Uranium mineralization has been intersected at or near the unconformity
between the Athabasca sandstone and basement rock units, often graphitic, with associated base metals values and rare gold occurrences at downhole depths ranging between 463 metres and 682 metres.
Almost all of the mineralization is located in the basal Athabasca sandstone, with the sub-Athabasca unconformity
being intersected at 331.4m.
The mineralisation is considered to be unconformity
related sandstone hosted Zn Pb type and is later than the MVT carbonate hosted mineralisation defined by previous explorers.
"There must have been some sort of special event in Earth's history that led to widespread erosion," said Steve Marshak, a geologist at the University of Illinois at Urbana-Champaign who studies what has come to be known as the Great Unconformity
. New research suggests it was something special indeed.
Chiltan Limestone of Jurassic age The Jurassic age Chiltan Limestone underlies the more deltaic to shallow marine sequence of Sembar and Lower Goru Formation of cretaceous age with an unconformity
High-grade intercepts were obtained at the sub-Athabasca unconformity
to the northeast of Gryphon from reconnaissance drill fences spaced 200 meters apart, including: 0.55% eU3O8 over 5.6 meters, including 2.3% eU3O8 over 1.0 meter; and 0.94% eU3O8 over 3.5 meters, including 2.7% eU3O8 over 1.0 meter.
A glacially-driven regression and transgression sequence could account for the Pleistocene/Holocene unconformity
(Broster and Legere 2016a, b) that is widely recognized to depths as deep as -90 m (Kelley et al.
The main controlling factors of the Ordovician karst systems are uplift, unconformity
, fault systems, rock physical properties, and sedimentary facies [13, 26].
Each one of the erosional episodes is indicated by the presence of an unconformity
affected sedimentary material, which had already been consolidated into rock before subsequent layers of sediment were deposited.
Investigations performed along the Middle Jurassic Alpine Tethyan unconformity
surface of E Sardinia evidenced an elaborate surface that developed over older Late Paleozoic to Triassic rocks.