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Long-term (2010-19) water-quality monitoring on the Colorado River downstream from Moab Utah indicated the persistent presence of Bioactive Chemicals (BC), such as pesticides and pharmaceuticals. This stream reach near Canyonlands National Park provides critical habitat for federally endangered species. The Moab wastewater treatment plant (WWTP) outfall discharges to the Colorado River and is the nearest potential point-source to this reach. The original WWTP was replaced in 2018. In 2016-19, a study was completed to determine if the new plant reduced BC input to the Colorado River at, and downstream from, the outfall. Water samples were collected before and after the plant replacement at sites upstream and downstream from the outfall. Samples were analyzed for as many as 243 pesticides, 109 pharmaceuticals, 20 hormones, 51 wastewater indicator chemicals, 20 metals, and 8 nutrients. BC concentrations, hazard quotients (HQs), and exposure activity ratios (EARs) were used to identify and prioritize contaminants for their potential to have adverse biological effects on the health of native and endangered wildlife. There were 22 BC with HQs >1, mostly metals and hormones; and 23 BC with EARs >0.1, mostly hormones and pharmaceuticals. Most high HQs or EARs were associated with samples collected at the WWTP outfall site prior to its replacement. Discharge from the new plant had reduced concentrations of nutrients, hormones, pharmaceuticals, and other BC. For example, all 16 of the hormones detected at the WWTP outfall site had maximum concentrations in samples collected prior to the WWTP replacement. The WWTP replacement had less effect on instream concentrations of metals and pesticides, BC whose sources are less directly tied to domestic wastewater. Study results indicate that improved WWTP technology can create substantial reductions in concentrations of non-regulated BC such as pharmaceuticals, in addition to regulated contaminants such as nutrients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Published by Elsevier B.V.)

The Late Jurassic, 'single surface' Moab Megatracksite between Green River, Utah and the Colorado-Utah State line is associated with the sharp, colour-enhanced, inter-formational contact between white, reworked dune sandstones from the aeolian Moab Member of the Curtis Formation and red, sabkha facies siltstones and sandstones of the upper tongue of the Summerville Formation. Previous studies described theropod (Megalosauripus and Therangospodus) dominated assemblages from ~25 sites in the megatracksite core area around Arches National Park, and briefly interpreted the transgressive mechanisms of the Sundance sea which helped create and preserve the megatracksite. Since the 1990s ~20 newly studied tracksites reveal a cumulative total of ~4,300 tracks and three sites are now designated as, federally managed, interpretative tourist destinations. Similar track assemblages, collectively constituting Megalosauripus-Therangospodus ichnocoenoses have now also been found at lower stratigraphical levels associated with J-3 Unconformity contact zones. These new discoveries relate to stratigraphic studies associated with short-term changes in Sundance Sea level affecting coastal dune facies (Slick Rock and Moab members) across low gradient, inter- and sub-tidal sand flats, and sabkha-like deposits under arid conditions. The multiple (>50) theropod dominated ichnofaunas are integral to palaeobiological understanding of an area from which no body fossils are known. [ABSTRACT FROM AUTHOR]

Slip planes and slip directions of subsequent generations of faults were measured and analysed in the interaction damage zone of two abutting faults in porous sandstones in order to understand the palaeostress/palaeostrain evolution. The Courthouse branch point of the Moab Fault in SE Utah (USA) is a much-studied, spectacular outcrop of two abutting faults, located in the footwall block of the main fault and in the hanging wall block of the abutting fault. The abutting fault is synthetic to the main fault. The outcrop shows a wide range of deformation structures and fault-related diagenesis such as striated slip planes, deformation bands, veins, Liesegang bands and copper-rich mineralization. By combining our own measurements with published data on the relative age of these structures, we classified the data in four sets. Using a Numeric Dynamic Analysis (NDA) to calculate the orientation of the kinematic axes we found three different palaeo-extension directions in the four sets, recording the evolution of stress/strain axes during the abutting process. The first phase of deformation is regional extension in the NE–SW direction. As the second fault approached the main fault from its footwall side and the two faults started to become kinematically linked, the extension direction changed so that the overall extension became perpendicular to the approaching fault (NW–SE). Finally, the extension direction changed back to being perpendicular to the first segment (NE–SW) when the two faults became geometrically linked and regional extension became dominant again. [ABSTRACT FROM AUTHOR]

