10.6084/m9.figshare.3453452.v1
E. D. McGregor
E. D.
McGregor
S. B. Nielsen
S. B.
Nielsen
R. A. Stephenson
R. A.
Stephenson
K. D. Petersen
K. D.
Petersen
D. I. M. MacDonald
D. I. M.
MacDonald
Long-term exhumation of a Palaeoproterozoic orogen and the role of pre-existing heterogeneous thermal crustal properties:
a fission-track study of SE Baffin Island
Geological Society of London
2016
age discontinuities
exhumation scenario
track lengths
age v
Palaeoproterozoic orogenies
track length
200 Ma
3 D exhumation
SE Baffin Island exhibit
440 Ma
annealing zone
variability
300 Ma
topography
crustal heat production
cooling
crustal properties
Palaeoproterozoic orogen
sample
data
Geology
2016-06-21 11:25:54
Dataset
https://geolsoc.figshare.com/articles/dataset/Long-term_exhumation_of_a_Palaeoproterozoic_orogen_and_the_role_of_pre-existing_heterogeneous_thermal_crustal_properties___a_fission-track_study_of_SE_Baffin_Island/3453452
<p>New apatite fission-track data from SE Baffin Island exhibit central ages that range from just under 200 Ma to 440 Ma, and
mean track lengths that vary between <em>c</em>. 12 and 13.3 µm. First-order analysis of the data (a plot of central age v. mean track length) reveals an approximate ‘boomerang’
trend, typical of samples that have experienced contemporaneous cooling from an array of initial temperatures. One-dimensional
inverse thermal modelling of single samples suggests that cooling through the partial annealing zone (<em>c</em>. 120–60 °C) occurred over discrete periods ranging from 100 to 300 Ma. Modelling the 3D exhumation of a heterogeneous crust
with flat topography demonstrates that some of the variability in observed fission-track ages could be attributed to heterogeneity
in crustal heat production and thermal conductivity. The remaining variability in the observed dataset is attributed here
to differential erosion from a variable initial topography. However, age discontinuities over short distances require other
explanations such as faulting and/or unidentified compositional effects. Collectively, these results suggest that the observed
data are consistent with a simple exhumation scenario where the present-day high topography is a remnant of that created during
Palaeoproterozoic orogenies. The new data do not require any recent (Cenozoic) periods of exhumation.
</p>