100th Anniversary Special Paper: Numerical Models of Extensional Deformation, Heat Transfer, and Fluid Flow across Basement-Cover Interfaces during Basin-Related Mineralization

Oliver, Nicholas H.S.; McLellan, John G.; Hobbs, B. E.; Cleverley, James S.; Ord, Alison; Feltrin, Leonardo

doi:10.2113/101.1.1

Cited by 40 publications

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“…The results collectively demonstrate that the Zn and Pb contents in saline solutions strongly correlate with temperature and the salinity of the fluid. Besides magmatic fluids exsolved from crystallising plutons (Holland 1972) resulting in, e.g., skarn deposits (e.g., Meinert 1987), proposed metal sources for PbZn include (1) sedimentary basins where Pb and Zn are leached via interaction with formation waters (Leach et al 2005 and therein), (2) crystalline basements where metals are mobilised by sedimentary formation waters (Russell 1978;Oliver et al 2006) and (3) leaching of metals by fluid flow during regional metamorphism (e.g., Lebedev and Nagaytsev 1980;Haack et al 1984). However, in many cases, there are still great uncertainties from where the metals are Editorial handling: D. Huston Electronic supplementary material The online version of this article (doi:10.1007/s00126-015-0600-5) contains supplementary material, which is available to authorized users.…”

Section: Introductionmentioning

confidence: 99%

Zn and Pb mobility during metamorphism of sedimentary rocks and potential implications for some base metal deposits

et al. 2015

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Comprehension of the genesis of Pb-Zn ore systems is currently limited by a poor understanding of where these metals are sourced from. Our study of metal mobility during regional metamorphism in the Mt. Lofty Ranges, South Australia, demonstrates that in staurolite-absent siliciclastic metasedimentary rocks, biotite contains >80 % of the bulk rock Zn, as well as a considerable proportion of the total Pb. Fluid flow through these metasedimentary rocks led to a continuous depletion of Pb and Zn on a mineral and bulk rock scale during prograde regional metamorphism. We calculate that ∼80 % of the bulk rock Zn and ∼50 % of the bulk rock Pb were mobilised, mainly through reactions involving biotite. These reactions led to a calculated Pb and Zn Bloss^of ∼2.7 and 27 Mt, respectively, in the high-grade metamorphic zone. Halogen contents of apatite and biotite and bulk rock Zn isotope data provide evidence that Cl-rich metamorphic fluids were important for metal transport. Hence, fluid flow accompanying prograde metamorphism of typical sedimentary rocks can mobilise base metals to the degree required to potentially supply significant Pb-Zn ore systems.

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Section: Introductionmentioning

confidence: 99%

Zn and Pb mobility during metamorphism of sedimentary rocks and potential implications for some base metal deposits

et al. 2015

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“…The defined zinc metal resource of 1.57×10 7 t [1] at the Mount Isa deposit could be accounted for with a metal deposition efficiency of about 26%. Also given the temperature constraint of the Mount Isa mineralization [21][22][23] and the simulated thermal patterns stated above, cases 1, 3 and 4 seem to be favorable for the formation of a Mount Isa-type ore body adjacent to a major fault system. The numerical modeling studies presented here therefore support the following final conclusion: buoyancy force is an efficient and effective driving mechanism for basin-scale fluid flow and heat transport, and it is viable enough to give rise to the generation of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia.…”

Section: Discussionmentioning

confidence: 99%

“…Grid discretization of the faults can be found in Figure 1(b). Similar general geological structure of the Mount Isa-McArthur basin region has been also used in previous fluid flow models [12][13][14]18,22,23] . Like in the previous studies [22,23] , Fault 1 on the left is equivalent to the Mount Isa fault system, and Fault 2 on the right simulates a fault zone to farther north, such as the Termite Range fault at the Century deposit.…”

Section: Governing Equations and Finite Element Modelingmentioning

confidence: 99%

“…framework for regional-scale fluid flow. The permeabilities and thermal conductivities assigned to the stratigraphic elements and faults are given in Table 1, following the previous numerical investigations in the Mount Isa-McArthur basin region [13,14,18,22,23] . We assume that the vertical permeability of the host rocks is two orders of magnitude less than the horizontal one due to bedded and stratified nature of these sedimentary rocks.…”

Section: Conceptual Hydrological Modelmentioning

confidence: 99%

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On the role of buoyancy force in the ore genesis of SEDEX deposits: Example from Northern Australia

Yang

Feng

et al. 2009

Sci. China Ser. D-Earth Sci.

