Scales of columnar jointing in igneous rocks: field measurements and controlling factors

Hetényi, György; Taisne, Benoît; Garel, Fanny; Médard, Étienne; Bosshard, S. A.; Mattsson, Hannes B.

doi:10.1007/s00445-011-0534-4

Cited by 68 publications

(54 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…If the observed fractures are cooling joints in volcanic formations, certain fracture patterns should be present. The morphology of cooling joints in lava units varies depending on numerous factors such as the chemical composition and preexisting topography [Hetényi et al, 2012], the location within the flow and cooling rates [DeGraff and Aydin, 1987], and the interaction with glaciers [Spörli and Rowland, 2006]. Columnar-jointed lava flows usually contain units of entablatures (where columns are disordered), and colonnades (where columns are subparallel to each other) which can have pentagonal to hexagonal cross sections with variable strike orientations [Budkewitsch and Robin, 1994].…”

Section: Discussionmentioning

confidence: 99%

Heterogeneity of structure and stress in the Rotokawa Geothermal Field, New Zealand

et al. 2015

View full text Add to dashboard Cite

Geometric characterization of a geothermal reservoir's structures, and their relation to stress field orientation, is vital for resource development. Subsurface structure and stress field orientations of the Rotokawa Geothermal Field, New Zealand, have been studied, for the first time, using observations obtained from analysis of three acoustic borehole televiewer logs. While an overall NE-SW fracture strike exists, heterogeneity in fracture dip orientation is evident. Dominant dip direction changes from well to well due to proximity to variously oriented, graben-bounding faults. Fracture orientation heterogeneity also occurs within individual wells, where fractures clusters within certain depth intervals have antithetic dip directions to the well's dominant fracture dip direction. These patterns are consistent with expected antithetic faulting in extensional environments. A general S Hmax orientation of NE-SW is determined from induced features on borehole walls. However, numerous localized azimuthal variations from this trend are evident, constituting stress field orientation heterogeneity. These variations are attributed to slip on fracture planes evidenced by changes in the azimuth of drilling-induced tensile fractures either side of a natural fracture. Correlation of observed fracture properties and patterns to well permeability indicators reveal that fractures play a role in fluid flow in the Rotokawa geothermal reservoir. Permeable zones commonly contain wide aperture fractures and high fracture densities which have a dominant NE-SW strike orientation and NW dip direction. Studies of this kind, which show strong interdependency of structure and stress field properties, are essential to understand fluid flow in geothermal reservoirs where structural permeability dominates.

show abstract

Section: Discussionmentioning

confidence: 99%

Heterogeneity of structure and stress in the Rotokawa Geothermal Field, New Zealand

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Svartifoss or Black Falls (N 66 ∘ 01 40.1 , W 16 ∘ 58 33.2 ) sits 140 m above the coastal plain and is accessed by a 1.5 km trail from a parking area at Skaftafell (Figure 1). The basalt exposure at Svartifoss ( Figure 2) features a single flow colonnade without entablature approximately 15 to 20 m high and approximately 30 m wide [20]. The south-facing cliff forms a V-shaped notch by headward erosion from the stream Baejargil.…”

Section: Locationmentioning

confidence: 99%

Surface Morphology of Basalt Columns at Svartifoss, VatnajökulsÞjóðgarður, Southern Iceland

Tanner

2013

Journal of Geological Research

View full text Add to dashboard Cite

A spectacular example of columnar-jointed basalt occurs at Svartifoss in the Vatnajökull National Park of southern Iceland. The columns are notable for a variety of features on the vertical joint surfaces and the horizontal parting surfaces. The jointed surfaces of the columns display horizontal striations at a spacing of centimeters to decimeters. The individual striations exhibit crescentic hackles with a plumose pattern, the orientation of which varies between adjacent striations. Also present are gently dipping, millimeter-scale laminations not previously described. Horizontal parting surfaces of the columns display a circular ring that inscribes most of the diameter column. The ring features alternately positive or negative relief against the perimeter of the column and exhibits a radiating pattern of hackles originating at the center of the ring. Petrographic examination reveals that the basalt contains an interlocking network of plagioclase laths preferentially aligned perpendicular to the column axes. The circular features have been described previously and attributed to late-stage melt migration driven by a load-induced pressure gradient. The striations were formed from stepwise, downward propagation of the polygonal fracture system, and the plumose structures were formed from tensile stresses during fracture propagation. The small-scale laminations may result from preferential grain alignment of plagioclase laths.

show abstract

“…Igneous columnar jointing occurs in lava flows, lava lakes, sills, dikes, and ash‐flow tuffs [ Hetényi et al , ; Spry , ]. The columns are commonly polygonal shaped, with the diameter being approximately constant over a significant fraction of their height.…”

Section: Introductionmentioning

confidence: 99%

“…The columns are commonly polygonal shaped, with the diameter being approximately constant over a significant fraction of their height. The observed diameters range from a few centimeters up to 3 m while the column height can be up to 30 m. The regular columns tend to have five, six, or seven sides, although three‐, four‐, and eight‐sided columns exist as well [ Hetényi et al , ; Phillips et al , ; Spry , ]. As illustrated in Figure b, the regular columns can be intersected by a highly disorganized region with smaller curvy columns.…”

Section: Introductionmentioning

confidence: 99%

“…Hetényi et al [] further found that the geological setting (lava flow, lava lake, lava dome, sill, and dyke) exerted control on the columnar diameter, through control of the surfaces where heat can be exchanged with the environment and thereby the cooling rate. When the bodies were geometrically unconstrained (lava flows), they found chemistry to play a role, through its control of material properties and through its control of emplacement geometry, which in turn affects the cooling rate.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Scale selection in columnar jointing: Insights from experiments on cooling stearic acid and numerical simulations

et al. 2016

View full text Add to dashboard Cite

Many natural fracture systems are characterized by a single length scale, which is the distance between neighboring fractures. Examples are mud cracks and columnar jointing. In columnar jointing the origin of this scale has been a long‐standing issue. Here we present a comprehensive study of columnar jointing based on experiments on cooling stearic acids, numerical simulations using both discrete and finite element methods and basic analytical calculations. We show that the diameter of columnar joints is a nontrivial function of the material properties and the cooling conditions of the system. We determine the shape of this function analytically and show that it is in agreement with the experiments and the numerical simulations.

show abstract

Scales of columnar jointing in igneous rocks: field measurements and controlling factors

Abstract: International audienc

Cited by 68 publications

References 64 publications

Heterogeneity of structure and stress in the Rotokawa Geothermal Field, New Zealand

Heterogeneity of structure and stress in the Rotokawa Geothermal Field, New Zealand

Surface Morphology of Basalt Columns at Svartifoss, VatnajökulsÞjóðgarður, Southern Iceland

Scale selection in columnar jointing: Insights from experiments on cooling stearic acid and numerical simulations

Contact Info

Product

Resources

About