Origin of Breccias in the CRP-1 Core

Sandra Passchier, T. J. Wilson, T. S. Paulsen

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)401-409
Number of pages9
JournalTerra Antarctica
Volume5
Issue number3
StatePublished - 1 Dec 1998

Fingerprint

Oceans and Seas
seafloor
texture
breccia
sediments
sediment
redeposition
sequence boundary
deformation mechanism
mass movement
slope failure
dewatering
silt
lithology
Injections
Miocene
clay
injection

Cite this

Passchier, S., Wilson, T. J., & Paulsen, T. S. (1998). Origin of Breccias in the CRP-1 Core. Terra Antarctica, 5(3), 401-409.
Passchier, Sandra ; Wilson, T. J. ; Paulsen, T. S. / Origin of Breccias in the CRP-1 Core. In: Terra Antarctica. 1998 ; Vol. 5, No. 3. pp. 401-409.
@article{b764b251992646c2b57b2deefbc92e8d,
title = "Origin of Breccias in the CRP-1 Core",
abstract = "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.",
author = "Sandra Passchier and Wilson, {T. J.} and Paulsen, {T. S.}",
year = "1998",
month = "12",
day = "1",
language = "English",
volume = "5",
pages = "401--409",
journal = "Terra Antarctica",
issn = "1122-8628",
publisher = "Terra Antarctica Publication",
number = "3",

}

Passchier, S, Wilson, TJ & Paulsen, TS 1998, 'Origin of Breccias in the CRP-1 Core', Terra Antarctica, vol. 5, no. 3, pp. 401-409.

Origin of Breccias in the CRP-1 Core. / Passchier, Sandra; Wilson, T. J.; Paulsen, T. S.

In: Terra Antarctica, Vol. 5, No. 3, 01.12.1998, p. 401-409.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Origin of Breccias in the CRP-1 Core

AU - Passchier, Sandra

AU - Wilson, T. J.

AU - Paulsen, T. S.

PY - 1998/12/1

Y1 - 1998/12/1

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=0005395104&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0005395104

VL - 5

SP - 401

EP - 409

JO - Terra Antarctica

JF - Terra Antarctica

SN - 1122-8628

IS - 3

ER -

Passchier S, Wilson TJ, Paulsen TS. Origin of Breccias in the CRP-1 Core. Terra Antarctica. 1998 Dec 1;5(3):401-409.