Lab 3 Sedimentary Rocks
A. Identify the sedimentary rock samples provided on Canvas. For each sample, determine the composition of the rock, its grain size
(if it has grains to begin with), any structures or fossils you may see, and the energy of the water (or wind) by which the sediments
would be deposited.
Sample
#
Biogenic,
Chemical, or
Clastic
Grain Size
(gravel / sand / mud,
“NA” if not clastic)
Structures, Fossils or
Other Comments
Depositional
Energy
(hi, med, low?)
Rock Name
1
Clastic /
Biogenic
NA / Seashells in the
Matrix
Lots of fossils, snails,
bivalves
low
Coquina
2
Biogenic
NA
Loose sedimentary rock
with shell and coral
fragments
low
Coquina
3
Clastic
Gravel
Poorly sorted
High
Conglomerate
4
Clastic
NA
Conchoidal Fracture
Low
Anthracite / Coal
5
Clastic
Mud
Laminated
Low
Shale
6
Clastic
Sand Sized
Sand sized mineral
particles or rock
fragments
Medium
Sandstone
7
Chemical
Mud
Conchoidal Fractures
Medium
Chert
8
Biogenic
NA
Microscopic organisms
skeletal.
Low
Chalk
9
Chemical
NA
Effervescence when
powder
Low
Dolostone
10
Clastic
Gravel
Angular Fragments
High
Breccia
11
Clastic
sand / mud
Poorly sorted structure
High
Graywacke Sandstone
12
Chemical
Mud
Conchoidal Fractures
High
Chert
