Glauconite Sand, offshore Chile

 

Box corer in use

Macro

Location

200 km offshore Concepcion, south central Chile, outer shelf, ca. 160 m water depth

Depositional facies

Outer shelf, ca. 160 km water depth

Provenance

Glauconitic fecal pellets (peloids)

Composition

Mainly glauconite, some phosphate

Texture

Well sorted, well rounded coarse-grained pellets. This is not really a natural sand because the grains were concentrated by washing and sieving from a muddy box corer sample

Petrographic thin section:

Description

Glauconitic fecal pellets with a phosphatic rind. The bottle-green color and the granular texture is a strong indicator for glauconite; the pleochroic wood-brown rind indicates the presence of phosphate.
Digested and excreted phosphatic components from the fecal pellets diffused outwards and precipitated at the contact with the seawater as Fe-phosphate

 

Bright field

Dark field

Sample number

heubeck0025

Collector

Christoph Heubeck, Institut für Geologische Wissenschaften, FU Berlin

Date of sampling

Dec. 2001

Comments:

This is not really a natural sand because the grains were concentrated by washing and sieving from a muddy box corer sample

Additional data page