Seds refs

Question 1

Structures

Answer 1

Mike Leader, 2011

Question 2

Skewness

Answer 2

M Tucker 2001
A measure of the symmetry of the distribution of grain size and sorting
• +0.3 = strongly fine skewed to -0.3 = strongly coarse skewed
• Reflects the depositional environment
o Beach sands have a negative skew because finer components are carried off by wave action
o River sands are positively skewed as the silt and clay is not removed by currents but is trapped between larger grains
• In general sediment becomes more negatively skewed and finer grained along its transport path

Question 3

Compaction

Answer 3

Bjørlykke 2013
Grain size, shape and sorting, both in sandstones and mudstones, play an important role in determining the mechanical compaction prior to chemical compaction
Also temps for chemical compaction
- 90-130 for quartz over growth
- 60-80 for calcite cement
- 80-90 illite
Fawad (2010) – poorly sorted sediments are more resistant to mechanical compaction

Question 4

Evaporites

Answer 4

Leader, 2011
Although several periods during the Phanerozoic have been marked by impressive occurences, e.g. opening of the Atlantic and the Red Sea ocean basins, and desiccation of the Miocene Mediterranean

Question 5

Alluvial fans

Answer 5

Iran - Zagros Mountains and fault zone
Jones - 2013 - This study has demonstrated that although tectonism can induce fan development, it is the sensitive balance between aridity and humidity resulting from changes in the climate regime of a region that influences the nature of fan sequences and how they interrelate to associated fa- cies. This is easily overlooked in the need to identify tectonic events and interpret ancient basin history

Question 6

Deep ocean seds

Answer 6

Leader 2013
Ocean floor above the CCD = biogenic calcareous oozes dominate - cocolithophore
Ocean floor below CCD = red clay

Question 7

Controls on seds

Answer 7

Jones 2103 - The concept of autocyclic and allocyclic controls on sedimentation and stratigraphy, emphasizing the climatic variable - Allocyclic vs autocyclic controls
Humphrey and Heller (1995) – Perturbed by allocyclic tectonics and climate but use autocyclic to stay in equilibrium

Question 8

Pebble Clusters

Answer 8

Renzo DalCin (1968)