TY - DATA T1 - 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 PY - 2016/06/21 AU - E. D. McGregor AU - S. B. Nielsen AU - R. A. Stephenson AU - K. D. Petersen AU - D. I. M. MacDonald UR - 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 DO - 10.6084/m9.figshare.3453452.v1 L4 - https://ndownloader.figshare.com/files/5422862 L4 - https://ndownloader.figshare.com/files/5422865 L4 - https://ndownloader.figshare.com/files/5422868 L4 - https://ndownloader.figshare.com/files/5422871 L4 - https://ndownloader.figshare.com/files/5422874 L4 - https://ndownloader.figshare.com/files/5422877 L4 - https://ndownloader.figshare.com/files/5422880 L4 - https://ndownloader.figshare.com/files/5422883 L4 - https://ndownloader.figshare.com/files/5422886 L4 - https://ndownloader.figshare.com/files/5422889 L4 - https://ndownloader.figshare.com/files/5422892 L4 - https://ndownloader.figshare.com/files/5422895 L4 - https://ndownloader.figshare.com/files/5422898 L4 - https://ndownloader.figshare.com/files/5422901 L4 - https://ndownloader.figshare.com/files/5422904 KW - age discontinuities KW - exhumation scenario KW - track lengths KW - age v KW - Palaeoproterozoic orogenies KW - track length KW - 200 Ma KW - 3 D exhumation KW - SE Baffin Island exhibit KW - 440 Ma KW - annealing zone KW - variability KW - 300 Ma KW - topography KW - crustal heat production KW - cooling KW - crustal properties KW - Palaeoproterozoic orogen KW - sample KW - data KW - Geology N2 - 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 c. 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 (c. 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. ER -