Second Field Season, Summer 2007

Field studies continued from 2006 work, with the objectives to better understand stratigraphic and structural relationships, depositional histories, and petroleum potential. The crew was again helicopter-supported; and moved westward to span the map-areas of Sans Sault Rapids (NTS 106H), Upper Ramparts River (NTS 106G), and Snake River (NTS 106F).  More work took place in the Yukon this season than in 2006.

Research on Lower and Middle Devonian age rocks included measuring 14 stratigraphic sections; these were described in detail.  Several other sites visited, with about 70 samples collected, including: 1) lithological samples for sedimentary petrology (composition and characteristics); 2) shale for source rock potential; 3) potentially porous carbonate (limestone and dolostone) and siliciclastic (sandstone) rocks for reservoir potential; 4) various lithologies for microfossil analysis; 5) oil chemistry to characterize hydrocarbons present; and 6) detrital zircons for provenance studies.  Winter 2007-2008 work will include preparing data collected for inclusion into the project digital geodatabase.  Sample analytical results will be studied when they come back from lab.
About 90 samples were taken from the Imperial Formation to assess source rock and reservoir potential.  These samples included total organic carbon (TOC) content, thermal maturity, porosity and permeability.  One new section of the lower Imperial Formation was measured in the Snake River map area.  These samples were sent for analysis in late August and results should be available in the fall.  Field work for next summer will depend on results from the 2007 field season. If there are small holes in the data, short targeted sampling will take place summer 2008.

Two gamma ray profiles of Devonian source rocks (Hare Indian and Canol Formations) were conducted from sections that were identified last year.  This will enable our field observations to be directly correlated to drill hole gamma logs throughout the NWT.

As part of a provenance study, mainly of the Imperial Formation, 22 shale samples were collected spanning the entire Paleozoic succession to be analyzed for whole rock geochemistry and three detrital zircon samples were collected from the Imperial Formation.

A study of detailed sedimentology of the Imperial Formation was undertaken by Shane Tylosky as part of a B.Sc. thesis under supervision of Octavian Catuneanu at University of Alberta.  This included detailed measured sections from three locations east-west along the Mackenzie Mountain front.

Last year’s work on Cretaceous age rocks was largely exploratory.  This summer four sections were revisited and measured in detail.  Three of these sections were of the Martin House Formation, the most prospective reservoir unit within the Cretaceous stratigraphy of the study area.  In addition to sampling, detailed sedimentological and ichnological observations were made.

The fourth Cretaceous section will be the basis for a Master’s thesis by Danielle Thomson under supervision of Professor Claudia Schröder-Adams at Carleton University.  This is the only location in the study area that has a complete Cretaceous section and was sampled for Rock-Eval/TOC, porosity, radiometric age dating of volcanic ash beds, and a common well log characterization using a gamma ray spectrometer.  The focus of the thesis is biostratraphy using Foraminifera and it will provide the most comprehensive synthesis of Cretaceous stratigraphy within the region.

Current project research will be presented at a number of events in the fall of 2007; including the CSPG Gussow Geoscience Conference Arctic Energy Exploration in October, as well as the Yellowknife and Yukon Geoscience forums in late November.

First Field Season, Summer 2006

New studies were initiated in an area where much of the geological mapping dates back to the 1960’s. From June 28th to July 27th, geological field studies took place in stratigraphic sections (layered rocks) exposed along ridges at the northern front of the Mackenzie Mountains, in uplifted areas within the Interior Plain such as Imperial Hills, and along river valleys and canyons. The work was helicopter-supported, and spanned the map-areas of Norman Wells (NTS 96E), Fort Good Hope (NTS 106I-96L), Sans Sault Rapids (NTS 106H), Upper Ramparts River (NTS 106G), and Snake River (NTS 106F). Bedrock ranges in age from the Proterozoic Era (about 800 Million years old), through Paleozoic Era (about 540 to 350 Million years old), to Mesozoic Era (early Cretaceous Period, 120-90 Million years old). Several different formations make up the stratigraphy, and many of these are of interest for their petroleum potential, either as hydrocarbon source rocks, or as reservoir rocks.

In total, more than 20 stratigraphic sections were measured and described in detail. In addition, more than 30 sites were visited to study key parts of the stratigraphy and examine structural features (folds and faults). New measurements were taken from surface in order to correlate the subsurface of Peel Plateau and Plain. Sample collection included: 1) lithological samples for sedimentary petrology (composition and characteristics); 2) black, organic shale for source rock potential; 3) potentially porous carbonate (limestone and dolostone) and siliciclastic (sandstone) rocks for reservoir potential; 4) various lithologies for microfossil analysis. The goal of these analyses is to better understand which formations across the sedimentary basin have favourable source and reservoir characteristics as part of a hydrocarbon resource assessment. Fossils are needed to provide accurate dates for the different formations to improve regional correlations within the sedimentary basin.

The stratigraphy represents a series of stacked sedimentary basins through time. Paleoenvironments changed through both time and space, which requires studying a large region. Paleozoic rocks represent deposition along the ancient Pacific continental margin edge, which includes the development of extensive Devonian reef systems such as the one that contains the prolific Norman Wells oil fields. In the late Devonian, and again in the Cretaceous, mountain building events to the west created a foreland basin (a basin marginal to a mountain belt) setting across the Peel Plateau and Plain region. The tectonic and depositional setting of this Cretaceous basin is similar to that of economically important, oil and gas-bearing rocks of Alberta.

Results from laboratory analyses are expected in early 2007. Data and interpretations from this year’s field work will be presented at upcoming conferences and published in a series of government open files and reports.

Reconnaissance Geoscience, Summer 2005

A reconnaissance survey focused on both geology along the Dempster Highway, and remote regions of Richardson Mountains and northern Mackenzie Mountains. The Dempster Highway from Inuvik, NT to Eagle Plains, YT transects the northwest corner of Peel Region and exposes strata that spans the Proterozoic to Quaternary. Geology of 25 stops was documented in order to update data for a now out-of-print roadside geological guide for the Dempster Highway.

Helicopter reconnaissance work took place along river exposures in Peel Region and along the deformation fronts that flank the western and southern edge of Peel Plateau (Richardson and Mackenzie Mountains, respectively). Parts of Trail River (NTS 106L), Snake River (NTS 106F), Ramparts River (NTS 106G) and Sans Sault Rapids (NTS 106H) map areas were covered. In total, 17 stratigraphic sections containing 16 different formations of Neoproterozoic to Cretaceous age (ca. 900 to 100 Ma) were examined. Preliminary collections from key sections included: 1) representative lithological samples for sedimentology; 2) Paleozoic carbonate rock for conodont microfossil analysis; and 3) Paleozoic and Mesozoic black shale for organic geochemistry analysis (Rock-Eval/TOC pyrolysis). Reconnaissance data provides a framework for evaluating prospective stratigraphic horizons (source and reservoir facies), dating formations using biostratigraphy, and assessing hydrocarbon potential of different formations.