Question

What environment of deposition would produce a coarsening upward sequence of sand to fine siltstone, local cross-bedding, cut by distributary channel crossbedded sands that overlay marine clay deposits?

A. Braided stream

B. Glacial moraine

C. Volcanic arc

D. Delta

Answer 1

Answer: D. Delta

Delta form where river fall in to an ocean or sea. the sediment carried by river deposited at the mouth of the river forming a coarsening upward sequence means grain size increases upward. Many small channels cut the surface of delta and overlained by marine clay deposited from suspension during calm conditions.