Name/Title
Fossil Fern LeafEntry/Object ID
07.57.14Description
A low-detail fern imprint (really? The black material seems to suggest carbonization to me).
Leaf fossils in this case are carbon films that remain on the bedding surfaces of fine-grained sediments. Fossilization happened after the leaves sank to the bottom of a pond or lake and were later buried by additional fine-grained sediments. With burial, the leaves were compressed and the sediment surrounding them solidified. Eventually these fine-grained sediments became shale or mudstone. When all the volatile organic material in the living leaf was pressed out, only a thin carbon residue was left in the sediment, marking the outline and veins of the leaf.
Clade: Tracheophytes
Division: Polypodiophyta
Class: Polypodiopsida
Family: Unknown
Genus: Unknown
Common name: Fern
Rock and Mineral Data (Silica):
Assemblage Zone: shale
Chemical Composition: Si O2
Crystal System: Subhedral
Type of Fossils Present: Plants
Fracture: conchoidal
Grain Size: Medium
Hardness: 7 Quartz
Luster: Vitreous
Occurrence: The concretion occurred in localized deposits within the silty to sandy mudstones on the lower four meters of the formation. The paleoecosystem is believed to be a large river delta system deposited by at least one major river system flowing from the northeast. The sediments are believed to derive from the Appalachian orogeny events. The delta had a tropical climate, a result of the area being within 10 degree north latitude of the equator during the Pennsylvanian.
The remains of plants and animals were rapidly buried by the sediment deposited in the deltaic system. Bacterial decomposition of the remains produced carbon dioxide that combined with dissolved iron from groundwater. This process formed siderite in the sediments surrounding the remains, forming detailed casts of their structure. Lithification of the sediments formed protective nodules of ironstone around the now fossilized remains. The ironstone concretions are recovered from exposures along streams, roadcuts, and in active or abandoned coal mine areas.
Pressure: Moderate
Rock Color: Dark
Rock Origin: Marine/Freshwater
Rock Type: Sedimentary
Specific Gravity: 2.6
Surface Process: Not apparent
Temperature: Low
Texture: fine grainCollection
Fossil CollectionAcquisition
Accession
07.57Source or Donor
Fossil CollectionAcquisition Method
DonationOther Names and Numbers
Other Number
Other Number: 2007.57.14Dimensions
Width
2-3/4 inDepth
1/4 inLength
3 inDimension Notes
Dimensions taken at widest pointsLocation
Location
Container
RightDrawer
2nd ShelfShelf
RightCabinet
Case #102Wall
East WallBuilding
Mentzer Hall - Petrified Wood RoomCategory
PermanentNotes
Labeled as 05.57.14 in exhibit, but this seems to be in error.
