Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand

Virginia Gail Toy, Rupert Sutherland, John Townend, Michael J. Allen, Leeza Becroft, Austin Boles, Carolyn Boulton, Brett Carpenter, Alan Cooper, Simon C. Cox, Christopher Daube, Daniel R. Faulkner, Angela Halfpenny, Naoki Kato, Stephen Keys, Martina Kirilova, Yusuke Kometani, Timothy Little, Elisabetta Mariani, Benjamin Melosh & 50 others Catriona D. Menzies, Luiz Morales, Chance Morgan, Hiroshi Mori, Andre Niemeijer, Richard Norris, David Prior, Katrina Sauer, Anja M. Schleicher, Norio Shigematsu, Damon A. H. Teagle, Harold Tobin, Robert Valdez, Jack Williams, Samantha Yeo, Laura-May Baratin, Nicolas Barth, Adrian Benson, Carolin Boese, Bernard Célérier, Calum J. Chamberlain, Ronald Conze, Jamie Coussens, Lisa Craw, Mai-Linh Doan, Jennifer Eccles, Jason Grieve, Julia Grochowski, Anton Gulley, Jamie Howarth, Katrina Jacobs, Lucie Janku-Capova, Tamara Jeppson, Robert Langridge, Deirdre Mallyon, Ray Marx, Cécile Massiot, Loren Mathewson, Josephine Moore, Osamu Nishikawa, Brent Pooley, Alex Pyne, Martha K. Savage, Doug Schmitt, Sam Taylor-Offord, Phaedra Upton, Konrad C. Weaver, Thomas Wiersberg, Martin Zimmer, DFDP-2 Science Team

Research output: Contribution to journalArticleResearchpeer-review

Abstract

During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.

LanguageEnglish
Pages497-518
Number of pages22
JournalNew Zealand Journal of Geology and Geophysics
Volume60
Issue number4
DOIs
Publication statusPublished - 2017

Fingerprint

New Zealand
bedrock
geology
drilling
boreholes
slip
quartz
sampling
schist
lithology
mica
stopping
microbalances
rivers
proximity
grain size
occurrences
rocks
shear
borehole

Keywords

  • Alpine Fault
  • New Zealand
  • scientific drilling
  • mylonite
  • cataclasite

Cite this

@article{1e36471c50a240a88ff97260a0ed5e8f,
title = "Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand",
abstract = "During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.",
keywords = "Alpine Fault, New Zealand, scientific drilling, mylonite, cataclasite",
author = "Toy, {Virginia Gail} and Rupert Sutherland and John Townend and Allen, {Michael J.} and Leeza Becroft and Austin Boles and Carolyn Boulton and Brett Carpenter and Alan Cooper and Cox, {Simon C.} and Christopher Daube and Faulkner, {Daniel R.} and Angela Halfpenny and Naoki Kato and Stephen Keys and Martina Kirilova and Yusuke Kometani and Timothy Little and Elisabetta Mariani and Benjamin Melosh and Menzies, {Catriona D.} and Luiz Morales and Chance Morgan and Hiroshi Mori and Andre Niemeijer and Richard Norris and David Prior and Katrina Sauer and Schleicher, {Anja M.} and Norio Shigematsu and Teagle, {Damon A. H.} and Harold Tobin and Robert Valdez and Jack Williams and Samantha Yeo and Laura-May Baratin and Nicolas Barth and Adrian Benson and Carolin Boese and Bernard C{\'e}l{\'e}rier and Chamberlain, {Calum J.} and Ronald Conze and Jamie Coussens and Lisa Craw and Mai-Linh Doan and Jennifer Eccles and Jason Grieve and Julia Grochowski and Anton Gulley and Jamie Howarth and Katrina Jacobs and Lucie Janku-Capova and Tamara Jeppson and Robert Langridge and Deirdre Mallyon and Ray Marx and C{\'e}cile Massiot and Loren Mathewson and Josephine Moore and Osamu Nishikawa and Brent Pooley and Alex Pyne and Savage, {Martha K.} and Doug Schmitt and Sam Taylor-Offord and Phaedra Upton and Weaver, {Konrad C.} and Thomas Wiersberg and Martin Zimmer and {DFDP-2 Science Team}",
year = "2017",
doi = "10.1080/00288306.2017.1375533",
language = "English",
volume = "60",
pages = "497--518",
journal = "New Zealand Journal of Geology and Geophysics",
issn = "0028-8306",
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}

Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand. / DFDP-2 Science Team.