Slip planes and slip directions of subsequent generations of faults were measured in the interaction damage zone two abutting faults in porous sandstones, to understand the evolution of paleostress/paleostrain evolution. The Courthouse branch point, of the Moab Fault in SE Utah, is a much-studied spectacular outcrop of two abutting faults. It shows a wide range of deformation structures and fault related diagenesis: striated slip planes, deformation bands, veins, Liesegang bands and copper-rich mineralization. By combining our own measurements with published results on the relative age of these structures, we classified our data in four sets. Using the Numeric Dynamic Analysis (NDA) to calculate the orientation of the kinematic axes we found three different paleo-extension directions in the four sets, recording the evolution of stress/strain axes during the abutting process. The first phase of deformation direction is the regional extension in the NE-SE direction. As the second fault approached the main fault from its footwall side and the two faults start to become kinematically linked, the extension direction changed so that the overall extension became perpendicular to the approaching fault (NW-SE). Finally, the extension direction changed back to perpendicular to the first segment (NE-SW), when the two faults become geometrically-linked and regional extension dominates. [ABSTRACT FROM AUTHOR]

Faults in sandstone are frequently composed of two classes of structures: (1) deformation bands and (2) joints and sheared joints. Whereas the former structures are associated with cataclastic deformation, the latter ones represent brittle fracturing, fragmentation, and brecciation. We investigated the distribution of these structures, their formation, and the underlying mechanical controls for their occurrence along the Moab normal fault in southeastern Utah through the use of structural mapping and numerical elastic boundary element modeling. We found that deformation bands occur everywhere along the fault, but with increased density in contractional relays. Joints and sheared joints only occur at intersections and extensional relays. In all locations, joints consistently overprint deformation bands. Localization of joints and sheared joints in extensional relays suggests that their distribution is controlled by local variations in stress state that are due to mechanical interaction between the fault segments. This interpretation is consistent with elastic boundary element models that predict a local reduction in mean stress and least compressive principal stress at intersections and extensional relays. The transition from deformation band to joint formation along these sections of the fault system likely resulted from the combined effects of changes in remote tectonic loading, burial depth, fluid pressure, and rock properties. In the case of the Moab fault, we conclude that the structural heterogeneity in the fault zone is systematically related to the geometric evolution of the fault, the local state of stress associated with fault slip, and the remote loading history. Because the type and distribution of structures affect fault permeability and strength, our results predict systematic variations in these parameters with fault evolution. [ABSTRACT FROM AUTHOR]

This paper reports the results of both standard and truncated count data travel cost demand models for estimating demand for and the economic value to participants in mountain biking in the Moab, Utah, area. The empirical estimates for average trip demand per person per season were 2.25 and 2.53 trips under truncated Poisson and truncated negative binomial models, respectively. Consumer surplus per person per trip for both models was approximately US $585. The total annual use value for mountain biking in the Moab area was US $1.33 million. This value suggests that this recreation has a higher value than most other activities in the area and that public land managers should be aware of the relative value of mountain biking as they make allocation decisions. [ABSTRACT FROM AUTHOR]

Assesses the age and chemistry of manganese mineralization in the Moab and Lisbon fault systems, Utah using argon-argon isotope dating. Geologic setting; Field occurrences and manganese mineralogy; Influence of fluids originating from the Paradox Formation in iron and manganese mineralizations.

• Sustainable management depends on accurate concepts and water budgets. • Tracers and geochemistry yield conceptual revision of vital groundwater resource. • Water-budget estimates verified using lumped-parameter model of groundwater age. The Glen Canyon Group Aquifer (GCGA) is the sole source of public water supply for the city of Moab, Utah, a domestic and international tourist destination. Population and tourism growth are likely to target the GCGA for future water resources, but our analysis indicates that additional withdrawals would likely be sourced from groundwater storage and not be sustained by recharge. A quantitative estimate of groundwater discharge from the GCGA is problematic because the downgradient aquifer boundary is the Colorado River, and groundwater discharge to the river is very small compared to the river flow. A water budget based on a conceptual model of GCGA discharging into an adjacent alluvial Valley-Fill Aquifer (VFA) was reported by Sumsion (1971) and numerous subsequent studies have repeated and utilized this water budget. The GCGA contains stable isotopes, tritium, 3He/4He ratios, dissolved solids, and sulfate concentrations that contrast with the VFA, indicating it is instead recharged by local streams rather than from the GCGA. Water-budget calculations, based on: (1) measured spring discharge and streamflow gains, (2) horizontal gradients in VFA groundwater age, and (3) GCGA outcrop area vadose-zone pore waters are all less than previously thought. Using a lumped parameter model and 14C groundwater ages, we estimate recharge to the deeper GCGA (DGCGA) to be 4.2 ± 2.3 × 106 m3/yr, which is approximately equal to the measured discharge from wells and springs. [ABSTRACT FROM AUTHOR]

