Late Cretaceous-early Eocene Laramide uplift, exhumation, and basin subsidence in Wyoming: Crustal responses to flat slab subduction

Majie Fan, Barbara Carrapa

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

Low-angle subduction of the Farallon oceanic plate during the Late Cretaceous-early Eocene is generally considered as the main driver forming the high Rocky Mountains in Wyoming and nearby areas. How the deformation was transferred from mantle to upper crust over the great duration of deformation (∼40 Myr) is still debated. Here, we reconstruct basin subsidence and compile paleoelevation, thermochronology, and provenance data to assess the timing, magnitude, and rates of rock uplift during the Laramide deformation. We reconstruct rock uplift as the sum of surface uplift and erosion constrained by combining paleoelevation and exhumation with regional stratigraphic thickness and chronostratigraphic information. The amount (and rate) of rock uplift of individual Laramide ranges was less than 2.4-4.8 km (∼0.21-0.32 mm/yr) during the early Maastrichtian-Paleocene (stage 1) and increased to more than ∼3 km (∼0.38-0.60 mm/yr) during the late Paleocene-early Eocene (stage 2). Our quantitative constraints reveal a two-stage development of the Laramide deformation in Wyoming and an increase of rock uplift during stage 2, associated with enhanced intermontane basin subsidence. Exhumation and uplift during stage 1 is consistent with eastward migration of Cordilleran deformation associated with low-angle subduction, whereas the change in exhumation during stage 2 seems to follow a southwestward trend, which requires an alternative explanation. We here suggest that the increase of rock uplift rate during the late Paleocene-early Eocene and the southwestward younging trend of uplift may be a response to the rollback and associated retreating delamination of the Farallon oceanic slab.

Original languageEnglish (US)
Pages (from-to)509-529
Number of pages21
JournalTectonics
Volume33
Issue number4
DOIs
StatePublished - 2014

Fingerprint

Subsidence
subsidence
exhumation
slab
Eocene
slabs
subduction
uplift
Rocks
rocks
Cretaceous
basin
Paleocene
rock
Rocky Mountains (North America)
trends
Delamination
erosion
Erosion
crusts

Keywords

  • basin subsidence
  • exhumation
  • Farallon plate
  • Laramide
  • paleoelevation

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

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title = "Late Cretaceous-early Eocene Laramide uplift, exhumation, and basin subsidence in Wyoming: Crustal responses to flat slab subduction",
abstract = "Low-angle subduction of the Farallon oceanic plate during the Late Cretaceous-early Eocene is generally considered as the main driver forming the high Rocky Mountains in Wyoming and nearby areas. How the deformation was transferred from mantle to upper crust over the great duration of deformation (∼40 Myr) is still debated. Here, we reconstruct basin subsidence and compile paleoelevation, thermochronology, and provenance data to assess the timing, magnitude, and rates of rock uplift during the Laramide deformation. We reconstruct rock uplift as the sum of surface uplift and erosion constrained by combining paleoelevation and exhumation with regional stratigraphic thickness and chronostratigraphic information. The amount (and rate) of rock uplift of individual Laramide ranges was less than 2.4-4.8 km (∼0.21-0.32 mm/yr) during the early Maastrichtian-Paleocene (stage 1) and increased to more than ∼3 km (∼0.38-0.60 mm/yr) during the late Paleocene-early Eocene (stage 2). Our quantitative constraints reveal a two-stage development of the Laramide deformation in Wyoming and an increase of rock uplift during stage 2, associated with enhanced intermontane basin subsidence. Exhumation and uplift during stage 1 is consistent with eastward migration of Cordilleran deformation associated with low-angle subduction, whereas the change in exhumation during stage 2 seems to follow a southwestward trend, which requires an alternative explanation. We here suggest that the increase of rock uplift rate during the late Paleocene-early Eocene and the southwestward younging trend of uplift may be a response to the rollback and associated retreating delamination of the Farallon oceanic slab.",
keywords = "basin subsidence, exhumation, Farallon plate, Laramide, paleoelevation",
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T1 - Late Cretaceous-early Eocene Laramide uplift, exhumation, and basin subsidence in Wyoming

T2 - Crustal responses to flat slab subduction

AU - Fan, Majie

AU - Carrapa, Barbara

PY - 2014

Y1 - 2014

N2 - Low-angle subduction of the Farallon oceanic plate during the Late Cretaceous-early Eocene is generally considered as the main driver forming the high Rocky Mountains in Wyoming and nearby areas. How the deformation was transferred from mantle to upper crust over the great duration of deformation (∼40 Myr) is still debated. Here, we reconstruct basin subsidence and compile paleoelevation, thermochronology, and provenance data to assess the timing, magnitude, and rates of rock uplift during the Laramide deformation. We reconstruct rock uplift as the sum of surface uplift and erosion constrained by combining paleoelevation and exhumation with regional stratigraphic thickness and chronostratigraphic information. The amount (and rate) of rock uplift of individual Laramide ranges was less than 2.4-4.8 km (∼0.21-0.32 mm/yr) during the early Maastrichtian-Paleocene (stage 1) and increased to more than ∼3 km (∼0.38-0.60 mm/yr) during the late Paleocene-early Eocene (stage 2). Our quantitative constraints reveal a two-stage development of the Laramide deformation in Wyoming and an increase of rock uplift during stage 2, associated with enhanced intermontane basin subsidence. Exhumation and uplift during stage 1 is consistent with eastward migration of Cordilleran deformation associated with low-angle subduction, whereas the change in exhumation during stage 2 seems to follow a southwestward trend, which requires an alternative explanation. We here suggest that the increase of rock uplift rate during the late Paleocene-early Eocene and the southwestward younging trend of uplift may be a response to the rollback and associated retreating delamination of the Farallon oceanic slab.

AB - Low-angle subduction of the Farallon oceanic plate during the Late Cretaceous-early Eocene is generally considered as the main driver forming the high Rocky Mountains in Wyoming and nearby areas. How the deformation was transferred from mantle to upper crust over the great duration of deformation (∼40 Myr) is still debated. Here, we reconstruct basin subsidence and compile paleoelevation, thermochronology, and provenance data to assess the timing, magnitude, and rates of rock uplift during the Laramide deformation. We reconstruct rock uplift as the sum of surface uplift and erosion constrained by combining paleoelevation and exhumation with regional stratigraphic thickness and chronostratigraphic information. The amount (and rate) of rock uplift of individual Laramide ranges was less than 2.4-4.8 km (∼0.21-0.32 mm/yr) during the early Maastrichtian-Paleocene (stage 1) and increased to more than ∼3 km (∼0.38-0.60 mm/yr) during the late Paleocene-early Eocene (stage 2). Our quantitative constraints reveal a two-stage development of the Laramide deformation in Wyoming and an increase of rock uplift during stage 2, associated with enhanced intermontane basin subsidence. Exhumation and uplift during stage 1 is consistent with eastward migration of Cordilleran deformation associated with low-angle subduction, whereas the change in exhumation during stage 2 seems to follow a southwestward trend, which requires an alternative explanation. We here suggest that the increase of rock uplift rate during the late Paleocene-early Eocene and the southwestward younging trend of uplift may be a response to the rollback and associated retreating delamination of the Farallon oceanic slab.

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KW - Farallon plate

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KW - paleoelevation

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