Chikkim Fm
Type Locality and Naming
Name derived from Chikkim (Chichim) village in the Spiti (In Zanskar it outcrops from the Spanboth River to the middle Uma Chu). [Original Publication: Stoliczka, F. 1865. Geological section across the Himalayan mountain range from Wangtu Bridge on the river Sutlej to Sungdeo with an account of formations in Spiti accompanied by a revision of all known fossils from that district. Memoirs of Geological Survey of India, 5: 153pp]
Synonyms: Stoliczka, 1865 (Chikkim Limestone), Srikantia, 1981. (upper part is the Chikkim Shale)
[Figure: Zanskar-Spiti-Kumaun region location (provided by Om Bhargava)]
Lithology and Thickness
Limestone and Claystone. Lower part is grey, slightly nodular, well-bedded limestone. Upper part is grey shale (Chikkim Shale). 30-80m (in Zanskar), 105m (In Spiti),
[Figure 1: Field photograph of the Chikkim shale, Spiti)]
Relationships and Distribution
Lower contact
Sharp contact with the Giumal Fm.
Upper contact
In Zanskar, the limestone part forms steep rugged slopes below the gentle profile of the overlying Kangi La Fm shale.
Regional extent
Zanskar-Spiti and Himachal Pradesh to Kumaun-Garhwal region of Northwest Tethyan Himalaya.
GeoJSON
Fossils
Lower Chikkim Member: calcispheres; foraminifera (Anaticinella sp. ?, Biticinella breggiensis, Contusotruncana fornicata, Dicarinella asymetrica, Dicarinella concavata, Dicarinella hagni ?, Dicarinella primitiva, Globotruncana linneiana, Hedbergella sp., Helvetoglobotruncana helvetica, Helvetoglobotruncana praehelvetica, Marginotruncana coronata, Marginotruncana pseudolinneiana, Marginotruncana sigali, Marginotruncana sinuosa, Planomalina buxtorfi, Pseudotextularia sp., Rotalipora appenninica, Rotalipora cushmani, Rotalipora gandolfii, Rotalipora globotruncanoides, Rotalipora greenhornensis, Rotalipora montsalvensis, Rotalipora reicheli, Rotalipora subticinensis, Rotalipora ticinensis, Whiteinella archaeocretacea); belemnites; irregular echinoderms;
Upper Chikkim Member: foraminifera (Gansserina gansseri, Globotruncana arca, Globotruncana linneiana, Globotruncanita elevata, Globotruncanita stuarti, Globotruncanita stuartiformis, Pseudotextularia sp., Radotruncana calcarata, Radotruncana subspinosa). Microfacies are dominated by planktonic foraminifera with radiolarian and Calciphaerae ex. Globotrancana arca; Whiteinella, Globigerinelloides, Praeglobotrucncana helvetica Zone, D. asymetrica Zone; Haplophragnoids sp., Textularia Sp., ? Gaudryina sp., Lenticulina Sp., Marginotruncana pseudolinneiana etc.
Age
Depositional setting
The Chikkim Formation is interpreted as deposited under shelf to off-basinal environment with occasional periods of restricted circulation. The upper shaly part was deposited in outer shelf (Bhargava and Bassi, 1998).
Additional Information