On the development of gneiss domes

Bell, T. H.; Ham, A.P.; Hayward, Nicholas; Hickey, Kenneth A.

doi:10.1080/08120090500139398

Cited by 14 publications

(10 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Williams and Schoneveld (1981) dealt with this problem using antithetic shear on the crenulated cleavage to rotate the porphyroblasts. However, a large amount of data on foliation intersection/inflection axes preserved in porphyroblasts (FIAs) from the same region reveals that these porphyroblasts did not rotate (Bell et al 2003(Bell et al , 2005.…”

Section: Inclusion Trails Defined By a Differentiated Crenulation Clementioning

confidence: 97%

“…Several vertical thin sections must be cut around the compass to make sure that the inclusion trails are not truncated by the matrix schistosity. This has the advantage that the FIAs can be measured and such data provide a powerful tool for resolving structural (Bell et al 2005), metamorphic (Sayab, 2008), age (Cihan et al 2006), deformation partitioning ) and tectonic (Bell and Mares, 1999;Bell and Newman, 2006;Aerden and Sayab, 2008) problems. Once it is known that the inclusion trails are continuous with the matrix foliation, then the sense of shear on that schistosity can be determined.…”

Section: Ages From Fia Successionsmentioning

confidence: 99%

“…A fivefold succession of FIAs is present in the rocks of South Central Vermont (Bell et al 2005) with up to seven foliations preserved around each. Successive foliations Fig.11.…”

Section: Foliation Re-use and Shear Sensementioning

confidence: 99%

“…Once it is known that the inclusion trails are continuous with the matrix foliation, then the sense of shear on that schistosity can be determined. If the inclusion trails are truncated by the matrix foliation, a shear sense can be determined using the asymmetry of inclusion trails in porphyroblasts in thin sections that lie near orthogonal to the FIA trend to examine what took place on foliations that predate those preserved in the matrix (e.g., Bell et al 2003Bell et al , 2005. …”

Section: Ages From Fia Successionsmentioning

confidence: 99%

See 3 more Smart Citations

Foliations and shear sense: A modern approach to an old problem

Bell

Hobbs

2010

J Geol Soc India

View full text Add to dashboard Cite

Argument about shear on foliations began in the mid 19 th century and continues to the present day. It results from varying interpretations of what takes place during the development of different types of foliations ranging from slaty cleavages through differentiated crenulation cleavages, schistosity and gneissosity to mylonites. Computer modelling, quantitative microstructural work and monazite dating have provided a unique solution through access to the history of foliation development preserved by porphyroblasts. All foliations involve shear in their development and most can be used to derive a shear sense. The shear sense obtained is consistent between foliation types and accords with recent computer modelling of these structures preserved within porphyroblasts relative to those in the matrix. The asymmetry of curving foliation into a locally developing new one allows determination of the shear sense along the latter foliation in most rocks. The problem of shear on fold limbs and parallelism of foliation and the flattening plane of the strain ellipse is resolved through the partitioning of shearing and shortening components of deformation into zones that anastomose around ellipsoidal domains lying parallel to the XY plane. Conflicts in shear sense occur if multiple reuse or reactivation of foliations is not recognized and allowed for but are readily resolved if taken into account.

show abstract

Section: Inclusion Trails Defined By a Differentiated Crenulation Clementioning

confidence: 97%

Section: Ages From Fia Successionsmentioning

confidence: 99%

“…A fivefold succession of FIAs is present in the rocks of South Central Vermont (Bell et al 2005) with up to seven foliations preserved around each. Successive foliations Fig.11.…”

Section: Foliation Re-use and Shear Sensementioning

confidence: 99%

Section: Ages From Fia Successionsmentioning

confidence: 99%

See 2 more Smart Citations

Foliations and shear sense: A modern approach to an old problem

Bell

Hobbs

2010

J Geol Soc India

View full text Add to dashboard Cite

show abstract

“…More than 10 years of research and data have already been published using this technique from tectonically complex regions around the world (e.g., Bell et al 1998Bell et al , 2003Bell et al , 2005Bell and Chen 2002;Cihan 2004;Kim and Bell 2005;Sayab 2005Sayab , 2006Bell and Bruce 2007;Sanislav 2010;Sanislav and Shah 2010;Ali 2010;Sanislav and Bell 2011).…”

Section: Introductionmentioning

confidence: 99%

Ninety million years of orogenesis, 250 million years of quiescence and further orogenesis with no change in PT: Significance for the role of deformation in porphyroblast growth

Shah

Bell

2012

J Earth Syst Sci

View full text Add to dashboard Cite

In situ dating of monazite grains preserved as inclusions within foliations defining FIAs (foliation inflection/intersection axes preserved within porphyroblasts) contained within garnet, staurolite, andalusite and cordierite porphyroblasts provides a chronology of ages that matches the FIA succession for the Big Thompson region of the northern Colorado Rocky Mountains. FIA sets 1, 2 and 3 trending NE-SW, E-W and SE-NW were formed at 1760.5 ± 9.7, 1719.7 ± 6.4 and 1674 ± 11 Ma, respectively. For three samples where garnet first grew during just one of each of these FIAs, the intersection of Ca, Mg, and Fe isopleths in their cores indicate that these rocks never got above 4 kbars throughout the Colorado Orogeny. Furthermore, they remained around approximately the same depth for ∼250 million years to the onset of the younger Berthoud Orogeny at 1415 ± 16 Ma when the pressure decreased slightly as porphyroblasts formed with inclusion trails preserving FIA set 4 trending NNE-SSW. No porphyroblast growth occurred during the intervening ∼250 million years of quiescence, even though the PT did not change over this period. This confirms microstructural evidence gathered over the past 25 years that crenulation deformation at the scale of a porphyroblast is required for reactions to re-initiate and enable further growth.

show abstract

Foliation intersection/inflection axes within porphyroblasts (FIAs): a review of advanced applications and significance

Kim

Sanislav

2017

Geosci J

View full text Add to dashboard Cite

On the development of gneiss domes

Cited by 14 publications

References 53 publications

Foliations and shear sense: A modern approach to an old problem

Foliations and shear sense: A modern approach to an old problem

Ninety million years of orogenesis, 250 million years of quiescence and further orogenesis with no change in PT: Significance for the role of deformation in porphyroblast growth

Foliation intersection/inflection axes within porphyroblasts (FIAs): a review of advanced applications and significance

Contact Info

Product

Resources

About