Diego Fernandez, Ph.D - US grants

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5). The goal of this project is to create an inductively coupled plasma mass spectrometry (ICP-MS) facility with capabilities to study trace elemental content and isotopic ratios for gaseous and liquid solutions, colloids, minerals, fossils, gels and tissue. Research areas to be initially addressed are: 1) carbonates as records of environmental and paleoenvironmental change; 2) colloid transport and trace elements cycling in aquatic systems; 3) dating of archeological and geological material; 4) earth transformations caused by geological forces; 5) provenance studies of carbonates, hair and organic materials; 6) elemental distribution in tissues and fossils; 7) origin and evolution of magmas, igneous and metamorphic rocks and ore deposits; and 8) correlations of volcanic ashes for the study of stratigraphic sequences. The facility will have: 1) a multicollector ICP-MS; 2) a collision cell quadrupole ICP-MS; 3) a laser ablation sampling system; 4) peripheral equipment for introducing liquid/gas samples; and 5) clean lab space for wet chemistry and sample handling.

Chemical elements move around the Earth via geological, biological and anthropological processes. Even when the concentration for some of these elements is tiny (a few parts per billion), they can impact ecosystems and organisms in crucial ways as beneficial or damaging components. In addition, the concentration changes of these trace elements through sediments or rocks can be related to the geological, environmental and climatic variations that occurred during their formation. In the case of fossils, elemental variation can also reveal diet changes and in the case of tissue, elucidate physiological mechanisms. Finally, those trace elements that are radioactive can be used to obtain geological ages. When coupled with a laser, ICP-MS can directly detect these minute amounts in solids, gels or tissue without laborious chemical procedures. The research achieved using the facility will contribute to solutions to regional and national technological problems, specifically in the fields of environmental sustainability, forensics, energy and mineral resources, and advanced materials.

This research will develop methods for the detection and monitoring of engineered nanomaterials in aquatic systems. Advanced low-invasive fractionation techniques will be refined to fractionate across the nanoscale (e.g. between 2 and 450 nm). Elemental distributions, size and charge distributions, as well as isotopic signatures and morphology, will be explored among various sources of engineered and other nanomaterials. Critical steps in the research include developing a new analytical methodology (SPLITT) that splits elements into dissolved versus particulate fractions. Research will explore to what extent SPLITT fractionates nanomaterials that have equilibrated with aquatic media. It will also examine the optimal fields for different nanomaterial sources, and to what extent composition, size, and charge distributions affects differentiation: (a) between natural and incidental/engineered nanomaterials and (b) among various sources of a nanoparticle class. The research will determine to what extent existing manufacturing processes produce nanomaterials with distinct isotopic signatures relative to natural and incidental nanomaterials and among various sources of a nanoparticle class. Broader impacts of this work include significant outreach to students and teachers at the K-12 level. It also supports an investigator at an institution in an EPSCOR state.

This study will examine isotopic and geochemical records preserved in the laminae of pedogenic carbonate coatings in soils in the Capitol Reef--Boulder Mountain region of the Colorado Plateau. First, the team will check for preservation of stratigraphic order in the laminae of coatings by microscopy, high-resolution X-ray mapping, and Th/U age dating. Coatings that preserve an intact stratigraphy will be micro-sampled for detailed Th/U age transects, stable isotope analysis, and trace element analysis. The team will compare well-dated profiles of stable isotope shifts from coatings collected at various depths below the soil-air interface to reconstruct the timing and magnitude of ecological and climatological changes that occurred over the measured time interval. This study will evaluate the problem of discontinuities in the pendant record which could be related to climate change on orbital time scales. Timing and mechanisms of carbonate formation will be evaluated with in situ soil moisture, respiration, and temperature measurements.

Stable isotope analysis of modern and fossil pedogenic carbonate has advanced the understanding of continental paleoclimatology, as well as documenting worldwide ecological shifts. Most stable isotope studies of pedogenic carbonate have sampled soil carbonate at a fairly coarse resolution; only a few have studied the stable isotope record of soil carbonate coatings of the large clasts within a soil horizon. This work will test thick, well-laminated, pedogenic carbonate coatings for records of a meaningful paleoclimate signal in terms of their stable isotope record (13C/12C and 18O/16O) when coatings preserve an intact stratigraphy. If true, and there is some preliminary Th/U and stable isotope data that supports this, then the world's deserts may contain a vast and untapped quantitative archive of past continental climactic and ecological variability.

This project is a collaborative effort between the University of Utah and Western State Colorado University. It will enhance education opportunities for both a research institution and an undergraduate institution, and its results will be incorporated into an international course, taught each year at the University of Utah, using stable isotopes as tracers in anthropology, ecology, forensics, geology, hydrology, oceanography, and zoology.

Collaborative Research: Investigation of the fate of dust-borne trace metals and solutes during snowmelt

Abstract

Wind-blown dust contributes trace metals and soluble salts to mountain snowpack, with potential negative impacts on water quality during snowmelt. Sediment records from mountain lakes in the western U.S. suggest that dust deposition has increased five-fold over the past 150 years due to human disturbance of desert soils, with more dust expected in the future due to climate change. Little is known, however, concerning the impacts of dust on the chemistry of mountain streams. Snowmelt-fed streams are a primary source of drinking water in the western U.S. The Provo River is a prime example of this, supplying water to over 50% of the residents of Utah. This project investigates the effects of dust on water quality during snowmelt in the upper Provo River watershed in the Uinta Mountains. Assessment of dust contributions to mountain snowpack and demonstration of pathways of trace metal and salt transport during snowmelt have the potential to extend across the Intermountain West and beyond the U.S. to other mountainous areas receiving substantial dust input, including the Andes, Himalayas, and European Alps. This project provides K-16 student outreach opportunities during inquiry-based field exercises, fosters cross-campus collaborations for graduate students at Utah's three major research institutions (University of Utah, Utah State University, and Brigham Young University), and broadens participation of underrepresented groups by involving women and minorities.

The project investigates the fate and transport of dust-derived trace metals and solutes during snowmelt building from detailed field sampling and comprehensive analyses. Dust contributions to stream solute budgets during snowmelt are quantified with isotopic tracers (e.g., strontium, boron, sulfur, oxygen and hydrogen) and mixing analyses. The role of organic matter-facilitated trace-metal transport from snowpack to streams is examined through application of several novel analytical methods. Spatial heterogeneity in dust deposition is quantified, and the availability of trace metals in dust is characterized via sequential leaching experiments. The Provo River watershed is an ideal location for investigating impacts of dust on water chemistry because it is underlain by relatively simple siliciclastic bedrock that permits clear observations of exogenous dust and is well instrumented with atmospheric and aquatic monitoring stations from the Innovation Urban Transitions and Aridregion Hydro-sustainability (iUTAH) observatory funded by NSF. The geological setting and extensive instrumentation provide an unprecedented opportunity to explore the impacts of dust deposition on stream chemistry during snowmelt.