|
Records |
Links |
|
Author |
Min, M.; Xu, H.; Chen, J.; Fayek, M. |
|
|
Title |
Evidence of uranium biomineralization in sandstone-hosted roll-front uranium deposits, northwestern China |
Type |
Journal Article |
|
Year |
2005 |
Publication |
Ore Geology Reviews |
Abbreviated Journal |
|
|
|
Volume |
26 |
Issue |
3 |
Pages |
198-206 |
|
|
Keywords |
Biomineralization, China, Roll-front uranium deposit, Sandstone |
|
|
Abstract |
We show evidence that the primary uranium minerals, uraninite and coffinite, from high-grade ore samples (U3O8\textgreater0.3%) in the Wuyiyi, Wuyier, and Wuyisan sandstone-hosted roll-front uranium deposits, Xinjiang, northwestern China were biogenically precipitated and psuedomorphically replace fungi and bacteria. Uranium (VI), which was the sole electron acceptor, was likely to have been enzymically reduced. Post-mortem accumulation of uranium may have also occurred through physio-chemical interaction between uranium and negatively-charged cellular sites, and inorganic adsorption or precipitation reactions. These results suggest that microorganisms may have played a key role in formation of the sandstone- or roll-type uranium deposits, which are among the most economically significant uranium deposits in the world. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0169-1368 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
THL @ christoph.kuells @ min_evidence_2005 |
Serial |
186 |
|
Permanent link to this record |
|
|
|
|
Author |
Lightfoot, D.R. |
|
|
Title |
Moroccan khettara: Traditional irrigation and progressive desiccation |
Type |
Journal Article |
|
Year |
1996 |
Publication |
Geoforum |
Abbreviated Journal |
|
|
|
Volume |
27 |
Issue |
2 |
Pages |
261-273 |
|
|
Keywords |
|
|
|
Abstract |
A 300 km network of khettara (qanat) subsurface irrigation channels was excavated in the Tafilalt basin beginning in the late 14th century. More than 75 of these chains provided perennial water following the breakup of the ancient city of Sijilmassa. Khettara continued to function for much of the northern oasis until the early 1970s, when new technologies and government policies forced changes. Data on origins, maintenance, and current use were collected from archival sources, aerial photographs, Landsat imagery, and from interviews. Insufficient water resources and unsustainable practices have dramatically lowered the water table, drying up khettara. This has resulted in a loss of local control over water resources, abandonment of a sustainable irrigation system, and progressive desiccation. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
0016-7185 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
THL @ christoph.kuells @ Lightfoot1996261 |
Serial |
257 |
|
Permanent link to this record |
|
|
|
|
Author |
Wolfe, P. |
|
|
Title |
The Simplex Method For Quadratic Programming |
Type |
Journal Article |
|
Year |
1959 |
Publication |
Econometrica |
Abbreviated Journal |
|
|
|
Volume |
27 |
Issue |
|
Pages |
170 |
|
|
Keywords |
|
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
|
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
THL @ christoph.kuells @ Wolfe1959 |
Serial |
285 |
|
Permanent link to this record |
|
|
|
|
Author |
Klock, H.; Külls, C.; Udluft, P. |
|
|
Title |
Estimation of relative recharge values for the northern Kalahari catchment, Namibia |
Type |
Journal Article |
|
Year |
2000 |
Publication |
Journal of African Earth Sciences |
Abbreviated Journal |
|
|
|
Volume |
30 |
Issue |
4 |
Pages |
47-48 |
|
|
Keywords |
|
|
|
Abstract |
|
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
|
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
|
Approved |
no |
|
|
Call Number |
THL @ christoph.kuells @ Klock2000estimation |
Serial |
33 |
|
Permanent link to this record |
|
|
|
|
Author |
Schwiede, M.; Duijnisveld, W.H.M.; Böttcher, J. |
|
|
Title |
Investigation of processes leading to nitrate enrichment in soils in the Kalahari Region, Botswana |
Type |
Journal Article |
|
Year |
2005 |
Publication |
Physics and Chemistry of the Earth, Parts A/B/C |
Abbreviated Journal |
|
|
|
Volume |
30 |
Issue |
11 |
Pages |
712-716 |
|
|
Keywords |
Nitrate, Arenosol soils, Semi-arid, Kalahari, Cattle, Chloride, Travel time |
|
|
Abstract |
In Southern Africa elevated nitrate concentrations are observed in mostly uninhabited semi-arid areas. In the Kalahari of Botswana groundwater locally exhibits concentrations up to 600mg/l. It is assumed, that nitrate found in the groundwater originates mainly from nitrogen input and transformations in the soils. Our investigations in the Kalahari between Serowe and Orapa show that cattle raising is an important source for enhanced nitrate concentrations in the soils (Arenosols). But also in termite mounds very high nitrate stocks were found, and under natural vegetation (acacia trees and shrubs) nitrate concentrations were mostly unexpectedly high. This nitrate enrichment in the soils poses a serious threat to the groundwater quality. However, calculated soil water age distributions in the unsaturated zone clearly show that today’s nitrate pollution of the groundwater below the investigation area could originate from natural sources, but cannot be caused by the current land use for cattle raising. |
|
|
Address |
|
|
|
Corporate Author |
|
Thesis |
|
|
|
Publisher |
|
Place of Publication |
|
Editor |
|
|
|
Language |
|
Summary Language |
|
Original Title |
|
|
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
|
Series Volume |
|
Series Issue |
|
Edition |
|
|
|
ISSN |
1474-7065 |
ISBN |
|
Medium |
|
|
|
Area |
|
Expedition |
|
Conference |
|
|
|
Notes |
Integrated Water Resources Management (IWRM) and the Millennium Development Goals: Managing Water for Peace and Prosperity |
Approved |
no |
|
|
Call Number |
THL @ christoph.kuells @ Schwiede2005712 |
Serial |
276 |
|
Permanent link to this record |