In the front ranges of the SW Rocky Mountains near the village of Exshaw, the hanging wall of the McConnell thrust sheet exhibit stratigraphic successions of the Devonian-Carboniferous boundary interval. Starting from parking lot, the trail winds along the Jura Creek gravel bed for 3.2 km to see the Devonian/Carboniferous boundary in the so-called middle canyon, where the Famennian platform carbonate of the Palliser Formation are overlain abruptly by the black pyritiferous shale of the Exshaw Formation, one of major sourcerocks in the subsurface Alberta.
The two way trip is 6.4 km. Besides being popular among geoscientists, the Jura Creek hike is loved by Calgarians for easy hiking and dog walking. The nature of drowning surface in top of the Palliser Formation is debatable and referred in the literature to as the hardground, shoreface ravinement, or drowning unconformity. A review of this knowledge will be provided in the field guidebook.
There are indications of paleokarst development at this surface in other localities. The surface is phosphatized and contains volcaniclastic material. It is onlapped by thin (1.4 m) black laminated pyritiferous shale of the lower member of the Exshaw Formation. The upper Exshaw Formation is a dark grey, weathering yellow, laminated siltstone. A lot of data have been published on the absolute dating and conodont biostratigraphy of this interval, allowing to pinpoint the Devonian-Carboniferous boundary inside the black shale of the lower Exshaw member. A number of sedimentary features within the upper Palliser Formation, such as stromatolites and various carbonate-platform facies, can be seen in creekside exposures between the creek delta and the type Exshaw section in the middle canyon.
Lunch and water will be provided for attendees.