Compared with compositions of many other oil shales of the world , including the Estonian Paleozoic kukersite , and graptolite argillite
[15-18], the Near East oil shales have specifically high contents of carbonate (calcite), silica (quartz, in places with admixture of tridymite and cristobalite--unpublished data by the authors) and sulfur .
The overlying argillites
(Unit M5/5) have a sharp contact with sandstones.
In order to identify the clays and other minerals within the argillites
as well as sandstone matrix of the Dasht Murgha group Malthanai formation and Bostan Formation we carried out bulk mineralogical analyses on 31 samples.
It is composed of several igneous layers emplaced into argillites
The massive sulfide lenses commonly contained ribbon-like bands or large irregular masses of argillite
(mudrock), which had been silicified and mineralized.
On the lower parts of the Middle Hayden and nearby Lower Hayden brooks, about 19 km southwest of the Lower Birch Island type locality, the Lower Birch Island Member consists of about 6 metres of steeply dipping, thin-bedded, medium grey calcareous argillite
, silty argillite
and siltstone, overlying the Miramichi Group on the northwest, conformably and perhaps gradationally.
At the famous Muzo mines, the emeralds reside in deep veins of calcite, which crisscross Lower Cretaceous argillites
and layers of black, pyritiferous shale.
The topmost part of the upper Ballysteen Limestone contains lenses of Waulsortian biomicrite with associated calcarenites and argillites
and two tuff horizons also occur.
Rock units on the surface of Anomaly Ridge are primarily siliceous siltstones, argillites
, and cherts of the upper plate of the RMT and generate gold values in soil samples up to 0.
The Lower and Upper Fezouata formations consist mainly of argillites
and, together with the overlying Zini Sandstones and the Tachilla Formation, comprise the Outer Feijas Shale Group (Tremadocian to Darriwilian).
The formation is overlain by a sequence of quartzites and argillites
termed Misri Banda Formation (Pogue and Hussain 1986; Pogue et al.
Mineralogy of Tremadoc graptolitic argillites
of North Estonia.
Sedimentary incision will be presented by Neogene carbonates, Paleogene terrigenous cliffs, Valange carbonates and Paleozoic in the interval 1085-2400 m-karbonski argillites
, siltstones and sandstone with thin carboniferous layers.
The bulk of economic mineralization is hosted by quartz veins and stockwork developed within a sequence of siltstones, argillites
, and quartzites of the Upper Grass Valley Formation.
The Vine 1 occurrence is a shear-related vein system in Middle Aldridge Formation argillites