Lower Paleozoic Franklin Mountain and Mount Kindle formations, District of Mackenzie: their type sections and regional development
Authors: Norford B S , Macqueen R W 
Published: July 2015

At its type section on Mount Kindle near Wrigleyin the southern Franklin Mountains, the Franklin Mountain Formation is more than 917 feet (280 m) thick. It includes varicoloured, thin to thick bedded dolomite and argillaceous dolomite, and represents
shallow-marine and peritidal environments. The formation is widely distributed in the eastern Mackenzie Mountains and in the Franklin Mountains; in these areas, it appears to be less than 2,500feet (760 m) thick. In the Interior Plains, where the formation also is widespread, surface thicknesses
appear to be less than 2,500 feet (760 m); but more than 3,400 feet (1,035 m) of strata can be assigned to the Franklin Mountain in the subsurface of the Colville Hills area. Three informal unit scan be recognized widely within the Franklin Mountain Formation. From base to top these are: the cyclic
unit (0-450 ft.; 0-137 m), the rhythmic unit (?100-1,600 ft.; ?30-490 m), and the cherty unit(0-?2,400 ft.; 0-?730 m). Over the entire area of out crop, distribution and thickness of these units may be affected by erosion associated with unconformities beneath the Mount Kindle Formation, beneath
Devonian sediments, beneath Cretaceous sediments, and by the present Pleistocene-Holocene surface of erosion. The rhythmic unit (at least 872ft.; 266 m, thick) and the cherty unit (45 ft.; 14m, thick) can be recognized clearly at the type section, despite poor exposures. A fourth unit, the porous
dolomite unit (381 ft.; 116 m, thick), local lyis developed above the cherty unit in the subsurface northwest of the Colville Hills
Recessive fossiliferous rocks, originally assigned to the uppermost part of the type Franklin Mountain Formation (Williams, 1923), belong to the Mount Kindle Formation (thus emended), and are separated from the underlying Franklin Mountain strata by an erosion surface of regional extent. Removal of
these rocks to emend the type Franklin Mountain Formation means that no fossils other than stromatolites are known from its type section. Regionally, Late Cambrian and Early Ordovician faunas are known from the Franklin Mountain Formation. The location of the Cambro-Ordovician boundary is not known;
it may lie within the rhythmic unit, or between the rhythmic unit and the overlying cherty unit.
The Mount Kindle Formation is about 895 feet(237 m) thick at its type section at Mount Kindle, and consists of grey, thinly to thickly bedded dolomite; some of which is biostromal and all is of shallow-water, shelf aspect. Distribution and thickness of the Mount Kindle on a regional scale also has
been affected strongly by erosion associated with sub-Devonian and sub-Cretaceous unconformity sand with the present Pleistocene-Holocene erosion surface. Locally, the Mount Kindle Formation attains thicknesses up to 1,500 feet (455 m) in outcrop. Regionally, the formation consists of a monotonous
succession of uniform, medium to dark brownish grey, finely to medium crystalline dolomite containing abundant chert and, in its lowest few hundred feet, halysitid , favositid and solitarycorals, brachiopods and orthoconic cephalopods. Facies changes appear to be minimal in the area discussed. The
formation, generally, is thinnest or absent in the Interior Plains and northern Franklin Mountains, somewhat thicker in the frontal Mackenzie Mountains, and thickest in the central Mackenzie Mountains where, apparently, it is equivalent to most of the Whittaker Formation. At the type section, the
lower 500 feet (152 m) of the Mount Kindle Formation contain Late Ordovician (Richmond) and Early Silurian (Llandovery) fossils; the upper 400feet (122 m) are not dated. No overlying strata outcrop at the type section on Mount Kindle, but a supplementary section at the north end of Smith Ridge, four
miles (6.5 km) south of Mount Kindle, shows the top of the formation to be separated from the overlying Devonian Bear Rock Formation by about450 feet (137 m) of poorly exposed beds. These rocks cannot be assigned with confidence to any formation, but may belong to the Delorme Formation(Late Silurian
and Early Devonian).