Individual mineralized beds are locally interbedded
with black siliceous shale beds.
Recent drilling into fresh rock suggests the ironstone is a weathered sequence of sulphidic shale and massive sulphides interbedded
with a chert of either sedimentary or hydrothermal/exhalative origin.
In the Permian, the Jimusaer Lucaogou Formation sequence was divided into six sections from bottom to top according to lithologic characteristics: dolostone ([P.sub.2][I.sup.1]), dolostone interbedded
with sandstone ([P.sub.2][I.sup.2]), lower oil shale ([P.sub.2][I.sup.3]), sandstone ([P.sub.2][I.sup.4]), upper oil shale ([P.sub.2][I.sup.5]) and shale ([P.sub.2][I.sup.6]) (Fig.
The Bellary Formation is described by the Geological Survey of Western Australia (GSWA) as the lowermost unit of the Fortescue Group and comprises fine grained sediments, sandstone, interbedded
conglomerate, basaltic breccia and tuff.
The wells in the area were drilled in a mixed sequence, mainly of carbonates and clastic sedimentary rocks, where certain kind of limestones have been reported as hydrocarbon producer; in this research two SVMs were trained to identify automatically sections with fossiliferous limestones and intervals of calcareous shales interbedded
with limestone; the remaining carbonates rocks, not classified by the SVMs, were grouped as carbonate laminated rock by applying a logic function.
The source rocks in the Lower Jurassic and lower Middle Jurassic succession are composed of lacustrine-swamp deep gray mudstones and carbargilites interbedded
with thin coal-beds.
The geology in the vicinity of Cisna is mainly characterized by the Carpathian flysch, called the Cisna Beds (Bak and Wolska, 2005), which is interbedded
with sandstones, marls, shales and mudstones.
Resedimented carbonates interbedded
with basinal facies are described in Tethyan Middle Jurassic carbonate stratigraphy, as demonstrated by the Vajont limestone (Bosellini et al., 1981), Jabalcuz Formation (Ruiz-Ortiz, 1982) and Hawasina complex (Blechschmidt et al., 2004)).
A sixth occurrence of open water facies occurs interbedded
with poorly drained deposits is present between 853.9-875.6 m.
Carbonate-dominated FA-1 (Facies 7 and 8) consists of thin, lenticular packstone/grainstone, interbedded
with fair-weather bioturbated mudstone/wackestone in the upper Pavillon Member.
The Nammal Formation having 30 to 35 meters thickness is predominantly composed of nodular limestone interbedded
with marl and shale.