Collaborative Research: The legacy of transience: Understanding dynamic landscape adjustment following mountain uplift in two CZO field areas

Idaho State University, Pocatello ID

Investigators

Abstract

This project will further geologic understanding of tectonic history and its imprint on the current landscape. Understanding landscape response to tectonics can inform land management decisions and aid in quantifying hazard risk. The project focuses on two specific landscapes from NSF supported Critical Zone Observatories (CZO) and leverages existing data and resources from these two sites. The project combines field work, laboratory analysis, and modeling. Project outcomes will benefit the Earth science research community as well as policy makers. Landlab, the computational model that will be used and further developed in this project, will be made available through the Community Surface Dynamics Modeling System (CSDMS) website. The project will also provide a K-12 training module and Landlab numerical modeling exercises for undergraduate and graduate students. This study explores the unique signature of landscape adjustment following a change in tectonics in two different settings: South Fork Eel River, Northern California, USA and Rio Icacos, in Northeastern Puerto Rico. In both field areas, the current topography indicates that part of the landscape has not yet adjusted to a past or ongoing tectonic disturbance. The overall objective of the project is to understand and quantify the temporal evolution of the entire landscape, focusing specifically on the transformation of the relict topography to adjusted topography in these two field sites. A framework to interpret tectonic history of landscapes based on distribution of relict and adjusted topography will be developed through a combination of field work, cosmogenic nuclide geochronology, and landscape evolution modeling. Field work will include mapping relict parts of the landscape and quantifying morphologic features that vary between the adjusted and relict topography. Field observations will be combined with analyses of digital topographic maps. This work will allow future studies to easily identify relict topography in other landscapes. Geochemical techniques will be used to measure the spatially averaged denudation rate across the two landscapes. Numerical experiments using Landlab will be performed to understand how the tectonic history is expressed in the topography and denudation rate patterns.