| Title | Emplacement and reworking of Cretaceous, diamond-bearing, crater facies kimberlite of central Saskatchewan, Canada |
| |
| Author | Leckie, D A; Kjarsgaard, B A ; Bloch, J; McIntyre, D; McNeil, D; Stasiuk,
L; Heaman, L |
| Source | Geological Society of America Bulletin vol. 109, no. 8, 1997 p. 1000-1020, https://doi.org/10.1130/0016-7606(1997)109<1000:EAROCD>2.3.CO;2 |
| Year | 1997 |
| Alt Series | Geological Survey of Canada, Contribution Series 1996188 |
| Publisher | Geological Society of America |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Province | Saskatchewan |
| NTS | 73H/02; 73H/03; 73H/04; 73H/05; 73H/06; 73H/07 |
| Area | Prince Albert; Smeaton; Saskatchewan River |
| Lat/Long WENS | -106.0000 -104.5000 53.5833 53.1667 |
| Subjects | economic geology; diamond; kimberlites; emplacement; craters; Mesozoic; Cretaceous |
| Released | 1997 08 01 |
| Abstract | In central Saskatchewan, Canada, kimberlites were emplaced into Cretaceous marine and nonmarine clastic sediments. Core recovered from one drill hole that intersects kimberlite (Smeaton FAC/UK core
169/8) was selected for an integrated study involving sedimentology, volcanology, mineralogy, geochemistry, palynology, micropaleontology, organic petrology, and radiometric age determination. Only crater facies kimberlite has been observed; there is
no indication of the locations of feeder dikes. Four varieties of kimberlite occur, all originating from subaerial volcanism: (1) fluvial-reworked kimberlite; (2) diamondiferous kimberlite lapillistone air-fall deposits; (3) kimberlite olivine
crystal-tuff air-fall deposits; and (4) diamondiferous marine wave-reworked kimberlite. Within the multiple primary eruptive phases of the kimberlite air-fall deposits, the volcanic style changed upward with time, from violent Strombolian to more
explosive volcanism. The bulk of the volcanism formed conformable, air-fall deposits on terrestrial sediments of the Cantuar Formation, resulting in the development of positive-relief tephra cones. Subsequent marine transgression associated with the
Westgate Formation partially beveled the top of the cone. The kimberlite air-fall deposits contain microdiamonds, 5 to 25 µm in diameter. The maximum temperature and vitrinite reflectance values of coaly matter in the kimberlites indicate that these
deposits, although originally derived from magma at high temperatures, did not thermally affect entrained surficially derived clasts or the country rock during emplacement. The chemical content of intrakimberlite shale clasts is markedly different
from the marine and nonmarine shales and indicates significant synemplacement and postemplacement fluid movement through the volcanic pile. At least two episodes of kimberlite volcanism occurred in the middle and late Albian (paleontologically
assigned). A U-Pb perovskite radiometric age of 101.1 ± 2.2 Ma from a kimberlite lapillistone from the younger episode of volcanism is internally consistent with biostratigraphic studies that constrain the kimberlite volcanism as post-middle Albian
and pre-late Albian to late Albian. |
| GEOSCAN ID | 207810 |
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