In: New Zealand Journal of Geology and Geophysics, Vol. 60, No. 4, 2017, p. 497-518.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Bedrock geology of DFDP-2B, central Alpine Fault, New Zealand

AU - Toy, Virginia Gail

AU - Sutherland, Rupert

AU - Townend, John

AU - Allen, Michael J.

AU - Becroft, Leeza

AU - Boles, Austin

AU - Boulton, Carolyn

AU - Carpenter, Brett

AU - Cooper, Alan

AU - Cox, Simon C.

AU - Daube, Christopher

AU - Faulkner, Daniel R.

AU - Halfpenny, Angela

AU - Kato, Naoki

AU - Keys, Stephen

AU - Kirilova, Martina

AU - Kometani, Yusuke

AU - Little, Timothy

AU - Mariani, Elisabetta

AU - Melosh, Benjamin

AU - Menzies, Catriona D.

AU - Morales, Luiz

AU - Morgan, Chance

AU - Mori, Hiroshi

AU - Niemeijer, Andre

AU - Norris, Richard

AU - Prior, David

AU - Sauer, Katrina

AU - Schleicher, Anja M.

AU - Shigematsu, Norio

AU - Teagle, Damon A. H.

AU - Tobin, Harold

AU - Valdez, Robert

AU - Williams, Jack

AU - Yeo, Samantha

AU - Baratin, Laura-May

AU - Barth, Nicolas

AU - Benson, Adrian

AU - Boese, Carolin

AU - Célérier, Bernard

AU - Chamberlain, Calum J.

AU - Conze, Ronald

AU - Coussens, Jamie

AU - Craw, Lisa

AU - Doan, Mai-Linh

AU - Eccles, Jennifer

AU - Grieve, Jason

AU - Grochowski, Julia

AU - Gulley, Anton

AU - Howarth, Jamie

AU - Jacobs, Katrina

AU - Janku-Capova, Lucie

AU - Jeppson, Tamara

AU - Langridge, Robert

AU - Mallyon, Deirdre

AU - Marx, Ray

AU - Massiot, Cécile

AU - Mathewson, Loren

AU - Moore, Josephine

AU - Nishikawa, Osamu

AU - Pooley, Brent

AU - Pyne, Alex

AU - Savage, Martha K.

AU - Schmitt, Doug

AU - Taylor-Offord, Sam

AU - Upton, Phaedra

AU - Weaver, Konrad C.

AU - Wiersberg, Thomas

AU - Zimmer, Martin

AU - DFDP-2 Science Team

PY - 2017

Y1 - 2017

N2 - During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.

AB - During the second phase of the Alpine Fault, Deep Fault Drilling Project (DFDP) in the Whataroa River, South Westland, New Zealand, bedrock was encountered in the DFDP-2B borehole from 238.5–893.2 m Measured Depth (MD). Continuous sampling and meso- to microscale characterisation of whole rock cuttings established that, in sequence, the borehole sampled amphibolite facies, Torlesse Composite Terrane-derived schists, protomylonites and mylonites, terminating 200–400 m above an Alpine Fault Principal Slip Zone (PSZ) with a maximum dip of 62°. The most diagnostic structural features of increasing PSZ proximity were the occurrence of shear bands and reduction in mean quartz grain sizes. A change in composition to greater mica:quartz + feldspar, most markedly below c. 700 m MD, is inferred to result from either heterogeneous sampling or a change in lithology related to alteration. Major oxide variations suggest the fault-proximal Alpine Fault alteration zone, as previously defined in DFDP-1 core, was not sampled.

KW - Alpine Fault

KW - New Zealand

KW - scientific drilling

KW - mylonite

KW - cataclasite

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U2 - 10.1080/00288306.2017.1375533

DO - 10.1080/00288306.2017.1375533

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JO - New Zealand Journal of Geology and Geophysics

T2 - New Zealand Journal of Geology and Geophysics

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