FORAMINIFERA: Part x - Foram Test Shapes & Apertures GEOL 3213 Micropaleontology

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 INTERPRETED FROM DEEP-SEA CORES O18/O16 ratios from used to determine –Paleotemperature changes with planktic species & –Ice-volume changes with benthic species Triserial, planktic