Open Access. Powered by Scholars. Published by Universities.®

Geochemistry Commons

Open Access. Powered by Scholars. Published by Universities.®

818 Full-Text Articles 1574 Authors 152886 Downloads 83 Institutions

All Articles in Geochemistry

Faceted Search

818 full-text articles. Page 1 of 28.

Exploring The Calvert Cliffs: Interpreting Classic Miocene Sequences Through The Application Of Strontium Isotope Stratigraphy And Paleoecology, Joshua B. Zimmt 2017 College of William and Mary

Exploring The Calvert Cliffs: Interpreting Classic Miocene Sequences Through The Application Of Strontium Isotope Stratigraphy And Paleoecology, Joshua B. Zimmt

Undergraduate Honors Theses

The Calvert Cliffs (Maryland, USA) is a classic condensed Miocene sequence that has attracted much scientific attention for its laterally extensive and highly condensed fossil beds (Kidwell, 1982a). Several meters thick and up to 70% shell material, the period of formation of these major complex shell beds has been debated for decades. Kidwell (1989) and associated studies have demonstrated that the major complex shell beds possess certain characteristics that suggest the beds formed as a succession of condensed parasequences during a transgressive systems tract. However, no quantitative analysis has calculated the period of formation of the major complex shell beds ...


Permafrost, Ice Sheets, And Sea Level, Beth Caissie, Julie Brigham-Grette 2017 Iowa State University

Permafrost, Ice Sheets, And Sea Level, Beth Caissie, Julie Brigham-Grette

Beth Caissie

Sea level rise and inhabited coastlines. Ice shelves and sea ice do not contribute to sea level but they can buttress the land ice sheets from rapid retreat. Causes of Sea Level Rise:

•Melting of glaciers, ice caps, ice sheets •Thermal expansion of sea water ••Small scale changes due to anthropogenic land water storage (damming rivers, over-pumping of water and fuels, wetland and forest destruction) •Relative changes in sea level due to tectonic movements (land subsidence or rebound)


Sea Ice Food Webs—Hands On Sampler Teacher Guide, Beth Caissie 2017 Iowa State University

Sea Ice Food Webs—Hands On Sampler Teacher Guide, Beth Caissie

Beth Caissie

This activity is a variation on a food web game that I’ve seen played many times before, but it is adapted to reflect a sea ice food web and show the many organisms that are intimately connected to polar bears.


Brine Rejection Activity, Beth Caissie, Rob Snyder 2017 Iowa State University

Brine Rejection Activity, Beth Caissie, Rob Snyder

Beth Caissie

As salt water freezes, the salt is pushed out of solution through channels in the ice. This process is called brine rejection or brine exclusion. These channels are often used as microhabitats by ice algae, zooplankton, and even tiny fish. You can easily demonstrate what these channels look like.


Glacier Goo Activity, Beth Caissie 2017 Iowa State University

Glacier Goo Activity, Beth Caissie

Beth Caissie

We provided the students with background information about what a glacier is, where they are, how they move. Then split the students into four groups each tasked with a question to answer through experimentation

Group s 1 and 2: How does temperature change the way a glacier flows? (we provided frozen, and room temperature goo, and a microwave for heating the goo)

Groups 3 and 4: How does friction or obstacles change the way a glacier flows? (we provided different pvc tubes—tubes with nothing done to them, tubes with paintable sand applied to them, and tubes with rocks glued ...


Play Doh Coring Sampler Teacher Guide, Beth Caissie 2017 Iowa State University

Play Doh Coring Sampler Teacher Guide, Beth Caissie

Beth Caissie

Sediment cores are one of the most valuable types of samples for researchers who would like to learn about past climate or ecological changes. Cores can be retrieved from lakes, marshes, swamps, fields, and the ocean. The layers often reveal striking changes in color (see photos) reflecting changing sediment composition (i.e. more clay deposition or more microfossil s). This easy activity illustrates the basic geologic principle that horizontal layers of sediment become older the deeper you go below the Earth’s surface (Law of Superposition). Each layer contains sediment, fossils and organic matter etc. that can inform us about ...


