. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . EXPLANATION Sea - Floor Spreading Motion Young Subduction Zone AAA Older Subduction Zone T c> Transform Fault a Megasheor 140 180 170 160 150 ^ Drifting Motion = =^ Rifting Motion I ^ ^"^ Oroclinal Bending I ^--^â Syntaxial Bending â ^~~' ^ Thrust Fault tzz, Strike - Slip Fault Figure 18-7. Compilation of proposed crustal movements affecting Alaska and northeastern Siberia (after Lathram 1973). SUMMARY The long-term similarity in the geologic histories of northern Alaska and nort
. The Eastern Bering Sea Shelf : oceanography and resources / edited by Donald W. Hood and John A. Calder . EXPLANATION Sea - Floor Spreading Motion Young Subduction Zone AAA Older Subduction Zone T c> Transform Fault a Megasheor 140 180 170 160 150 ^ Drifting Motion = =^ Rifting Motion I ^ ^"^ Oroclinal Bending I ^--^â Syntaxial Bending â ^~~' ^ Thrust Fault tzz, Strike - Slip Fault Figure 18-7. Compilation of proposed crustal movements affecting Alaska and northeastern Siberia (after Lathram 1973). SUMMARY The long-term similarity in the geologic histories of northern Alaska and northeastern Siberia and the close relationship between adjacent elements pre- cludes the possibility that any large relative move- ments have occurred, especially in a north-south di- rection, between these two land masses. Within the restrictions imposed by this observation and the es- tablished chronologies and character of the major tec- tonic features of this region, a tectonic model can be formulated which accounts for the observed displace- ments and deformational styles. Two important assumptions have been corrobor- ated by field observations: the Seward Peninsula is more closely related to the Chukchi Peninsula than to adjacent parts of Alaska, and the Kobuk Trench rep- resents a major transcurrent fault along which the most recent sense of movement has been left-lateral. The model requires eastward movement of the Siber- ian block toward Alaska, and involves a net transport of approximately 100-150 km. After the Late Cretaceous development of north- ward-directed thrust and slide sheets in the De Long Mountains and Brooks Range, strong eastward-direc- ted compressive forces resulted in the formation of a long arcuate thrust belt extending from eastern Se- ward Peninsula across the Lisburne Hills and Lis- bume-Wrangel Arch to Wrangel Island. A long-estab- lished seaway connecting the Arctic and Pacific basins across eastern Seward Peninsula was closed by this thrusting a
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