Maceral Variations and Maceral Assemblages within the Upper and Lower Members of the Bakken Formation, Williston Basin, Saskatchewan, Canada.
type: CreativeWork
description: Argillaceous rocks are most often considered to be homogeneous entities, because, at the macroscopic scale, they appear to be so. The Bakken Formation within southern Saskatchewan contains two black shale members, the Upper and Lower Bakken Formation. This study has examined the organic matter within the Upper and Lower members of the Bakken Formation using fluorescence light microscopy on samples taken from core, at closely-spaced intervals across southern Saskatchewan. The organic constituents, or macerals, vary significantly both along with depth within a given borehole (i.e. temporally) and from one well to another (i.e. spatially). The macerals present in the Upper and Lower members of the Bakken Formation include: amorphous organic matter identified as the maceral bituminite with minor amounts of alginite, and ‘degraded alginite’. Bituminite is the dominant maceral and forms the groundmass of the Bakken Formation black shales. Bituminite was unequivocally distinguished from clay or other inorganic material by prolonged exposure to ultraviolet/blue light for a designated time period, using the ‘alteration effect’ of liptinites. Two sub-macerals of bituminite were distinguished, identified as bituminite A and bituminite C. These two sub-macerals ‘substitute’ for one another across a given east-west transect, such that: the sub-maceral bituminite A is the dominant maceral within the centre of the study area, whereas bituminite C occurs as the groundmass along the peripheral area of the sub-crop preceded by a transitional area where there is a mixture of both bituminite A and bituminite C. The considerable variation in maceral assemblages, both with depth and along a given section, have implication toward the hydrocarbon generative potential of these source rocks and, in order to comprehend the variation in organic matter, the maceral assemblages were grouped into organic facies. Four groups of organic facies were identified and defined, each with their own respec…
abstract: Argillaceous rocks are most often considered to be homogeneous entities, because, at the macroscopic scale, they appear to be so. The Bakken Formation within southern Saskatchewan contains two black shale members, the Upper and Lower Bakken Formation. This study has examined the organic matter within the Upper and Lower members of the Bakken Formation using fluorescence light microscopy on samples taken from core, at closely-spaced intervals across southern Saskatchewan. The organic constituents, or macerals, vary significantly both along with depth within a given borehole (i.e. temporally) and from one well to another (i.e. spatially). The macerals present in the Upper and Lower members of the Bakken Formation include: amorphous organic matter identified as the maceral bituminite with minor amounts of alginite, and ‘degraded alginite’. Bituminite is the dominant maceral and forms the groundmass of the Bakken Formation black shales. Bituminite was unequivocally distinguished from clay or other inorganic material by prolonged exposure to ultraviolet/blue light for a designated time period, using the ‘alteration effect’ of liptinites. Two sub-macerals of bituminite were distinguished, identified as bituminite A and bituminite C. These two sub-macerals ‘substitute’ for one another across a given east-west transect, such that: the sub-maceral bituminite A is the dominant maceral within the centre of the study area, whereas bituminite C occurs as the groundmass along the peripheral area of the sub-crop preceded by a transitional area where there is a mixture of both bituminite A and bituminite C. The considerable variation in maceral assemblages, both with depth and along a given section, have implication toward the hydrocarbon generative potential of these source rocks and, in order to comprehend the variation in organic matter, the maceral assemblages were grouped into organic facies. Four groups of organic facies were identified and defined, each with their own respec…
author: Wrolson, Bree Morgan
language: en
date published: 2014-07
date modified: 2026-07-24T04:03:50Z
provider: University of Regina
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Faculty of Graduate Studies and Research, University of Regina

PropertyValue
property ID: Handle
value: https://hdl.handle.net/10294/5785

PropertyValue
property ID: DOI
value: 10.82465/5071