Tectonic controls on the hydrogeology of the Rio Grande Rift, New Mexico (original) (raw)
Related papers
Geosphere
A comprehensive survey of geologic structures formed in the Earth's brittle regime in the eastern Española Basin and flank of the Rio Grande rift, New Mexico, reveals a complex and protracted record of multiple tectonic events. Data and analyses from this representative rift flank-basin pair include measurements 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 in poorly lithified Tertiary sedi ments, as well as in Paleozoic sedimentary and Proterozoic crystalline rocks. Data and analyses include geologic maps; field observations and measurements; orientation, kinematic, and paleostress analyses; statistical examination of fault trace lengths derived from aeromagnetic data; mineralogy and chemistry of host and fault rocks; and investigation of fault versus bolideimpact hypotheses for the origin of enigmatic breccias found in the Proterozoic basement rocks. Fault 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 rift extension, perhaps de coupled 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 hydro thermal alteration and nearly isochemical transformation of feldspars to clay minerals. In sediments, faulted minerals are characterized by mechanical entrainment with minor secondary chemical changes. Enigmatic breccias in rift-flanking Protero zoic rocks are autoclastic and isochemical with respect to their protoliths and exist near shatter cones believed to be related to a previously reported 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. Major fault zones along the eastern rift-flank mountain front are discontinuous and unlikely to impede regional groundwater flow into Española Basin aquifers. The breccia bodies are not large enough to constitute aquifers, and no fault-or breccia-related geochemical anomalies were identified as potential contamination sources for ground or surface waters. The results of this work provide a broad picture of structural diversity and tectonic evolution along the eastern flank of the central Rio Grande rift and the adjacent Española Basin representative of the rift as a whole and many rifts worldwide.
Tectonophysics, 2019
Extension orientation is a key parameter in rift tectonics. While a clockwise rotation of the extension orientation is widely accepted for the southern Rio Grande rift and the Basin and Range province in western U.S., in which direction(s) the northern Rio Grande rift opened has been controversial. Moreover, slip reorientation , a phenomenon caused by local stress rotation on weak faults under a unidirectional regional extension, imposes a serious impact on kinematic interpretations. We investigate the presently oblique Tusas-Abiquiu segment of the Rio Grande rift in north-central New Mexico to assess the rifting kinematics with the presence of pre-existing crustal weaknesses. Fault-slip data show an overall NE-SW extension on the NW-trending Tusas border faults, and WNW-ESE extension on the NNE-trending Abiquiu border and internal faults. The slip vectors on the border faults show a wide variety of oblique-slip component, whereas those on the internal faults are predominantly pure dip-slip. The majority of our field measurements can be reproduced by the slip reorientation model, although this model's setting does not satisfy regional geological records. Clockwise rotation of the extension axes from NE-SW to WNW-ESE can also explain our fault-slip data, as well as other structures in the rift. Tectonic reactivation during the extension also influenced the landscape evolution of the early rift. The Rio Grande rift shared similar extension orientation with the southern Basin and Range during the late Oligocene. The extensional strain field of the southwestern North American plate shows a progressive, time-transgressive rotational pattern, implying that plate boundary processes, instead of asthenospheric upwelling, governed the initiation and early evolution of this intracontinental rift.
