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Title: Partial Relinquishment Report for EL 25406 Fog Bay and Final Report for EL 26420 Fog Bay East Year Ending 9 April 2009
Title Holder / Company: Hapsburg Exploration
Report id: CR2009-0548
Tenure: EL25406;  EL26420
Year: 2009
Author: McGregor-Dawson, J
Abstract: Hapsburg Exploration Pty Ltd was granted EL 25406 (Fog Bay) on the 10th of April 2007, for a period of six years. EL 25406 (Fog Bay) tenement consisted of 25 sub-blocks and covers an area of 77 km2. On the second anniversary of grant (10th April 2009), EL 25406 was reduced by about half, to 13 sub-blocks covering about 40 km2. This report represents the Partial Relinquishment Report for the 12 sub-blocks released. On the 23rd of April 2008, Hapsburg was granted EL-26420 (Fog Bay East) consisting of 7 sub-blocks totalling about 17 km2. The sub-blocks of EL 26420 occur along the north and east side of EL 25406. EL 26420 was relinquished in entirety in mid 2009 and this report represents the Final Report for this exploration licence. These two tenements are located on the north side of the mouth of the Finniss River, about 60 km south-west of Darwin. These tenements are bordered by 5 Mile Beach on the west, Wagait Aboriginal Reserve on the south, the residential areas of Dundee Beach and Fog Bay Road on the north and north-east. The eastern boundary used to be bordered by tenements held by Uranex NL, but these have since been relinquished. The Fog Bay tenements are located in the northern part of the Litchfield Province, which is described as a medium to high grade metamorphic terrane comprising metasedimentary and igneous rocks of Archean(?) to Lower Proterozoic age. This basement block (or province) lies on the west side of the Pine Creek Orogen and extends for several hundred kilometres in a north-south direction, and is up to 60 km wide. The Litchfield Province is also cut by (and in part bound by) several major faults which appear to be part of the Halls Creek Mobile Zone fault system. The Litchfield Province contains a centrally located syn-orogenic granitoid of presumed Lower Proterozoic age. This granitoid is enveloped by a suite of recrystallised carbonate rocks, calc-silicate rocks, amphibolite, biotite quartzofeldspathic gneiss, graphitic schist/gneiss, quartzite, sideritic iron formation and ultramafic rocks. This suite of rocks forms the Sweets Unit of the Welltree Metamorphics, and corresponds with pronounced aeromagnetic and radiometric anomalies. This unit has been correlated (by some) with the Cahill Formation of the East Alligator Rivers Uranium Field (the Cahill Formation is host to the Jabiluka, Koongarra, Nabarlek and Ranger Uranium Province). Within Hapsburg's tenements, the main rock exposure is a linear outcrop of mildly metamorphosed ferruginous, and pebbly sandstone which is correlated with the Depot Creek Sandstone that forms the Tolmer Plateau. Cretaceous age lateritic sandstone (Bathurst Island Formation) covers the northern and eastern parts of the tenements to a depth of up to 60m. A geology map of the Fog Bay area (by Idemitsu) shows possible Burrell Creek Formation occurring to the east of the Depot Creek Sandstone (presumably underlying the laterite cover seen on EL 26420). Then further to the east is a north to north-east trending unconformity that separates the Burrell Creek Formation from the Port Patterson sequence. To the west of the Depot Creek Formation, the basement rock is interpreted to be the Wagait Granite (however Idemitsu had no drilling in this area). The area to the west of the Depot Creek Formation is covered by the Quaternary age sand dunes and is very difficult to access. The sub-blocks of EL 25406 which covered this sand dune area were relinquished. No significant magnetic anomalies are present in this relinquished area. The NTGS geology of the area shows Wagait Granite occurring on both sides (E & W) of the Depot Creek Sandstone in the south part of Hapsburg's tenement. This is based on two NTGS stratigraphic drill holes in the south part of Hapsburg's tenement. In contrast, the NTGS shows the Depot Creek Sandstone in the northern part of Hapsburg's tenement to be bracketed by Palaeoproterozoic gneissic rocks. This is based on four NTGS stratigraphic drill holes within or adjacent to the northern part of Hapsburg's tenement. Only minor surface work has been done directly on Hapsburg's tenements (EL 25406 & 26420). However, significant exploration for uranium and base metals was done about 15 to 25 km to the east of Hapsburg's tenements; without success. The Fog Bay area has seen past exploration for a diverse range of commodities. In the 1960s Placer Limited explored for mineral sands in the beach deposits, without success. Others (including BHP) have explored for base metals (Pb & Zn) in the Proterozoic basement rocks, especially to the east of Hapsburg's tenements. This work showed only weak Pb-Zn values in fault structures largely cutting carbonate units. Various companies such as Greenbushes have explored pegmatite bodies for tin and tantalum, with several small operators having exploited small deposits. To the east of Hapsburg's Fog Bay tenements, there has been substantial uranium exploration conducted by Esso Australia Limited, AOG Minerals Limited in joint venture with Union Oil Development Corporation, and the Urangesellschaft - Idemitsu Joint Venture. Virtually all airborne radiometric anomalies were investigated without any significant uranium responses being found. Much effort was expended on evaluating the stratigraphy in this area, in an effort to show it to be equivalent to the Cahill Formation of the East Alligator Rivers Uranium Field. Despite the apparent success of proving stratigraphic equivalence, the surface surveys and drilling still failed to locate any uranium. Hapsburg's exploration target for this area is an unconformity type uranium deposit (vein type) within a unit thought to be analogous to the Cahill Formation of the East Alligator region. It is suggested that vein pitchblende mineralisation could occur within graphitic micro-gneiss units of the Fog Bay Metamorphics, showing Mg metasomatism and chlorite alteration and related to intrusives. A government regional geophysical survey had previously been flown in a north-south direction generally parallel to stratigraphy. This limits the full magnetic response, so Hapsburg commissioned a new aeromagnetic survey to be flown with east-west flight lines, 100m spaced lines and a sensor height of 50m. Universal Tracking Systems (UTS) of Perth was awarded the contract, and the survey of 2,210 line kilometres was flown in late December 2007. This resulted in the selection of four areas (A to D) for follow-up ground magnetic surveys and geological reconnaissance. No physical exploration was conducted on the relinquished sub-blocks of EL 25406 or EL 26420 during the 2008 field season.
Date Added: 24-Oct-2013
Appears in Collections:Minerals Exploration Reports (MEX)

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