Rotations and convergence in the Northern Talesh mountains, Iran
The Talesh mountains of NW Iran
have a striking characteristic compared to associated mountain ranges
(Caucasus and Alborz mountains), as they have a dominantly N-S
strike instead of an E-W one like the larger mountain ranges.
The formation of these mountain ranges is related to collision of a
number of continental blocks following subduction of the paleo- and
neotethyan terranes, but the exact mechanism that has caused the
apparent rotation of the mountain belt remains disputed. Determining
the mechanism responsible for the current geometry of the mountain
range is a crucial step in understanding the tectonic history of the
Recent work by Chris
Kuijper has investigated vertical axis rotations of the southern Talesh range
at 3 localities, with the results suggesting an increasing clockwise rotation
of the Talesh around the Caspian Basin, resulting in a secondary curvature in
the orogen, and accounting for part of the convergence between Eurasia and
Arabia. However, the mechanism behind this rotation and the role of rigid
blocks in the collision are unclear, interpretations being hindered by the
complex faulted and folded geometry of the area, and an absence of paleomagnetic
data north of the area investigated by Kuijper.
The objective of this projectis
to better understand the tectonic history of the Talesh area and its
relationship to the Alborz range to the east and Caucasus to the west.
This requires integrating paleomagnetic and structural research. Field
research and sampling of rocks of volcanic origin will be performed in
the northern Talesh. In addition, constructing an accurate VGP
path for the Talesh requires U/Pb isotope dating is required.
The main questions which will be answered in this research are:
Does the Talesh show progressive secondary rotation along the edge of the Caspian Basin?
What is the role of strike-slip movement in acquiring the curved geometry of the Talesh?
How much convergence between Eurasia and Arabia was accomodated in the Talesh?