Fracture network characteristics of a deep borehole in the Table Mountain Group (TMG), South Africa

Li, Lin; Jia, Housheng; Xu, Yongxin

doi:10.1007/s10040-007-0184-y

Cited by 9 publications

(10 citation statements)

References 25 publications

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“…On Earth, fractures are ubiquitous in rock units at the outcrop or larger scales. Natural fractures and fracture zones are commonly found in deep boreholes [e.g., Seeburger and Zoback, 1982;Lin et al, 2007], and although fracture connectivity and apertures generally decrease with depth [e.g., Snow, 1968], wide fracture zones have been identified at depths down to 9 km [Emmermann and Lauterjung, 1997].…”

Section: Introductionmentioning

confidence: 99%

Limits on the brittle strength of planetary lithospheres undergoing global contraction

Klimczak

2015

JGR Planets

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The degree and depth of fracturing of the lithospheres of Mars, Mercury, and the Moon remain poorly known. It is these two properties, however, that govern the mechanical behavior of a planetary lithosphere. Considering the lithosphere as a cohesive rock mass that consists of small and large blocky, interlocked rock fragments, as opposed to an intact body or a body entirely lacking cohesion, provides insight into the effect of lithospheric fracturing on tectonic processes on these bodies. Characterization of the near‐surface lithospheric brittle strength that incorporates the degree of fracturing is necessary for a realistic assessment of the lithospheric response to global contraction resulting from interior secular cooling. Such an assessment shows that all of these bodies could have accommodated substantial amounts of global contraction prior to the formation of thrust fault‐related landforms. In fact, their lithospheres were sufficiently strong so as to experience changes in radius of as much as 2.2 ± 0.4 km (Mars), 2.1 ± 0.4 km (Mercury), and 1.4 ± 0.3 km (the Moon) prior to the onset of widespread thrust faulting. These values imply that the process of global contraction begins before any evidence of it is established in the geologic record, requiring an earlier onset, and for Mars and Mercury a faster initial strain rate, of global contraction than previously thought. Such results add a heretofore unrecognized component of planetary radial decrease with implications for timing and strain rate to studies of global contraction on Mars, Mercury, and the Moon, in particular, and to planetary bodies, in general.

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Section: Introductionmentioning

confidence: 99%

Limits on the brittle strength of planetary lithospheres undergoing global contraction

Klimczak

2015

JGR Planets

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“…On a single site, the connectivity patterns vary in different directions, as has been discussed above, which shows the potential of preferential flow paths in the study domain and implies the necessity of studying groundwater problems in three dimensions. From site to site, the pattern of fracture 271 connectivity varies, particularly the size of clusters with interconnected fractures, which is additionally shown by the results derived from the Rietfontein (Lin et al, 2007) and Rawsonville sites (Fig. 10).…”

Section: Fracture Connectivity Patternmentioning

confidence: 76%

“…For the realisation of fractures on 2D profiles, based on the core sample study at the adjacent Rietfontein site (Lin et al, 2007), it is necessary to propose the assumption that fracture orientation and density do not change much at depth in the locally homogeneous Peninsula sandstone.…”

Section: Application To the Fieldmentioning

confidence: 99%

Characterisation of fracture network and groundwater preferential flow path in the Table Mountain Group (TMG) sandstones, South Africa

Li¹,

Lin²,

Xu³

2014

WSA

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Characterisation of fractured rocks and evaluation of fracture connectivity are essential for the study of subsurface flow and transport in fractured rock aquifers. In this study, we use a new method to present fracture networks and analyse the connectivity of the fractures, based on the technique of randomly-generated realisations. The application of the method aims to provide more detailed insights into the flow path and dynamics for sustainable utilisation of groundwater in the Table Mountain Group (TMG) aquifers, South Africa. Focusing on a representative wellfield in the TMG, the interpretation and integration of fracture data derived from field measurements, existing geological maps and remotely-sensed imagery, and observed responses of hydraulic tests, led to the development of a conceptual model for fracture network characterisation, which forms the basis of fracture connectivity analysis. The result shows that the a dominant number of the interconnected fractures are in the form of separated fracture clusters (networks) which is considered to be a common connectivity pattern in the TMG rocks and alike. The result also suggests that the connectivity pattern is collectively dependent on such factors as orientation, length, and density of fractures and implies that in a study domain only a small part of the fractures are responsible for flow circulation.

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“…This effective horizontal conductivity can capture increases in saturated flow when the groundwater level rises (Jiang et al, 2009;Bobo et al, 2012;Chen et al, 2018;Cheema, 2015;Taylor, 1960;Lin et al, 2007). Figure 6 reveals the effective horizontal conductivity changes along with different groundwater levels.…”

Section: Groundwatermentioning

confidence: 99%

Solver for Hydrologic Unstructured Domain (SHUD): Numerical modeling of watershed hydrology with the finite volume method

Shu¹,

Ullrich²,

Duffy³

2020

Preprint

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Abstract. Hydrological modeling is an essential strategy for understanding natural flows, particularly where observations are lacking in either space or time, or where topographic roughness leads to a disconnect in the characteristic timescales of overland and groundwater flow. Consequently, significant opportunities remain for the development of extensible modeling systems that operate robustly across regions. Towards the development of such a robust hydrological modeling system, this paper introduces the Solver for Hydrological Unstructured Domain (SHUD), an integrated multi-process, multi-scale, multi-timestep hydrological model, in which hydrological processes are fully coupled using the Finite Volume Method. The SHUD integrates overland flow, snow accumulation/melting, evapotranspiration, subsurface and groundwater flow, and river routing, while realistically capturing the physical processes in a watershed. The SHUD incorporates one-dimension unsaturated flow, two-dimension groundwater flow, and river channels connected with hillslopes via overland flow and baseflow. This paper introduces the design of SHUD, from the conceptual and mathematical description of hydrological processes in a watershed to computational structures. To demonstrate and validate the model performance, we employ three hydrological experiments: the V-Catchment experiment, Vauclin's experiment, and a study of the Cache Creek Watershed in northern California, USA. Possible applications of then SHUD model include hydrological studies from the hillslope scale to regional scale, water resource and stormwater management, and coupling research with related fields such as limnology, agriculture, geochemistry, geomorphology, water quality, and ecology, climatic and landuse change. In general, SHUD is a valuable scientific tool for any modeling task involving simulating and understanding the hydrological response.

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Fracture network characteristics of a deep borehole in the Table Mountain Group (TMG), South Africa

Cited by 9 publications

References 25 publications

Limits on the brittle strength of planetary lithospheres undergoing global contraction

Limits on the brittle strength of planetary lithospheres undergoing global contraction

Characterisation of fracture network and groundwater preferential flow path in the Table Mountain Group (TMG) sandstones, South Africa

Solver for Hydrologic Unstructured Domain (SHUD): Numerical modeling of watershed hydrology with the finite volume method

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