Origin of Breccias in the CRP-1 Core
CoreScan images were examined to determine the origin of breccias in the CRP-1 core. Breccias occur throughout the core, but are dominant deformation features in the upper 85 m. Breccia textures, boundaries and texture arrangements suggest that in situ fracturing and horizontal planar shearing are i...
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ftmontclairstuni:oai:digitalcommons.montclair.edu:earth-environ-studies-facpubs-1460 2023-07-23T04:20:16+02:00 Origin of Breccias in the CRP-1 Core Passchier, Sandra Wilson, T. J. Paulsen, T. S. 1998-12-01T08:00:00Z https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/461 unknown Montclair State University Digital Commons https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/461 Department of Earth and Environmental Studies Faculty Scholarship and Creative Works text 1998 ftmontclairstuni 2023-07-03T21:48:47Z CoreScan images were examined to determine the origin of breccias in the CRP-1 core. Breccias occur throughout the core, but are dominant deformation features in the upper 85 m. Breccia textures, boundaries and texture arrangements suggest that in situ fracturing and horizontal planar shearing are important deformation mechanisms in the upper part of the Miocene section. Forceful injections of silt and clay into fractures point to dewatering of overpressurised sediment. Breccias located below 55 metres below the sea floor (mbsf) occur associated with soft-sediment deformation, which is absent in younger intervals of the core. Deformation styles interpreted from the breccia textures, their downcore distribution, and the relations of breccias with sequence boundaries and lithologies, such as diamictites and graded beds, suggest brecciation occurred as a result of subglacial shearing and mass-movement processes. These mechanisms were also proposed for breccias and soft sediment deformation features observed in other McMurdo Sound cores. Subglacial shearing was a possible cause for the development of two thick brecciated intervals at ∼44 and at ∼79 mbsf, whereas slope failure and redeposition was probably the cause of brecciation below ∼85 mbsf. Text McMurdo Sound Montclair State University Digital Commons McMurdo Sound |
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Montclair State University Digital Commons |
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CoreScan images were examined to determine the origin of breccias in the CRP-1 core. Breccias occur throughout the core, but are dominant deformation features in the upper 85 m. Breccia textures, boundaries and texture arrangements suggest that in situ fracturing and horizontal planar shearing are important deformation mechanisms in the upper part of the Miocene section. Forceful injections of silt and clay into fractures point to dewatering of overpressurised sediment. Breccias located below 55 metres below the sea floor (mbsf) occur associated with soft-sediment deformation, which is absent in younger intervals of the core. Deformation styles interpreted from the breccia textures, their downcore distribution, and the relations of breccias with sequence boundaries and lithologies, such as diamictites and graded beds, suggest brecciation occurred as a result of subglacial shearing and mass-movement processes. These mechanisms were also proposed for breccias and soft sediment deformation features observed in other McMurdo Sound cores. Subglacial shearing was a possible cause for the development of two thick brecciated intervals at ∼44 and at ∼79 mbsf, whereas slope failure and redeposition was probably the cause of brecciation below ∼85 mbsf. |
format |
Text |
author |
Passchier, Sandra Wilson, T. J. Paulsen, T. S. |
spellingShingle |
Passchier, Sandra Wilson, T. J. Paulsen, T. S. Origin of Breccias in the CRP-1 Core |
author_facet |
Passchier, Sandra Wilson, T. J. Paulsen, T. S. |
author_sort |
Passchier, Sandra |
title |
Origin of Breccias in the CRP-1 Core |
title_short |
Origin of Breccias in the CRP-1 Core |
title_full |
Origin of Breccias in the CRP-1 Core |
title_fullStr |
Origin of Breccias in the CRP-1 Core |
title_full_unstemmed |
Origin of Breccias in the CRP-1 Core |
title_sort |
origin of breccias in the crp-1 core |
publisher |
Montclair State University Digital Commons |
publishDate |
1998 |
url |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/461 |
geographic |
McMurdo Sound |
geographic_facet |
McMurdo Sound |
genre |
McMurdo Sound |
genre_facet |
McMurdo Sound |
op_source |
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works |
op_relation |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/461 |
_version_ |
1772184145024253952 |