Title

Formation of Iron-Rimmed Sandstone Nodules; Terrestrial Analogue for Martian Blueberries?

Presenter Information

Katherine Downs

Department

Geosciences and Geological and Petroleum Engineering

Major

Geology

Research Advisor

Wronkiewicz, David J.

Advisor's Department

Geosciences and Geological and Petroleum Engineering

Funding Source

UMR Opportunities for Undergraduate Research Experiences (OURE) Program, and the UMR Department of Geological Sciences and Engineering

Abstract

Spherical hematite (Fe2O3) nodules (“Blueberries”) occur on Mars and hint at a watery past for this planet. Moqui Marbles, a terrestrial analogue to the Martian Blueberries that are found in Utah, have hematite and manganese oxide cemented rims surrounding a central core of quartz cemented sandstone. Our initial experiments have demonstrated a plausible precipitation mechanism for the Moqui Marbles. A glass tube packed with loose quartz sand and isolated grains of calcite were exposed to slow flowing solution of water and ferrous (Fe2+) ammonium sulfate at a steady flow rate. A pH rise in the solution following reaction with calcite induced the precipitation of reaction rims of ferric (Fe3+) iron oxide. Flow tests were also conducted with mechanically rounded samples of calcite cemented Dakota Sandston. Two tubes were filled, one with relatively friable Dakota Sandstone and the other with tightly cemented sandstone. Both of the samples produced iron oxide rings around their outer edge.

Biography

Katherine is a senior from Kewanee, Illinois majoring in Geology. She is the daughter of Robert and Christina Downs. She is a member of the DAKE Society. Katherine presented her research at MAS in 2005 and took third overall. She plans to pursue a master’s degree in geochemistry.

Research Category

Natural Sciences

Presentation Type

Oral Presentation

Document Type

Presentation

Presentation Date

12 Apr 2006, 10:00 am

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Apr 12th, 10:00 AM

Formation of Iron-Rimmed Sandstone Nodules; Terrestrial Analogue for Martian Blueberries?

Spherical hematite (Fe2O3) nodules (“Blueberries”) occur on Mars and hint at a watery past for this planet. Moqui Marbles, a terrestrial analogue to the Martian Blueberries that are found in Utah, have hematite and manganese oxide cemented rims surrounding a central core of quartz cemented sandstone. Our initial experiments have demonstrated a plausible precipitation mechanism for the Moqui Marbles. A glass tube packed with loose quartz sand and isolated grains of calcite were exposed to slow flowing solution of water and ferrous (Fe2+) ammonium sulfate at a steady flow rate. A pH rise in the solution following reaction with calcite induced the precipitation of reaction rims of ferric (Fe3+) iron oxide. Flow tests were also conducted with mechanically rounded samples of calcite cemented Dakota Sandston. Two tubes were filled, one with relatively friable Dakota Sandstone and the other with tightly cemented sandstone. Both of the samples produced iron oxide rings around their outer edge.