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.

黄钾铁矾和其他金属硫酸盐在火星上很常见，据解释是在极端酸性盐水环境中形成的，类似于现代地球上黄钾铁矾沉淀的类似物。我们在加拿大北极地区西北地区的 Smoking Hills（被 Inuvialuit 称为 Ingniryuat）研究了另一种地球类似物。Smoking Hills 的特点是极地沙漠中 Smoking Hills 组的自燃黄铁矿泥岩。在晚白垩世海洋缺氧事件期间，Smoking Hills 地层沉积在外陆架上以倾斜海洋环境。该单元的氧化风化产生了大量富含黄钾铁矾的沉积物，以及富含黄钾铁矾和页硅酸盐的带状泥岩，类似于在火星上观察到的那些泥岩。这些泥岩的坍塌使大量物质暴露在大气中的氧气中，从而通过黄铁矿氧化产生高温（足以产生副熔岩），随后形成多种水合金属硫酸盐矿物。风化燃烧地点的特征是更简单的富含黄钾铁矾的矿物学以及热变质泥岩。远离自燃点 (bocannes)，泥岩中富含黄铁矿的层氧化成黄钾铁矾，在露头中形成黄色带状外观。这些富含黄钾铁矾的层，类似于在火星上观察到的泥岩夹层，反映了沉积后的氧化过程——而不是沉积期间的酸性条件。因此，这可能反映了比通常解释的火星更宜居的环境。