Late Quaternary Floodplain History of the Brazos River in East-Central Texas

1995 ◽  
Vol 43 (3) ◽  
pp. 311-319 ◽  
Author(s):  
Michael R. Waters ◽  
Lee C. Nordt
Keyword(s):  
Late Quaternary ◽  
Thick Layer ◽  
Soil Formation ◽  
Coarse Grained ◽  
Vertical Accretion ◽  
Brazos River ◽  
East Central ◽  
Central Texas ◽  
History Of ◽  
Quaternary History

AbstractThe floodplain along a 75-km segment of the Brazos River, traversing the Gulf Coastal Plain of Texas, has a complex late Quaternary history. From 18,000 to 8500 yr B.P., the Brazos River was a competent meandering stream that migrated from one side of the floodplain to the other, creating a thick layer of coarse-grained lateral accretion deposits. After 8500 yr B.P., the hydrologic regime of the Brazos River changed. The river became an underfit meandering stream that repeatedly became confined within narrow and unstable meander belts that would occasionally avulse. Avulsion occurred four times; first at 8100 yr B.P., then at 2500 yr B.P., again around 500 yr B.P., and finally around 300 yr B.P. The depositional regime on the floodplain also changed after 8500 yr B.P., with floodplain construction dominated by vertical accretion. Most vertical accretion occurred from 8100 to 4200 yr B.P. and from 2500 to 1250 yr B.P. Two major and three minor periods of soil formation are documented in the floodplain sequence. The two most developed soils formed from 4200 to 2500 yr B.P. and from around 1250 to 500 yr B.P. These changes on the floodplain appear to be the result not of a single factor, but of the complex interplay among changes in climate, sediment yield, and intrinsic floodplain variables over time.

The Late Quaternary history of east-central Ireland

1978 ◽  
Vol 115 (6) ◽  
pp. 397-413 ◽  
Author(s):  
A. M. McCabe ◽  
P. G. Hoare
Keyword(s):  
Large Scale ◽  
Late Quaternary ◽  
Entire Area ◽  
East Central ◽  
Ice Caps ◽  
The North ◽  
Organic Horizons ◽  
History Of ◽  
Complex Sequences ◽  
Quaternary History

SummaryThe drift succession in east-central Ireland is the result of a series of ice movements spreading from major centres of dispersion within theIrish Sea Basin and over the north-central Irish plain, and from local mountain sources. These glaciations have produced laterally and vertically complex sequences of deposits. The large-scale events influenced almost the entire area; problems of correlation emerge when considering episodes of relatively restricted extent such as those associated with upland ice-caps in the S and the hitherto unreported readvances which interrupted the withdrawalof ice-sheets across the northern part of the region under examination. Thetask of assigning the older units to particular Quaternary cold stages is frustrated by the absence of interstratified organic horizons. Two possible models of glaciation are considered: one may be regarded as ‘traditional’; the other requires a much shorter period of time by assuming that the stratigraphy records differences in the relative strengths of essentially contemporaneous ice-masses.

Late Quaternary history of colluvial deposition and erosion in hollows, central California Coast Ranges

1990 ◽  
Vol 102 (7) ◽  
pp. 969-982 ◽  
Author(s):  
STEVEN L. RENEAU ◽  
WILLIAM E. DIETRICH ◽  
DOUGLAS J. DONAHUE ◽  
A. J. TIMOTHY JULL ◽  
MEYER RUBIN
Keyword(s):  
Late Quaternary ◽  
California Coast ◽  
Central California ◽  
History Of ◽  
Quaternary History ◽  
Coast Ranges ◽  
California Coast Ranges

Late Quaternary Geological History of the Dead Sea Area, Israel

1993 ◽  
Vol 39 (1) ◽  
pp. 59-67 ◽  
Author(s):  
Y. Yechieli ◽  
M. Magaritz ◽  
Y. Levy ◽  
U. Weber ◽  
U. Kafri ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Thick Layer ◽  
Time Frame ◽  
Dead Sea ◽  
Polar Regions ◽  
Geological History ◽  
The Holocene ◽  
History Of ◽  
The Dead ◽  
Sea Area

