Tectonic ironstone encompasses siliceous and ferruginous rock types that are characterized by the presence of chert or cherty quartzite, iron sulphides and their alteration products.
The beige-to-ochre tropical ferruginous soil displays in its first horizons a sandy texture at slope bottom, and is sandy-clayey on the remainder.
A mixture of bruised arum leaves and stalks with a quantity of dark, ferruginous earth and water was put into the gourd.
The lenses are separated by locally discordant horizons of ferruginous , silicic or graphitic, strongly schistose sedimentary to volcanic rocks.
An upwards change in palaeosol type from gley to ferruginous within the Ketch Member has been cited as evidence for improving drainage through Late Westphalian time as a result of tectonic uplift.
The rock is cemented by a mixture of quartz overgrowths, K-rich feldspar, and an oxidized ferruginous clay now dominated by chlorite.
In the case of more intense Fe impregnation, scattered quartz clasts supported by a ferruginous matrix may be the only remains of former sandstone.
The latter, a series of ferruginous shelly sands, are the only preserved in situ product of the late Miocene-early Pliocene marine transgression.