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Landscape evolution within New Zealand's Marlborough Fault System

Updated: Dec 30, 2021


We examine the landscape of New Zealand's Marlborough Fault System, where the Australian and Pacific plates obliquely collide, in order to study landscape evolution at a long-lived plate boundary.



Funding Source: US National Science Foundation

Collaborators: Phaedra Upton (co-I) - GNS Science, Greg Tucker and Becky Flowers (Co-Is) - CU Boulder, John Stone - UW

GeoScape Team Members: Alison Duvall (PI), Seth Williams (graduate student), Sarah Harbert (PhD 2019), Camille Collett (MS 2015)

Using the MFS as a natural case study, we probe how landscapes evolve in complex tectonic settings and how extreme events disrupt and shape the landscape.


Overview


The active New Zealand plate boundary serves as a type locality for investigating the tectonic, structural, and landscape response to oblique plate collision. In particular, the landscape of the Marlborough Fault System (MFS) and Kaikōura Mountains at the NE end of the South Island, where oblique plate collision transitions to subduction, offers an excellent case study in landscape evolution at a long-lived plate boundary.


Our research contributes new discoveries in MFS mountain-uplift, drainage development and erosion over long (106), medium (104) and short (earthquake) timescales.


Low-temperature thermochronology from this region shows that spatial and temporal patterns in exhumation reflect a complex and evolving deformation field in the Marlborough Fault System over the past ~25 million years of Kaikōura orogeny.






Maps of drainage anomalies and channel steepness, as well as an analysis of the plan-view orientations of rivers and faults allows us to explore a history of drainage capture and rearrangement in response to mountain building and strike-slip faulting.





Our latest research using a time series of cosmogenic beryllium-10 (10Be) in river sediment examines the landscape response to the Mw 7.8 Kaikōura earthquake, which triggered over 30,000 landslides in 2016.



image: Sean LaHusen (2017)




Related Publications:


Duvall, A.R., Harbert, S.A., Upton, P., Tucker, G.E., Flowers, R.M., and Collett, C.M.,

2020, River patterns reveal landscape evolution at the edge of subduction, Marlborough

Fault System, New Zealand: Earth Surface, v.8, 177-194. https://doi.org/10.5194/esurf 8- 177-2020


Collett, C.M., Duvall, A.R., Flowers, B., Tucker, G.E., and Upton, P., 2019, The timing and

style of oblique deformation within New Zealand’s Kaikōura Ranges and Marlborough

Fault System, based on low-temperature thermochronology: Tectonics, v.38, 23 pp.

http://doi.org/10.1029/2018TC005268.


Harbert, S.A., Duvall, A.R., and Tucker, G.E., 2018, The role of near-fault relief elements in

creating and maintaining a strike-slip landscape: Geophysical Research Letters, 45, 10 pp. http://doi:10.1029/2018GL080045.

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