Results 21 to 30 of about 313 (146)

Distinguishing pedogenic and non-pedogenic silcretes in the landscape and geological record [PDF]

, 2016
Silcrete is a type of duricrust formed by the near-surface accumulation of secondary silica within a soil, sediment, rock or weathered material. A variety of models of formation have been put forward, involving silicification in both pedogenic and non ...
Nash, David; id_orcid, Ullyott, John
core   +1 more source

A numerical model for duricrust formation by water table fluctuations [PDF]

Earth Surface Dynamics
Duricrusts are hard mineral layers forming in climatically contrasted environments. They form in tropical to arid environments and can be currently observed all around the world in areas such as Europe, Africa, South America, India, and Australia.
C. Fenske, C. Fenske, J. Braun, J. Braun, F. Guillocheau, C. Robin   +5 more
doaj   +1 more source

Cathodoluminescence and electron probe micro-analysis of silcretes and puddingstones: towards a better understanding of silcretization and sourcing quartzitic materials

, 2016
International audienceWe have investigated quartz cement in silcretes and puddingstones from uppermost Paleocene to lowermost Eocene, terrestrial to coastal and shallow marine sediments in north France and Belgium using cathodoluminescence (CL) and trace
Baele, J.M., Quesnel, Florence, Dupuis, C.   +2 more
core   +1 more source

Silcretes of Central Australia [PDF]

Nature, 1964
THE widespread occurrence in central Australia of silcrete which there caps numerous mesas and forms extensive stony pavements on the dissection slopes below them has long awaited a satisfactory explanation. A recent recording1 of the nature and disposition of certain lateritic and desertic soils, taken in conjunction with the location of major ...
openaire   +1 more source

From Highlands to Henge: Refining the Provenance and Transport Pathways of Stonehenge's Altar Stone

Journal of Quaternary Science, EarlyView.
ABSTRACT The Altar Stone, the 6000 kg central sandstone megalith at Stonehenge in southern England, is suggested to have originated from the Orcadian Basin in northeast Scotland, some 700 km away. However, its source location within this large basin remains unresolved and its mode of transport uncertain.
Anthony J. I. Clarke, Remy L. J. Veness, Christopher L. Kirkland, Chris D. Clark, Niall Gandy, Andy Emery, Sarah L. Bradley, Jeremy C. Ely, Ignéczi Ádám   +8 more
wiley   +1 more source

Lithic analysis in African archaeology: Advances and key themes

Archaeometry, EarlyView.
Abstract Stone artifacts (lithics) preserve for extended periods; thus they are key evidence for probing the evolution of human technological behaviors. Africa boasts the oldest record of stone artifacts, spanning 3.3 Ma, rare instances of ethnographic stone tool‐making, and stone tool archives from diverse ecological settings, making it an anchor for ...
Deborah I. Olszewski, Amanuel Beyin, Justin Pargeter   +2 more
wiley   +1 more source

Under the Shade of a Coolabah Tree: A Second Cache of Tulas From the Boulia District, Western Queensland

Archaeology in Oceania, Volume 61, Issue 1, Page 39-54, April 2026.
ABSTRACT This paper reports on the excavation of a cache of stone artefacts, buried on the bank of a waterhole or ‘billabong’ in central western Queensland. This is an extremely rare find, and yet it is the second such site to be reported within less than a 10 km radius.
Yinika L. Perston, Lynley A. Wallis, Heather Burke, Lorna Bogdanek, Trevina Rogers, Justine Kemp   +5 more
wiley   +1 more source

Lithic Miniaturization Provides a Signature of an MIS4‐3 Southern Dispersal of Homo sapiens

Evolutionary Anthropology: Issues, News, and Reviews, Volume 35, Issue 1, March 2026.
ABSTRACT Fossil and artefactual evidence shows Homo sapiens in Eurasia well before 75 ka. However, genetic evidence suggests all extant non‐African populations derive almost all of their ancestry from a dispersal that only diverged in the last 60–50 ka. In northern Eurasia, the Upper Paleolithic with its laminar blade knapping provides an archeological
Ceri Shipton
wiley   +1 more source

Origin and K/Ar age of cryptomelane-bearing Sn placers on silcretes, SE Germany

, 2012
During the early Miocene (Aquitanian-Burdigalian) an alluvial-fluvial drainage system evolved along the boundary fault of the Munchberg Gneiss Complex in SE Germany.
Wemmer, Klaus, Dill, Harald G.
core   +1 more source

Aeolian and Biogeochemical Transformations of Detrital Gold Morphology in the Pool Burn Basin, Central Otago, New Zealand

New Zealand Journal of Geology and Geophysics, Volume 69, Issue 1, March 2026.
The Pool Burn basin is a tectonic depression that became almost isolated from the regional drainage system by river reorientation during Pleistocene uplift of surrounding ridges. Consequently, detrital gold in the basin was largely locally derived, from supergene zones on orogenic deposits and recycled from paleoplacers in erosional remnants of Miocene
Marshall Palmer, Dave Craw
wiley   +1 more source