Birch

Object/Artifact

-

Crater Rock Museum

Name/Title

Birch

Entry/Object ID

05.58.10

Description

Assemblage Zone: sediments Chemical Composition: Si O2 Crystal System: Hexagonal Description: Family: Betulauae Genus: Betula-like Common Name: Birch Age: Late Eocene to Early Oligocene Location data: Payne Cliff Formation, Sams Valley, Jackson County, Oregon, USA Description: Small round piece of petrified wood from Sams Valley. The specimen is filled with opal and agate on the uncut side. The polished face shows a tan color with cracks clear agate and one spot of white agate. Growth rings, rays and grain are apparent. Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz Lithofacies: nearshore environments Luster: Glassy Occurrence: Late Eocene nearshore environments are represented by conglomerates and sand of the Payne Cliffs formation exposed in a northwest trending belt along the Bear Creek Valley near Ashland. Grading upward into ash, tuffs and lava flows, the Payne also record the earliest volcanic activity of the Western Cascades and the deposition was primarilyby a extensive braided river which flowed to the north. Pressure: Moderate Rock Color: Medium Rock Origin: Post-depositional Rock Type: Sedimentary Specific Gravity: 2.6 Surface Process: Not apparent Streak: white Temperature: Low to moderate Texture: Mircrocrystalline Variety: Petrified woods here are hydrous microcrystalline variety of quartz that can be generally termed as chalcedony. Silicified wood, which is the fossilization and opalization of organic woody matter by the deposition of SiO2 in a anaerobic environment to prevent decay. This means that the wood must somehow be buried in an oxygen free enviroment, possibly in the silt-laden river or the bottom of a lake or buried by volcanic ash or related volcanic mudflow. The organic material in the wood is then replaced by silica (SiO2), other minerals determined its colors.

Collection

Petrified Wood Collection

Acquisition

Accession

05.58

Source or Donor

Petrified Wood Collection

Acquisition Method

Donation

Other Names and Numbers

Other Number

Other Number: 2005.58.10

Dimensions

Width

2-1/4 in

Depth

1 in

Length

2-1/4 in

Dimension Notes

Dimension taken at widest points

Location

Location

Display Case

PW-7

Room

Petrified Wood Room

Building

Crater Rock Museum

Category

Exhibit

Moved By

Jillian Mather Kettley

Notes

Location/inventory