In addition, the critical nano-scale structural differences will be determined between abiologic artefacts such as carbon coatings on botryoidal quartz or adsorbed carbon on silica biomorphs and true microfossils in hydrothermal cherts
Two periods of searing-hot hydrothermal activity had cooked both the seafloor cherts
and the surface glacial sediments.
Most are a variety of cryptocrystalline silicates, divided into fibrous chalcedony, granular cherts
, and microcrystalline silicates (MCS), distinguished by coarser grains visible under a hand lens.
In this regard, he suggested construction of a railway that would link the Balajan deposit of cherts
and the Balachichkana deposit of iron ore.
The phosphate beds are thick to thin and are associated with Cherts
at most of the places.
Francis Mountain rhyolite (fine to coarse-grained; pink, red, green, gray; massive or flow banded, pebble to cobble size), Keokuk geodes (cauliflower cherts
lined inside with rock crystal quartz, quartz druse, or chalcedony; pebble to large cobble size), sandstone (fine to coarse-grained; white, pink, red, green, gray; cobble to boulder size; some sandstones are loosely cemented as a result of quartz overgrowths displaying prismatic crystal faces on individual grains and commonly containing authigenic feldspars), Arkose and weathered granite (pink, coarse-grained, pebble to cobble size, very rare), quartz (milky, pink, clear, gray; pebble to large cobble size).
Kneller had developed an extensive reference collection of Ohio and North American cherts
with accompanying thin sections, Ohio coal pellets, and maceral photographs.
The basinward (western) facies is very fine-grained to medium-grained, sparsely cherty limestone and dolomite to almost pure chert
and represents the Grassy Knob and Clear Creek Cherts
The rocks exposed at the Hale Creek mine are typical of the Franciscan-Knoxville group of late Jurassic age and consist of sandstones, shales, cherts
, greenstones and graywackes.
remarked that "The similarity of isotopic composition of these Permian cherts
to younger cherts
suggests that [.
Of particular interest, drilling in holes F-05-03 and two holes currently in progress in Q2-2006 (F-05-4, F-05-05) on Metco properties 1-2 km northeast of the Horne-Quemont Mines, have intersected Horne Rhyolite, cherts
and exhalite-sulphide-bearing rocks typical of the Horne Mine stratigraphy.
While ED-XRF has traditionally been used for sourcing obsidian and other volcanic rocks (Shackley, 2011b), recent studies show that it is also a useful method for establishing the geochemical signatures of cherts