The Middle East regions include a number of Cambrian
rocks that are generally little known, inadequately investigated and often poorly
understood. The best known areas include regions in Iran such as in the Alborz
Mountains and in the Kerman area of the Central Iran Microcontinent, Afghanistan,
the Salt Range area in Pakistan and the Lesser Himalaya.
The regions undoubtedly were far more separated during
deposition of the sediments in the Cambrian so that that display a transition
from the West Gondwana type of Lower-Middle Cambrian depositional Grand Cycles
to East Gondwanan type lithosequences. Particularly the lithostratigraphy in
the Alborz Mountains suggests strong similarities with those known from Saudi
Arabia and even Morocco, with siliciclastics dominating the Lower Cambrian and
a pronounced regressive trend during the Early Cambrian and with a regressive
peak at the Lower-Middle Cambrian boundary interval. Although medium diverse
small
shelly fossils assemblages are known from lowermost Cambrian rocks of the
Alborz Mountains, the rest of the Lower Cambrian is virtually devoid of body
fossils. By contrast, the middle Middle Cambrian to early Ordovician rocks are
dominated by carbonates which include well developed faunas with trilobites,
brachiopods, echinoderms, mollusks, etc. Trilobite are progressively similar
to east Asian faunas.
The Salt Range is classical locality for Cambrian rocks
because it has been studied more than 100 years ago and included the first typical
Early Cambrian fossils known from Asia. The trilobite genus Redlichia, first
described from thus area, was eponymous for the Redlichiid assemblage that was
thought to characterize the "oriental faunal realm."
Lower and Middle Cambrian silicilastically dominated depositits
disconformably overlain by Ordovician to Devonian rocks in the Kerman
area, central Iran.
Copyright (c) , J. Wendt, 2002
Lower and Middle Cambrian silicilastically dominated deposits (left
and center of the slope)
overlain by Devonian rocks (note angular unconformity in the mid slope)
