A fossil scallop shell (Talochlamys gemmulata) found in a 270,000 yr old marine sediment that has been uplifted 600 m vertically from the Tasman Sea (in distance) by movement across the Alpine Fault. This indicates an average uplift rate of ~2.2 mm/yr. This uplift likely occurs 1–2 meters at a time every 200–400 years from large magnitude (~M 8) earthquakes on the Alpine Fault.
My Research
Links to sections below:
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My research interests span almost all aspects of geology but are broadly centered on a core of structural geology, tectonophysics, tectonics, geomorphology and geological hazards. I strive to employ a multi-disciplinary field-based, lab-supported, collaborative approach to explore far-reaching, broader picture research that is widely beneficial and societally relevant.
During my Ph.D., free-thinking and geological intuition guided me to a number of big picture ideas that had not been previously considered—a regionally preserved 8 km dextral Alpine Fault offset, a ~10 km2 earthquake-triggered rock avalanche, a 40 km x 1 km tectonic mélange, several major drainage captures along the main divide of the Southern Alps, a 103–100 m scale dependence of Alpine Fault partitioning. By developing collaborative ties to colleagues with specialties as diverse as remote sensing, geochemistry, geochronology, experimental rock deformation, amino acid racemization, palynology, and even nannopaleontology, I was able to initiate pilot studies exploring these big ideas with a bare minimum of available funding. As I found out, even a 5 µm-wide nannofossil can have a staggeringly important tectonic story to tell when paired with careful stratigraphic and geomorphic observations. Combined with detailed fieldwork, most of these avenues of research led to coherent, high impact, publishable studies (see below).
At the end of the day, I seek to be branded as a capable and hard-working geologist able to explore, observe, study, collaborate, and publish on high-impact research. I aim to solve applicable geological problems. I strive to communicate effectively to both technical and general audiences.
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First Authored (presented):
(1) Barth, N.C., V.G. Toy, R.M. Langridge, and R.J. Norris (2011), Shallow transpressional segmentation & partitioning revealed by LiDAR data, central Alpine Fault, New Zealand, Poster T31B-2343 presented at 2011 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec.
(2) Barth, N.C., V.G. Toy, R.M. Langridge, and R.J. Norris (2011), Shallow transpressional segmentation and partitioning revealed by LiDAR data: central Alpine Fault, New Zealand, Talk and poster presented at the Cooper & Norris Retirement Symposium: The Alpine Fault, Earthquakes and Mountain Building, University of Otago, Dunedin, New Zealand, 23-24 Nov.
(3) Barth, N.C., V.G. Toy, C.J. Boulton, and B.M. Carpenter (2010), Anatomy of a plate boundary at shallow crustal levels: A composite section from the Alpine Fault, New Zealand, Poster T41B-2110 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 11-17 Dec.
(4) Barth, N.C., V.G. Toy, C.J. Boulton, and B.M. Carpenter (2010), Anatomy of a plate boundary at shallow crustal levels: A composite section from the Alpine Fault, New Zealand, Talk presented at the GeoNZ 2010 Conference, Auckland, New Zealand, 21-24 Dec.
(5) Barth, N.C., B.R. Hacker, G. Seward, S.M. Johnston, D. Young, E. Walsh, and D.B. Root (2007), Strain within the ultrahigh-pressure Western Gneiss Region of Norway recorded by quartz LPOs, Talk 219-5 presented at 2007 GSA Annual Meeting, Denver, CO, 28-31 Oct.
Co-Authored:
(6) Boulton, C.J., V.G. Toy, N.C. Barth, and B.M. Carpenter (2012), Along strike applicability of results from the Deep Fault Drilling Program, Alpine Fault, New Zealand, Abstract T31C-2617 presented at 2012 Fall Meeting, AGU, San Francisco, Calif., 3-7 Dec.
(7) Boulton, C.J., N.C. Barth, B.M. Carpenter, and V.G. Toy (2012), Weak Fault Cores, Alpine Fault, New Zealand, Abstract presented at the Geosciences 2012 Conference, Hamilton, New Zealand, 25-28 Nov.
(8) Langridge, R., N.C. Barth, G. De Pascale, and R. Sutherland (2012), The character of Holocene Alpine Fault deformation near DFDP-1 and DFDP-2 sites: Insights from LiDAR, Abstract presented at the Geosciences 2012 Conference, Hamilton, New Zealand, 25-28 Nov.
(9) Toy, V.G., Boulton, C.J., Barth, N.C., Carpenter, B., IODP Expedition 343 Scientists and IODP-MI, Goldsby, D., Kopf, A., Mitchell, T., Marone, C., Sutherland, R., Townend, J., Tullis, T. (2012), What can microstructural observations of natural faults tell us about dissipative mechanisms that operated at the earthquake source?, Abstract presented at Earthquake Source Physics on Various Scales Conference, Luxembourg, 3-5 Oct.
