BRYSON BURKE
Home
Mission
Board
History
Business Plan
Latest Information
Building Our Drill
Innovation
Photo Album
Satellite Weather
Free News - Sign Guestbook

INVESTING
Investment
Stock Quotes

COMMUNICATION
Press Releases
Newsletter
Current Information
Contact

SITE GEOLOGY
Geology Reports
Site Geologic History
Magnetic Maps Index
Heavy Minerals Index
Grenville Province Index

DIAMOND POLITICS
Blood Diamonds
Kimberley Process

DIAMOND GEOLOGY
Indicator Minerals
Kimberlites
Decay of Kimberlites
Kimberlites & Magnetics
Placer Deposits
Magnetic Reversal
Crustal Thickness
How Diamonds are Made
Glaciation Issues
Mineral Transport Index
Doing the Map Work
Gathering Samples
World Mining Index
Excavation and Recovery
Mining Corporations
Mining News Magazines
Environmental Issues
Diamonds in Space
World's Only MineCam
Live Volcano Geo-Cams

EXPLORATION
Site Exploration History
Topography Map Index
Location Map
Claim Maps Index

DIAMONDS
Diamonds and Graphite
Diamond Formation
Grading Diamonds
Price of Diamonds
Industrial Diamonds
Drilling Equipment
Medical Use of Diamonds
Gemstones
Birthstones
Hall of Fame

DIAMONDS IN CULTURE
Good Books on Diamonds
Cremains to Diamonds
Diamonds in Lawsuits
Irish Diamonds
Unusual Diamond News
Diamonds in the Media
Famous Jewelers
In Advertisements
Top Twenty Cut Diamonds
Top Diamonds
Diamond Lore
Theft/Hoaxes/and Fraud
Religion Index
Diamond/ Culture Index
Television
Movies
Games - Play Now
Music
Weddings
Royals
Our Darlings
Diamond Animal Index

INTERACTIVE
Reflection/Refraction Index
Crossword Puzzle Index
Which Is A Diamond I
Which is a Diamond II
Become a Gemologist

Indicator Mineral Formation in Hydrous Eclogitic Environment

In order to investigate the distribution of trace elements including REE in Ca-, Al-rich eclogites (grospydites) we have performed high-pressure piston cylinder experiments (Bayerisches Geoinstitut) on glasses of natural plagioclase-rich cumulates doped with 500 ppm of Rb, Sr, Zr, Hf, REE, Th and U. Experimental conditions were 1100°C at 3.0 to 3.5 GPa for times of 86, 168 and 184 hours in Ag25Pd75 capsules. The total iron loss was < 0.5 wt.%. The aim of these experiments is to understand the phase transformations and element partitioning that occurs in delaminated continental crust.

Anhydrous experiments produced garnet, kyanite, clinopyroxene, and glass as well as very fine-grained trace element-rich phases (allanite-type, oxides). The small grain size (< 15 µm), the impurity of crystals (inclusions, zoning) and the heterogeneous distribution of the trace element-rich phases prohibits in-situ trace element measurements.

Addition of 2 wt.% H2O yields fully crystallized assemblages of garnet, kyanite, clinopyroxene; in these experiments the fine-grained trace element-rich phases are absent. These run products differ from natural grospydites by the presence of abundant zoisite. Their grain size of up to 30 µm allows in-situ trace element partitioning measurements.

Small amounts of water seem to be essential in the formation of eclogite. The appearance of fine-grained trace element enriched phases under dry conditions points to difficulties in forming homogeneous mineral compositions on a hundred-ppm trace element level and may related to the very slow diffusion rate. The production of relatively large amounts of zoisite is an unforeseen effect in the hydrous experiments however, addition of water yields a homogeneous trace element distribution among the mineral phases probably due to the faster distribution rate. Comparison of EMP mineral data from natural grospydites and the experimental assemblages will allow us to better understand the partitioning of trace elements in natural grospydites.

Eclogite Formation
Prototerozoic Reworking of Archean Lower Crust and MOHO

Kimberlite Steals Diamonds from Eclogite!

Kimberlites are generally much younger than the diamonds they bring to Earth's surface. Kimberlites and lamproites have been dated between 50 and 1,600 million years old. Diamonds associated with harzburgites are about 3.3 billion years old -- more than two thirds the age of Earth itself, and those from eclogites generally range from 3 billion to less than 1 billion years old. These age differences help clarify a picture of diamonds having crystallized and been stored beneath the ancient continental cratons and only later being lifted to Earth's surface by kimberlites.

Since inclusion minerals crystallized simultaneously with their diamond host, the age of the inclusions gives the age of the diamond. The ancient age of peridotite diamonds suggests that the formation of ancient Archean continental cores (archons) included diamond crystallization in the underlying mantle lithosphere. A relatively cool, rigid, deep keel beneath these continental nuclei provided a stable environment in which diamonds crystallized and were stored. Subsequently, oceanic crust diving into the mantle was metamorphosed into eclogite and pasted onto this keel. Much later passage of kimberlite magmas through the keel dislodged diamonds from both peridotite and eclogite and sent them to Earth's surface.