Question

What kind of environments produce fine horizontal bedding (laminated bedding) in sedimentary rocks? a) Glacial deposition b) Transitional environments c) Acolian deposition d) Running Water e) Still water What is the most abundantmineral in biochemically precipitated sedimentary rocks? a) Clay minerals b) Feldspar c) Metal oxides d) Quartz e) Calcite In which of the following sedimentary environments would you expect the sand deposits to be the most poorly sorted? a) Delta b) Alluvial Fan c) Beach d) Sand dune e) Marine Basin I You find a series of sedimentary rocks that contains evaporate beds (gypsum and halite) between finely laminated mudstones and limestone. In what environment were these rocks probably deposited? a) A seasonally dry salt lake b) A seasonally flooded riverbed c) A lagoon behind a reef d) An anoxic marine basin e) An alluvial fan

Answer 1

1.The correct option is Aeolian deposition because sedimentary rocks are deposited in the form of beds (mostly in horizontal layers). Hence, these aeolian deposition through wind actions produce horizontal bedding in sedimentary rocks. Whereas other given features are not found in horizontal or laminated bedding form.

2.The correct option is calcite. Calcite is a carbonate mineral which produces limestone. It is found in biochemically precipitated sedimentary rock in limy ooze.

3. The correct option is alluvial fan because they are a mixture of rock and fragments in heterogeneous form which also consists of coarse grained sand and mud whereas other sedimentary environment Delta, beach, sand dunes and Marine Basin are formed through a long process of sand deposit.

4. The correct option is A, a seasonally dry salt lake because gypsum and halite are rocks found in evaporated salt lake or saline water. Whereas in other options they don't contain gypsum or halite and aren't evaporated beds.