I‘m so stuck. I‘m completely lost! T-TCan someone please please help by parapharsing this paragraph!In Australia iron ore is won from three main sources: pisolite channel iron deposit ore derived by mechanical erosion of primary banded-iron formations and accumulated in alluvial channels such as at Pannawonica, Western Australia; and the dominant metasomatically-altered banded iron formation related ores such as at Newman, the Chichester Range, the Hamersley Range and Koolyanobbing, Western Australia. Other types of ore are coming to the fore recently, such as oxidised ferruginous hardcaps, for instance laterite iron ore deposits near Lake Argyle in Western Australia.
OK: Pisolite is a mineral form made up of small rounded nodules. It is often the result of long-term weathering of iron and aluminium rich bedrock, such as in the formation of bauxite deposits. It can also apply to a particular form of calcite deposit. In your case, it refers to a particular form of iron ore that has been produced from the long-term weathering of banded iron formation rocks. Metasomatic alteation refers to hydrothermal or sub-hydrothermal weathering through the action of circulating waters. Banded iron formation is a particular rock formation formed in proterozoic times; thought to have been deposited when the earth's atmosphere was different to what it is today. It often consists of alternating layers of iron oxide abd chert (silica). It is not a suitable iron ore in itself; as it contains too much silica. What happens id that the circulating groundwater chemically alters the banded ironstone, leaving the silica and transporting the iron rich minerals to the surface; where they are deposited as small concretions or pisolites. This is a common weathering affect today in tropical climates, and is simillar to lateritisation. In summary, the Banded iron formations get weathered by goundwater, and the iron rich minerals get transported to the surface; where they are deposited as pisolitic concretions. These concretions later get eroded away themselves, and are deposited in alluvial channels. In some cases, such as at Mt Newman, the altered banded ironstone do not get re-eroded. The third type of ferruginous hardcap are iron rich alteration caps which later become oxidised. They remain in place, and are not transported. These are also common at the surface layer of many ore bodies. Al these terms can be found in pedia.
