Late Miocene–Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley–Costilla Plain, San Luis Basin, New Mexico and Colorado

Ruleman, Chester A.; Thompson, Ren A.; Shroba, Ralph R.; Anderson, M. L.; Drenth, Benjamin J.; Rotzien, Jonathan R.; Lyon, Jr. Marcus Ward

doi:10.1130/2013.2494(03)

Cited by 12 publications

(38 citation statements)

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“…The Sangre de Cristo fault system is divided into northern, central, and southern zones, with the southern zone extending from southern Colorado to the area southeast of Taos, thus forming the eastern margin of the southern San Luis Basin (Figs. 2 and 3) (Personius and Machette, 1984;Menges, 1990;Ruleman and Machette, 2007;Ruleman et al, 2013).…”

Section: Faultingmentioning

confidence: 99%

“…Furthermore, the temporal evolution of the structures bounding the basin and its subbasins has not been fully described. A previous model of the basin based on gravity modeling (Keller et al, 1984) is now obsolete in several areas due to (1) new information on basin-bounding structures; (2) a better understanding of rocks that constitute rift-related deposits; (3) better estimates of physical properties; (4) a better understanding of the geophysical signature of pre-rift and transitional rocks; and (5) more sophisticated approaches to geophysical modeling (Grauch and Keller, 2004;Drenth et al, 2011Drenth et al, , 2013Ruleman et al, 2013;Grauch et al, 2015Grauch et al, , 2017Thompson et al, in press;Turner et al, in press). These more recent concepts, developed locally within or at the edges of the present study area, await integration into a broader synthesis of the geometry and development of the southern San Luis Basin.…”

Section: Introductionmentioning

confidence: 99%

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A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.

Drenth

Grauch

Turner

et al. 2019

Rocky Mountain Geology

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Interpretation of gravity, magnetotelluric, and aeromagnetic data in conjunction with geologic constraints reveals details of basin geometry, thickness, and spatiotemporal evolution of the southern San Luis Basin, one of the major basins of the northern Rio Grande rift. Spatial variations of low-density basin-fill thickness are estimated primarily using a 3D gravity inversion method that improves on previous modeling efforts by separating the effects of the low-density basin fill from the effects of pre-rift rocks. The basin is found to be significantly narrower—and more complex in the subsurface—than indicated or implied by previous modeling efforts. The basin is also estimated to be significantly shallower than previously estimated. Five distinct subbasins are recognized within the broader southern San Luis Basin. The oldest and shallowest subbasin is the Las Mesitas graben along the northwestern basin margin, formed during the Oligocene transition from Southern Rocky Mountain volcanic field magmatism to rifting. In this subbasin, sediments are estimated to reach a maximum thickness of ~400 m within a north–south elongated structural depression. Other subbasins that likely initially developed during the Miocene are the dominant tectonic features in the southern San Luis Basin. This includes the Tres Orejas subbasin, which formed in the southwestern portion of the basin by the Embudo fault zone and a hypothesized fault zone along its western margin. This subbasin reaches a maximum thickness of ~2 km, as indicated by magnetotelluric and gravity modeling. The Sunshine Valley, Questa, and Taos subbasins occupy the eastern part of the southern San Luis Basin. The southern Sangre de Cristo fault zone is the dominant tectonic feature that controlled their development after ~20 Ma. The east-down Gorge fault zone controlled the western margins of significant parts of these eastern subbasins, although much of the Taos subbasin may be superimposed on the Tres Orejas subbasin. Maximum low-density basin-fill thicknesses are estimated to be 1.2 km for the Sunshine Valley subbasin, 800 m for the Questa subbasin, and 1.8 km for the Taos subbasin. Subbasin-forming tectonic activity along the Gorge fault zone and within the Tres Orejas subbasin ceased by the end of the development of the largely Pliocene Taos Plateau volcanic field. After that, rift-related subsidence became more narrowly centered on the eastern margin of the basin, controlled mainly by the linked Embudo and southern Sangre de Cristo fault zones.

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Section: Faultingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.

