The correct option is Tillite.
Explanation
Sedimentary rocks are classified based on their mode of formation and the agents responsible for transporting the sediments. In geological history, specific sedimentary rocks serve as indicators of past climatic conditions, such as the glacial phases associated with the Gondwana system.
- Placer is incorrect: Placer deposits refer to concentrations of heavy, durable minerals (such as gold or diamonds) formed by gravity separation during sedimentary processes, typically driven by water currents in rivers or beaches. They are not a rock type formed specifically from glacial deposits.
- Tillite is correct: Tillite is a sedimentary rock formed by the lithification (consolidation) of glacial till. Glacial till is unsorted sediment deposited directly by a glacier. The presence of tillite in the Talcher Series of the Gondwana system provides geological evidence of widespread glaciation on the Gondwana supercontinent during the Carboniferous period.
- Basalt is incorrect: Basalt is an extrusive igneous rock formed from the rapid cooling of basaltic lava exposed at or very near the surface. It is not a sedimentary rock.
- Granite is incorrect: Granite is an intrusive igneous rock formed from the slow crystallization of magma below the Earth's surface. It is not formed from glacial sediments.
Key Takeaway: Tillite is the lithified form of glacial till (unsorted glacial debris). It is a characteristic feature of the Gondwana system, serving as paleoclimatic evidence for ancient glacial ages.