of the Singhora-Saraipali area, south-eastern Chattisgarh Basin - fieldi

subordinate conglomerate and shale-siltstone. It is best exposed near the Rehathikhol
village (21º18'33.7"N; 83º15'34.5"E). The lower part of the formation is characterised
by pebbly sandstone with matrix- and clast-supported conglomerate. They grades to
coarse to very coarse grained, poorly sorted arkose to subarkosic sandstones. Topmost
part of the formation consists of medium grained, moderate to well-sorted
quartzarenite, characterised by planar stratified beds, often mantled by symmetrical
ripples on top.
Formation B (~630 m): It gradationally overlies formation A and consists of mudstone
dominated succession (MDS), with a ~200 m thick sandstone unit (SS), dividing the
mudstone dominating succession into two parts, lower ~150 m thick MDS 1 and upper
~280 m thick MDS 2. The sandstone (SS) laterally pinches out towards north where
MDS 1 and MDS 2 amalgamate to produce a single mud dominant succession (Fig.2).
The MDS 1 and MDS 2 are characterised by broadly similar lithological characters,
comprising shale and sandstone-shale heterolith. The green shale dominates the
succession with subordinate red and black shale and is best exposed near Banjhapali
(21º20'12.5"N; 83º14'31.1"E), Sishupal hill (21º13'00"N; 83º09'00"E). Siltstone and
very fine-grained sandstone layers occur as interlayers within shale. Amount of
sandstones increase towards the upper part of these mudstone dominated successions
(MDS 1 and MDS 2), and lithology becomes sandstone-shale heterolithic.
A persistent tuff horizon (~5 m thick) occurs in the lowermost part of MDS 1,
which is laterally traceable for about 500 m and are well exposed near Dewanguri
(21º16'29.2"N; 83º12'08.1"E), Chiwrakuta (21º18'34.5"N; 83º13'05.2"E) and Balenda
(21º21'15"N; 83º14'52"E) sections.
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