Polar Remote Sensing, Beth Caissie 2017 Iowa State University

Polar Remote Sensing, Beth Caissie

Beth Caissie

•Satellite sensors specialize in collecting data about specific wavelengths The Geostationary Operational Environment Satellites (GOES) operated by NASA, NOAA, and the U.S. Department of Commerce provide continuous monitoring of weather conditions. Orbiting the Earth’s equatorial plane at a speed exactly matching the planet’s rotation, satellites in the GOES network seem to hover over fixed spots. They monitor atmospheric conditions that lead to hurricanes, flash floods, tornadoes, and hail storms.


Atmospheric Co2 And Temperature. What Is Normal?, Beth Caissie, Julie Brigham-Grette 2017 Iowa State University

Atmospheric Co2 And Temperature. What Is Normal?, Beth Caissie, Julie Brigham-Grette

Beth Caissie

–How much of a change in CO2 concentration and other GHGs is natural? –What is the normal range of CO2 and temperature variability? How is normal defined in this context? –What is the relationship between CO2 and global temperatures?


Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali, Marcelo I. Guzman 2017 University of Kentucky

Catalyzed Synthesis Of Zinc Clays By Prebiotic Central Metabolites, Ruixin Zhou, Kaustuv Basu, Hyman Hartman, Christopher J. Matocha, S. Kelly Sears, Hajatollah Vali, Marcelo I. Guzman

Chemistry Faculty Publications

How primordial metabolic networks such as the reverse tricarboxylic acid (rTCA) cycle and clay mineral catalysts coevolved remains a mystery in the puzzle to understand the origin of life. While prebiotic reactions from the rTCA cycle were accomplished via photochemistry on semiconductor minerals, the synthesis of clays was demonstrated at low temperature and ambient pressure catalyzed by oxalate. Herein, the crystallization of clay minerals is catalyzed by succinate, an example of a photoproduced intermediate from central metabolism. The experiments connect the synthesis of sauconite, a model for clay minerals, to prebiotic photochemistry. We report the temperature, pH, and concentration dependence ...


Mineralogy And Geochemistry Of The Heddleston Porphyry Cu-Mo Deposit, Montana, Ben Schubert 2017 Montana Tech

Mineralogy And Geochemistry Of The Heddleston Porphyry Cu-Mo Deposit, Montana, Ben Schubert

Graduate Theses & Non-Theses

The Heddleston porphyry Cu-Mo deposit is located in Lewis and Clark County, Montana, near the headwaters of the Blackfoot River. It is immediately west of the historic Mike Horse mine, an important producer of Pb-Zn from polymetallic veins and lodes. The Heddleston property was explored extensively by the Anaconda Company in the 1960s and 1970s, but was never mined. Specimens of polished drill core from the deposit are archived in the Anaconda Research Collection at Montana Tech campus. The purpose of this research project was to use the archived samples to examine the geochemistry and mineralogy of the Heddleston and ...


Supergene Mineralization Of The Continental Pit, Butte, Silver Bow County, Montana, Kyle Eastman 2017 Montana Tech

Supergene Mineralization Of The Continental Pit, Butte, Silver Bow County, Montana, Kyle Eastman

Graduate Theses & Non-Theses

The Butte porphyry Cu-Mo-Ag deposit has been considerably altered by supergene processes that enriched Cu and Ag, and mobilized other metals. Supergene enrichment provided early miners with excellent ore grades, and contributes significantly to current mining operations in Butte. The Continental Pit exhibits the classic leached and enriched vertical zonation that is common in near-surface porphyry systems around the world. Although studied by the Anaconda Copper Mining Company during the mid-20th century, significant and economically relevant questions remain regarding this deposit’s supergene heavy metal geochemistry and its relationship to the local hydrology and tectonic history.

This thesis investigates the ...


Iron Addition To Soil Specifically Stabilized Lignin, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel 2017 Iowa State University

Iron Addition To Soil Specifically Stabilized Lignin, Steven J. Hall, Whendee L. Silver, Vitaliy I. Timokhin, Kenneth E. Hammel

Steven J. Hall

The importance of lignin as a recalcitrant constituent of soil organic matter (SOM) remains contested. Associations with iron (Fe) oxides have been proposed to specifically protect lignin from decomposition, but impacts of Fe-lignin interactions on mineralization rates remain unclear. Oxygen (O2) fluctuations characteristic of humid tropical soils drive reductive Fe dissolution and precipitation, facilitating multiple types of Fe-lignin interactions that could variably decompose or protect lignin. We tested impacts of Fe addition on 13C methoxyl-labeled lignin mineralization in soils that were exposed to static or fluctuating O2. Iron addition suppressed lignin mineralization to 21% of controls, regardless ...


