Salt Crust, Brine, and Marginal Groundwater of Great Salt Lake's North Arm (2019 To 2021)

Following the construction of the railroad causeway in 1959, a perennial halite (NaCl) bottom crust has been known to exist in the north arm (Gunnison Bay) of Great Salt Lake, Utah, but the lake conditions controlling accumulation or dissolution of the crust are not well defined, including how depth-controlled chemodynamic and hydrodynamic factors influence the degree of the halite saturation. Immediately prior to the opening of a new bridge in the causeway in early December 2016 when north arm lake elevation was at a historical low (just above 4189 feet), the north arm lake brine was at halite saturation. After the opening, inflow of less saline south arm water mixed with north arm water, raised lake elevation, and diluted the north arm lake brine to undersaturation with respect to halite. The following five years have resulted in annual and seasonal fluctuations of halite saturation states. Beginning in mid-2019, the Utah Geological Survey began a study of the north arm to better understand and document the transitions of halite saturation state following the bridge opening using newly collected data as well as reviewing available past data.

Magnetised quark nuggets in the atmosphere

A search for magnetised quark nuggets (MQN) is reported using acoustic signals from hydrophones placed in the Great Salt Lake (GSL) in the USA. No events satisfying the expected signature were seen. This observation allows limits to be set on the flux of MQNs penetrating the Earth’s atmosphere and depositing energy in the GSL. The expected signature of the events was ​derived from pressure pulses caused by high-explosive cords between the lake surface and bottom at various locations in the GSL. The limits obtained from this search are compared with those obtained from previous searches and are compared to models for the formation of MQNs.

Influence of Salinity on the Resources and Uses of Great Salt Lake

The salinity of Great Salt Lake (GSL) plays a very influential role in shaping the lake’s unique ecological, recreational, and mineral resource uses. This memorandum summarizes a review of the literature and GSL databases to describe critical salinity ranges that influence these resources and uses. It presents a GSL Salinity Matrix intended to provide decision-makers with an important illustration; not to predict how GSL’s salinity will change, but to illustrate the potential consequences of salinity changes.

Viruses and Their Interactions With Bacteria and Archaea of Hypersaline Great Salt Lake

Viruses play vital biogeochemical and ecological roles by (a) expressing auxiliary metabolic genes during infection, (b) enhancing the lateral transfer of host genes, and (c) inducing host mortality. Even in harsh and extreme environments, viruses are major players in carbon and nutrient recycling from organic matter. However, there is much that we do not yet understand about viruses and the processes mediated by them in the extreme environments such as hypersaline habitats. The Great Salt Lake (GSL) in Utah, United States is a hypersaline ecosystem where the biogeochemical role of viruses is poorly understood. This study elucidates the diversity of viruses and describes virus–host interactions in GSL sediments along a salinity gradient. The GSL sediment virosphere consisted of Haloviruses (32.07 ± 19.33%) and members of families Siphoviridae (39.12 ± 19.8%), Myoviridae (13.7 ± 6.6%), and Podoviridae (5.43 ± 0.64%). Our results demonstrate that salinity alongside the concentration of organic carbon and inorganic nutrients (nitrogen and phosphorus) governs the viral, bacteria, and archaeal diversity in this habitat. Computational host predictions for the GSL viruses revealed a wide host range with a dominance of viruses that infect Proteobacteria, Actinobacteria, and Firmicutes. Identification of auxiliary metabolic genes for photosynthesis (psbA), carbon fixation (rbcL, cbbL), formaldehyde assimilation (SHMT), and nitric oxide reduction (NorQ) shed light on the roles played by GSL viruses in biogeochemical cycles of global relevance.

A Paleo-Lake and wetland paleoecology associated with human use of the distal Old River Bed Delta at the Pleistocene-Holocene transition in the Bonneville Basin, Utah, USA

