Regolith Flashcards
What are the two stages of Regolith growth?
- Bedrock excavation by impacts
- Layer growth
What are contributors to space weathering?
- Comminution (bombardment)
- Agglutination (min./rock welding)
- Solar Wind Particle Implantation
- Exposure to Solar Flares
What are Agglutanates?
- Individual particles < 1 mm
- Aggregates of smaller particles
- Irregular shape
- Contain Fe droplets and solar wind implants (He, H)
How do Agglutinates form?
- Soil with solar wind elements impacted
- Melting forms glass and liberation of gases forms vesicles
- H reduces FeO in glass resulting in Fe and H20
- Cooling, trapping of some gases
What are some indicators of surface Maturation?
- I_s/FeO
- Mean grain size
- Track density
- Agglutinate content
- Content of solar wind elements
- Depletion of volatiles
- Presence and degree of isotopic mass fraction
What are the effects of space weathering?
- Degradation of absorption lines
- Darkening
- Reddening
- Bluing of NUV spectrum
What is the effect of turnover / gardening?
- Size sorting
- Mixing of layers
What are the 5 classifications of regolith?
- Mineral fragments
- Pristine crystalline rock fragments
- Breccia fragments
- Glasses
- Agglutinates
What are Martian Blueberries?
- Hematite (Fe_2O_3) spheres several mm in diameter
What is Breccia?
- Rocks composed of compressed, fine-grained surface material caused by impact
What are the two types of breccia and what do they consist of?
Regolith breccia: Contains glass spherules and agglutinates
Fragmental breccia: contains only fragmental material
What kind of composition do Lunar Mare/ Lunar Highlands have?
Basaltic / Anorthositic
What is a mineral?
A solid chemical compound that
- Occurs naturally
- Has composition with minimal variance
- Has definite arrangement of atoms
- Can be mechanically separated from other minerals in rock
Are glasses considered minerals?
No
What are the most common lunar minerals and what are they called?
Silicates:
- Pyroxene
- Plagioclase feldspar
- Olivine
What are the second most common lunar minerals and what are they called?
Oxides:
- Ilmenite
- Spinel
What are the dark / bright spots on the moon made of?
Basalt / Anorthosite
What is the average thickness of regolith on Moon and Mars?
Moon: 4 to 5 m in mare and 10 to 15 in highland
Mars: Several meters
What is regolith subdivided into?
- Pedolith
- Saprolith
What are crater rays?
Fragmental material ejected from primary and secondary craters during impact events
What is lunar orange/green soil?
- Volcanic glass
What are important mineral properties?
from an ISRU perspective
- Separation ability
- Abundance
- Composition
