Regional Chemostratigraphic Correlation and Interpretation of the Montney Formation: New Insights and Perspectives

Abstract

The Lower Triassic Montney Formation of the Western Canada Sedimentary Basin consists of sandstone, siltstone and coquina that were deposited along the western margin of Pangaea. However, stratigraphic complexity has made regional, internal characterization of the formation difficult, not only because of the fine-grained nature of the deposits, but also because of large-scale, regional unconformities. These complexities necessitate the use of alternative correlative methods such as chemostratigraphy, which allows for the recognition of chemical-related packages not identified using traditional methods. Utilizing both ICP-MS and ICP-AES elemental data, we outline detailed correlations of chemostratigraphic packages within the Montney Formation, including 5 wells and one outcrop, tying them directly to gamma-ray logs. Analysis of outcrop samples, and comparison with samples from an adjacent well, has allowed for direct correlation from the surface to subsurface, tying together surface and subsurface stratigraphic intervals. Elemental correlations were statistically analyzed using Pearson Product and eigenvector analyses and these correlative relationships were used to support mineralogical data obtained using XRD analysis. Observed elemental changes and inferred mineralogical changes highlight trends in sediment provenance as well as episodes of volcanic input. Our findings suggest a change in sediment input from mafic to granitic sources over time, which is significant as the mafic input coincides with the volcanic activity associated with the Siberian Traps during the Early Triassic. This work has also added clarification to our regional understanding of the internal stratigraphy of the Montney Formation, as well as highlighted production-related information such as dolomite and calcite cemented zones.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016