(10) Boulton, C.J., B.M. Carpenter, N.C. Barth, and V.G. Toy (2012), Mineralogy, microstructures, and frictional properties of weak fault core phyllosilicates, Alpine Fault, New Zealand, Abstract presented at 2012 Gordon Research Conference: Feedback Processes in Rock Deformation, Andover, N.H., 19-24 Aug.
(11) Ikari, M.J., B.M. Carpenter, A.J. Kopf, N.C. Barth, C. Marone, D.M. Saffer, R. Oberhansli, V.G. Toy (2012) Frictional behavior of the Alpine Fault, New Zealand, sampled from DFDP drilling and surface outcrops, Abstract presented at the Joint Colloquium of the Integrated Ocean Drilling Program (IODP) and the International Continental Scientific Drilling Program (ICDP), Kiel, Germany, 7-9 Mar.
(12) Boulton, C.J., N.C. Barth, B.M. Carpenter, and V.G. Toy (2011), Significant along-strike variations in fault gouge thickness, friction coefficient and mineralogy, Alpine Fault, New Zealand, Abstract T41C-04 presented at 2011 Fall Meeting, AGU, San Francisco, Calif., 4-9 Dec.
(13) Boulton, C.J., B.M. Carpenter, N.C. Barth, V.G. Toy, and C. Marone (2011), Frictional and hydrological properties of Alpine Fault cataclastic fault rocks, Abstract presented at the Cooper & Norris Retirement Symposium: The Alpine Fault, Earthquakes and Mountain Building, University of Otago, Dunedin, New Zealand, 23-24 Nov.
(14) Langridge, R.M., N.C. Barth, G. De Pascale, and V.G. Toy (2011), Geomorphic structure and paleoseismicity of the central Alpine Fault revealed through LiDAR imagery, Abstract presented at Geosciences NZ 2011 Conference, Nelson, New Zealand, 27 Nov-1 Dec.
(15) Langridge, R.M., V.G. Toy, N.C. Barth, G.P. De Pascale, R. Sutherland, and T. Farrier (2010), First LiDAR images of the Alpine Fault, central South Island, New Zealand, Abstract EP43E-06 presented at 2010 Fall Meeting, AGU, San Francisco, Calif., 13-17 Dec.
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Ph.D. Geology at University of Otago, New Zealand (2013): "A Tectono-Geomorphic Study of the Alpine Fault, New Zealand" under Virginia Toy, Richard Norris, Alan Cooper and external advisor Simon Cox
My thesis was distinguished as a 2013 Exceptional Thesis by the University of Otago
Division of Sciences. This is awarded when "all three examiners of a candidate's thesis
agree that the thesis is of an exceptional standard in every respect – research content,
originality, quality of expression and accuracy of presentation – and is amongst the
top 10% of theses examined." More information can be found here.A full PDF version of my Ph.D. thesis is publicly available here (69 MB).
The colorful Red Mountain in South Westland is part of the Dun Mountain Ultramafics offset 460 km from the Red Hills at the top of the South Island by the Alpine Fault. Distance to foreground: Haast Schist, Caples Group, Dun Mountain Ultramafics (red), Livingstone Group, Maitai Group
Abstract with Figures: [see thesis for full figure captions and references]
The Alpine Fault is a ~900 km-long, active Australian-Pacific plate boundary structure, which accommodates up to 70–90% of total plate boundary motion across the South Island of New Zealand. Despite abundant evidence that large to great (~M 8) magnitude earthquakes have occurred frequently and regularly on the fault in the past, it has not ruptured historically and is thought to pose one of the greatest seismic hazards to the country of New Zealand at present.
Tectonic setting of New Zealand (left) and basement geology of the South Island (right)
Relationships between topography and climate (left) and tectonic deformation (right) on the South Island
This study adopts a multi-disciplinary field-based approach to examine fault zone structure and mechanics, spatio-temporal variations in fault behavior, and geomorphic evidence of key coseismic hazards on the central and southern Alpine Fault. The first three complete sections through the fault core of the southern Alpine Fault show that modern slip is localized to a single 1 to 12 m-thick fault core composed of impermeable (k = 10-20 to 10-22 m2), frictionally weak (µss = 0.12–0.37), velocity-strengthening, illite-chlorite and saponite-chlorite-lizardite fault gouges. The frictionally-weakest fault gouge occurs in the widest fault core and is spatially associated with a newly-identified serpentinite-bearing tectonic mélange.