Geosphere, 2017
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near Taos, New Mexico. Geologic evidence for all but its young rift history is concealed under Quaternary cover. We focus on under standing the preQuaternary evidence that is in the subsurface by integrat ing diverse pieces of geologic and geophysical information. As a result, we present a substantively new understanding of the tectonic configuration and evolution of the northern extent of the Embudo fault and its adjacent subbasin. We integrate geophysical, borehole, and geologic information to interpret the subsurface configuration of the rift margins formed by the Embudo and Sangre de Cristo faults and the geometry of the subbasin within the Taos em bayment. Key features interpreted include (1) an imperfect Dshaped subbasin that slopes to the east and southeast, with the deepest point ~2 km below the valley floor located northwest of Taos at ~36° 26′N latitude and 105° 37′W longitude; (2) a concealed Embudo fault system that extends as much as 7 km wider than is mapped at the surface, wherein fault strands disrupt or truncate flows of Pliocene Servilleta Basalt and step down into the subbasin with a minimum of 1.8 km of vertical displacement; and (3) a similar, wider than ex pected (5-7 km) zone of stepped, westdown normal faults associated with the Sangre de Cristo range front fault. From the geophysical interpretations and subsurface models, we infer relations between faulting and flows of Pliocene Servilleta Basalt and older, buried basaltic rocks that, combined with geologic mapping, suggest a re vised rift history involving shifts in the locus of fault activity as the Taos sub basin developed. We speculate that faults related to northstriking grabens at the end of Laramide time formed the first westdown master faults. The Em budo fault may have initiated in early Miocene southwest of the Taos region. Normaloblique slip on these early fault strands likely transitioned in space and time to dominantly leftlateral slip as the Embudo fault propagated to the northeast. During and shortly after eruption of Servilleta Basalt, proto Embudo fault strands were active along and parallel to the modern, NEaligned Rio Pueblo de Taos, ~4-7 km basinward of the modern, mapped Embudo fault zone. Faults along the northeastern subbasin margin had northwest strikes for most of the period of subbasin formation and were located ~5-7 km basinward of the modern Sangre de Cristo fault. The locus of fault activity shifted to more northerly striking faults within 2 km of the modern range front sometime after Servilleta volcanism had ceased. The northerly faults may have linked with the northeasterly protoEmbudo faults at this time, concurrent with the de velopment of Nstriking Los Cordovas normal faults within the interior of the subbasin. By middle Pleistocene(?) time, the Los Cordovas faults had become inactive, and the linked Embudo-Sangre de Cristo fault system migrated to the south, to the modern range front.
Tectonophysics, 1990
As part of a major cooperative seismic experiment, a series of seismic refraction profiles have been recorded in south -central New Mexico with the goal of determining the crustal structure in the southern Rio Grande rift. The data gathered greatly expand the seismic data base in the area and consist of three interlocking regional profiles: a reversed E-W line across the rift, an unreversed N-S axial line, and an unreversed SW-SE line. The reversed E-W line shows no significant dip along the Moho ('32 km thick crust) and a 7.7 km/s Pn velocity. Results from the N-S axial line and the NW-SE line indicate an apparent Pn velocity of 7.95 km/s and significant dip along the Moho with crustal thinning toward the south and southeast. When interpreted together, these data indicate a crustal thinning in the southern rift of 4-6 km with respect to the northern rift and the adjacent Basin and Range province and establish the regional Pn velocity to be approximately 7.7 km/s. These results suggest that the Rio Grande rift can be identified as a crustal feature separate and distinct from the Basin and Range province. Gas Company, Dallas, Texas. 