Rock Varnish and the Manganese Oxide Connection
نویسندگان
چکیده
منابع مشابه
Oxidation State of Manganese in Rock Varnish
Rock varnish is generally understood to be a 5-500 micrometer thick nanostratigraphic coating consisting of approximately 70% clay glued together by 30% iron and manganese oxides, which forms on the surfaces of rocks in most semi-arid to hyper-arid climates. Many investigators believe that manganese exists in rock varnish mainly as birnessite, and that varnish has at least a partial biological ...
متن کاملCharacterization of manganese oxide mineralogy in rock varnish and dendrites using X-ray absorption spectroscopy
Rock varnish is a dark-colored Mnand Fe-rich coating that forms on exposed rock surfaces in almost every terrestrial weathering environment, particularly in arid and semiarid regions. Varnishes average about 100 μm in thickness but can reach thicknesses of several hundred micrometers, with accumulation rates of 1–15 μm/1000 years (Liu and Dorn 1996). Rock varnishes have attracted considerable r...
متن کاملAstrobiological implications of rock varnish in Tibet.
The study of terrestrial geomicrobiology and its relationship to rock weathering processes is an essential tool in developing analogues for similar processes that may have occurred on Mars. Most studies of manganese-enhanced rock varnish have focused on samples taken from warm arid desert regions. Here, we examine samples obtained from eolian-abraded lava flows of the 4700-4800 m high Ashikule ...
متن کاملPreliminary XPEEM Analysis of Rock Varnish
We have performed preliminary mapping of the manganese and iron present in a cross-section of a rock varnish from the Cima volcanic flows in the Mojave Desert, California. Rock varnish is a nanostratigraphic deposit found on typically fine-grained rocks in hyper-arid to semi-arid deserts (Figure 1a) [1]. Rock varnish is defined as consisting of about 70% clay particles held together by about 30...
متن کاملThe influence of mineral detritus on rock varnish formation
1875-9637/$ see front matter 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.aeolia.2013.04.005 ⇑ Corresponding author. E-mail addresses: [email protected] (R.I. Dorn), [email protected] (D.H. Krinsley), [email protected] (K.A. Langworthy), [email protected] (J. Ditto), [email protected] (T.J. Thompson). Ronald I. Dorn a,⇑, David H. Krinsley , Kurt A. Langworthy , Jef...
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ژورنال
عنوان ژورنال: Analytical Chemistry
سال: 2005
ISSN: 0003-2700,1520-6882
DOI: 10.1021/ac053494x