Please enable JavaScript.
Coggle requires JavaScript to display documents.
Serpentinite (Accomodating size discrepency ( Tetrahedron rotated, …
Serpentinite
Accomodating size discrepency
Tetrahedron rotated
Sheets flexed & periodically reversed
4 major structural types
Sheets flexed & coiled
Polygonal serpentine
Serpentine
= hydrated phyllosilicate minreal
ideal formula Mg3 Si2 O5 (OH)4
TO type
tetrahedron layer - Si groups
octahedron groups - Mg
Size discrepency Mg vs Si
Layers cannot fit together
Unless structure accomodates this
4 serpentine structures types
Lizardite
slight tetrahedron rotation
Antigorite
Slight flexure & periodic reversal
Stripes show alternating T-O
Chrysotile
Flexing of sheets to form coils
Very fibrous
Cannot form
large structures
flexure greatest @ coil centre ∴ layers stretched less there
moving outward, layers increasingly stretched
Polygonal Serpentine
Discontinuities accommodate flexure disparity btwn outer & inner coils
Allows bigger coils to form
Serpentine Formation
via hydration of Mg silicates i.e. olivine & pyroxene
mantle rock + water ---> serpentinite
density reduction accompanies formation (3.3. - 2.7 g/cm^3)
Serpentinite Rock
= rock composed of serpentine group minerals
Weathering / alteration minerals i.e. formed via serpentinisation
Shapes vary
Usually green
Serpentine
group minerals
form via serpentinisation
i.e. hydration & metamorphic transformation of ultramafic rock from Earth's mantle