3Department of Geosciences, Purdue University, West Lafayette, Indiana. Laramide orogenic activity [Chapin and Seager, 1975]. From late Eocene through most of the Oligocene, voluminous calcalkalic volcanism took place throughout most of the southwestern United States as a result of subduction of the Farallon plate beneath the North American plate [Atwater, 1970; Lipman et al., 1972; Coney and Reynolds, 1977]. In the rift area, this activity is evidenced by the formation of the San Juan, Datil-Mogollon, and Davis Mountains, as well as other smaller volcanic fields that flank the rift [Chapin and Seager, 1975]. By late Oligocene to early Miocene time, magmatism changed from predominantly calc-alkalic compositions to more basic compositions [Seager and Morgan, 1979; Chapin, 1979]. This change in volcanism in the rift area was contemporaneous with the transition from a subduction regime to a regime of regional extension [Lipman and Mehnert, 1975] and the early initiation of rifting. The basaltic-andesitic volcanism lasted to about 20 Ma in the northern rift and to about 26 Ma in the southern rift and was followed by a magmatic lull which lasted until 13 Ma [Chapin, 1970; Seager and Morgan, 1979]. Following this lull, basaltic-rhyolitic volcanism started with basaltic activity peaking around 5 Ma [Seager andMorgan, 1979]. Basaltic fields and individual flows dotted the floor of the Rio Grande rift from southern Colorado to the Mexican border [Seager and Morgan, 1970; Chapin and Seager, 1975]. The major volcanic activity was concentrated in the Jemez Mountains-Taos Plateau area, the Socorro Peak area, and the Magdalena Peak area where major northeast trending lineaments intersect the rift [Chapin, 1971]. About 7-4 Ma, the Southern Rocky Mountains and adjacent areas were strongly uplifted due to mantle upwelling [Eaton, 1979]. In the southern Rio Grande rift, Seager et al. [1984] interpreted the change from basaltic andesite to alkali-olvine basalt to represent two different but transitional extension regimes. In the early regime (starting around 28 Ma), extension developed in a back arc setting and resulted in the eraplacement of basaltic andesite, the formation of broad NW trending basins, and the uplift of some of the region's fault-block mountains. The later 6143 helped with the CARDEX experiment, especially L.W. Braile and Carl
Geological Society of America Special Papers, 2013
The structural geometry of transfer and accommodation zones that relay strain between extensional domains in rifted crust has been addressed in many studies over the past 30 years. However, details of the kinematics of deformation and related stress changes within these zones have received relatively little attention. In this study we conduct the fi rst-ever systematic, multi-basin fault-slip measurement campaign within the late Cenozoic Rio Grande rift of northern New Mexico to address the mechanisms and causes of extensional strain transfer associated with a broad accommodation zone. Numerous (562) kinematic measurements were collected at fault exposures within and adjacent to the NE-trending Santo Domingo Basin accommodation zone, or relay, which structurally links the N-trending, right-stepping en echelon Albuquerque and Española rift basins. The following observations are made based on these fault measurements and paleostresses computed from them. (1) Compared to the typical northerly striking normal to normal-oblique faults in the rift basins to the north and south, normal-oblique faults are broadly distributed within two merging, NE-trending zones on the northwest and southeast sides of the Santo Domingo Basin. (2) Faults in these zones have greater dispersion of rake values and fault strikes, greater dextral strikeslip components over a wide northerly strike range, and small to moderate clockwise defl ections of their tips. (3) Relative-age relations among fault surfaces and slickenlines used to compute reduced stress tensors suggest that far-fi eld, ~E-W-trending σ 3 stress trajectories were perturbed 45° to 90° clockwise into NW to N trends within the Santo Domingo zones. (4) Fault-stratigraphic age relations constrain the stress perturbations to the later stages of rifting, possibly as late as 2.7-1.1 Ma.
Geodetic measurement of horizontal deformation across the Rio Grande Rift Near Socorro, New Mexico
Journal of Geophysical Research: Solid Earth, 1980
Trilateration surveys of a geodetic network across the Rio Grande rift near Socorro, New Mexico, in 1972, 1973, 1976, and 1979 have failed to detect any significant strain accumulation. The surveys place an upper bound (95% confidence limit) of 1 mm/a (a = years) on east‐west spreading cross the rift in 1972–1979. There is marginal evidence from triangulation for an episode of east‐west spreading across the rift within the interval 1954–1972. The trilateration network lies on the south flank of an uplift caused by magma intrusion into a midcrustal sill during this century according to Reilinger and Oliver. The horizontal deformation induced by sill inflation is sufficiently small that continued uplift during 1972–1979 cannot be excluded by the observed absence of significant horizontal deformation.
