https://wserv3.esc.cam.ac.uk/p1acollections/items/browse?sort_field=Dublin+Core%2CTitle&page=27&output=atom <![CDATA[1A Collections]]> 2024-04-09T21:26:13+01:00 Omeka https://wserv3.esc.cam.ac.uk/p1acollections/items/show/267 <![CDATA[<h2>Zonation</h2>]]> Have a look at the granodiorite (L120) in the 1A Reference Series.]]> 2019-07-04T09:53:29+01:00

Title

Zonation

Subject

As a crystal grows slowly in a magma chamber the magma from which it is crystallising may evolve, changing its composition. Thus later crystallising regions or “zones” of the crystal will have a slightly different composition from earlier crystallising regions. The crystal thus displays zonation.
Zonation is seen under cross-polarised light by variations in the birefringence colours of the different zones.

Description

Have a look at the granodiorite (L120) in the 1A Reference Series.
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/269 <![CDATA[Chronostratigraphic Chart]]> 2019-08-06T11:11:01+01:00

Title

Chronostratigraphic Chart
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/268 <![CDATA[Michel-Levy Chart]]> 2019-07-04T14:13:12+01:00

Title

Michel-Levy Chart
]]> https://wserv3.esc.cam.ac.uk/p1acollections/items/show/239 <![CDATA[Pleochroism]]> Have a look at hornblende amphibole (M201, M211) and biotite mica (M303, M304) in the 1A Reference Series.]]> 2019-07-04T09:53:21+01:00

Title

Pleochroism

Subject

Some minerals are pleochroic. When rotated under plane polarised light they change colour. Biotite and the amphibole hornblende are pleochroic.

Description

Have a look at hornblende amphibole (M201, M211) and biotite mica (M303, M304) in the 1A Reference Series.
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