AbstractA 34.5 m borehole, which was drilled near the Dead Sea coast (altitude -394 m) in the southern part of the fan delta of Wadi Zeelim, reveals the geological history of that area from the latest Pleistocene to present. The depositional time frame is based on six 14C dates and two U-Th dates. An erosional (or nondepositional) period is implied by the hiatus between 21,100 yr B.P. (U-Th age, depth 33 m) and 11,315 yr B.P. (14C age, depth 32 m). A subsequent arid phase is recorded by a 6.5-m-thick layer of halite; based on 14C dates this phase relates to the abrupt Younger Dryas cold period reported in temperate to polar regions. The fragility of the environment in this region is indicated by the fact that the region experienced such a severe, short aridification phase (less than 1000 yr), evidence of which is found widely in the desert fringes of the Middle East and North Africa. The aragonite found in most of the Holocene section indicates that the well site was covered by the lake for most of the Holocene. Exceptions are the intervals at 0-3 and 10-14 m depths which represent low stands of the lake.

Late Quaternary glacial and interglacial environments of the Nechako River - Cheslatta Lake area, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 719-731 ◽  
Author(s):  
A Plouffe ◽  
V M Levson
Keyword(s):  
British Columbia ◽  
Late Quaternary ◽  
Late Glacial ◽  
Lake Area ◽  
Glacial Lakes ◽  
Ice Flow ◽  
Coast Mountains ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Quaternary History

The Quaternary stratigraphy of the Nechako River – Cheslatta Lake area of central British Columbia is described and interpreted to reconstruct the late Quaternary history of the region. Exposures of glacial and nonglacial sediments deposited prior to the last glaciation (Fraser) are limited to three sites. Pollen assemblages from pre-Fraser nonglacial sediments at two of these sites reveal forested conditions around 39 000 BP. During the advance phase of the Fraser Glaciation, glacial lakes were ponded when trunk glaciers blocked some tributary valleys. Early in the glaciation, the drainage was free in easterly draining valleys. Subsequently, the easterly drainage was blocked either locally by sediments and ice or as a result of impoundment of the Fraser River and its tributaries east of the study area. Ice generally moved east and northeast from accumulation zones in the Coast Mountains. Ice flow was influenced by topography. Major late-glacial lakes developed in the Nechako River valley and the Knewstubb Lake region because potential drainage routes were blocked by ice.

The physical geography and geology of the estuary and Firth of Forth, Scotland

1987 ◽  
Vol 93 (3-4) ◽  
pp. 235-244 ◽  
Author(s):  
Michael A. E. Browne
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Physical Geography ◽  
Glacial Till ◽  
Estuarine Sediments ◽  
Volcanic Origin ◽  
Quaternary Glaciation ◽  
History Of ◽  
Quaternary History ◽  
Firth Of Forth

SynopsisThe Upper Palaeozoic bedrock, which is of sedimentary and volcanic origin, is briefly described. The origin of the Forth as a series of depressions in the bedrock surface probably owes much to erosion of a pre-existing Tertiary landscape during phases of Quaternary glaciation. The late Quaternary history of the area is described, relating the distribution of the sediments deposited in the Forth to climatic events and changes in relative sea-level. Since the acme of the last main glaciation about 20,000 years ago, late Devensian marine and estuarine sediments have been deposited on the underlying glacial till sheet at altitudes ranging from more than 120 m below O.D. to at least 46 m above O.D. Similarly, raised and buried beaches and their deposits occur at altitudes from 40 m above O.D. down to around 10 m below O.D. in the estuary. During the Flandrian, sea-level has fluctuated, reaching its maximum (about 11 to 15 m above O.D.) about 6500 years ago. The typical deposit of this period is the carse clay which forms a series of extensive, fertile raised mudflats around the estuary. The calcareous marine faunas of the carse clay and older deposits are outlined.

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