| Title | Extensive jarosite deposits formed through auto-combustion and weathering of pyritiferous mudstone, Smoking Hills (Ingniryuat), Northwest Territories, Canadian Arctic - a potential Mars analogue |
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| Author | Grasby, S E ;
Percival, J B; Bilot, I; Ardakani, O H; Smith, I R; Galloway, J; Bringué, M; McLoughlin-Coleman, T |
| Source | Chemical Geology vol. 587, 120634, 2021 p. 1-17, https://doi.org/10.1016/j.chemgeo.2021.120634  Open Access |
| Image |  |
| Year | 2021 |
| Alt Series | Natural Resources Canada, Contribution Series 20210377 |
| Publisher | Elsevier |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf; html |
| Province | Northwest Territories |
| NTS | 97C/05; 97C/06; 97C/11; 97C/12; 97C/13; 97C/14 |
| Area | Ingniryuat; Smoking Hills |
| Lat/Long WENS | -127.7500 -126.0333 69.8833 69.3167 |
| Subjects | mineralogy; geochemistry; extraterrestrial geology; Science and Technology; Nature and Environment; jarosite; metals; sulphates; bedrock geology; lithology; sedimentary rocks; mudstones; pyrite;
weathering; paleoenvironment; marine environments; continental margins; acidity; salinity; precipitation; phyllosilicates; depositional history; Smoking Hills Formation; Phanerozoic; Mesozoic; Cretaceous |
| Illustrations | tables; location maps; geoscientific sketch maps; photographs; profiles; plots; photomicrographs |
| Program | GEM-GeoNorth: Geo-mapping for Energy and Minerals GEM Program Coordination |
| Released | 2021 11 16 |
| Abstract | Jarosite and other metal sulphates are common on Mars and are interpreted to have formed in an extreme acidic saline aqueous environment, similar to modern Earth analogues where jarosite precipitates.
We examined an alternative Earth analogue, at the Smoking Hills (known as Ingniryuat by Inuvialuit), Northwest Territories, Arctic Canada. The Smoking Hills are characterised by auto-combusting pyritic mudstones of the Smoking Hills Formation in a
polar desert. The Smoking Hills Formation was deposited in an outer shelf to slope marine environment, during a Late Cretaceous Ocean Anoxic Event. Oxidative weathering of this unit creates extensive jarosite-rich deposits, and banded jarosite- and
phyllosilicate-rich mudstones, similar to those observed on Mars. Slumping of these mudstones exposes large masses to atmospheric oxygen leading to generation of high temperatures (sufficient to produce paralavas) through pyrite oxidation, and the
subsequent formation of a diverse suite of hydrated metal-sulphate minerals. Weathered combustion sites are characterised by a simpler jarosite-rich mineralogy along with thermally-altered mudstone. Away from sites of auto-combustion (bocannes),
pyrite-rich layers within the mudstone oxidise to jarosite, creating a yellow-banded appearance in outcrops. These jarosite-rich layers, similar to those observed interbedded in mudstones on Mars, reflect post depositional oxidation processes - not
acidic conditions during the time of deposition. As such, this could reflect a more habitable environment than is commonly interpreted for Mars. |
| Summary | (Plain Language Summary, not published)
Naturally burning shales were examined in the Smoking Hills area. A complex array of rare minerals including jarosite are found at the site that are
similar to those found on Mars and used to interpret Mars as having standing water, but that which was highly acidic, being inhospitable to life. The Smoking Hills area has similar exposures to those at Mars but we are able to show that the jarosite
deposits there are formed by weathering of pyrite rich layers in the shale. This means that the deposits on Mars could reflect much more habitable environments than originally thought. |
| GEOSCAN ID | 329151 |
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