This formation is divided into two graptolite
biozones, the Corymbograptus retroflexus and Didymograptus clavulus biozones (Kraft et al.
Alum shale as well as Estonian graptolite
argillite (GA) contains remarkably high concentrations of trace metals such as U, Mo, V and Ni, but may also be locally enriched with REE, Cd, Au, Sb, As and Pt.
Les parties superieures de la Formation de Bear River dans le secteur nord-ouest et la Formation de Feltzen dans les secteurs sud-est contiennent par endroits le graptolite
Rhabdinopora flabelliformis du debut de l'Ordovicien, ce qui porte a croire que les Formations sous-jacentes d'Acacia Brook, de Cunard, de Bloomfield et de Moshers Island dateraient du Cambrien moyen au Cambrien tardif et qu'il y aurait une discordance importante entre le group de Halifax et la Formation de White Rock sus-jacente, qui date du Silurien.
This observation allows us to date in terms of graptolite
biostratigraphy also the topmost Silurian rocks in the shelly facies realm.
In Estonia the Lower Ordovician succession is represented by quartzose sandstones of the Kallavere Formation, dark laminated graptolite
argillites of the Turisalu Formation, and light claystone of the Varangu Formation of the Tremadoc Age, followed by glauconitic silts, sands or calcareous sandstones of the Leetse Formation, and glauconitic limestones of the Toila Formation of the Arenig Age (Mannil & Meidla 1994).
The studies of two vertical sequences of graptolite
argillite (GA) show the existence of pronounced fine-scale trace metal variability in GA.
org], in the sedgwickii and triangulatus graptolite
Report on graptolite
from Mactaquac, New Brunswick, collected by D.
Thus, the base of the Sixth Stage of the Ordovician System correlates with the lower to middle part of the Keila Stage in Baltoscandia, and is in close proximity to the foliaceous/clingani graptolite
Restudy of graptolite
collections of Decker (1942, 1952) from nearby wells in Crane County, Texas, indicates that dark shales (Frame Member) previously assigned to the Silurian, range from the Ludlovian (Silurian) into the Pragian (Early Devonian).
3]) was observed when the soil with a background eU concentration was overlain by a dense and thick (> 20 cm) humus horizon and there existed an additional inflow of Rn from graptolite
argillite and obolus phosphorite lying at a depth of 65-75 m.
Metallogenesis of early Paleozoic graptolite
shales from the Graefenthal Horst (Northern Bavaria-Federal Republic of Germany): Economic Geology, 81, 889-903.