Geobulletin alpha

Source info:

Author:	Kentuckiana Mike
Date:	2011-09-27 11:30:00
Blog:	Louisville Area Fossils
URL:	http://louisvillefossils.blogspot.com/2011/09/uv-fluorescent-brachiopods.html

Summary:

This fossil plate of a cluster of Sowerbyella brachiopod shells appears to have a unique property of fluorescence under longwave ultraviolet light (394? nm).  My light produces a lot of visible purple light so the specimen appears quite purple with some orange-brown color on some shells.  In person, the orange-brown color is much more pronounced.I believe the mineral present is aragonite with a manganese activator.  Referring to the book The Uranium and Fluorescent Minerals: A Handbook of Uranium Minerals and A Field Guide for Uranium Prospecting 3rd Ed. by H.C. Dake, page 21, it lists "ARAGONITE. A calcium carbonate that fluoresces and phosphoresces variably.... When manganese is the chief activator the luminescence is orange or red-orange, and usually faint."These fossils are from the Kope Formation of Kentucky and that layer is known for its aragonite fossils (usually brown).  I need to now go through the collection and test them for fluorescence.Another issue I need to solve is filtering visible purple light from my UV light. I might have to go Thomas Edison on it and just start trying different materials for filtering properties.

Content analysis:

Stratigraphic context:

Recognized stratigraphic terms [n]:	Kope Formation [1]
Agenames chronostratigraphy [rating]:	[0.1] Upper Ordovician [0.1] Middle Ordovician [0.1] Ordovician [0.5] Paleozoic [0.5] Phanerozoic [0.5]

Geographic context:

Location	Country	Latitude	Longitude
Kentucky	US	37.8224	-85.6909
Aragonite	US	40.7422	-113.002

Keywords:

aragonite, aragonite fossils, calcium carbonate, chief activator, different materials, Field Guide, fluorescence, Fluorescent Minerals, fossil, Kope Formation, longwave ultraviolet light, luminescence, manganese activator, mineral present, minerals, orange-brown color, ordovician, Prospecting, Sowerbyella brachiopod shells, specimen, Thomas Edison, ultraviolet, unique property, Uranium, Uranium Minerals, UV Fluorescent Brachiopods, UV light, visible purple, visible purple light