FORAMINIFERA:

Part x - Foram Test Shapes & Apertures

GEOL 3213

Micropaleontology

Foram Test Shapes

Foram Test Shapes

• Pyrgo (= Biloculina)

• Triloculina

• Quinqueloculina

Accessory Structures on Foram Tests

Foram Test Shapes, A Review

Shapes of Unilocular Tests

Modes of Chamber Addition

• Uniserial growth is shown for simplicity.

Stopped Here

Chamber shapes

Chamber Shapes

Foram Apertures

• Position of hole(s):

Foram Apertures

• Shapes of the hole itself:

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Microscopes used in Studies

• Transmitted light – whole mounts• Transmitted light – thin sections• Reflected light• SEM

Generalized History Based on Wall Composition & Structure• Note:

– Early organic walled & arenaceous forams in Cambrian

– Calcareous microgranular forams in Ordovician

– Porcelaneous in Carboniferous

– Hyaline in Permian– Planktic in Late Jurassic– Nummulitids = Late K to

Early Cenozoic

Review Early History of Forams

Review Later History of Forams

CLIMATE CHANGES INTERPRETEDFROM DEEP-SEA CORES

• O18/O16 ratios from used to determine – Paleotemperature changes with planktic species & – Ice-volume changes with benthic species

Triserial, planktic