Comparative biogeochemical analysis of modern tufa and Ordovician dolostone source utilizing X-ray fluorescence spectroscopy
Location
Poster #26
Department
Earth Science
Abstract
A sample of tufa (freshwater limestone) was found in an aggregate quarry in northern Illinois while collecting fossils. The quarry actively mines dolomitized limestone (dolostone) that formed during the middle Ordovician period (~450Ma) when Illinois was an equatorial shallow sea and contains a normal marine fossil assemblage characterized by an abundance of calcareous algae, trilobites, mollusks, and nautiloid cephalopods. However, this porous tufa is precipitated around modern organic floral material, including seeds of invasive species introduced to North America only within the last 150 years. This project will utilize X-ray fluorescence spectroscopy methods to reveal the chemical make-up of this tufa to discern how it compares to the elemental composition of the surrounding Ordovician dolostone and investigate how it could have formed in post-mining operations. Biological and textural analysis of the tufa fabric will be used to confirm its modern age while study of the fossil assemblages contained within the surrounding material will confirm the parent rocks ancient origin. Further analysis of chemical ratios between Ca, Mg, Sr, and other trace elements may be able to constrain the post-industrial revolution environmental impacts on the groundwater and photosynthetic microbiological communities that formed the tufa.
Faculty Sponsor
Sheldon Turner
Comparative biogeochemical analysis of modern tufa and Ordovician dolostone source utilizing X-ray fluorescence spectroscopy
Poster #26
A sample of tufa (freshwater limestone) was found in an aggregate quarry in northern Illinois while collecting fossils. The quarry actively mines dolomitized limestone (dolostone) that formed during the middle Ordovician period (~450Ma) when Illinois was an equatorial shallow sea and contains a normal marine fossil assemblage characterized by an abundance of calcareous algae, trilobites, mollusks, and nautiloid cephalopods. However, this porous tufa is precipitated around modern organic floral material, including seeds of invasive species introduced to North America only within the last 150 years. This project will utilize X-ray fluorescence spectroscopy methods to reveal the chemical make-up of this tufa to discern how it compares to the elemental composition of the surrounding Ordovician dolostone and investigate how it could have formed in post-mining operations. Biological and textural analysis of the tufa fabric will be used to confirm its modern age while study of the fossil assemblages contained within the surrounding material will confirm the parent rocks ancient origin. Further analysis of chemical ratios between Ca, Mg, Sr, and other trace elements may be able to constrain the post-industrial revolution environmental impacts on the groundwater and photosynthetic microbiological communities that formed the tufa.