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Finite element modeling on a highly conceptualized 2-D model of fluid flow and heat transport is undertaken to simulate the paleo-hydrological system as if the Mount Isa deposits were being formed in the Mount Isa basin, Northern Australia, and to evaluate the potential of buoyancy force in driving basin-scale fluid flow for the formation of sedimentary-exhalative (SEDEX) deposits. Our numerical case studies indicate that buoyancy-driven fluid flow is controlled mainly by the fault penetration depth and its spatial relation with the aquifer. Marine water recharges the basin via one fault and flows through the aquifer where it is heated from below. The heated metalliferous fluid discharges to the basin floor via the other fault. The venting fluid temperatures are computed to be in the range of 115 to 160℃, with fluid velocities of 2.6 to 4.1 m/year over a period of 1 Ma. These conditions are suitable for the formation of a Mount Isa-sized zinc deposit, provided a suitable chemical trap environment is present. Buoyancy force is therefore a viable driving mechanism for basin-scale ore-forming hydrothermal fluid migration, and it is strong enough to lead to the genesis of supergiant SEDEX deposits like the Mount Isa deposit, Northern Australia. hydrothermal fluid flow, finite element modeling, SEDEX deposits, Mount Isa basinSedimentary-exhalative (SEDEX) deposits are a major source of lead and zinc, and an important source of silver. On the global scale, they account for about 40% of zinc production and about 60% of lead production [1] . Geological and sulphide paragenetic studies suggest that this type of deposits may be formed by hydrothermal exhalative processes of metal-bearing brines discharging onto the basin floor. Despite this general understanding, geologists continue to debate the mechanisms of fluid migration, heat flow and mass transport for ore deposition.Several factors have been deemed responsible for basin-scale fluid flow, including topography, compaction, buoyancy, and deformation [2] . Among these, buoyancy driven flow is potentially of great importance because it can lead to fluid flow and mass transport over large distances and significantly shorter time scales, compared with diffusion alone. This is because diffusion results from molecular collision, representing a micro-scale process. In certain circumstances, buoyancy may become even more important than other forces in enhancing hydrodynamic mixing of the dense fluid with the less dense ambient groundwater [3] .A buoyancy force results from variations in fluid density due to spatial and temporal changes in temperature and salinity. Buoyancy driven fluid circulation is commonly termed free convection because of the lack of external inputs and outputs [4] . The importance of this type of fluid flow has long been recognized in mid-ocean ridge hydrothermal systems [5,6] , seawater intrusion [7,8] , and solute transport [9,10] . Recently, buoyancy-

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“…In the models considered here, this is usually reached by varying the permeability until optimal values are attained, as recorded by local or averaged values of Nusselt numbers or some other measurement of heat transfer efficiency (such as local measurement of T/q in fluid upflow zones, where q is the fluid flux, e.g. Oliver et al, 2006). At even higher Rayleigh numbers, such as for models with higher permeability than those with optimum stable convection, fluid and heat flow behaviour becomes more unpredictable.…”

mentioning

confidence: 99%

Convection stability in the Taupo Volcanic Zone, New Zealand

McLellan

Oliver

Hobbs

et al. 2009

Journal of Geochemical Exploration

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100th Anniversary Special Paper: Numerical Models of Extensional Deformation, Heat Transfer, and Fluid Flow across Basement-Cover Interfaces during Basin-Related Mineralization

Cited by 40 publications

References 0 publications

Zn and Pb mobility during metamorphism of sedimentary rocks and potential implications for some base metal deposits

Zn and Pb mobility during metamorphism of sedimentary rocks and potential implications for some base metal deposits

On the role of buoyancy force in the ore genesis of SEDEX deposits: Example from Northern Australia

Convection stability in the Taupo Volcanic Zone, New Zealand

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