviving rigorous conditions in Siberia by ≥260,000 yr B.P.

Alluvial deposits evolution in the Inaouene river valley (Morocco) during late Pleistocene and Holocene epoch.

2021 ◽  
Author(s):  
Mohammed Lghamour ◽  
Lhoucine Karrat ◽  
Vincenzo Picotti ◽  
Irka Hajdas ◽  
Negar Haghipour ◽  
...  
Keyword(s):  
Organic Matter ◽  
Late Pleistocene ◽  
Ion Source ◽  
River Valley ◽  
Middle Pleistocene ◽  
Annual Rainfall ◽  
Carbonate Content ◽  
Alluvial Deposits ◽  
Homogeneous Surface ◽  
Middle Atlas

<p>      The Inaouène wadi is a river located in the northern region of Morocco. Its catchment area covers about 5124 km² with an average altitude of 800 m. The tributaries drain the marly reliefs of the Prerif in the northern side, as well as its southern ones are crossing the liasic carbonate and the Paleozoic crystalline rocks of the last Middle Atlas foothills. This region is characterised by a semi-arid Mediterranean climate influenced by the ocean oscillations, the average annual rainfall records 600 mm with a very significant spatial and interannual irregularity.</p><p>Along the major part of its flow, the Inaouène river has cut its bed between the Prerif and the Middle Atlas belts, by following the foreland corridor that separates them. From a pass (Touaher) that marks the corridor closing, the river valley widens from East to West, forming an alluvial plain with a maximum width of 5 km incised by a meandering and highly sinuous stream.</p><p>      Alluvial deposits in this valley are more developed on the Atlas side than at the Prerif foot; At least five levels representing the vestiges of the Lower and Middle Pleistocene terraces are present in the landscape.</p><p>More recent deposits occupy the valley floor, they constitute a more homogeneous surface showing low terraces abrupts and lateral limits between different sedimentary units. These alluvial deposits correspond to the terminal Pleistocene, middle and upper Holocene epoch. About 30 samples of charcoal and TOC have been selected and analysed using the  AMS 14C dating. Due to the scarcity of organic matter, some of the samples contained less than 0.1 mg of carbon and had to be analysed using the gas ion source (GIS) interface of the MICADAS (Haghipour et al., 2019; Wacker et al.,2013). 12 sections were described in the field and of which 8 sections were analysed regarding grain size, mineralogical composition, carbonate content as well as organic matter in soils and sediments.</p><p>      The analysis results indicate that the late Pleistocene is characterised by a high fluvial activity reflected by the development of braided system river and so coarse material, while fine deposits of floodplains are more abundant during the Holocene.</p><p>……...........</p><p><strong>Haghipour, N., Ausin, B., Usman, M. O., Ishikawa, N., Wacker, L., Welte, C., Ueda, K., and Eglinton, T. I., 2019, Compound-Specific Radiocarbon Analysis by Elemental Analyzer-Accelerator Mass Spectrometry: Precision and Limitations: Analytical Chemistry, v. 91, no. 3, p. 2042-2049.</strong></p><p><strong>Wacker, L., Fahrni, S., Hajdas, I., Molnar, M., Synal, H., Szidat, S., and Zhang, Y., 2013, A versatile gas interface for routine radiocarbon analysis with a gas ion source: Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions With Materials and Atoms, v. 294, p. 315-319.</strong></p>

Moraine chronosequence of the Donnelly Dome region, Alaska

2010 ◽  
Vol 74 (1) ◽  
pp. 63-72 ◽  
Author(s):  
A. Matmon ◽  
J.P. Briner ◽  
G. Carver ◽  
P. Bierman ◽  
R.C. Finkel
Keyword(s):  
Late Pleistocene ◽  
Age Distribution ◽  
River Valley ◽  
Pleistocene Glaciation ◽  
Alaska Range ◽  
Depositional Processes ◽  
Reference Locality ◽  
Northern Alaska ◽  
Exposure Ages

AbstractWe present 10Be exposure ages from moraines in the Delta River Valley, a reference locality for Pleistocene glaciation in the northern Alaska Range. The ages are from material deposited during the Delta and Donnelly glaciations, which have been correlated with MIS 6 and 2, respectively. 10Be chronology indicates that at least part of the Delta moraine stabilized during MIS 4/3, and that the Donnelly moraine stabilized ∼ 17 ka. These ages correlate with other dates from the Alaska Range and other regions in Alaska, suggesting synchronicity across Beringia during pulses of late Pleistocene glaciation. Several sample types were collected: boulders, single clasts, and gravel samples (amalgamated small clasts) from around boulders as well as from surfaces devoid of boulders. Comparing 10Be ages of these sample types reveals the influence of pre/post-depositional processes, including boulder erosion, boulder exhumation, and moraine surface lowering. These processes occur continuously but seem to accelerate during and immediately after successive glacial episodes. The result is a multi-peak age distribution indicating that once a moraine persists through subsequent glaciations the chronological significance of cosmogenic ages derived from samples collected on that moraine diminishes significantly. The absence of Holocene ages implies relatively minor exhumation and/or weathering since 12 ka.

scholarly journals Evolution of the Bystrzyca River valley during Middle Pleistocene Interglacial (Sudetic Foreland, south-western Poland)

2020 ◽  
Vol 12 (1) ◽  
pp. 1679-1703
Author(s):  
Dariusz Krzyszkowski ◽  
Lucyna Wachecka-Kotkowska ◽  
Marcin Krawczyk
Keyword(s):  
Distal Part ◽  
System Development ◽  
River System ◽  
River Valley ◽  
Oxbow Lake ◽  
Middle Pleistocene ◽  
Alluvial Deposits ◽  
The North ◽  
Study Results ◽  
Tectonic Movements

AbstractThe article depicts the problem of river system development during the Middle Pleistocene Interglacial in the Bystrzyca River Valley (Sudetic Foreland, south-western Poland). Ten research sites located within the Świdnica Plain are presented, in which the structural, grain size (granulometry), petrographic, quartz grain morphoscopy, and heavy mineral analyses were carried out. The study results show the formation of piedmont fan deposits 2–8 km to the NE of the Sudetic Marginal Fault. The location of the fluvial deposits between the Sanian and Odranian tills indicates that they were deposited during the Holsteinian Interglacial (Krzczonów Formation, Mazovian; see Table 1). According toxthe lithofacies analysis, vast alluvial plains, composed of angular gravel grains in the south and of sands in the north, were deposited in the Sudetic Foreland in the environment of a very dynamic river. They are covered with a discontinuous layer of Odranian till. The petrographic spectrum shows 90–99% of local rocks, namely, Sudetic porphyry, Sowie Mts Gneiss and milky quartz, and 1–10% of Scandinavian rocks. In the proto-Bystrzyca river system, the existence of an oxbow lake in the distal part of the Krzczonów fan has been proved, which was developing at the end of the Holsteinian Interglacial. The continuity of the alluvial deposits is interrupted in the vicinity of Świdnica due to both the tectonic movements and the formation of the narrow tectonic graben of Roztoka–Mokrzeszów.

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