Deposits are ranging from shallow-water carbonate facies in the west to deep-water graptolitic
shales and cherts in the east (Wenzel 1997).
von Helmersen started his field studies of the 1838 summer in Keila-Joa and classified the "burning stone" discovered there as graptolitic
argillite which had no industrial value .
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).
Although a deep-water anoxic environment similar to that of the Silurian organic-rich graptolitic
shales (Radkovets 2015) is not evident there, oxygen-poor environments must have existed locally.
They grade to the Aeronian graptolitic
black shales with rare clayey limestones.
Late Early Silurian (Wenlockian) general circulation model--generated upwelling, graptolitic
black shales, and organic-rich source rocks--An accident of plate tectonics?
(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 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.
The Dalmanitina Member, a limestone bed between the graptolitic
shales, may correspond to the second major glacial episode of the Hirnantian glaciations, the mid-Hirnantian glacial episode, equivalent to the stratigraphic position of the Kuanyinchiao Bed in South China in the stratotype section of the Hirnantian Stage.
On the geochemistry of postsedimentary mineral formation in the Tremadoc graptolitic
argillites of North Estonia.