Late Cretaceous to middle Tertiary tectonic history of the northern Rio Grande Rift, New Mexico
Journal of Geophysical Research, 1986
Apatite fission track ages for samples collected from three mountain ranges on the eastern margin of the Rio Grande rift are used to examine the late Cretaceous to middle Miocene uplift and erosional history of north central New Mexico. The dates indicate that uplift and erosion was in progress in the Sandia Mountains near Albuquerque and in the Taos Range portion of the Sangre de Cristo Mountains near Taos at least 30-35 m.y. ago. Uplift and erosion continued in the Sandia Mountains at a relatively constant rate (81 m/m.y.) until 15 Ma; the rate of uplift and erosion in this area has approximately tripled in the past 15 m.y. (230 m/m.y.). Igneous activity in the Taos Range has largely obscured the early Tertiary uplift and erosional history of this portion of the Sangre de Cristo Mountains. A fission track date from one of the middle Tertiary intrusions in the Taos Range is used to calculate the cooling rate due to uplift and erosion in this area for the past 14 m.y. (210 m/m.y.). The uplift and erosion rates derived from the fission track data for the past 14-15 m.y. are similar to those obtained from other geological evidence. In contrast to the Oligocene to Miocene ages found in the other two areas, the apatite fission track ages from the Santa Ire Range portion of the Sangre de Cristo Mountains near Santa Fe are Late Cretaceous to early Eocene. These dates record the cooling of the area due to uplift and erosion during the Laramide event. The preservation of these older ages indicates that the Santa Fe Range was a low-lying area during the Oligocene to Miocene, while the surrounding areas (Sandia Mountains and Taos Range) underwent uplift and erosion. Volcanic activity occurred in the vicinity of the two areas of positive relief. Localized crustal extension associated with the volcanism may have contributed, in part, to the uplift of these areas. Using simple, two-dimensional thermal models, we found that the apparent denudation rates derived from the fission track age data may represent true denudation rates, given certain geologic conditions that may have existed during the uplift and erosion of the Sandia Mountains in the middle Tertiary and the Santa Fe Range in the late Cretaceous. tween absolute denudation rates and the denudation rates derived from the fission track age data is examined. Second, the uplift and erosion results derived from the fission track ages are used in conjunction with published geological information to reconstruct the palcogeography of northern New Mexico between the late Cretaceous and the early Miocene.
Cenozoic thermal, mechanical and tectonic evolution of the Rio Grande Rift
Journal of Geophysical Research, 1986
Careful documentation of the Cenozoic geologic history of the Rio Grande rift in New Mexico reveals a complex sequence of events. At least two phases of extension have been identified. An early phase of extension began in the mid-Oligocene (about 30 Ma) and may have continued to the early Miocene (about 18 Ma). This phase of extension was characterized by local high-strain extension events (locally, 50-100%, regionally, 30-50%), low-angle faulting, and the development of broad, relatively shallow basins, all indicating an approximately NE-SW •-25 ø extension direction, consistent with the regional stress field at that time. Extension events were not synchronous during early phase extension and were often temporally and spatially associated with major magmatism. A late phase of extension occurred primarily in the late Miocene (10-5 Ma) with minor extension continuing to the present. It was characterized by apparently synchronous, high-angle faulting giving large vertical strains with relatively minor lateral strain (5-20%) which produced the moderu Rio Grande rift morphology. Extension direction was approximately E-W, consistent with the contemporary regional stress field. Late phase graben or half-graben basins cut and often obscure early phase broad basins. Early phase extensional style and basin formation indicate a ductile lithosphere, and this extension occurred during the climax of Paleogene magmatic activity in this zone. Late phase extensional style indicates a more brittle lithosphere, and this extension followed a middle Miocene lull in volcanism. Regional uplift of about 1 km appears to have accompanied late phase extension, and relatively minor volcanism has continued to the present. We have estimated geotherms and calculated lithospheric strength curves for the two phases of extension, using geologic data to constrain earlier events and geophysical data to constrain the modern geotherm and crustal structure. A high geotherm was deduced for early phase extension, resulting in a shallow crustal brittle-ductile transition and negligible mantle strength. The lithosphere cooled after early phase extension, resulting in a deeper crustal. brittle-ductile transition, and, perhaps more significantly, a considerable zone of mantle strength immediately beneath the Moho. These results indicate that early phase extensional style was controlled by a crustal decollement near the brittle-ductile transition, which was prevented during late phase extension by significant strength in the uppermost mantle. Late Cenozoic uplift of the rift zone cannot be explained by crustal thinning during extension and geotherm evolution predicted from simple cooling. However, this uplift does not appear to be restricted to the rift zone, and Pliocene to Recent volcanism and heat flow data suggest that uplift may be caused by magmatic thickening of the crust, perhaps unrelated to rifting. The complex interrelationship among regional and local prerifting, synrifting, and postrifting events in the Rio Grande rift suggests that rifting, at least in this region, should not be considered in isolation of other geologic events. Lafayette, IN 47907.
