R. Rettori et al., Lower Carnian foraminifers from the type locality of the Calcare del Predil (Raibl Group, northeastern Italy), RIV IT PAL, 104(3), 1998, pp. 369-379
Citations number
32
Categorie Soggetti
Earth Sciences
Journal title
Rivista italiana di paleontologia e stratigrafia (Testo stampato)
Foraminiferal content from the type section of the Calcare del Predil, Earl
y Carnian in age, is here firstly reported. Dolomites, dololimestones and b
lackish limestones alternate black shales, marls and marry limestones; in a
ddition turbiditic deposits and debris flow consisting of calcirudites and
thin to coarse calcarenites occur in the stratigraphical unit. The bottom o
f the Rio der Lago Formation overlying the Calcare der Predil, was also inv
estigated from a micropaleontological point of view. Nineteen taxa were cla
ssified; they are mainly represented by Aulotortinae Zaninetti, Lamelliconi
nae Zaninetti et al., Triadodiscinae Zaninetti, Turriglomininae Zaninetti a
nd Ophthalmidiidae Wiesner. Furthermore, some Ammodiscidae Reuss, "Trochamm
inidae" Schwager, Piallinidae Rettori & Zaninetti, Duostominidae Brotzen an
d are Lagenina Delage & Herouard have been recorded. Undetermined encrustin
g foraminifers also occur. Nine taxa are in common with the lowermost pan:
of the Rio del Lago Formation. The specimens referable to the superfamily I
nvolutinacea Butschli are dominant and represent the 40% of the finely grai
ned laminas inside the black limestones. The turriglominas occurring in the
muddy lithotypes pertain to the morphogroup which is considered as typical
of basinal environment. The occurrence almost constant in the micritic lim
estones of the ophthalmidiid Gsolbergella spiroloculiformis (Oravecz-Scheff
er) (few specimens) leed to suggest this species as inhabitant basinal envi
ronment also. Two Julic species of the Austriacum zone are firstly reported
from the Aon zone (Cordevolian Auct.). The suprageneric position of the ge
nus Prorakusia di Bari & Laghi is also discussed.