Cu-Pd Mineralization And Exploration Geochemistry Of The Eastern Gabbro, Coldwell Alkaline Complex, On, Canada, Yonghua Cao 2017 The University of Western Ontario

Cu-Pd Mineralization And Exploration Geochemistry Of The Eastern Gabbro, Coldwell Alkaline Complex, On, Canada, Yonghua Cao

Electronic Thesis and Dissertation Repository

The Eastern Gabbro forms the northern and eastern margin of the Coldwell Alkaline Complex. It contains three magma series: the barren meta-basalt, the Layered Series, and the Marathon Series which hosts all known PGE mineralization. The Marathon Series can be distinguished from other Series using the combination of portable X-ray fluorescence (pXRF) and benchtop scanning electron microscope (bSEM). Whole-rock Ba, Mg# (molar Mg/(Mg+Fe)*100), Zr and V/Ti values acquired from pXRF, and Mg#s of olivine and clinopyroxene, and anorthite content (molar Ca/(Ca+Na)*100) of plagioclase acquired from bSEM-EDS are key parameters. The Layered Series ...


Secondary Minerals From Salt Caves In The Atacama Desert (Chile): A Hyperarid And Hypersaline Environment With Potential Analogies To The Martian Subsurface, Jo De Waele, Cristina Carbone, Laura Sanna, Marco Vattano, Ermanno Galli, Francesco Sauro, Paolo Forti 2017 University of Bologna

Secondary Minerals From Salt Caves In The Atacama Desert (Chile): A Hyperarid And Hypersaline Environment With Potential Analogies To The Martian Subsurface, Jo De Waele, Cristina Carbone, Laura Sanna, Marco Vattano, Ermanno Galli, Francesco Sauro, Paolo Forti

International Journal of Speleology

Over the past 15 years several expeditions by French, American and especially Italian cavers have unveiled over 50 caves in the Cordillera de la Sal (Atacama Desert, Northern Chile). Many of these caves contain a variety of speleothems and minerals, some of which have rarely been observed within karst systems. Most of the secondary deposits in these caves are composed of halite, but also other halide, carbonate, sulphate, nitrate, phosphate, and silicate minerals have been found. Among the sixteen cave mineral species recognized, atacamite, darapskite, blödite, leonite, anhydrite, and especially antarcticite are worth mentioning. In one of the samples an ...


Petrographical And Geochemical Changes In Bosnian Stalagmites And Their Palaeo-Environmental Significance, Veronica Chiarini, Isabelle Couchoud, Russell Drysdale, Petra Bajo, Simone Milanolo, Silvia Frisia, Alan Greig, John Hellstrom, Jo De Waele 2017 University of Bologna

Petrographical And Geochemical Changes In Bosnian Stalagmites And Their Palaeo-Environmental Significance, Veronica Chiarini, Isabelle Couchoud, Russell Drysdale, Petra Bajo, Simone Milanolo, Silvia Frisia, Alan Greig, John Hellstrom, Jo De Waele

International Journal of Speleology

Detailed petrographic observations have been coupled with trace element and δ13C - δ18O analyses in order to investigate their dynamics in two Holocene Bosnian speleothems. The potential of this multiproxy approach in providing a means to extract palaeo-environmental information from stalagmites whose stable isotope signals are noisy and without obvious trends has been tested. The studied stalagmites are mostly characterized by columnar microcrystalline fabric. At the sub-millimetre scale of lamination, different microcrystalline columnar sub-types (open and closed) have been detected and classified on the basis of the observed porosity and the crystallite size. The presence of variations ...


Mercury Increases In Lake Tanganyika Since ~1850, Troy A. Bole 2017 The University of Akron

Mercury Increases In Lake Tanganyika Since ~1850, Troy A. Bole

Honors Research Projects

A series of three sediment cores were collected in Lake Tanganyika, Africa, and were analyzed for mercury concentrations. For all three cores, a decrease in mercury (Hg) levels was observed from the 1600’s (appx. 20 ng/g) until concentrations reached a minimum during the mid-1800’s (appx. 10 ng/g). The mid-1800’s marked a change from decreasing mercury levels to an increase over the following century. The core tops (circa 2006) have concentrations greater than 70 ng/g. The onset of the rise in mercury concentrations coincides with the beginning of the Industrial Revolution in the mid to ...