Mollusk and ostracode assemblages from the distal Old River Bed delta (ORBD) contribute to our understanding of the Lake Bonneville basin Pleistocene-Holocene transition (PHT) wetland and human presence on the ORBD (ca. 13,000–7500 cal yr BP). Located on U.S. Air Force-managed lands of the Great Salt Lake Desert (GSLD) in western Utah, USA, the area provided 30 samples from 12 localities. The biological assemblages and the potential water sources using 87Sr/86Sr analyses showed wetland expansion and contraction across the PHT, including the Younger-Dryas Chronozone (YDC). The record reflects cold, freshwater conditions, which is uncharacteristic of the Great Salt Lake Desert, after recession of Lake Bonneville. Lymnaea stagnalis jugularis, Cytherissa lacustris, and possibly Candona sp. cf. C. adunca, an endemic and extinct species only reported from Lake Bonneville, suggest cold-water environments. Between 13,000–12,400 cal yr BP, a shallow lake formed, referred to as the Old River Bed delta lake, fed by Lake Gunnison, as shown by 87Sr/86Sr ratios of 0.71024–0.71063 in mollusk fossils collected at the ORBD, characteristic of the Sevier basin. These findings add paleoenvironmental context to the long-term use of the ORBD by humans in constantly changing wetland habitats between 13,000–9500 cal yr BP.

CFD Model of the Density-Driven Bidirectional Flows through the West Crack Breach in the Great Salt Lake Causeway

Stratified flows and the resulting density-driven currents occur in the natural environment and commonly in saline lakes. In the Great Salt Lake, Utah, USA, the northern and southern portions of the lake are divided by an east-to-west railroad causeway that disrupts natural lake currents and significantly increases salt concentrations in the northern section. To support management efforts focused on addressing rising environmental and economic concerns associated with varied saltwater densities throughout the lake, the causeway was recently modified to include a new breach. The purpose of this new breach is to enhance salt exchange between the northern and southern sections of the lake. Since construction, it typically exhibits a strong density-driven bidirectional flow pattern, but estimating flows and salt exchange has proven to be difficult. To obtain much needed insights into the ability of this hydraulic structure to exchange water and salt between the two sections of the lake, a field campaign coupled with CFD modeling was undertaken. Results from this study indicate that the vertical velocity profile in the breach is sensitive to density differences between flow layers along with breach geometry and water surface elevations. The CFD model was able to accurately represent the bidirectional flows through the breach and provides for improved estimates of water and salt exchanges between the north and south sections of the lake.

Microbial Carbonate Reservoirs and Analogs from Utah

Multiple oil discoveries reveal the global scale and economic importance of a distinctive reservoir type composed of possible microbial lacustrine carbonates like the Lower Cretaceous pre-salt reservoirs in deepwater offshore Brazil and Angola. Marine microbialite reservoirs are also important in the Neoproterozoic to lowest Cambrian starta of the South Oman Salt Basin as well as large Paleozoic deposits including those in the Caspian Basin of Kazakhstan (e.g., Tengiz field), and the Cedar Creek Anticline fields and Ordovician Red River “B” horizontal play of the Williston Basin in Montana and North Dakota, respectively. Evaluation of the various microbial fabrics and facies, associated petrophysical properties, diagenesis, and bounding surfaces are critical to understanding these reservoirs. Utah contains unique analogs of microbial hydrocarbon reservoirs in the modern Great Salt Lake and the lacustrine Tertiary (Eocene) Green River Formation (cores and outcrop) within the Uinta Basin of northeastern Utah. Comparable characteristics of both lake environments include shallowwater ramp margins that are susceptible to rapid widespread shoreline changes, as well as compatible water chemistry and temperature ranges that were ideal for microbial growth and formation/deposition of associated carbonate grains. Thus, microbialites in Great Salt Lake and from the Green River Formation exhibit similarities in terms of the variety of microbial textures and fabrics. In addition, Utah has numerous examples of marine microbial carbonates and associated facies that are present in subsurface analog oil field cores.

Historic low stand of Great Salt Lake, Utah: I

Great Salt Lake of Utah is among the largest and most ecologically important water bodies in North America. Since the late 1950s, the lake has been divided into two hydrologically distinct water bodies by a rock-fill railroad causeway. Flux through the causeway is driven by two forces: differential surface elevation and differential density between the north and south arms. The south arm features episodic vertical stratification due to the influx of deep, dense brine from the north arm. The source of this brine (a breach, two culverts, or subsurface flow) has been investigated over the past 50 years. Quantification of subsurface water flux through the causeway has been problematic due to the heterogeneous and slowly compacting nature of the causeway fill over time. Between 2008 and 2015, enhanced gauging of various surface inflows and outflows and density measurements made throughout the lake permitted detailed water volume calculations of both lake arms. Results show that during high precipitation years, density-driven, north-to-south flow through the causeway predominates due to freshening of water in the south arm. At other times, south-to-north head gradient driven flow and north-to-south density-driven flow are approximately equal. The model suggests subsurface flux through the causeway is one important driver of the ecologically important deep brine layer in the south arm of the lake over the past 20 years.