Saser Brangsa Fm
Type Locality and Naming
Upper Shyok Valley: Type section is in Saser Brangsa locality in Upper Shyok Valley, Eastern Karakoram, India. [Original Publication: Gergan, J. T. & Pant, P. C., 1983. Geology and stratigraphy of eastern Karakoram, Ladakh. In: Thakur, V. C. and Sharma, K. K., (eds), Geology of Indus Suture Zone of Ladakh, Wadia Institute of Himalaya Geology, Dehra Dun, India, 99-106; Juyal, K.P. 2018. Lithostratigraphy, biostratigraphy and palaeogeography of the Eastern Karakoram, India. WIHG Monograph series, No. 3. 1-126.]
Lithology and Thickness
Limestone. Crystallized grey limestone/or marble, siltstone, carbonaceous shale and sandstone. Limestone in the basal part is intruded by the Karakoram Granite Fm in the southwest of Saser Brangsa locality. The actual thickness of this formation could not be measured because most of parts of this succession is covered by snow; however, the thickness of this can be estimated as >1000 m. Juyal and Raju (ca. 2006) entry: 1200m. Basal gray Limestone intruded by granite and with dark marl. Middle is brown to black Shale; Upper is cherty Limestone.
[Figure 1: Major tectonostratigraphic blocks, sutures with index map (inset) of the Pamir-Karakoram knot (adopted from Gaetani, 1997). The boxes indicates location 1=Upper Shyok Valley and location 2= Lower Shyok Valley (after Juyal, 2018)]
[Figure 2: Field photograph showing the Saser Brangsa Formation in Upper Shyok Valley, Eastern Karakoram (photograph taken by K.P. Juyal)]
[Figure 3: Caught up patches (white colored) of limestone of lower part of Saser Brangsa Formation within the Karakoram Granite]
Relationships and Distribution
Lower contact
Not known.
Upper contact
Not known, but next younger unit is the Aq Tash Fm.
Regional extent
Upper Shyok Valley: Not known.
[Figure 4: Geological Map of the Upper Shyok Valley, eastern Karakoram (after Gergan and Pant, 1983; Thakur, 1992; and Juyal, 2018)]
GeoJSON
Fossils
Foraminifer, gastropod and algae. One foraminifer assemblage zone and one unzone are recognized in the upper part of the Saser Brangsa Formation (Juyal, 2018).
(i) Unzoned (Zone-I): The rocks of this unzoned part are traversed by the Karakoram batholiths and poor preservation of fossils do not allow for proper identification.
(ii) Arakaevella arakaica - Elenella corpulenta Assemblage Zone (Zone. II): Arakaevella arakaica, Elenella corpulenta, Cribrosphaeroides, ?Biorbis, Parathurammina, ? Neoarchaesphaera, Irregularina lobata, Criboraroria lobata (Poyarkiva) (forams), Tubiphytes (algae) and gastropods.
[Figure 5: Vertical section showing the distribution of fossils in Saser Brangsa Formation]
Age
Depositional setting
Not known.
Additional Information