The transition between the aeolian Moab Member of the Curtis Formation and the marginal marine upper tongue of the Summerville Formation, in the area of Arches National Park, Utah, facilitated the registration of the distinctive theropod-dominated Moab Megatracksite complex, which is something of an ichnological cause célèbre. The complex reveals three interpenetrating ichnofaunas each with distinctive ichnofacies characteristics. The present study focuses on the small theropod-dominated assemblages from the coastal dune facies and applies Walther's Law of Facies to the sequence relationship between onshore ichnoassemblages, the late pulse of transgression by the Summerville sea, and the development of the shallow marine Pteraichnus ichnocoenosis. Together, these spatio-temporal facies relationship between onshore terrestrial, shoreline and shallow marine facies and their contained ichnofaunas shed useful light on the Late Jurassic tetrapod ecology of the region, in an area entirely lacking tetrapod body fossils. The small theropod dune ichnofauna has obvious precursors in other Jurassic dune facies. The shoreline and shallow marine ichnocoenosis also fit certain ichnofacies models, despite the lack of comparable ichnofaunas in the area. Abundant trackway size frequency data yield body mass estimates which allow testing of recently proposed palaeobiological theories on theropod ontogeny and community structure based on the skeletal record. [ABSTRACT FROM AUTHOR]

New discoveries show that very small theropod tracks (cf. Wildeichnus) are abundant in the upper part of the Moab Member, recently assigned to the Curtis Formation (formerly considered part of the Entrada Formation) in the Mid-?Late Jurassic of eastern Utah. The tracks represent a distinct small-theropod ichnofacies associated with eolian dune deposits that is easily differentiated from the water-lain beds of the overlying Megalosauripus-Therangospodus ichnofacies, which comprises the single-surface Moab megatracksite. Pterosaur track assemblages, representing the Pteriachnus ichnofacies, are found a few meters above the megatracksite surface in the upper tongue of the Summerville Formation.The small theropod ichnofacies is reminiscent of other early Mesozoic dune facies ichnofaunas from the Wingate and Navajo formations (Late Triassic and Early Jurassic) where small theropod tracks occur in association with other small tetrapod footprints. All such examples evidently represent a recurrent dune facies ecosystem dominated by diminutive vertebrates. Because the small theropod ichnofacies is one of three ichnofacies found in a thin stratigraphic sequence (<20 m) that contains no body fossils, it is clear that vertebrate tracks play an important role in providing insight into the paleoecology of units previously considered devoid of any useful fossil evidence. The three successive ichnofacies represent a transgressive transition from sand dunes, through sandy shoreline to shallow marine environments, each with its quite distinct vertebrate fauna. [ABSTRACT FROM AUTHOR]

When compared to their temperate coastal counterparts, sediments deposited and preserved along arid aeolian to shallow‐marine margins remain relatively poorly understood, particularly at the scale of lithofacies units and architectural elements. These systems often record evidence for relative sea‐level change within sedimentary basins. This work focusses on the Entrada–Curtis–Summerville formations that crop out in central eastern Utah, USA, and provides a detailed analysis of the aeolian Moab Member of the Curtis Formation (informally known as the Moab Tongue) that was impacted by cycles of marine transgressions and regression in the late Jurassic. This study utilises photogrammetry, sedimentary logging and sequence‐stratigraphical analysis techniques. Results indicate that four short‐lived transgressive‐regressive cycles are preserved within the Moab Member, followed by a broad regressive event recorded at the transition between the Curtis and Summerville formations. These cycles relate to changes in the relative sea level of the Sundance Sea and the deflation and expansion of the neighbouring aeolian dune field. During periods of normal regression, marine sediments displayed evidence of tidal and wave action, whereas the continental domain was characterised by growth of the aeolian system. However, when regression occurred within optimal physiographic conditions such as a restricted, semi‐enclosed basin, and at sufficient magnitude to outpace erg expansion, this acted to shut‐down bedform development and preservation. A rapid restriction of aeolian sediment availability and the inability of the dune field to recover resulted in the formation of deflationary sandsheets, arid coastal plain strata and contemporaneous shallow‐marine deposits that are starved of wind‐sourced sediments. This study highlights how a rapidly developing high‐magnitude regression can lead to the overall retraction of the erg. Deciphering the evolution and sequence stratigraphical relationships of arid aeolian to shallow marine margins is important in both understanding environmental interactions and improving the characterisation of reservoir rocks deposited in these settings. [ABSTRACT FROM AUTHOR]