ERS - Department of Earth Sciences

Phaedra Upton

Faculty Associate
PhD, Otago University, New Zealand, Geodynamics
Research Fellow, University of Otago


Address:

5790 Bryand Global Sciences Center
Room: 225
Tel: (207) 581 2221
Fax: (207) 581 2202
E-Mail: pheadra.upton@maine.edu


I am now based at the University of Otago , Dunedin, New Zealand but plan to return to UMaine now and then. When at Orono I can be found in the Geodynamic modelling laboratory.


Research Interests:

Active deformation in the Southern Alps of New Zealand

The tectonically active Southern Alps of New Zealand are an ideal setting in which to study the geodynamic response of a collisional orogen to far-field tectonic boundary conditions and the extent to which rheological parameters can influence that response. A wealth of geological and geophysical data exists for the Southern Alps, enhanced by the recent SIGHT transect across the Southern Alps, which provides valuable constraints for mechanical analysis. Using three-dimensional mechanical models (with Peter Koons) I have an ongoing project aimed at investigating the geodynamics of the Southern Alps orogen. In particular, I am interested in the three-dimensional nature of the orogen, which results from the obliquely convergent relative plate motion vector and from variations in the nature of the two colliding plates along strike of the plate boundary.

In conjunction with mechanical modeling, I have mapped active faults in the central eastern Southern Alps, concentrating on the Mackenzie and Rangitata/Lake Heron Basins. NE- and N-striking, oppositely dipping thrust fault pairs dominate active faulting in the region. I am interested in the style of faulting and what it can tell us about the nature of pre-existing structures, the response of the crust to the current tectonic regime and if pre-existing structure is exerting any control on the modern tectonics.

Fluids can play a significant role in how the crust responses to tectonic driving forces. My work in the central eastern Southern Alps has shown that near-surface fluids, with a small but measurable component of deeply sourced fluid, dominate upper crustal fluid flow in this region.  These fluids have been imaged by magnetotellurics by the SIGHT research group. I use this information as input into mechanical models, which investigate the influence of fluids on the geodynamics of the orogen.


By combining field studies unraveling the geology and the terrane history of the Northern Appalachians with thermo-mechanical modeling, we can develop a better understanding of the ancient orogeny. Using well-constrained model templates designed for modern oblique collisional systems, I (with Peter Koons and graduate students) am developing three-dimensional numerical models that test the thermal influence of various heat transport mechanisms within the lower and middle crust including magma intrusion, asthenosphere interaction and exhumation related thermal advection within the framework of the Acadian orogeny. I condition these models using data and observations from graduate students working on different aspects of the orogen with whom I work closely. 

Interaction between erosion and tectonics

I am working on various problems related to the coupling between tectonics and surficial processes. I am particularly interested in how erosion affects deformation of both the upper and lower crust. Using three-dimensional numerical mechanical modeling and collaborating with field-based research groups working in Taiwan (Karl Mueller and Greg Tucker, University of Colorado Boulder) and the Himalaya (Rasmus Theide and Manfred Strecker, Universität Potsdam), I am attempting to quantify the temporal and spatial scales at which this coupling takes place.  Preliminary results from Taiwan suggest that enhanced exhumation on a time frame of c. 200 kyrs has led to back stepping of deformation from the Range Front to reactive thrust faults within the Puli Basin . This project is funded for three years by NSF.

For my University of Otago research projects see: http://www.otago.ac.nz/geology/pu.htm


Recent Publications:

Upton, P. and Koons, P.O. (in press) Three-dimensional geodynamic framework for the Central Southern Alps, New Zealand: Integrating geology, geophysics and mechanical observations.  In: D Okaya, Stern T, Davey F (eds) AGU volume, Geotectonic Investigation of a Modern Continent-Continent Collisional Orogen: Southern Alps, NZ

Johnson, S.E., Vernon , R.H., and Upton , P. (2004) Initiation of microshear zones and progressive strain-rate partitioning in the crystallizing carapace of a tonalite pluton: microstructural evidence and numerical modeling. Journal of Structural Geology. 26, 1845-1865.

Upton, P., Craw, D., James, Z., and Koons, P.O. (2004) Structure and late Cenozoic tectonics of the Southern Two Thumb Range, mid-Canterbury, New Zealand .  New Zealand Journal of Geology and Geophysics. 47, 141-153.

Upton , P., Koons, P.O., and Eberhart-Phillips, D. (2003) Extension and partitioning in an oblique subduction zone, New Zealand : Constraints from three-dimensional numerical modeling. Tectonics, 22, 1068, doi:10.1029/2002 TC 001431.

Upton, P., Craw, D., Caldwell, T.G., Koons, P.O. James, Z., Wannamaker, P.E., Jiracek, G.J., and Chamberlain, C.P. (2003) Upper crustal fluid flow in the outboard region of the Southern Alps, New Zealand. Geofluids, 3, 1-12.

Koons, P.O., Upton , P. and Terry, M.P. (2003) Three-dimensional mechanics of UHPM terrains and resultant P-T-t paths. EMU Notes in Mineralogy, Vol. 5, Chapter 9, 27 p.

