Sedimentary basin geometry from global gravity field models: A case study from Lost River Valley (ID)
Abstract
The Basin and Range Province is defined by partially-filled sedimentary basins and normal fault-bound ranges. The main purpose of this study is to figure out how well sedimentary basins, in particular the Lost River Valley (ID) and adjacent areas, can be modeled utilizing global gravity models compared with traditional, ground-based gravity data. If satellite models are sufficient for discriminating tectonic structures on the scale of these basins, it represents a major advance in our capabilities for regional tectonic investigations. The model XGM2019e with spheroidal harmonics up to degree and order of 2190 was evaluated for this purpose. This model is compared to regional gravity data, both compiled by the USGS and augmented with our own data sets in the Lost River Valley. Both data sets were modeled using a grid of rectangular prisms constrained by a uniform density contrast but varying geometries . We used a wide range of parameters for the models to ensure the solution set did not belong to a local minima. The density contrast was constrained to similar values for both datasets to observe the sensitivity of the basin depth to the data collection method. The ground data and global model both yield a similar basin depth of ~4900 meters but vary in the ability to resolve short wavelength anomalies near the surface. The ground-based data puts the top of the basins at ~300 meter depth while the global model resolves the top of the basins at ~1000 meter depth. A huge advantage of the global gravity model is that different regions can be compared with a highly self-consistent framework. We show that the global gravity field model is a powerful tool for basin analysis though it has limitations in short wavelength anomaly resolution compared to ground-based data.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMG011.0008S
- Keywords:
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- 1217 Time variable gravity;
- GEODESY AND GRAVITY;
- 1219 Gravity anomalies and Earth structure;
- GEODESY AND GRAVITY;
- 1244 Standards and absolute measurements;
- GEODESY AND GRAVITY;
- 1294 Instruments and techniques;
- GEODESY AND GRAVITY