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Data for a Comprehensive Survey of Fault Zones, Breccias, and Fractures in and Flanking the Eastern Española Basin, Rio Grande Rift, New Mexico

Metadata Updated: October 8, 2025

This release provides the data for a comprehensive survey of geologic structures in the eastern Española Basin of the Rio Grande rift, New Mexico. The release includes data and analyses from 53 individual fault zones and 22 other brittle structures, such as breccia zones, joints, and veins, investigated at a total of just over 100 sites. Structures were examined and compared from poorly lithified Tertiary sediments, as well as Paleozoic sedimentary and Proterozoic crystalline rocks. Data and analyses, include geologic maps; field observations and measurements; orientation, kinematic paleostress analyses and modeling; statistical examination of 575 fault trace lengths derived from aeromagnetic data in the Española and adjacent basins; mineralogy and chemistry of host and fault rocks; and investigation of fault versus bolide impact hypotheses for the origin of enigmatic breccias found in the Proterozoic basement rocks. Kinematic and paleostress analyses suggest a record of transitional, and perhaps partitioned, strains from the Laramide orogeny through Rio Grande rifting. Normal faults within Tertiary basin fill sediments are consistent with more typical WNW-ESE Rio Grande extension, perhaps decoupled from bedrock structures due to strength contrasts favoring the formation of new faults in the relatively weak sediments. Analyses of the fault length data indicate power law length distributions similar to those reported from many geologic settings globally. Mineralogy and chemistry in Proterozoic fault-related rocks reveal geochemical changes tied to hydrothermal alteration and nearly isochemical transformation of feldspars to clay minerals. In sediments, fault rocks are characterized by mechanical entrainment with minor secondary chemical changes. Enigmatic breccias are autoclastic, isochemical with respect to their protoliths, and occur near shatter cones believed to be related to a pre-Pennsylvanian impact event. A weak iridium anomaly is associated with the breccias as well as adjacent protoliths, thus an impact shock wave cannot be ruled out for their origin. The types of faults, associated brittle structures, and geochemical attributes provided here can aid in development of conceptual models and approaches useful in identifying testable hypotheses grounded in geological data when assessing ground- and surface-water resources.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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Dates

Metadata Created Date September 12, 2025
Metadata Updated Date October 8, 2025

Metadata Source

Harvested from DOI USGS DCAT-US

Additional Metadata

Resource Type Dataset
Metadata Created Date September 12, 2025
Metadata Updated Date October 8, 2025
Publisher U.S. Geological Survey
Maintainer
Identifier http://datainventory.doi.gov/id/dataset/usgs-581130c5e4b0f497e799591b
Data Last Modified 2020-09-29T00:00:00Z
Category geospatial
Public Access Level public
Bureau Code 010:12
Metadata Context https://project-open-data.cio.gov/v1.1/schema/catalog.jsonld
Metadata Catalog ID https://ddi.doi.gov/usgs-data.json
Schema Version https://project-open-data.cio.gov/v1.1/schema
Catalog Describedby https://project-open-data.cio.gov/v1.1/schema/catalog.json
Harvest Object Id eb97356d-d4af-4779-9f54-a244a3b27f8c
Harvest Source Id 2b80d118-ab3a-48ba-bd93-996bbacefac2
Harvest Source Title DOI USGS DCAT-US
Metadata Type geospatial
Old Spatial -107.172451286, 34.426013078, -105.856454456, 36.100944487
Source Datajson Identifier True
Source Hash 5057097fa6824290dd9e3c6c1430c581adcc3bb66a60e896ebf4e6c390e11c4a
Source Schema Version 1.1
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