Recent research on the Brabant Massif

Verniers, Jacques; Vos, W. De

doi:10.1007/bf02295827

Cited by 7 publications

(2 citation statements)

References 11 publications

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“…The metamorphic grade is epizonal (Van Grootel et al 1997). These Cambrian series consist of the Oisquercq Group, a Lower to Middle Cambrian pelitic sequence , and the underlying Tubize Group, a Lower Cambrian terrigenous sequence Verniers & De Vos, 1995). The outcrops studied belong stratigraphically to the Rogissart Unit (Vander Auwera & André, 1985), which forms the upper part of the Tubize Group and consists of rhythmic series of feldspathic sandstones, siltstones, greywackes, greenish slates and phyllites, often characterized by graded bedding.…”

Section: Regional Settingmentioning

confidence: 99%

Cleavage–fold relationships in the Lower Cambrian Tubize Group, southeast Anglo-Brabant Fold Belt (Lembeek, Belgium)

Sintubin

Brodkom²,

Laduron

1998

Geol. Mag.

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Little is known about the cleavage-fold relationships in the Lower Palaeozoic Brabant Massif, primarily because of the scarcity of suitable exposures. Moreover, to date, folds have only been described in the Ordovician and Silurian sequences along the southern extremity of the basement. However, excavation works for the construction of the TGV(railway)-track south of Brussels created an opportunity to study cleavage-fold relationships in the Lower Cambrian terrigenous series (Tubize Group) in a more central part of the Brabant Massif. The structural features observed seemed inconsistent with the suspected regional trends. Primarily, a divergent cleavage fan was observed in a region thought to have a regular cleavage attitude. The symmetrical but divergent disposition of the cleavage with regard to the fold hinges is explained by flexural folding of a pre-existing bedding-parallel compaction fabric. Cleavage development and folding are considered synchronous. The divergent cleavage fan reflects local strain variations. Also the steeply plunging hinge lines of the open, subangular folds are seemingly inconsistent with the regional trend characterized by subhorizontal fold hinges. Taking into account the structural position of the fold assemblage in the subvertical limb of a large-scale, upright, isoclinal fold structure, the fold assemblage is interpreted as an incongruous parasitic feature. The steeply plunging hinge lines are considered to be caused by fold hinge rotation during progressive coaxial deformation. Although this incongruous fold assemblage with its divergent cleavage fan is localized, it provides important information on both local and regional deformation circumstances in this part of the Anglo-Brabant Fold Belt.

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Section: Regional Settingmentioning

confidence: 99%

Cleavage–fold relationships in the Lower Cambrian Tubize Group, southeast Anglo-Brabant Fold Belt (Lembeek, Belgium)

Sintubin

Brodkom²,

Laduron

1998

Geol. Mag.

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“…Differing styles of extension, such as horst‐and‐graben, half‐graben, metamorphic core complexes and areas of distributed crustal thinning are observed on Earth. Successions of horst and grabens can be seen in the Condroz and Ardennes region of Wallonia [e.g., Verniers and De Vos , ]. Half‐graben subbasins can be seen in the Gulf of Suez, East African Rift, Rio Grande rift system and the North Sea [ Holdsworth and Turner , ; Russell and Snelson , ].…”

Section: Introductionmentioning

confidence: 99%

Styles of rifting and fault spacing in numerical models of crustal extension

et al. 2015

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Extension of the Earth's crust can result in differing styles of rifting, such as horst-and-graben, half-graben, metamorphic core complexes and areas of distributed crustal thinning. Faulting patterns can range from either being distributed to highly localized. Observations indicate that the factors controlling the extensional deformation, symmetry, and fault spacing include rheological aspects such as the yielding mechanism and strain softening, and physical aspects such as initial heterogeneities and the strength of the lower crust compared to the upper crust. Time-dependent numerical models of extension are presented, which investigate the influence of the yielding mechanism, lower crust strength, strain weakening, and initial heterogeneity in the crust have on (a) the style of rifting, (b) fault spacing, and (c) integrated strength in the upper crust. Models with an anisotropic yielding mechanism result in more realistic lithospheric strength profiles, slip plane angle distributions, and fault interaction than models with an isotropic yielding mechanism. Heterogeneity type and yielding mechanisms have the largest effect on the resulting symmetry of deformation, whereas the amount of strain weakening has the greatest influence on asymmetry. The likelihood of the metamorphic core complex mode occurring is primarily controlled by lower crust strength. Crustal thinning is encouraged by both low amounts of strain weakening and a strong lower crust. Lower crust viscosity exerts the primary control on whether the resulting deformation is distributed or localized. The degree of strain weakening has the largest influence on the average strength of the upper crust and the slope of the strength profile in the upper crust.

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