Lithic grains in thin section – avoiding ambiguity
The utility of lithic grains as provenance indicators The composition of terrigenous sandstone is usually described in terms of the […]
Under the microscope
Neomorphic textures in thin section
The term neomorphism is reserved for recrystallization of a mineral and its polymorphs to new crystal phases having the same
Ignimbrites in outcrop and thin section
Ignimbrite is a rock name. Ignimbrites form primarily from the collapse of eruption columns during explosive volcanism and are included
Glauconite in thin section
Glauconite – an important stratigraphic and paleoenvironmental indicator Glauconite is one of the most recognizable minerals in the entire sediment
Carbonates in thin section: Forams and sponges
Two important contributors to bioclastic limestones – foram tests and skeletal sponge spicules Foraminifera Foraminifera (forams) are single celled,
Carbonates in thin section: Bryozoans
Bryozoa – are a complex but important group of reef and non-reef invertebrates and contributors to bioclastic sediment. Bryozoa
Carbonates in thin section: Echinoderms and barnacles
Echinoderms and barnacles are important contributors to bioclastic limestones Echinoids are a diverse phylum with a geological history dating back
Carbonates in thin section: Molluscan bioclasts
Molluscan bioclasts are important components of tropical, and cool-temperate water limestones Bioclasts are probably the most important components of Phanerozoic
Optical mineralogy: Some terminology
Petrographic (optical, polarizing) microscopes open doors to the architecture of rocks – crystals, grains, cements – a riot of colour
Greywackes in thin section
Greywacke petrography On the outside, greywacke is generally presented in varying shades of grey commonly with greenish hues, hammer-ringing hard,