The Alpha-Mendeleev ridge, a large igneous province with continental affinities

ABSTRACT

The Alpha Ridge-Mendeleev Rise (AMR) is the major bathymetric feature in the Amerasia Basin of the Arctic Ocean. Its tectonic history is controversial due to its remote location in ice covered waters making data acquisition difficult, resulting in the lack of diagnostic data. Analysis of the wide-angle reflection/refraction data based on the compressional waves (P-waves) from the AMR indicates that its velocity/depth structure is typical of large igneous provinces (LIPs). LIPs can form on either oceanic or continental crust and can exhibit complex history of development. Here converted shear waves (S-wave) on the Alpha Ridge have been used to calculate Poisson’s ratios and many of measured values are within the felsic range in the upper crust. They are comparable to published S-waves from the Mendeleev Rise. They are also consistent with the results of Rayleigh-wave group-velocity analysis that indicate the Alpha Ridge in adjacent northern Canada has an intermediate composition. Based on magnetics, pseudogravity and volumetric considerations the High Arctic Large Igneous Province (HALIP) most closely resembles the Kerguelen Plateau, a LIP with a continental component. The geophysical characteristics of the AMR are compatible with a number of other LIPs that have continental affinities. A variety of offshore information from dredges and cores and onshore geological data support continental fragments incorporated in the AMR.

KEYWORDS:

• Arctic
• seismics
• LIP
• tectonics

Acknowledgments

The scientific program was financially support by and run under the auspices of the Geological Survey of Canada. The data presented here were collected in difficult conditions in and on ice covered waters. We appreciate the tireless efforts of the participants on the LOREX and ARTA ice camps and the captain, officers and crew of the CCGS Louis S. St Laurent. The participants of ICAM VIII meeting in Stockholm in June of 2018 are thanked for their input into the ideas presented here. For the writing of this paper, the suggestions of the internal reviewers John Shimeld and Patrick Potter and those chosen by the journal Nina Lededeva-Ivanova and anonymous reviewers were invaluable and appreciated.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is a contribution of Canada’s Extended Continental (UNCLOS) Program, with funding from Natural Resources Canada (Geological Survey of Canada, Lands and Minerals Sector).