U.S. Geological Survey Certificate of Analysis
Dunite, Twin Sisters Mountain DTS-2B
Material used in the preparation of this reference material was collected from a quarry located in Twin Sisters Range, approximately 20-due-miles east of Bellingham, Washington. The Twin Sisters dunite is composed of virtually unaltered, coarse grained enstatite bearing dunite with accessory amounts of chromite and chromium diopside (Ragan, D.M., 1963). Mineralogical analysis of DTS-2B reveals that the dominant mineral is Fosterite (90+%) with minor amounts of chromite and trace amounts of lizardite. DTS-2B was collected from the same general location as DTS-1.
Element concentrations were determined in a round robin study involving 20 international laboratories. Recommended values are listed when analytical results provided by three independent laboratories using a minimum of two independent analytical procedures are in statistical agreement. Information values with standard deviations are listed when at least two independent laboratories have provided information. Information values without standard deviations represent information from a single laboratory or analytical procedure.
|Element||Wt %||±||Oxide||Wt %||±|
Dr. Stephen Wilson
U.S. Geological Survey
Crustal Imaging and Characterization Team
Ragan, D.M., 1963, Emplacement of the Twin Sisters Dunite, Washington: American Journal of Science, 261:549-565.
|±||One standard deviation|
|Wt %||Weight percent of element/oxide as received|
|µg/g||Micrograms of element per gram of sample, as received|
Unless otherwise indicated, total element concentrations are reported for material on an as-received basis.
Order and Pricing Information
Placing an Order
USGS reference materials may be obtained directly from Dr. Stephen A. Wilson. The price for each reference material is listed in U.S. dollars and are subject to change. For domestic orders, this cost includes all shipping and handling charges using normal mail delivery by the U.S. Postal Service. For foreign orders, delivery charges will be added to the final bill. Urgent requests for reference materials should be initiated by Fax or e-mail. If required, expedited delivery is available with any additional shipping charges added to the final bill.
Dr. Stephen A. Wilson
U.S. Geological Survey
Box 25046, MS 964D
Denver, CO 80225
FAX: 303-236-3200 or 303-236-1425
Domestic customers: Payment options include purchase order, check, money order, or credit card (Visa, Mastercard, American Express).
International customers: Payment on foreign orders can only be made using the following:
- Banker's draft against an international bank
- International money order
- Credit card (Visa, Mastercard, American Express)
Payments for domestic or international orders using a credit card receive a 10% discount on the per bottle price.
Beginning in 2006, users of USGS geochemical reference materials must complete a user agreement form prior to the order being processed. This agreement is required by the USGS Technology Transfer Office for complying with the United States Economy Act, 31 USC 1535A.
Please download the agreement form and follow the instructions on the form when placing your order.