Alpine Fault kinematics, particularly highlighting the change at the Martyr River
Complete composite cross sections through the Alpine Fault core at three key sites
Outcrop, hand sample, thin section- and SEM-scale images of the weakest phyllosilicate gouge at three key sites
In contrast to the relatively straight and localized dextral>normal-motion fault traces of the southern Alpine Fault, the central Alpine Fault is characterized by non-optimally-oriented oblique dextral-reverse motion, which causes the fault zone to partition in the upper ~1–2 km. Utilizing airborne light detection and ranging (LiDAR) data, the surface expression of a portion of the central Alpine Fault was mapped in unprecedented detail to confirm previous mapping that shows the fault is composed of serially-partitioned (i.e., sequenced) oblique-thrust and strike-slip faults at 1–10 km-length scales, and introduce for the first time the widespread occurrence of ~300 m-wide parallel-partitioned positive flower structures. A fault kinematic analysis predicts the fault trace orientations observed and supports the concept that the partitioning behavior is scale dependent, with different mechanisms (i.e., crustal-scale discontinuities, thermal weakening, fluvial incision, sediment interaction) exerting control at different scales (< 106–100 m). A slip stability analysis suggests that the newly-formed shallowly-rooted faults are kinematically stable, and thus the existing ~300 m-wide zone of fault traces defines a surface rupture hazard zone where future ruptures are expected to occur.
The effect of scale: remarkably straight, serially-partitioned (zig-zag), parallel-partitioned (parallel fault traces)
Virtual deforestation: aerial photograph and interpreted 2 m-resolution LiDAR hillshade of the same area
Deep-seated, long runout, catastrophic rock avalanches currently represent an underappreciated hazard of Alpine Fault earthquakes. The previously undescribed ~0.75 km3 c. 660 AD Cascade rock avalanche has an unambiguous structural relationship to pre-existing deep-seated bedrock failures. In comparison with other documented rock avalanches in the Southern Alps and Fiordland, it provides clues about precursory conditions for large catastrophic failures and suggests a mass above Franz Josef (town) poses a considerable risk.
Oblique aerial view (left) and geomorphic mapping (right) of the Cascade rock avalanche
Potential catastrophic failures: Mt Raddle (left) and Franz Josef (right)
A remarkable ~8 km dextral offset of major valleys and glacial deposits is recorded along ~100 km of the southern Alpine Fault. Tight age constraints allow correlation of this event to the Waimaunga Glaciation (Marine Isotope Stage 8; c. 270 ka) and indicate a dextral Alpine Fault slip-rate of 29.6 (-2.1/+2.3) mm/yr. Ages of marine sediments uplifted to ~600 m elevation yield fault-proximal Australian plate uplift rates of ~2.2–2.5 mm/yr. A re-assessment of the slip-rate and uplift rate catalog for the southern Alpine Fault suggests relatively constant rates over the last > 300 kyrs, and potentially > 3.5 Myrs.
Key strike-slip rate determinations along the Alpine Fault and main physiographic features (see legend below)
8000 m of dextral offset restored (landscape at c. 270,000 yrs ago)
Together, the results of this study frame a view of the southern half of the Alpine Fault as a highly-localized, long-lived, very weak locus of plate boundary motion that has had relatively constant spatio-temporal displacement rates in the latter part of its history, ruptures in hazardous large magnitude earthquakes with strong peak ground accelerations, and exerts a first-order control on landscape evolution of the South Island.
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M.Sc. Geological Sciences at UCSB: "Strain within the Ultrahigh-Pressure Western Gneiss Region of Norway Recorded by Quartz LPOs" under Brad Hacker
See Barth et. al (2010), “Strain within the Ultrahigh-Pressure Western Gneiss Region of Norway Recorded by Quartz CPOs” in Continental Tectonics and Mountain Building: the Legacy of Peach and Horne, Geological Society of London
The Nutshell
I used the exciting new technique of Electron Backscatter Diffraction (EBSD) at UCSB to study strain recorded in quartz and feldspar microstructures from the Western Gneiss Region (WGR) of Norway. Lattice preferred orientations (LPOs) can be used to tell the active slip system, deformation temperature, distortion (plane strain vs. flattening vs. constriction), vorticity (simple shear vs. pure shear) and sense of shear in a rock sample. I constructed a database of over 100 quartzite and quartzofeldspathic gneiss samples from all across the WGR so that I could better understand the exhumation of the Western Gneiss Region of Norway, one of the world’s two giant ultra-high pressure terranes (>50,000 km2).
Map of the Western Gneiss Region of Norway:
Abstract
Ultrahigh-pressure (UHP) metamorphism is a fundamental component of continental
orogenesis, but the exhumation of UHP rocks remains poorly understood. The Western
Gneiss Region (WGR) of Norway, the root zone of the Scandinavian Caledonides, is one of two giant UHP domains worldwide. Several conflicting exhumation hypotheses for the Western Gneiss Region have been proposed based on geochronologic, thermobarometric and petrologic data.
