Teredo-bored Wood

Object/Artifact

-

Crater Rock Museum

Name/Title

Teredo-bored Wood

Entry/Object ID

05.58.164

Description

North Dakota was one of the first states to have a state fossil. The state fossil of North Dakota is the 60-million-year-old petrified wood called Teredo-bored petrified wood Cannonball Fm. Teredo-bored petrified wood got its name because little clams called “teredos” drilled tiny holes into the wood before it fossilized. Sometimes those clams are called “shipworms” because they also bored holes in wooden ships. Assemblage Zone: mudstone & sandstone Chemical Composition: Si O2 Crystal System: Hexagonal Description: Family: Cupressaceae Genus: Cupressinoxylon Common name: cedar-like wood bored by "ship worms" (bi-valve Teredo mollusks) Age: Cretaceous Location data: Cannonball Formation, Morton County, North Dakota USA Description: Polished cut slab with colors white, grey, black, yellow and orange. The growth rings are apparent and the slab is a complete round *** CANNONBALL: NORTH DAKOTA’S LAST SEA**** The last sea to cover North Dakota was the Cannonball Sea. About 60 million years ago, during the Paleocene, that sea receded from North Dakota. Sediments deposited in the Cannonball Sea are called the Cannonball Formation and consist mostly of sandstones and mudstones. Fossils found in these rocks provide information about the kinds of animals that inhabited the sea. Remains of large marine reptiles, mosasaurs and plesiosaurs, that lived in Cretaceous seas are not found in the Cannonball Formation because they had become extinct at the end of the Cretaceous at the same time that dinosaurs became extinct. The main predators in the Cannonball Sea were sharks. Remains of several species of sharks, including the sand tiger shark, Carcharias, have been found. Many other kinds of fish including stingrays, eagle rays, and ratfish also lived in the sea. Invertebrate animals inhabited the shallow water areas and shorelines including cephalopods, clams, snails, crabs, shrimp, and lobsters. Teredobored petrified wood, North Dakota’s state fossil, occurs in the Cannonball Formation. This is driftwood that had been bored into by shipworms (which are clams) before becoming petrified. Type of Fossils Present: Plants Fracture: conchoidal Grain Size: Fine Hardness: 7 Quartz Lithofacies: Marine sediments Luster: Glassy Occurrence: 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. Pressure: Low-Moderate Rock Color: Medium Rock Origin: Post-depositional Rock Type: Sedimentary Specific Gravity: 2.6 Surface Process: Not apparent Streak: white Temperature: Low Texture: Mircrocrystalline Variety: Petrified woods here are hydrous microcrystalline variety of quartz that can be generally termed as chalcedony.

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: 2005.58.164

Dimensions

Width

5-1/2 in

Depth

3/4 in

Length

8 in

Dimension Notes

Dimension taken at widest points

Location

Location

Shelf

Top center in the ce, Top center in the ce

Wall

right - east

Room

Wood room

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent

Moved By

Catherine Boyd

Date

March 6, 2008

Location

Container

Left

Drawer

3rd Shelf

Shelf

Left

Cabinet

Case #104

Wall

East Wall

Building

Mentzer Hall - Petrified Wood Room

Category

Permanent