This boundary is obvious not only by the carbonate content, but it is also highlighted by a fluctuations in contents of classical sediment phase and other minerals (clay minerals, glauconite
, siderite, etc.
The variability in the thickness, grain-size distribution, and glauconite
content of the Leetse Formation has been studied for years (Kleesment & Magi 1975; Magi 1970, 1984).
The following terminal limestone is finer, strongly silty and bioturbated, and contains authigenic glauconite
, indicating reduced accumulation rates and incipient condensation (e.
muscovite, hydromuscovite, illite, glauconite
, pyrophyllite, dioctahedral expansible phyllosilicates, kaolinite, and donbassite with cookeite from chlorites.
The red rocks grade in space and time into grey limestones with glauconite
grains, sometimes with reddish spots of the Tootsi Member.
DOS was mixed up with other covering deposits such as limestone, sandstone, glauconite
sandstone, pyrite and Quaternary sediments or buried under the quarry waste heaps.
The rock shows extensive fossilized worm burrows filled with glauconite
Authigenic silicate minerals, where present in lower strata, are invariably represented by glauconite
with shifts to chamosite only in intervals where the rock is lutitic.
A succession of lithofacies belts, represented by bioclastic limestones, and argillaceous limestones with glauconite
and black shales, ranges from shallow to deep shelf (Hints & Meidla 1997) and has been interpreted as a proxy of a distinct humid climate episode.
Rarer species include "anglesite," celestine, chalcopyrite,(*) enargite,(*) galena, glauconite
,(*) marcasite(*) and pyrite.
An appraisal well was drilled on the half section and is currently pumping oil at a restricted rate of 35 barrels of oil per day (bbls/d) from the Glauconite
The main natural sources of Fe in groundwater are the dissolution of iron-bearing minerals like magnetite, pyrite, siderite, amphiboles, pyroxenes, olivine, biotite, glauconite
and smectite, and the reduction of Fe-oxyhydroxides as hematite ([Fe.
Illite (I) and glauconite
(G) very often contain smectite (S) component in various amounts, show some expandability and occur as different types of interstratifications.
Starting from the lowermost boundary of the Cambrian, the situation changes: marine glauconite
, several forms of phosphates, and diagenetic pyrite (also in concretional nodules) appear in rocks.
The most attractive specimens are ones in which the heulandite rests against traces of the earthy green glauconite
layer that lined the cavities.