This study uses quartz lattice-preferred orientation (LPO) data (collected using
electron backscatter diffraction) from over 100 samples across the WGR to assess deformation mechanisms (e.g. slip systems), deformation temperatures, distortion, fabric strength, vorticity and sense of shear. Quantitative quartz LPO data were then used to construct a pseudo-Flinn plot and to create interpolated maps of strain and LPO properties across the WGR. The data were used to test previous WGR exhumation hypotheses and develop a new exhumation model.
The principal findings are: 1) The sense of shear is predominantly top-W in the
western half of the study area and top-E in the east. 2) There are distinct domains of plane strain and apparent constriction that trend NE-SW parallel to km-scale folds: these domains may represent different structural levels. 3) The activated slip systems (basal <a> and prism <a> slip) correlate inversely with peak metamorphic temperature. 4) Fabric strength correlates inversely with peak metamorphic temperature: the hottest
regions (NW) have the weakest fabrics. 5) Vorticity values of 0.85–1.00, indicate a
dominance of simple shear. 6) No evidence of flattening was observed.
These findings imply that the exhumation of the WGR through crustal levels occurred
via a combination of plane strain and constriction, with a shift from plane strain to
constriction (and increasing top-W sense of shear) during cooling from amphibolite facies conditions to greenschist-facies conditions. Granulite-facies quartz LPOs predating peak metamorphism are rare, but generally indicate top-E shear sense and conditions approaching plane strain.
Interpolated map of Pn values (calculated from quartz LPOs). High Pn values (red) indicate regions dominated by plane strain while low Pn (blue) indicates constriction:
Ultrahigh-Pressure Metamorphism
The formation and exhumation of ultrahigh-pressure (UHP) rocks are intrinsic to a number of Earth processes including the generation and collapse of mountain belts, crust-mantle material exchange, and the creation of continental crust. The occurrence of multiple temporally-spaced UHP events in many of the best-known orogens indicate that UHP processes are fundamental to collisional orogenesis. Exposure of UHP rocks (with deep origins and perhaps frequently incompletely exhumed) may lead to a significant underestimate of the prevalence of UHP processes in Earth’s evolution.
Western Gneiss Region
The Western Gneiss Region, a root of the Scandinavian Caledonides, is considered by many to be the best-exposed UHP terrane in the world and is thus a prime locale to study UHP processes associated with collisional orogenesis. A late-stage amphibolite facies overprint prevalent throughout the WGR has obscured any higher-temperature structural boundaries that may define (U)HP terranes. The Western Gneiss Region (WGR) of Norway has ultrahigh-pressure minerals that indicate subduction to depths greater than 100 km and subsequent exhumation. Gathering evidence shows that ultrahigh-pressure (UHP) and high-pressure (HP) metamorphism are a fundamental component of continental orogenesis worldwide, but the exhumation processes of UHP and HP rocks remain poorly understood. Numerous models have been proposed, but there are few comprehensive field-based datasets. Several exhumation hypotheses have been proposed for the WGR.
Lattice Preferred Orientations
Quartz lattice preferred orientations represent a useful tool in this regard because they are reset by relatively small strains and should therefore not be as complicated as the hand-sample to orogen-scale structure, which record the cumulative effects of the long (c. 1 Ga) deformation history of the WGR. High-temperature deformation can produce mineral lattice-preferred orientations (LPOs). These preferred orientations can arise from dislocation glide along particular crystallographic slip systems in individual crystals as they deform. Electron Backscatter Diffraction (EBSD) can be used to efficiently and reliably map mineral textures and orientations in thin sections and determine mineral LPOs.
Here is a figure showing the range of LPOs common in the Western Gneiss Region:
Here is a nice example of a prism <a> slip amphibolite-facies LPO intermediate between constriction and plane strain. The textural map below is colored based on quartz orientations (other grains are feldspars and mica). Notice the large feldspar delta clast showing top-left shear sense, consistent with the LPO.
See also Brad Hacker's website for related research
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B.Sc. Geological Sciences at UCSB, Senior Thesis: "Geology of the South Branch of the Pareora and Otaio Rivers Region, Hunter Hills, Canterbury, New Zealand"
As an undergraduate I conducted a Senior Thesis project on the Hunter Hills of the South Island of New Zealand, while studying at the University of Otago, New Zealand. The study primarily focused on an inversion tectonic study of the range-front Hunters Fault and a reinterpretation of the type locality of the so-called "Marshall Paraconformity." Other studies included lithology, structure, petrography, macrofossil assemblages, hydrogeology, geomorphology, geological hazards and economic geology. Geologic mapping and cross sections constructed at 1:5,000.
Here's a excerpt from my mapping and a cross section:
My advisor for this project was Rick Sibson
Copyright © 2014 Nicolas C. Barth. All Rights Reserved.
