Shock metamorphic features in mafic and ultramafic inclusions in the Sudbury Igneous Complex: Implications for their origin and impact excavation

Yujian Wang,Peter C Lightfoot,J Paul Golightly,Edward F Pattison,C Michael Lesher

doi:10.1130/g39913.1

Abstract

Shock metamorphic features in mafic and ultramafic inclusions in the Sudbury Igneous Complex: Implications for their origin and impact excavation

Highlights

The Sudbury Igneous Complex is located at the boundary between the Archean Superior Province and the Paleoproterozoic Southern Province in northeastern Ontario, Canada
We have studied the shock metamorphic record in the refractory olivine-bearing mafic and ultramafic inclusions from the Sublayer and the Offset Dikes, which we argue are direct samples of the target rocks and provide better constraints on the depth of the impact process
The Sublayer occurs discontinuously within embayments and troughs along the basal contact of the Sudbury Igneous Complex and contains a similar inclusion population to the Offset Dikes, which occur as concentric and radial dikes that extend as much as 20 km into the country rocks (e.g., Pattison, 1979; Lightfoot, 2016)

Summary

INTRODUCTION

The Sudbury Igneous Complex is located at the boundary between the Archean Superior Province and the Paleoproterozoic Southern Province in northeastern Ontario, Canada. It is one of the world’s oldest, largest, and bestexposed meteorite impact structures (e.g., Grieve and Therriault, 2000) and contains some of the world’s largest magmatic Ni-Cu-PGE (PGE— platinum group element) sulfide deposits (e.g., Lightfoot, 2016). Previous studies focused on geochemical and/or isotopic analyses of the impact melt sheet itself (Offset Dike margins, averaged Main Mass lithologies, or glass shards contained in the overlying Onaping Formation breccias). All of these studies invoke significant degrees of impact homogenization of, and post-impact modification

BACKGROUND

C Phl Ol Pl

CONCLUSIONS