Constraining the physical–chemical conditions of Pleistocene cavernous weathering in Late Paleozoic granites

Dill, Harald G.; Weber, B.; Gerdes, Axel

doi:10.1016/j.geomorph.2010.04.025

Cited by 11 publications

(3 citation statements)

References 38 publications

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“…In the past, many hypogene U-mineralizations were dated by the U-Pb method (e.g., Holliger 1991;Fayek et al 2002;Evins et al 2005;Sharpe and Fayek 2011). However, recently also supergene assemblages were dated using various techniques (Löfvendahl and Holm 1981;Maas et al 2006;Neymark and Amelin 2008;Plášil et al 2010b;Dill et al 2010;Birch et al 2011;Dill et al 2011Dill et al , 2013. Timing the supergene U-mineralizations is also important from another point of the view as it brings information about paleoclimatic conditions or changes (e.g., Dill et al 2010).…”

Section: Weathering Processesmentioning

confidence: 99%

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Plášil¹

2014

Jour. Geosci.

127

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Oxidation-hydration weathering of uraninite, the most common U-bearing mineral in nature, comprises various physical and chemical processes that lead to the destruction of the fluorite-type structure of uraninite where U is present as tetravalent. This results in replacement of uraninite by weathering products containing U in hexavalent form, i.e. as uranyl ion, UO 2 2+. The final assemblage of the weathering products, uranyl minerals, and their compositions depend on the various factors, namely the composition of the primary minerals and percolating oxidizing fluids that cause the alteration. The knowledge of such processes and stabilities of the uranium minerals is of the great interest namely due to demand for U as the energy source. During the past decade there has been substantial progress in understanding the mineralogy, crystallography and thermodynamics of uranyl minerals and thus a substantially improved understanding of the weathering processes themselves. This review aims to summarize the state-of-art of the current knowledge on uranium-related topics as well and identify some of the important questions that remain unanswered.The following text is dedicated to Jiří Čejka on occasion of his 85 th birthday anniversary. Jiří greatly contributed not only to the spectroscopy and mineralogy of uranyl minerals, but also to the questions pertaining their origin and stability. Many important issues were addressed, even if briefly, in the pioneering book "Secondary Uranium Minerals" by Čejka and Urbanec (1990) which has served, for a long-time, as a guide for beginning uranium mineralogists.

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Section: Weathering Processesmentioning

confidence: 99%

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Plášil¹

2014

Jour. Geosci.

127

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“…La importancia de la fábrica y del sistema de discontinuidades de la roca en la génesis, crecimiento y degradación de los tafoni se reconoce en los trabajos que analizan el fenómeno en diversas escalas (Baonza Díaz, 1999;McBride y Picard, 2000 o.c. ;Turkington y Phillips, 2004;De Uña Álvarez y Vidal Romaní, 2008;Dill et al, 2010). La intensidad de los efectos en la meteorización y la erosión del relieve a largo plazo está regulada por sus transformaciones dimensionales, morfológicas o funcionales.…”

Section: Figura 4 Tendencias Evolutivasunclassified

Interpretación de sistemas naturales complejos: el problema de los Tafoni

Álvarez

2012

BAGE

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“…Tafoni are the most important geomorphic landforms which were studied in the world [1][2][3][4][5][6][7]. It was observed that in the Mediterranean climate tafoni and honeycombs (THs) are more common and better developed in arid and semiarid climate conditions [8][9][10]. A wide range of conditions may control the formation and development of tafoni and honeycombs (THs) such as mineralogy [9].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Sandstone Composition on Distribution of Tafoni Landforms in the Aghajari Sandstone, Northwest of Masjed Soleyman, Iran

Ahmadi

Moghimi

Zamanzadeh

et al. 2015

Advances in Geology

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The Aghajari sandstone layers are located in the west of Zagros Mountains from several centimeters thicknesses to maximum 6 meters with carbonating content. Laboratory and fieldwork show high amount of carbonate content through sandstone layers and tafoni and honeycombs (THs) in early layers. In the study area three parameters have the most effective impactful factors in tafoni and honeycombs (THs) including matrix, carbonate content, and porosity. In this study result shows overlays of high ranges of CaCO3, porosity, and low matrix in the early layers (especially in A, B, C, D, and H layers) with tafoni and honeycombs (THs). Overall, we conclude that matrix and CaCO3(carbonate clast including carbonate lithics, fragment fossils, and Pellet) and porosity have direct relationships and matrix reverse relationships with tafoni and honeycombs (THs) in the Aghajari sandstones layers.

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Constraining the physical–chemical conditions of Pleistocene cavernous weathering in Late Paleozoic granites

Cited by 11 publications

References 38 publications

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Oxidation-hydration weathering of uraninite: the current state-of-knowledge

Interpretación de sistemas naturales complejos: el problema de los Tafoni

The Effect of Sandstone Composition on Distribution of Tafoni Landforms in the Aghajari Sandstone, Northwest of Masjed Soleyman, Iran

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