| Title | Geochronology and structural setting of Latest Devonian - Early Carboniferous magmatic rocks, Cape Kiber, northeast Russia |
| |
| Author | Lane, L S ;
Cecile, M P; Gehrels, G E; Kos'ko, M K; Layer, P W; Parrish, R R |
| Source | Canadian Journal of Earth Sciences vol. 52, no. 3, 2015 p. 147-160, https://doi.org/10.1139/cjes-2013-0184  Open Access |
| Image |  |
| Year | 2015 |
| Alt Series | Earth Sciences Sector, Contribution Series 20120464 |
| Publisher | Canadian Science Publishing |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Area | Cape Kiber; Chukotka; Russian Federation |
| Lat/Long WENS | 172.5000 173.0000 70.0000 69.7500 |
| Subjects | geochronology; structural geology; geochemistry; tectonics; magmatic rocks; uranium lead dates; argon argon dates; petrographic analyses; deformation; geochemical analyses; igneous rocks; granites;
major element analyses; trace element analyses; Aptian; Albian; dykes; tectonic setting; magmatism; Carboniferous; Devonian |
| Illustrations | geological sketch maps; analyses |
| Program | GEM: Geo-mapping for Energy and Minerals Yukon Sedimentary Basins |
| Released | 2015 01 15 |
| Abstract | Cape Kiber on the Arctic coast of Chukotka, northeast Russia, consists of a granite intruding Devonian (and older?) strata in the core of a large southeast trending anticline. These strata are
structurally overlain by Carboniferous and younger strata. A U-Pb age of 351.4 ± 5.6 (2s) Ma shows that the granite is Early Carboniferous in age. A large granite cobble extracted from a Carboniferous conglomerate produced a Late Devonian or Early
Carboniferous U-Pb age of ~355-361 Ma. Also, a deformed and altered granitic dyke yielded an age of 363.7 ± 5.7 (2s) Ma. Major and trace elements suggest a syn-collisional (orogenic) setting. The granite's (biotite) Ar release spectrum is reset. The
granitic dyke also shows a disturbed Ar-Ar whole-rock spectrum implying an Early Cretaceous age (~122-130 Ma) for closure of the Ar system. We interpret this as due to widespread greenschist metamorphism accompanying regional deformation of the
Anyuy-Chukotka Fold Belt that accompanied closure of the South Anyuy Ocean. Regionally, this event predates deposition of Aptian and Albian strata and the eruption of Okhotsk-Chukotsk magmatic rocks. An Ar-Ar (biotite) plateau age of 96.4 ± 1.0 (2s)
Ma from a mildly deformed, lamprophyre dyke reflects intrusion in a setting of regional extension. Its deformation reflects a younger tectonic event. The record of Devonian-Carboniferous magmatism and early Carboniferous unroofing is younger and less
complex than that of Arctic Alaska. However, evidence for Early Devonian (Caledonian) or Late Devonian (Ellesmerian) deformation could have been masked by intense Mesozoic deformation. Outcrop data and geochronology support and refine regional
interpretations of Early Cretaceous deformation and mineral growth accompanying accretion of Chukotka to north Asia, followed by regional extension and subsequent convergent deformation. |
| Summary | (Plain Language Summary, not published)
Comparisons of chemistry and age data for granites of similar ages around the Arctic provide important clues to the geological evolution of the Arctic
Ocean basins. Up to one-quarter of the world's undiscovered petroleum resources are predicted to occur there. Other governments and major multinational companies are currently spending billions of dollars assessing the region's petroleum potential.
These data, collected during a previous scientific exchange with Russia, are compiled and interpreted in this study. The study area in northeastern Russia is remote and poorly accessible to westerners, making these rare data timely and
valuable. |
| GEOSCAN ID | 292412 |
|
|