Provenance constraints on Early Jurassic evolution of the northern Stikinian arc : Laberge Group, Whitehorse Trough, northwestern British Columbia ...

• Main Author: Johannson, Gary G.
• Format: Text
• Language: English
• Published: University of British Columbia 2009
• Subjects: Atlin Lake
• Online Access: https://dx.doi.org/10.14288/1.0052494; https://doi.library.ubc.ca/10.14288/1.0052494

The Lower to Middle Jurassic Inklin Formation forms part of the Laberge Group in northwestern B.C. which links the Stikine and Cache Creek terranes along much of the length of the Whitehorse Trough. Ammonite biochronology of the Inklin Formation in the Atlin Lake area constrain the age of the succession there to a range of Early Sinemurian to Late Pliensbachian and provide the temporal framework for analyzing petrofacies and interpreting basin history using paleocurrent data, ternary plots, and conglomerate clast age and provenance. Inklin Formation sediments record a complex arc-basin evolution during the Early Jurassic characterized by episodic flank uplifts, rejuvenated volcanism, and strike-slip influence on sedimentation. Strong temporal trends in both paleocurrent patterns and sandstone-conglomerate petrofacies are evident and allow definition of three discrete phases in basin-fill history. QFL, QmPK, and QpLvLs sandstone ternary plots, conglomerate clast trends and provenance, paleocurrent patterns ...