3) intracratonic and basinal depression (grey)--relatively deep-water graptolitic
marls and argillites occur in most of the lower part of the Pavilosta core and at the bottom of the Ventspils core.
The distribution of microelements in Tremadoc graptolitic
argillite of Estonia.
In Tammekann's opinion, graptolitic
argillite is as soft as glauconitic sand; however, to our mind, this is not correct.
Mafic volcanic rocks, minor tuff, chert, and graptolitic
slate of the Balmoral Group are also present (Wilson 2000b, c).
The studied section starts in laminated siliceous graptolitic
shales of the Oktavites spiralis graptolite Biozone (Horny 1955).
On the geochemistry of postsedimentary mineral formation in the Tremadoc graptolitic
argillites of North Estonia.
Late Early Silurian (Wenlockian) general circulation model--generated upwelling, graptolitic
black shales, and organic-rich source rocks--An accident of plate tectonics?
These samples come from sandstones that have rather low TOC values (less than 1%) and much higher porosities than the surrounding graptolitic
shales, which could make the alternation of carbon isotopic composition of primary organic matter easier.
To illustrate the matter, Table 1 provides fairly full borehole data for a typical Ronneburg, Thuringian graptolitic
shale  and for the Sillamae  and Toolse  uraniferous argillite.
In the Ventspils borehole section, a 1 m interlayer of nodular limestone of open shelf origin occurs at this level between basinal graptolitic
argillite and clayey marlstone of the slope facies (Gailite et al.
In the same section, and 5 m above the previous graptolitic
horizon, sample Kar4 has yielded remains of linguliform brachiopods (Fig.
Morphologically the formations in the Vadja rocks resemble most of all the structures described in the petroleum-bearing deposits of the Zechstein limestone [21, 29] and macrostructures (2-10 cm) of antraconite in Ordovician graptolitic
argillite (Dictyonema Shale) of Estonian .