Zircon As A Proxy For "Taking The Temperature" Of Granites: An Example Using Zircon Thermometry Applied To Grenvillian Mid-Crustal Magmas In The Blue Ridge Province, Virginia, Samantha Rae Burk 2017 University of Kentucky

Zircon As A Proxy For "Taking The Temperature" Of Granites: An Example Using Zircon Thermometry Applied To Grenvillian Mid-Crustal Magmas In The Blue Ridge Province, Virginia, Samantha Rae Burk

Theses and Dissertations--Earth and Environmental Sciences

The Grenville orogeny was a protracted (~200 m.y.) series of “hot” magmatic- metamorphic events that contributed to the growth of the Laurentian margin in the late Mesoproterozoic. The granites contain remarkably high Zr content, lack xenocrysts, and become zircon saturated at high temperatures, which are all unusual for felsic magmas. The “hot Grenville granite” hypothesis is tested and use of high-Zr granitoids as potential zones of crustal magma generation through: U-Pb geochronology and cathodoluminescence imaging to assess inherited zircon components; quantitative modeling of zircon crystallization history using rhyolite-MELTS; and Ti-in-zircon thermometry. U-Pb zircon ages for two samples from the ...


An Investigation Of Paleo-Wildfires During The Cretaceous-Paleogene (K-Pg) Boundary At El Kef, Tunisia, Michael Gross 2017 University of Colorado, Boulder

An Investigation Of Paleo-Wildfires During The Cretaceous-Paleogene (K-Pg) Boundary At El Kef, Tunisia, Michael Gross

Undergraduate Honors Theses

The causes and consequences of the Cretaceous-Paleogene mass extinction have long been a source of contention. Several models predict that enough thermal radiation from the bolide impact was produced to ignite wildfires at least regionally and possibly on a global scale, raising average temperatures by up to ~10°C, and releasing large amounts of CO2 and CO. However, the role of regional versus global wildfire events as an environmental stressor, as well as the sources of the fire (land vegetation vs. hydrocarbon reservoirs) and its expression in terrestrial and marine archives, remains controversial. Typically, wildfires are preserved in the ...


Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, XiXi Wang, Deguang Yu, Jun Xie 2017 Old Dominion University

Effects Of Nonaerated Circulation Water Velocity On Nutrient Release From Aquaculture Pond Sediments, Xiangju Cheng, Dantong Zhu, Xixi Wang, Deguang Yu, Jun Xie

Civil & Environmental Engineering Faculty Publications

Sustaining good water quality in aquaculture ponds is vital. Without an aerator, the dissolved oxygen in ponds comes primarily from mass transfer at the water-ambient atmosphere interface. As sediment can seriously affect water quality, this study used indoor experiments to examine the nutrient (nitrogen and phosphorus) release mechanisms and fluxes from sediment in aquaculture ponds with moving water but no aeration. The results showed that the ammonia nitrogen (NH3-N) concentration in the overlying water was inversely proportional to flow velocity and that a higher flow velocity tended to result in a lower concentration in the overlying water, a ...


Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins 2017 Utah State University

Hydrocarbon And Co2 Emissions From Oil And Gas Production Well Pad Soils Comparative To Background Soil Emissions In Eastern Utah, Cody S. Watkins

All Graduate Theses and Dissertations

Emissions of methane, non-methane hydrocarbons (NMHC), and carbon dioxide (CO2) at 27 natural gas well pads, 11 non-well locations in oil and gas fields, and 7 hydrocarbon-bearing outcrops in eastern Utah between 2013 and 2016 were measured using a dynamic flux chamber (DFC) in effort to answer the following questions: What effect does the development of oil and gas have on the observed air quality (increased ozone, CO2, volatile organic compounds (VOCs), and/or methane emissions) in northeastern Utah? What percentage of these gases is due to natural background emissions, and what percentage is due to oil and ...


Digital Commons powered by bepress