Gow, P.A., Upton, P., Zhao, C. and Hill, K.C. (2002) Predicting Cu-Au Mineralization in New Guinea : 2. Geodynamic Modeling of collision, fluid flow and intrusion-related hydrothermal systems. Australian Journal of Earth Sciences, 49. 753-771.

Koons, P.O., Craw, D., Cox, S., Upton, P., Templeton, A. and Chamberlain, C.P. (1998) Fluid flow during active convergence: A Southern Alps model from mechanical and geochemical observations. Geology. 26, 159-162.

Upton , P. (1998) Modeling localization of deformation and fluid flow in a compressional orogen: Implications for the Southern Alps of New Zealand. American Journal of Science. 289, 296-323.

Upton , P., Koons, P.O. and Chamberlain, C.P. (1995) Penetration of deformation-driven meteoric water into ductile rocks; isotopic and model observations from the Southern Alps , New Zealand . New Zealand Journal of Geology and Geophysics. 38, 535-544.


Recent Abstracts:

Upton, P., Mueller, K., Tucker, G., Wilcox, T. and Yanites, B. Do higher erosion rates lead to topographic highs or lows? An example from the Puli Embayment, West-Central Taiwan. Eos Trans. AGU, 87(52), Fall. Meet. Suppl. Abstract T24B-07, Dec 2006

Barker, A.D., Koons, P.O., Pavlis, T.L., Chapman, J.B., Upton, P., and Johnson, S.E, 3D modelling of the transition from oblique lateral to normal convergence at the plate corner of Southeast Alaska. Eos Trans. AGU, 87(52), Fall. Meet. Suppl. Abstract T23B-0493, Dec 2006

Upton, P., Koons, P.O. (2006) Three-dimensional geodynamic modeling of oblique orogenesis: Application to New Zealand and the Acadian orogen of Maine, Geological Society of America Abstracts with Programs, Vol. 38, No. 2, p. 67

Brown, L.E., Koons, P.O. Upton, P., (2006) Thermal-mechanical implications of a shallow asthenosphere in a deforming orogen: Constraints from 3D numerical modelling, Geological Society of America Abstracts with Programs, Vol. 38, No. 2, p. 68

Washburn, M., Johnson, S.E., Upton, P., Koons, P.O. (2006) Numerical modeling of fluid pressure gradients in anisotropic rocks undergoing heterogeneous deformation, Geological Society of America Abstracts with Programs, Vol. 38, No. 2, p. 62

Upton, P., Koons, P.O. (2005) Three-dimensional geodynamic modeling of the Southern Alps of New Zealand: integrating models and observations to understand crustal rheology, Eos Trans. AGU, 86(52), Fall Meet. Suppl., Abstract T12A-03

Upton, P., Markley, M., Begbie, M., Koons, P.O. (2005) Controls on fault-related folding, Eastern Southern Alps, New Zealand., Conference on the Theory and Application of Fault-Related Folding in Foreland Basins, Beijing, China, July 2005

Upton , P., Koons, P.O., Henderson , C.M., Three-dimensional geodynamic framework for the Southern Alps , New Zealand : Integrating geology, geophysics and mechanical observations. SIGHT workshop: Geotectonic investigation of a modern continent-continent collisional orogen:  Southern Alps , New Zealand .  Christchurch June 20^th-22^nd 2005

Koons, P.O., Upton , P., Craw, D., Henderson , C.M., Co-evolution of strain and topography of the Central South Island, New Zealand. SIGHT workshop: Geotectonic investigation of a modern continent-continent collisional orogen:  Southern Alps , New Zealand .  Christchurch June 20^th-22^nd 2005

Upton , P., Koons, P.O., Geodynamic modeling of collision zones: Integrating geology, geophysics and mechanical observations.  The Workshop on Geodynamic Modeling of Tectonic Processes, June 10-12, 2005 , Breckenridge, CO. Sponsors: The National Science Foundation and The Computational Infrastructure in Geodynamics (CIG).

Upton, P., Thiede, R., Bookhagen, B., Strecker, M.R. Coupling between erosion and tectonics at intermediate scales, Sutlej River, NW India. Geophysical Research Abstracts, Vol. 7, 05392, 2005


Employment History:

2006 – present, Research Fellow, Geology Department, University of Otago

2006 – present, Faculty Associate, Department of Earth Sciences, University of Maine , Orono , USA

2005 – 2006, Visiting Lecturer, Geology Department, Bates College

2002 – 2006, Post-doctoral Fellow/Research Associate, Department of Earth Sciences, University of Maine

1998 – 2002, Post-doctoral Fellow, Geology Department, University of Otago

1996 – 1998, Post-doctoral Fellow, CSIRO Exploration & Mining , Australia


Education:

University of Otago , Dunedin , New Zealand

PhD Geology 1995, Mechanics, reaction and fluid flow associated with continental collision along the Alpine Fault, Southern Alps , New Zealand .

DipGrad Geology 1989

Canterbury University , Christchurch , New Zealand

BSc Hons, Chemistry 1988