Sedimentology, 2000
Deposits of the ancestral Rio Grande (aRG) belonging to the Camp Rice Formation are preserved and exposed in the uplifted southern portion of the Robledo Mountains horst of the southern Rio Grande rift. The sediments are dated palaeomagnetically to the Gauss chron (upper Pliocene). The lower part of the succession lies in a newly discovered palaeocanyon cut into underlying Eocene rocks whose margins are progressively onlapped by the upper part. Detailed sedimentological studies reveal the presence of numerous river channel and floodplain lithofacies, indicative of varied deposition in channel bar complexes of low-sinuosity, pebbly sandbed channels that traversed generally dryland floodplains and shifted in and out of the study area five times over the 1 Myr or so recorded by the succession. Notable discoveries in the deposits are: (1) complexes of initial avulsion breakout channels at the base of major sandstone storeys; (2) common low-angle bedsets ascribed to deposition over low-angle dunes in active channels; (3) palaeocanyon floodplain environments with evidence of fluctuating near-surface water tables. Sand-body architecture is generally multistorey, with palaeocurrents indicative of funnelling of initial avulsive and main fluvial discharge from the neighbouring Mesilla basin through a narrow topographic gap into the palaeocanyon and out over the study area. An avulsion node was evidently located at the stationary southern tip to the East Robledo fault during Gauss times, with aRG channels to the north flowing close to the fault and preventing fan progradation. Subsequent Matuyama growth of the fault caused (1) deposition to cease as the whole succession was uplifted in its footwall, (2) development of a thick petrocalcic horizon, and (3) fan progradation into the Mesilla basin. Parameters for the whole aRG fluvial system are estimated as: active single channels 2 m deep and 25 m wide; valley slope 0·24–0·065°; maximum mean aggradation rate 0·05 mm year–1; major channel belt avulsion interval 200 ky; individual channel recurrence interval 100 ky; minimum bankfull mean flow velocity 1·54 m s–1, minimum single-channel discharge 77 m3 s–1, bed shear stress 22·3 N m–2; and stream power 34·3 W m–2.
Stratigraphy and tectonic development of the Albuquerque Basin, central Rio Grande rift
2001
This field-guide accompanied a pre-meeting field trip of the Geological Society of America Rocky Mountain and South-Central Section conference in Albuquerque, New Mexico. A limited quantity of guidebooks and minipaper compilations were produced for participants of this field trip. A number of typographical, grammatical, and editorial errors were found in this first version of the guidebook, mainly because of logistical constraints during preparation for the field trip. In the revised version, released on June 11, 2001, many errors have been corrected. Many photographs, figures, and maps, shown during the field trip but not included in the first version, are included in this revision. Numerous minor editorial changes and corrections have also been made to the guidebook minipapers. The field-guide has been separated into two parts. Part A (open-file report 454A) contains the three-days of road logs and stop descriptions. Part B (open-file report 454B) contains a collection of mini-papers relevant to field-trip stops. The contents of the road logs and mini-papers have been placed on open file in order to make them available to the public as soon as possible. Revision of these papers is likely because of the ongoing nature of work in the region.