Mineral Assessment Report 19970006

TUL Petroleums Ltd. - Assessment work report 1997, Part I: Lamprophyres of the Peace River District, Part II: Ashes of the Peace River District

Permit Holder: TUL Petroleums Ltd

Authors: Stapleton, Murray J.

Executive Summary

Part I The assessment report consists of 20 permits or 200,000 hectares located along the Montagneuse Fault in townships 80 to 89,ranges 1 to 13W6; NTS map sheet 84D.

South African diamond explorers have been telling North American geologists to look for diamonds on the North American Craton for twenty years. Diamonds have been found scattered around North America in a seemingly random pattern. That fact supported the South African claim that the ancient Precambrian North American Craton is sufficiently thick, cool and old to harbour diamond stability fields and that diamond formation and preservation regions in the upper mantle extruded diamond host rocks which breached the crust at one time or another and liberated diamond at surface.

Several source areas such as Crater of Diamonds State Park, Arkansas were identified in the United States, but none produced the quality and quantity of diamond that resulted in feasible consistent production of diamond. Instead, these diamond source locations remained oddities and academic centres of interest and study.

DeBeers has been sampling Canada for twenty years for diamond indicators and diamonds. Much of the information which they have gathered will never become public. DiaMet Minerals made an all-out effort to find a source of diamond during the 1980s and into the 90s. This historic exploration effort has been well documented in newspapers and conference presentations.

The DiaMet methodology relied almost entirely upon geochemistry. The geochemistry of diamond host rock is quite specific. In general, diamond is formed over long periods of time, under great pressures at low mantle temperatures. Once formed, mantle conditions must remain within a certain regime to preserve diamond. This regime called the diamond stability field, is generally agreed to be; 1) located under ancient cratons, 2) located near thick slabs of crust referred to as continental roots which have a constant history and temperatures below the temperature at which diamond is destroyed. North America has a number of such crustal regions. North America qualifies as a good diamond production craton. Further, diamond stability fields, no matter where they lie, are strictly theoretical, in that diamond is only found at surface where there has been a breach of the crust therein tapping the mantle of a diamond stability field and where an appropriate host rock carries diamond to surface, and where the dynamics of that intrusive event have not destroyed the "hitchhiker" diamond in the process.

All of these accepted ideas about diamond formation, host rock composition and transport to surface, are simple and acceptable to most people. However, to experts who deal with diamonds and host rocks and the dynamics of their to-surface emplacement, they know that each one of these ideas is in dispute and each one of these concepts is subject to scrutiny, exceptions to rules variations, refinements and re-interpretations. This Assessment Report addresses one or more of these issues specific to the Peace River District and the relationship of the ancient basement structure called the Peace River Arch, and overlying Phanerozoic sediments, to diamond stability fields and the host rocks which contain; diamond indicators, kimberlitic indicators and eclogite, in the Peace River District, and how these may be related to diamonds found elsewhere.

The Peace River District contains localities where diamond indicators and diamond stability field indicators can be found at surface. The Peace River District overlies potentially diamond productive craton. The Peace River District contains volcanic rocks at surface. These volcanic rocks are found as grabs; pebbles, cobbles and boulders; and sands, ashes and tuffs. The diamond indicators are located in trends. This report sets out our findings, following four years of investigating Peace River diamond indicator trends and where the Peace River volcanics are found, and challenges geologists as to the regional geochemistry and the connection between diamond indicators and the Peace River volcanic rocks.

Part II 1.There are volcanic ashes on the TUL properties in the Peace River District. 2.The continental crust of the Peace River Arch is thick enough to be a cool root which harbours a diamond preservation f field. 3.Ceochronology of the deep crust suggests fabric ancient enough for diamond formation. 4.Diamond host-type rocks are known in the West Peace River District and in the East Peace River District. 5.Diamonds have been found in west central Alberta and in the East Peace River District. 6.Volcanic ashes on the TUL properties in the West Peace River District suggest proximal intrusives on the properties TUL investigated bentonites in the West Peace River District. Volcanic ashes altered to bentonitic clays are a potential tool for exploration for diamond host rocks. Identifying the ashes and mapping and analysing their Rare Earths geochemistry, are likely ways to identify kimberlite targets.

By 1993 about twenty diamonds had been found in Alberta. No in-situ diamond host rocks were known. Diamonds and rumours of diamonds were treated with scepticism or as fluke occurrences and academic oddities.

In 1997 Alberta's basement has proved to host regions of potential diamond production. The Peace River District overlies a significant anticlinal basement structure known as the Peace River Arch. (PRA) The Peace River Arch produced diamond from a number of volcanic intrusive pipes drilled by Ashton Mining of Canada in the area called Buffalo Hills.

The Ashton pipes are hosted by the fault bounded PRA, which is segregated into the West PRA (WPRA) and the East PRA (EPRA) by an arcuate northwest trending shear zone. The Peace River area Precambrian continental landmass approximates the WPRA, while the EPRA was covered by a shallow sea. The shear zone which subdivides the WPRA from the EPRA approximates the location of the geochemical anomaly known as the Kimiwan Oxygen Isotope Anomaly. This is a basement geochemical anomaly which appears to be an ancient thrust zone. The granitic surface of the ancient Precambrian exhibits topographic positive anomalies on the arch in the EPRA and WPRA, within the north and south boundaries, which are not evident on the Precambrian as a whole. These seem to be related to the intrusives. Intrusives may be evidenced by ashes and crater facies material.

Both subdivisions of the PRA within the Peace River District, from the Alberta-B.C. border to Red Earth, contain reported kimberlite pipes. So far, its seems the WPRA - the Grande Prairie Pipes - have not been diamond productive, while the EPRA near Red Earth (Buffalo Hills) contains diamond productive kimberlite pipes. Much of the rock associated with the kimberlite finds is reported to be bedrock surface elevation crater facies material. TUL has proceeded with exploration on the basis that the WPRA ashes are related to local volcanic venting on the West Peace River Arch.

The Precambrian PRA is highly fractured and complex. Oil and gas exploration, diamond exploration and recent academic work have shown, that beyond the PRA having structure; fault systems, grabens and horsts; the Arch has also been the setting for volcanic activity not previously recognized. The results of TUL mapping the ashes may lead to diamond productive pipes on the WPRA.

 

Last modified: December 16, 2005