TY - JOUR
T1 - Tectonic and glacial contributions to focused exhumation in the Olympic Mountains, Washington, USA
AU - Michel, Lorenz
AU - Ehlers, Todd A
AU - Glotzbach, Christoph
AU - Adams, Byron
AU - Stübner, Konstanze
PY - 2018/4/6
Y1 - 2018/4/6
N2 - Tectonics and climate are major contributors to the topographic
evolution of mountain ranges. Here, we investigate temporal variations
in exhumation due to the onset of Pleistocene glaciation in the
Olympic Mountains (Washington State, USA). We present 29 new
apatite and zircon (U-Th)/He ages (AHe and ZHe), showing a decrease
in ages toward the interior of the mountain range for both thermochronometric
systems. Young AHe ages (<2 Ma) can be found on the
western side and the interior of the mountain range. Thermokinematic
modeling of sample cooling ages suggests, that ZHe ages can
be explained by an ellipse-shaped exhumation pattern with lowest/
highest rates of ~0.25 and 0.9 km/m.y. These rates are interpreted as
tectonically driven rock uplift, where the pattern of rates is governed
by the shape of the subducted plate. However, the youngest AHe ages
require a 50–150% increase in exhumation rates in the past 2–3 m.y.
This increase in rates is contemporaneous with Pliocene-Pleistocene
alpine glaciation of the orogen, indicating that tectonic rock uplift is
perturbed by glacial erosion.
AB - Tectonics and climate are major contributors to the topographic
evolution of mountain ranges. Here, we investigate temporal variations
in exhumation due to the onset of Pleistocene glaciation in the
Olympic Mountains (Washington State, USA). We present 29 new
apatite and zircon (U-Th)/He ages (AHe and ZHe), showing a decrease
in ages toward the interior of the mountain range for both thermochronometric
systems. Young AHe ages (<2 Ma) can be found on the
western side and the interior of the mountain range. Thermokinematic
modeling of sample cooling ages suggests, that ZHe ages can
be explained by an ellipse-shaped exhumation pattern with lowest/
highest rates of ~0.25 and 0.9 km/m.y. These rates are interpreted as
tectonically driven rock uplift, where the pattern of rates is governed
by the shape of the subducted plate. However, the youngest AHe ages
require a 50–150% increase in exhumation rates in the past 2–3 m.y.
This increase in rates is contemporaneous with Pliocene-Pleistocene
alpine glaciation of the orogen, indicating that tectonic rock uplift is
perturbed by glacial erosion.
U2 - 10.1130/G39881.1
DO - 10.1130/G39881.1
M3 - Article (Academic Journal)
SN - 0091-7613
VL - 46
JO - Geology
JF - Geology
IS - 4
ER -