期刊名称：IOP Conference Series: Earth and Environmental Science
印刷版ISSN：1755-1307
电子版ISSN：1755-1315
出版年度：2008
卷号：2
出版社：IOP Publishing
摘要：The Arabian plate has been converging with Eurasia for 20-30 Ma, currently at
2-3 cm/year. Convergence is manifested differently along strike, with collision
and tectonic escape in the west (Anatolia) and subduction of Arabia beneath
Eurasia in the east (Iran). The reason for these differences may reflect the
greater density of the Arabian lithosphere in the east relative to that in the
west. Five observations indicate that the eastern Arabian plate is more dense
and thus easier to subduct than the western Arabia Plate: (1) the >1000
km-long, N-S trending Central Arabian Magnetic Anomaly (CAMA) marks a ~600Ma-old
suture between E and W Arabia that (2) separates crustal tracts with distinct
Neoproterozoic histories (850-750 Ma crust in the east, 850-570 Ma in the west);
(3) E. Arabian (platform) crust is slightly thicker and more felsic than that of
W. Arabia (shield) and thus more buoyant; (4) E. Arabia is underlain by thicker
mantle lithosphere than W. Arabia; and (5) W. Arabia has a long history of
uplift whereas E. Arabia has subsided throughout Phanerozoic time. We infer that
regional variations in lithospheric thickness largely reflect the earlier
stabilization (and onset of conductive cooling) of E. Arabia relative to W.
Arabia, leading to the development of significantly thicker mantle lithosphere
in the east relative to the west. This also explains why Arabia east of CAMA was
inundated by shallow seas ~540 Ma ago and accumulated salt whereas Arabia west
of CAMA did not, as well as the long history of subsidence of the Arabian
Platform and uplift of the Arabian Shield. These differences in lithospheric
thickness may have been further modified by thermal erosion in Cenozoic time due
to Red Sea rifting and the Afar hotspot.
