Sedimentology

Question 1

What do low angles of undulosity show in detrial (survives weathering) quartz grains?

Answer 1

Lowest angles being plutonic (roughly 0-10) and (roughly 6-13) being metamorphic quartz

Question 2

Difference between the formation of annealed and sutured grain boundaries?

Answer 2

Sutured can form via dynamic recrystallisation and stress whilst annealed has only static recrystallisation and thermal grain growth

Question 3

What do red and blue colours in cathodoluminescence of quartz show about the grains formation?

Answer 3

Red = volcanic/plutonic/metamorphism
Blue = hydrothermal/high grade metamorphism

Question 4

What is provenance and the three methodologies?

Answer 4

“where the sediments came from and how they got where they are today” - petrographic, chemical and isotropic

Question 5

What is diagenesis and what conditions does it occur?

Answer 5

Physical and chemical alterations of sediment, occurring at low temperatures and pressures.

Question 6

What process determines the porosity and permeability of sedimentary rock?

Answer 6

Diagenesis

Question 7

What conditions are required for marine eogenesis? (early diagenetic processes in marine environments)

Answer 7

Salinity above 35 parts per thousand (average sea water), pH>7, SO4 2- (sulphate) and HCO3- (carbonic acid) are relatively high

Question 8

Characteristics of continental eogenesis?

Answer 8

Variable pH, lower sulphate and carbonic acid, pore waters acid where chemical weathering was intense, haematite beds

Question 9

What are the causes of sea level

Answer 9

Ice, thermal expansion, groundwater and lakes from 1-10ky and sf spreading, sedimentation and cont collision from 1my-100my