Sm-Nd Study of the Permian to Paleogene Strata, Verkhoyansk Foreland Basin: Provenance Interpretation

Sergey Malyshev¹, Andrei Khudoley¹, Andrei Prokopiev², and Victoria Ershova^1
1St.Petersburg State University, St.Petersburg, Russian Federation.
²Diamond and Precious Metal Geology Institute, Yakutsk, Russian Federation.

Priverkhoyansk foreland basin is located on the eastern margin of the Siberian craton and contains a thick Mesozoic sedimentary succession. Here we present results of Sm-Nd study of the Permian-Paleogene sedimentary rocks of the northern part of the Priverkhoyansk foreland basin. For provenance analysis we used variations in eNd(t) values where epsilon Nd value is referred to the time of sedimentation. Data on Th/Sc ratio values are incorporated as well.

Permian sediments have eNd(t) values varying from -4 to -10 that we interpret to reflect mixed cratonic and orogenic sources. More juvenile source is recorded in Triassic sandstones by increasing eNd(t) values up to 0. The Th/Sc ratio values from Triassic sediments are typical for mafic rocks pointing to their wide distribution in the provenance. Decreasing eNd(t) values in Jurassic sediments point to a shift from a juvenile or orogenic source to more cratonic one. Cretaceous and Paleogene sediments show significant decreasing in eNd(t) values indicating increasing importance of the cratonic source. Data on Th/Sc ratio values correspond with this conclusion.

According to the Nd and Th/Sc data, in Permian to Paleogene there were several types of sources for the Priverkhoyansk foreland basin such as cratonic, orogenic and juvenile sources. The cratonic sources were the Siberian craton basement uplifts including, probably, the Anabar and Aldan shields. Mafic rocks with juvenile component are likely related to Norilsk traps and their correlatives. Origin and location of orogenic source is not clear, but an orogenic belt with related Sm-Nd isotopic fingerprints is absent in the adjacent areas.

AAPG Search and Discovery Article #90130©2011 3P Arctic, The Polar Petroleum Potential Conference & Exhibition, Halifax, Nova Scotia, Canada, 30 August-2 September, 2011.