CID exercises: answers
Exercise 1
Exercise 2
I: basement, containing abundant well-ordered kaolinite
II: transition zone, with decreasing content of well-ordered kaolinite and increasing Fe-(oxyhydr)oxide content. Hematite is often present and remnant of original CID can be recognised.
III: layer of poorly-ordered kaolinite, laterally continuous through the channel
IV: iron ore layer, with absence of clays and iron ore mostly of ochreous goethitic composition
V: clay layer cover the ore zone. Some layers of well-ordered kaolinite indicate neoformation below
the water table. Fe-(oxyhydr-)oxides are mostly vitreous goethite in nature and their abundance
decreases towards the surface
VI: calcrete zone, dominated by a mixture of calcite and dolomite, with little clay and low Fe(oxyhydr-)oxide abundance that is mostly hematitic in nature
Exercise 3
Validation of Fe-(oxyhydr-)oxide abundance script (RMSE = 11.3 wt% Fe)
Validation of hematite-goethite composition (samples masked for Al, Ca and Fe content (see Haest et
al., 2012a)
Validation of AlOH-clay abundance script
Validation of carbonate composition script
Selected maps that can be derived from the hyperspectral-based RC mineralogy at the surface and at a
depth of 20 m