The Giumal Formation in Spiti Valley, India, contains marine deposits from the Lower Cretaceous period. A detailed study of the sedimentary development in the region was conducted, revealing eleven different types of sedimentary environments and twenty-three sequences of sedimentary layers. The research identified four major cycles of sea-level changes, with a total of 10 significant drops in sea level between the late Tithonian and late Albian periods. This information helps us understand how the Giumal Formation was deposited in Spiti Valley during the Late Jurassic and Cretaceous times.