6 research outputs found
New radiolarian biostratigraphic age constraints on Middle Triassic basalts and radiolarites from the Inner Hellenides (Northern Pindos and Othris Mountains, Northern Greece) and their implications for the geodynamic evolution of the early Mesozoic Neotethys
The Avdella Me´lange in the northern Pindos
Mountains and its equivalent formation, the Loggitsion Unit
in the Othris Mountains expose early Mesozoic (Mid-Late
Triassic) oceanic fragments beneath the Western Greek
Ophiolite Belt of the Inner Hellenides, Northern Greece. The
me´lange consists of locally interfingering blocks and slices
of ribbon radiolarite, radiolarian chert and pillow basalt and
is usually overthrust by Jurassic ophiolites. New Middle and
Upper Triassic radiolarian biostratigraphic data are presented
from radiolarites and basalt-radiolarite sequences
within me´lange blocks. Pillow basalts associated with the
radiolarites provide clues to the opening of the Neotethyan
ocean basin. The radiolarians indicate a Middle Triassic
age (latest Anisian, probably early Illyrian), which is
documented for the first time in the northern Pindos Mountains.
The new radiolarian biostratigraphic data suggest that
rift-type basalt volcanism already began in pre-Ladinian
time (late Scythian?—Anisian). These basalts were then
overlain by Upper Anisian to Carnian (?Norian) radiolarites