scholarly journals A synthesis of Jurassic and Early Cretaceous crustal evolution along the southern margin of the Arctic Alaska–Chukotka microplate and implications for defining tectonic boundaries active during opening of Arctic Ocean basins

Lithosphere ◽  
2016 ◽  
Vol 8 (3) ◽  
pp. 219-237 ◽  
Author(s):  
Alison B. Till
Keyword(s):  
Arctic Ocean ◽  
Early Cretaceous ◽  
The Arctic ◽  
Crustal Evolution ◽  
Southern Margin ◽  
Arctic Alaska ◽  
Tectonic Boundaries

scholarly journals An Early Cretaceous subduction-modified mantle underneath the ultraslow spreading Gakkel Ridge, Arctic Ocean

2020 ◽  
Vol 6 (44) ◽  
pp. eabb4340 ◽  
Author(s):  
Marianne Richter ◽  
Oliver Nebel ◽  
Roland Maas ◽  
Ben Mather ◽  
Yona Nebel-Jacobsen ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Early Cretaceous ◽  
Upper Mantle ◽  
Subduction Zones ◽  
The Arctic ◽  
Convergent Margins ◽  
Gakkel Ridge ◽  
Isotopic Heterogeneity ◽  
Oceanic Spreading ◽  
Geodynamic Processes

Earth’s upper mantle, as sampled by mid-ocean ridge basalts (MORBs) at oceanic spreading centers, has developed chemical and isotopic heterogeneity over billions of years through focused melt extraction and re-enrichment by recycled crustal components. Chemical and isotopic heterogeneity of MORB is dwarfed by the large compositional spectrum of lavas at convergent margins, identifying subduction zones as the major site for crustal recycling into and modification of the mantle. The fate of subduction-modified mantle and if this heterogeneity transmits into MORB chemistry remains elusive. Here, we investigate the origin of upper mantle chemical heterogeneity underneath the Western Gakkel Ridge region in the Arctic Ocean through MORB geochemistry and tectonic plate reconstruction. We find that seafloor lavas from the Western Gakkel Ridge region mirror geochemical signatures of an Early Cretaceous, paleo-subduction zone, and conclude that the upper mantle can preserve a long-lived, stationary geochemical memory of past geodynamic processes.

Geochronology and structural setting of Latest Devonian – Early Carboniferous magmatic rocks, Cape Kiber, northeast Russia

2015 ◽  
Vol 52 (3) ◽  
pp. 147-160 ◽  
Author(s):  
Larry S. Lane ◽  
Michael P. Cecile ◽  
George E. Gehrels ◽  
Mikhail K. Kos’ko ◽  
Paul W. Layer ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Early Carboniferous ◽  
Major And Trace Elements ◽  
The Arctic ◽  
Late Devonian ◽  
Northeast Russia ◽  
Tectonic Event ◽  
Magmatic Rocks ◽  
Arctic Alaska ◽  
North Asia

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 (2σ) 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 (2σ) 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 (2σ) 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.

USGS Arctic Ocean Carbon Cruise 2012: Field Activity L-01-12-AR to collect carbon data in the Arctic Ocean, August-September 2012

Data Series ◽  
10.3133/ds862 ◽  
2014 ◽  
Author(s):  
Lisa L. Robbins ◽  
Jonathan Wynn ◽  
Paul O. Knorr ◽  
Bogdan Onac ◽  
John T. Lisle ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
The Arctic ◽  
Field Activity ◽  
The Arctic Ocean ◽  
Ocean Carbon
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