Drenth

Grauch

Turner

et al. 2019

Rocky Mountain Geology

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“…The detail allows unprecedented views of the geomorphology, leading to the recognition of subtle, gently sloping fault scarps or other topographic expressions of faults that are time consuming to map using conventional methods. As demonstrated in the northern Rio Grande rift, mapping the geomorphology of surficial deposits also leads to identification of their relative ages, with younger deposits showing greater roughness than older ones [21,31]. Thus, the general age of fault activity and sense of fault motion can be determined from the deposits that are displaced.…”

Section: Identifying Faults From Lidar Datamentioning

confidence: 99%

“…However, similar to observations in the central Rio Grande rift [46], we expect that the sediments are stratified in layers of differing magnetic susceptibilities, with average values ranging from ∼0.0005 to 0.0030 SI. How such layers are arranged in the subsurface of our study area is unknown, but the history of tectonic activity [19,31] suggests that coarse-grained sediments, representing the more magnetic of the sediments, likely lie toward the base of the section and thicken into the deepest parts of the basin. Reconnaissance magnetic-sus- ceptibility measurements of Precambrian rocks in our study area range from <0.0010 to ∼0.0250 SI, similar to the range of values found immediately to the north of our area [40,55].…”

Section: Area 1 Examplementioning

confidence: 99%

“…From the youngest to the oldest, these deposits are Qfy, Qfi, and Qfo ( Figure 1) and are associated with Pinedale, Bull Lake, and pre-Bull Lake glaciations, respectively. Based on regional correlations from previous and recent work, the glaciations in this area correspond to the following age ranges: Pinedale (12-30 ka), Bull Lake (about 120-170 ka), and preBull Lake (170-640 ka) [21,[24][25][26][27][28][29][30][31]. The most recent (<10 ka) deposits in the area are Holocene stream and fan alluvium deposits, unit Qh ( Figure 1).…”

Section: Inset)mentioning

confidence: 99%

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Identifying Buried Segments of Active Faults in the Northern Rio Grande Rift Using Aeromagnetic, LiDAR, and Gravity Data, South-Central Colorado, USA

Grauch

Ruleman

2013

International Journal of Geophysics

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Combined interpretation of aeromagnetic and LiDAR data builds on the strength of the aeromagnetic method to locate normal faults with significant offset under cover and the strength of LiDAR interpretation to identify the age and sense of motion of faults. Each data set helps resolve ambiguities in interpreting the other. In addition, gravity data can be used to infer the sense of motion for totally buried faults inferred solely from aeromagnetic data. Combined interpretation to identify active faults at the northern end of the San Luis Basin of the northern Rio Grande rift has confirmed general aspects of previous geologic mapping but has also provided significant improvements. The interpretation revises and extends mapped fault traces, confirms tectonic versus fluvial origins of steep stream banks, and gains additional information on the nature of active and potentially active partially and totally buried faults. Detailed morphology of surfaces mapped from the LiDAR data helps constrain ages of the faults that displace the deposits. The aeromagnetic data provide additional information about their extents in between discontinuous scarps and suggest that several totally buried, potentially active faults are present on both sides of the valley.

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Low‐Rate Faulting on the Margin of the Colorado Plateau and Rio Grande Rift in North‐Central New Mexico

Jobe

Chupik

2021

Tectonics

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In northern New Mexico, seismic hazard outside of the Rio Grande Rift (RGR) is generally considered low due to limited historical seismicity and few mapped Quaternary faults. Although the region has a complex tectonic history, nearly all known faults are considered inactive because of a lack of faulted Quaternary deposits. Analysis of lidar and existing geologic and geomorphic mapping permits identification and characterization of four faults on the Colorado Plateau/RGR margin. The Gallina, Willow Creek, and East and West Brazos Peak faults are normal or dextral‐normal faults that strike NW‐SE with lengths from 15 to 50 km. The Willow Creek fault has scarp heights <0.5–6.4 m on five Quaternary surfaces, with displacement increasing with relative surface age. An ∼5‐m‐high scarp on the ∼250 ka Brazos basalt yields an ∼0.02 mm/yr minimum dip‐slip rate. Oblique slip is recorded by dextral offset (∼40 m) of a middle Quaternary (?) terrace riser, a linear and en‐echelon stepping fault pattern, and a consistent down‐to‐the‐northeast fault expression. The West Brazos Peak fault displaces late Quaternary (?) surfaces by <4 m down‐to‐the‐southwest. We interpret these faults are Laramide‐aged faults reactivated as normal or dextral‐oblique faults in the Quaternary, consistent with regional stress and geodetic data. Although the faults have low slip rates (<0.1 mm/yr), the fault lengths suggest they may rupture in M6‐7 earthquakes and may pose a previously unrecognized seismic hazard to the region. Dextral transtension within the eastern Colorado Plateau is consistent with geodetic strain rates and earthquake focal mechanisms.

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Late Miocene–Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley–Costilla Plain, San Luis Basin, New Mexico and Colorado

Cited by 12 publications

References 0 publications

A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.

A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.

Identifying Buried Segments of Active Faults in the Northern Rio Grande Rift Using Aeromagnetic, LiDAR, and Gravity Data, South-Central Colorado, USA

Low‐Rate Faulting on the Margin of the Colorado Plateau and Rio Grande Rift in North‐Central New Mexico

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