Showing papers on "Ankerite published in 1971"

A Note on the Trace Element Contents of Carbonatites of a MBA Dongar and Surrounding Areas, Chhota Udaipur

Abstract: The note incorporates trace element analyses of carbonatites from Amba Dongar and surrounding areas. Mineralogical study indicates that pyrochlore is the only diagnostic mineral present in some of these rocks. Though the rare earth minerals proper are absent, the analyses reveal a fair concentration of the rare earth elements. It is therefore concluded that these elements are mainly contained in calcite and ankerite. Also, some calcareous rocks of dyke-like nature from Bakhatgarh and Dehi, suspected to be carbonatites, have been analysed. However, their trace element contents do not conclusively prove them to be so.

The petrography of the mansfield marine band cyclothem at tinsley park, sheffield

Abstract: Summary The Mansfield (Aegir) Marine Band cyclothem in the Tinsley Park area exhibits the “classical” lithological sequence: marine band, non-marine shale and mudstone, siltstone and sandstone, rootlet bed, coal. Differences between two marine band sections, which occur within a kilometre and a half of one another, are attributed to sedimentological variations across a delta front. Authigenic free silica and clay minerals are quantitatively insignificant compared with the ubiquitous detrital complement. Apart from the well-known non-detrital minerals, pyrite and siderite (as well as a collophanous mineral, and in one section, ankerite), only zircon, rutile and apatite were significant heavy minerals in the marine strata. Other heavy mineral species are more common in the upper part of the cycle. Rutile in the cyclothem is believed to be dominantly (though indirectly) detrital whereas the morphology of apatite is more in keeping with a non-detrital origin. In general, many mineralogical features are consistent with a relatively mature suite of sediments. Brief reference is also made to the possibility that the neighbouring Don Monocline was a developing structure which may have influenced deposition.