TY - JOUR
T1 - Uplift rates of marine terraces as a constraint on fault-propagation fold kinematics
T2 - Examples from the Hawkswood and Kate anticlines, North Canterbury, New Zealand
AU - Oakley, David O.S.
AU - Fisher, Donald M.
AU - Gardner, Thomas W.
AU - Stewart, Mary Kate
N1 - Funding Information:
This research was funded by Geological Society of America Graduate Research grants, American Association of Petroleum Geologists Grants-in-Aid, Sigma Xi Grants-in-Aid of Research (Grant ID #s G20120315159423 and G20130315164439 ), a Shell Geosciences Energy Research Facilitation Award , the Penn State Deike grant and Scholten-Williams-Wright Scholarship in Field Geology , and Trinity University's Herndon Professorship Fund . Use of the Move software was provided by Midland Valley, through their academic software initiative. The InvertTrishear program used for inverse modeling can be downloaded at http://davidosoakley.com/trishear.html . We would like to thank Mark Quigley for discussions in the field, and for use of the DGPS system for terrace surveying. We thank Rebecca VanderLeest for assistance in the field. We would also like to thank the North Canterbury landowners who allowed us access to their land and GNS Science for access to their structural datasets and map record sheets. Finally, we would like to thank the reviewers Nestor Cardozo and Clément Perrin and editor Jean-Philippe Avouac for their comments, which have greatly improved this manuscript.
Funding Information:
This research was funded by Geological Society of America Graduate Research grants, American Association of Petroleum Geologists Grants-in-Aid, Sigma Xi Grants-in-Aid of Research (Grant ID #s G20120315159423 and G20130315164439), a Shell Geosciences Energy Research Facilitation Award, the Penn State Deike grant and Scholten-Williams-Wright Scholarship in Field Geology, and Trinity University's Herndon Professorship Fund. Use of the Move software was provided by Midland Valley, through their academic software initiative. The InvertTrishear program used for inverse modeling can be downloaded at http://davidosoakley.com/trishear.html. We would like to thank Mark Quigley for discussions in the field, and for use of the DGPS system for terrace surveying. We thank Rebecca VanderLeest for assistance in the field. We would also like to thank the North Canterbury landowners who allowed us access to their land and GNS Science for access to their structural datasets and map record sheets. Finally, we would like to thank the reviewers Nestor Cardozo and Clément Perrin and editor Jean-Philippe Avouac for their comments, which have greatly improved this manuscript.
PY - 2018/1/31
Y1 - 2018/1/31
N2 - Marine terraces on growing fault-propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates, providing a means to distinguish among otherwise non-unique kinematic model solutions. Here, we investigate this relationship at two locations in North Canterbury, New Zealand: the Kate anticline and Haumuri Bluff, at the northern end of the Hawkswood anticline. At both locations, we calculate uplift rates of previously dated marine terraces, using DGPS surveys to estimate terrace inner edge elevations. We then use Markov chain Monte Carlo methods to fit fault-propagation fold kinematic models to structural geologic data, and we incorporate marine terrace uplift into the models as an additional constraint. At Haumuri Bluff, we find that marine terraces, when restored to originally horizontal surfaces, can help to eliminate certain trishear models that would fit the geologic data alone. At Kate anticline, we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel-fault propagation fold kink-band model. Finally, we use our model results to compute new estimates for fault slip rates (~ 1–2 m/ka at Kate anticline and 1–4 m/ka at Haumuri Bluff) and ages of the folds (~ 1 Ma), which are consistent with previous estimates for the onset of folding in this region. These results are consistent with previous work on the age of onset of folding in this region, provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults, and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non-unique solutions.
AB - Marine terraces on growing fault-propagation folds provide valuable insight into the relationship between fold kinematics and uplift rates, providing a means to distinguish among otherwise non-unique kinematic model solutions. Here, we investigate this relationship at two locations in North Canterbury, New Zealand: the Kate anticline and Haumuri Bluff, at the northern end of the Hawkswood anticline. At both locations, we calculate uplift rates of previously dated marine terraces, using DGPS surveys to estimate terrace inner edge elevations. We then use Markov chain Monte Carlo methods to fit fault-propagation fold kinematic models to structural geologic data, and we incorporate marine terrace uplift into the models as an additional constraint. At Haumuri Bluff, we find that marine terraces, when restored to originally horizontal surfaces, can help to eliminate certain trishear models that would fit the geologic data alone. At Kate anticline, we compare uplift rates at different structural positions and find that the spatial pattern of uplift rates is more consistent with trishear than with a parallel-fault propagation fold kink-band model. Finally, we use our model results to compute new estimates for fault slip rates (~ 1–2 m/ka at Kate anticline and 1–4 m/ka at Haumuri Bluff) and ages of the folds (~ 1 Ma), which are consistent with previous estimates for the onset of folding in this region. These results are consistent with previous work on the age of onset of folding in this region, provide revised estimates of fault slip rates necessary to understand the seismic hazard posed by these faults, and demonstrate the value of incorporating marine terraces in inverse fold kinematic models as a means to distinguish among non-unique solutions.
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U2 - 10.1016/j.tecto.2017.12.021
DO - 10.1016/j.tecto.2017.12.021
M3 - Article
AN - SCOPUS:85044641766
VL - 724-725
SP - 195
EP - 219
JO - Tectonophysics
JF - Tectonophysics
SN - 0040-1951
ER -
