72 Toe to Toe: Cordilleran Systems from Trench to Retroarc Domains (Posters)

This session highlights research across geoscience disciplines to advance understanding of the deformation, magmatism, seismicity, topography, and sedimentation processes governing trench to retroarc evolution during ocean-continent plate convergence.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Geologic Mapping and Thermometry of the Luning-Fencemaker Thrust Belt Region: Constraints on the Evolution of the Auld Lang Syne Back-arc Basin

Paper number: 72-4
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

The thermal structure of orogenic belts is a primary influencer of lithospheric strength and subsequent deformation. The North American Cordilleran retroarc has experienced multiple tectono-thermal events such as back-arc opening, closure, and magmatism throughout the Mesozoic. To better understand the dynamics and kinematics of back-arc processes, here we present field and analytical observations from the ancient Mesozoic Auld Lang Syne (ALS) back-arc basin (BAB). The ALS BAB is located within the central latitudes of North American Cordillera and experienced high back-arc heat flow, heating from thrust related burial during back-arc closure, and heating from subsequent plutonism. This investigation seeks to constrain the kinematic and thermal evolution of the ALS BAB. Geologic mapping and structural analyses in the Jungo Hills area, west of Winnemucca, Nevada, show greenschist to amphibolite grade Triassic metapelites that exhibit range-scale overturned isoclinal folding and fold-nappe thrust transport along major thrust flats. Raman spectroscopy of carbonaceous material (RSCM) peak-temperature thermometry combined with temperature versus depth curves may be diagnostic in determining the origin of peak temperatures. Monotonic structural depth versus temperature trends may reflect Jurassic heating during Luning-Fencemaker thrust burial, whereas patchy localized hotspots likely correspond to local Late Cretaceous heating around major stocks and plutons. The integration of structural mapping with peak temperature data from RSCM allows us to assess the Cordilleran back-arc basin’s dominant thermal signature in the Mesozoic and compare our results with modern analogous BABs.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-412840

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