scholarly journals Late Holocene evolution of playa lakes in the central Ebro depression based on geophysical surveys and morpho-stratigraphic analysis of lacustrine terraces

Geomorphology ◽  
2013 ◽  
Vol 196 ◽  
pp. 177-197 ◽  
Author(s):  
F. Gutiérrez ◽  
B. Valero-Garcés ◽  
G. Desir ◽  
P. González-Sampériz ◽  
M. Gutiérrez ◽  
...  
Keyword(s):  
Late Holocene ◽  
Playa Lakes ◽  
Stratigraphic Analysis ◽  
Geophysical Surveys

First Trial Geophysical Surveys at Kintampo Open-Air Sites: Results, Recommendations, Research Prospects

2018 ◽  
Vol 16 (1) ◽  
pp. 105-115
Author(s):  
Carlos Magnavita ◽  
Friedrich Lüth ◽  
Siaw Appiah-Adu
Keyword(s):  
Pilot Study ◽  
Research Program ◽  
Late Holocene ◽  
Settlement Pattern ◽  
Northern Ghana ◽  
Geophysical Prospecting ◽  
Short Term ◽  
Research Issues ◽  
Geophysical Surveys

AbstractWithin the scope of a short-term pilot study, the authors conducted trial geophysical surveys at two sites of the late Holocene food-producing Kintampo Complex (ca. 2100-1400BC) in northern Ghana. Overall goal of research was an evaluation of the potential of employing geophysical prospecting to map the subsurface extent of Kintampo open-air settlements. From an archaeological viewpoint, the results of the surveys were satisfactory but not outstanding in view of post-depositional disturbances at the locations. Based on that knowledge, we argue for the need of developing a systematic archaeological reconnaissance and research program for locating new and virtually undisturbed open-air Kintampo sites. We maintain that such a preliminary measure will be crucial both for investigating hitherto neglected research issues such as Kintampo settlement pattern and landscape exploitation as well as allowing geophysical technologies to fully evolve as central explorative tools in regard to settlement-related spatial questions.

scholarly journals Radiocarbon Evidence for Holocene Recharge of Groundwater, Western Desert, Egypt

Radiocarbon ◽  
1980 ◽  
Vol 22 (3) ◽  
pp. 705-717 ◽  
Author(s):  
C Vance Haynes ◽  
Herbert Haas
Keyword(s):  
Ground Water ◽  
Late Holocene ◽  
Early Holocene ◽  
Western Desert ◽  
Playa Lakes ◽  
Carbon 14 ◽  
Water Analyses ◽  
Oxygen Stable Isotope ◽  
Dug Well ◽  
Apparent Age

During Pleistocene pluvial precipitation was sufficient for the maintenance of groundwater supported lakes and for the accumulation of playa lakes in wind-scoured depressions during the early Holocene pluvial. At places where ground water reaches near to the surface, wells (birs) have been dug and maintained in historic times. These birs have been used as sampling sites for water analyses, including carbon-14 levels, carbon and oxygen stable isotope ratios, tritium concentrations, and chemical data.All the waters from birs analyzed to date produced apparent radiocarbon ages ranging from late historic to early Holocene, and tritium analyses on some of these indicate no recharge during the Atomic age.Sources of error for the radiocarbon analyses, including exchange with atmospheric CO2, respiration by plant roots, and contact with carbonates of considerably older age, were evaluated. None of these factors have such an extreme impact on the measurements as to render the result invalid. Two trends revealed by these data are an increase in apparent age from northwest to southwest and with subsequent extractions at the same site where the hand-dug well was bailed out and sampled four times within two days.We conclude that recharge of shallow ground water occurred in early Holocene time, and some recharge of deeper aquifers may have occurred where infiltration paths permitted. Some recharge occurred in late Holocene (post pluvial) time, but the net trend has been toward hyper-aridity that characterizes the area today.

Integration of Multi-geophysical Approaches to Identify Potential Pathways of Heavy Metals Contamination - A Case Study in Zeida, Morocco

2020 ◽  
Vol 25 (3) ◽  
pp. 415-423
Author(s):  
Ahmed Lachhab ◽  
El Mehdi Benyassine ◽  
Mohamed Rouai ◽  
Abdelilah Dekayir ◽  
Jean C. Parisot ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Seismic Velocity ◽  
Seismic Refraction ◽  
Geophysical Methods ◽  
Low Frequency ◽  
Electrical Current ◽  
P Wave ◽  
Low Resistivity ◽  
Refraction Tomography ◽  
Geophysical Surveys

The tailings of Zeida's abandoned mine are found near the city of Midelt, in the middle of the high Moulouya watershed between the Middle and the High Atlas of Morocco. The tailings occupy an area of about 100 ha and are stored either in large mining pit lakes with clay-marl substratum or directly on a heavily fractured granite bedrock. The high contents of lead and arsenic in these tailings have transformed them into sources of pollution that disperse by wind, runoff, and seepage to the aquifer through faults and fractures. In this work, the main goal is to identify the pathways of contaminated water with heavy metals and arsenic to the local aquifers, water ponds, and Moulouya River. For this reason, geophysical surveys including electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and very low-frequency electromagnetic (VLF-EM) methods were carried out over the tailings, and directly on the substratum outside the tailings. The result obtained from combining these methods has shown that pollutants were funneled through fractures, faults, and subsurface paleochannels and contaminated the hydrological system connecting groundwater, ponds, and the river. The ERT profiles have successfully shown the location of fractures, some of which extend throughout the upper formation to depths reaching the granite. The ERT was not successful in identifying fractures directly beneath the tailings due to their low resistivity which inhibits electrical current from propagating deeper. The seismic refraction surveys have provided valuable details on the local geology, and clearly identified the thickness of the tailings and explicitly marked the boundary between the Triassic formation and the granite. It also aided in the identification of paleochannels. The tailings materials were easily identified by both their low resistivity and low P-wave velocity values. Also, both resistivity and seismic velocity values rapidly increased beneath the tailings due to the compaction of the material and lack of moisture and have proven to be effective in identifying the upper limit of the granite. Faults were found to lie along the bottom of paleochannels, which suggest that the locations of these channels were caused by these same faults. The VLF-EM surveys have shown tilt angle anomalies over fractured areas which were also evinced by low resistivity area in ERT profiles. Finally, this study showed that the three geophysical methods were complementary and in good agreement in revealing the pathways of contamination from the tailings to the local aquifer, nearby ponds and Moulouya River.

THE EVOLUTION OF THE BLACK SEA’S COASTAL ZONE OF TAMAN’ PENINSULAR IN THE LATE HOLOCENE

2015 ◽  
pp. 63
Author(s):  
A. V. Porotov ◽  
Yu. V. Gorlov ◽  
T. A. Yanina ◽  
E. Fouache
Keyword(s):  
Coastal Zone ◽  
Late Holocene
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