Hanging wall

Hanging wall—[he block located above and bearing down on the fault. surface. 

Foolwall—lhe block that occupies the position beneath the fault, regardless of whether the hanging wall ha.s moved up or dowm. 

Reverse faulting—h2ts c3. y dominated by compression forces and, therefore, the hanging wall is moved up relative to the footwall. The reverse fault that dips at 30° or less becomes a thrust fault. 

The footwall and hanging wall to the gold zone are characterised by intense alteration of the mafic phases to carbonate and felsic phases to micas, in addition to the influx of silica ... 

Isotopic mapping of five selected areas in Canada and Sweden has indicated that the isotopic zones (5 0 <6%o and >9%o separate fields. Fig. 1) are not fully coeval. Values of 5 0 >9%o in hanging wall rocks largely indicate waning temperature and fluid flow, and post-date much of the high... 

Fig. 2b. Where deposition continues post-VMS, cooling, fluids from the buried hydrothermal system can produce high-5 0 zones in the hanging wall above up-flow conduits.

Fig. 2c. Successive intrusive episodes associated with hydrothermal activity can produce compound zones of isotopically altered rocks. The outer O-isotope isopleth is the youngest feature of the reaction zone, and the high 5 0 zone in the hanging wall, the youngest alteration feature overall. Post-hydrothermal intrusions usually lack oxygen isotope alteration.

Abstract Black shales in the hanging wall to the Pb-Zn VHMS deposits of the Mount Read Volcanics may have been altered by the underlying hydrothermal systems and the signature of such alteration may provide vectors to mineralisation. The major and trace element chemistry of the Rosebery Hanging wall Shale and the trace element chemistry of the pyrite and pyrrhotite that it contains have been investigated. Preliminary results indicate that a whole-rock Sb and Tl halo at the base of the shale unit is not as extensive as has previously been suggested. The elevated Co, Zn, As and Mo contents and Co/Ni of early pyrite, proximal to the orebody may provide vectors to underlying mineralisation. 

At Rosebery, studies of the hanging wall alteration by Large et al (2001a) indicated that, based on a limited dataset, whole-rock Tl, Sb, and Ba were all elevated in shale above the orebody, while characterisation of the trace element signature of sulfides is limited to two analyses of Co and Ni in pyrite by Loftus-Hills and Solomon (1967). 

In this contribution I present the preliminary results of an investigation into the alteration signature of the Rosebery Hanging wall shale, using an expanded whole-rock chemical dataset and trace element analyses of pyrite and pyrrhotite, the major sulfide minerals in the shale. 

Rosebery Hanging-wall Shale samples were selected from drill core in proximal (<120m from ore), medial ( 1000m) and distal (>4km) locations. 

Vertical sections through the Rosebery Hanging wall shale were sampled in drill holes from proximal and medial locations and results compared with those from... 

Preliminary results indicate that base and precious metal, As, and Ba contents of shale in proximal and medial locations are within the range of shale samples from distal locations. Only Sb, up to 23 ppm, and Tl, up to 9 ppm, in the lower 10-15m of the hanging wall shale are significantly higher than in medial and distal samples, with <8 ppm Sb and <1.4 ppm Tl. 

Preliminary results indicate that the alteration signature of shales in the Hanging wall of the Rosebery orebody is characterised by ... 

Gemmell, J.B. Fulton, R.L. 2001. Geology, genesis and exploration implications of the footwall and hanging-wall alteration associated with the Hellyer volcanic-hosted massive sulfide deposit, Tasmania, Australia. Economic Geology, 96, 1003-1035. 

Layton-Matthews, D., Gemmell, J.B., Large R.R., Peter J. 2008. Trace-element budget of the Que River shale exploration implioations of hanging-wall modification of sulfide minerals at the Hellyer deposit, Tasmania, Abstract. 33 International geological Congress, Oslo. 

The Arnold Pit is on the steeply dipping, overturned limb of the Sylvia Lake Syncline, the structural hanging wall is the stratigraphic footwall. Commercial talc occurs in Unit 13 near the contact with Unit 14 of the Upper Marble from the metamorphism or impure evaporative dolomite. The upper section of Unit 13 grades from tremolite-rich talc ore into a pure talc schist up section. Unit 12 is a white massive doiomitic marble with convolute bands of grey and orange to... 

Fig. 2. NbAT vs Zr/Ti02 discrimination diagram showing distribution of hanging wall tuff samples. Field boundaries are from Pearce...

Lithogeochemistry Both Key Anacon deposits have large, well-developed footwall and hanging wall alteration halos. Therefore, major- and immobile trace-element data are used to help discriminate rock types. 

Compositional mass change calculations confirmed that both the hanging wall and footwall volcanic rocks that host the... 

Abstract The Key Anacon Zn-Pb-Cu-Ag massive sulfide deposits contain more than two Mt of 0.22% Cu, 3.47% Pb, 8.41 % Zn, and 111 g/t Ag. These deposits occur in the hinges of parasitic F2 folds of Middle Ordovician felsic volcanic rocks. Zone refining of massive sulfide deposits (Cu-rich footwall to the Zn-Pb rich hanging wall) is controlled by temperature, pressure, metal ion concentrations, stabilities of soluble complex ions during transport, multiple hydrothermal episodes and mixing, and mineral free energies. 

Coleman M. E. and Hodges K. V. (1998) Contrasting Oligocene and Miocene thermal histories from the hanging wall and footwall of the South Tibetan detachment in the central Himalaya from thermochronology, Marsyandi... 

Mammillary calcite on the hanging wall of Devils Hole is white, translucent, and unbanded. Footwall mammillary calcite, on the other hand, is strongly banded because silt and clay debris that settled on the up-facing surfaces were incorporated into the mammillary coating by continuing calcite precipitation. Well-developed bands on cross sections of up-facing mammillary calcite surfaces disappear abruptly wherever the depositional surface rolls over to vertical or overhanging. 

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