Kallamedu Fm
Type Locality and Naming
ARIYALUR-TRICHIRAPPALLI OUTCROP: Named after Kallamedu Village, Ariyalur district, TamilNadu. Best exposure between the villages of Ottakovil and Anandavadi. Stream section Kallamedu village (land mark is old abundant temple).
[Figure 1: Geologic map of Ariyalur area]
Lithology and Thickness
Sandstone. Medium to coarse, massive planar laminated and cross laminated micaceous sandstone, devoid of fossils (Sundaram et al., 2001). However a dinosaurian egg derived in Kallamedu that was transported to Limestone mines in Kallankurichchi Formation is reported. Thickness approximately 300 m.
[Figure 2: Field photo of Kallamedu Formation (provided by A. Nallapa Reddy and R. Nagendra)]
[Figure 3: Generalized Stratigraphy of Cauvery Basin (Provided by A. Nallapa Reddy & R. Nagendra)]
Relationships and Distribution
Lower contact
Unconformable with upper surface of Ottakovil Fm.
Upper contact
Unconformable with Niniyur Fm (Paleocene age). The C-Pg boundary is not traced in the outcrop
Regional extent
Ottakovil and Anandavadi. Kallamedu village
GeoJSON
Fossils
Barren strata. Dinosaur remains
Age
Depositional setting
Fluvial conditions are inferred based on cross laminations present in the Sandstone. The formation marked an end to the Cretaceous sedimentation in the basin. The variegated clays suggest soil formation in overbank muds with channelized sands showing a high degree of maturity and it appears to indicate rapid, shallow deposition channels. May indicate flash fluvial. Flood plain to coastal environment with marine influence (Tewari et al., 1996).
Additional Information