What is connate water?

• A. Original water trapped at the time of deposit
• B. Water derived from rainfall
• C. Water from magma that surfaces
• D. Groundwater introduced after deposition

Answer: (A)

Connate water is the water that was present in the pore spaces of sediment at the moment the sediment was deposited and became lithified. It is trapped there from the time of deposition, not water that infiltrates later from rainfall, not water derived from magma, and not groundwater that enters after deposition. The amount and salinity of connate water reflect the depositional environment and diagenesis, but the defining idea is that it is original pore water preserved in the rock.