Results 31 to 40 of about 313 (146)

Désilicification et quartzification par altération des grès albiens du Gard. Modèles géochimiques de la genèse des dalles quartzitiques et silcretes

, 1976
Quartzite und Sandsteine unterlagen Veränderungen, die durch zwei aufeinanderfolgende geoche-mische Mechanismen verursacht wurden. Der erste löst den Quarz, bildet den Glaukonit um und Kaolinit und Goethit neu : das ist die Umbildung glaukonithaltiger ...
Georges Millot, Millot, Georges, Bertrand Fritz, Parron, Claude, Hélène Paquet, Dahon, Daniel, Fritz, Bertrand, Paquet, Hélène, Claude Parron, Daniel Dahon   +9 more
core   +1 more source

Habitat Modification by Grazing Lawns Reduces Soil Mite Diversity in a South African National Park

African Journal of Ecology, Volume 64, Issue 2, March 2026.
ABSTRACT Soil mesofauna are an integral part of the functioning of an ecosystem. They are relatively small in body size, occur in varying habitats and operate in a range of ecological niches. Soil mites are quite sensitive to changes in their environment and contribute to several important ecosystem services in their environments.
Claire Grootboom, Igshaan Samuels, Adriaan Engelbrecht, Mmoto Masubelele   +3 more
wiley   +1 more source

Siliceous duricrusts as palaeoclimatic indicators:evidence from the Kalahari desert of Botswana

, 1994
Previous attempts to identify the environmental conditions associated with the development of siliceous duricrusts have used differences in bulk chemical compositions and cement mineralogy amongst other criteria to distinguish between samples.
Nash, David J.; id_orcid, Thomas, David S.G., Shaw, Paul A.   +2 more
core   +1 more source

Burn Selection: How Fire Injury Shaped Human Evolution

BioEssays, Volume 48, Issue 2, February 2026.
Intentional fire use exposed humans and their ancestors to high‐temperature burn injury, a risk rare in other species, bringing major survival benefits and technologies but also repeated exposure to extreme heat. The Burn Selection Hypothesis reframes this cost of fire mastery as a unique selective pressure, which shaped our evolution.
Joshua Cuddihy, Yuemin Li, Isobel Fisher, Zoltan Takats, Dominic Friston, Declan Collins, Marcela Vizcaychipi, Matteo Fumagalli, Istvan Nagy, Armand Leroi   +9 more
wiley   +1 more source

On Sourcing Stonehenge Sarsen Stone #58: A Response to Nash and Ciborowski's Comments

Archaeometry, Volume 68, Issue 1, Page 48-50, February 2026.
ABSTRACT This is a brief response to Nash and Ciborowski's comments in 2025 on our 2024 paper, which focused on the reinterpretation of geochemical data for Stonehenge stone #58 published by Nash et al. in 2020. We address the problems they perceived in our use of absolute elemental concentrations, our selection of discriminating elements, and single ...
R. G. V. Hancock, M. P. Gorton, W. C. Mahaney, S. Aufreiter, K. Michelaki   +4 more
wiley   +1 more source

Drainage-line silcretes of the Middle Kalahari:An analogue for Cenozoic sarsen trains?

, 1998
This paper describes models put forward to explain the development of silcretes within drainage lines at the distal end of the Okavango Delta system in the Middle Kalahari of Botswana, and proposes that they provide an analogue for the formation of ...
Nash, David J.; id_orcid, Shaw, Paul A., Ullyott, Stewart   +2 more
core   +1 more source

Evaluating Simulated Groundwater Contributions to Streamflow in a Data‐Scarce, Semi‐Arid Catchment in South Africa

Hydrological Processes, Volume 40, Issue 1, January 2026.
Calibration procedure selection should be carefully considered in data‐scarce circumstances, as good model efficiency does not necessarily guarantee a realistic representation of hydrological processes. Stable isotopes proved effective in validating model results and detecting shortcomings in the J2000 model caused by sparse hydroclimatic data and the ...
Marlene de Witt, Christian Birkel, Francois Roets, Andrew Watson   +3 more
wiley   +1 more source

Comment on: 'Stonehenge revisited: A geochemical approach to interpreting the geographical source of sarsen stone #58'

Archaeometry, Volume 67, Issue 6, Page 1423-1436, December 2025.
Abstract In a recent paper in this journal (Hancock et al. (2024) Stonehenge revisited: A geochemical approach to interpreting the geographical source of sarsen stone #58. Archaeometry https://www.doi.org/10.1111/arcm.12999), Hancock and colleagues present a reanalysis of the geochemical dataset used to identify the likely source for the majority of ...
David J. Nash, T. Jake R. Ciborowski
wiley   +1 more source

Raw Material Economisation in Aotearoa New Zealand: Evidence for Manufacture and Recycling of Adzes on Ahuahu Great Mercury Island

Archaeology in Oceania, Volume 60, Issue 3, Page 220-233, October 2025.
ABSTRACT Raw materials are used to characterise the early settlement of Aotearoa Te Wai Pounamu New Zealand by Māori. Current models suggest change in raw material use over time occurred in response to changing social organisation and reduced resource availability. However, few studies have examined spatial variation in raw material use.
Rebecca Phillipps, Joshua Emmitt, Stacey Middleton, Simon Holdaway   +3 more
wiley   +1 more source

Hydrated Silica in Oxia Planum, Mars

Journal of Geophysical Research: Planets, Volume 130, Issue 9, September 2025.
Abstract Hydrated silica (SiO2·nH2O; opal) is important for understanding the geological and aqueous history and habitability of Mars, owing to its genesis in a wide range of aqueous environments and its high biosignature preservation potential relative to other hydrated minerals.
Joseph D. McNeil, Peter Grindrod, Livio L. Tornabene, Peter Fawdon, Vidhya Ganesh Rangarajan   +4 more
wiley   +1 more source