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Diagenetic Analysis of Carbonates within the Dinwoody Formation at the Black Tail Creek Locality

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Title: Diagenetic Analysis of Carbonates within the Dinwoody Formation at the Black Tail Creek Locality
Author: Herz-Thyhsen, Ryan
Advisor: Marenco, Pedro J.
Department: Bryn Mawr College. Dept. of Geology
Type: Thesis (B.A.)
Issue Date: 2012
Abstract: Analysis of Lower Triassic carbonates using ICP-MS, thin section petrography, and cathodoluminescence reveals the diagenetic history of the Dinwoody formation at the Black Tail Creek (BTC) locality. The ratios between the elements of Ca, Mg, Fe, Mn and Sr provide an in depth look into the history of the rock. The results suggest that the carbonates have mostly undergone burial diagenesis, while some of the clasts appear to have been dolomitized. Because both clasts and matrices from the sections were sampled, differences between how each has been affected by burial diagenesis can be interpreted. Because these trends of diagenesis follow the direction of pore-fluid motion due to gravity, ion movement can be traced throughout the suite of carbonate rocks. The increase in Fe/Sr at the base of the section suggests that greater burial diagenesis has taken place, while increased Mn/Sr and Ca/Mg in higher sections of the formation suggest meteoric diagenesis has more influence on the signature of these rocks (although they still have undergone burial diagenesis). Under cathodoluminescence, clasts within the lowest thin sections analyzed did not appear to be diagenetically altered because they did not luminesce; however, after studying relative elemental abundances, it is clear that the clasts contain elevated levels of manganese and iron, indicating that there has been some form of diagenesis. Future studies of the rocks at BTC should attempt to quantify the absolute abundances of major and trace elements to compliment the results reported here.
Subject: Carbonate rocks -- Montana -- Black Tail Creek (Madison County)
Subject: Geology, Stratigraphic -- Montana -- Black Tail Creek (Madison County)
Subject: Diagenesis -- Montana -- Black Tail Creek (Madison County)
Terms of Use: http://creativecommons.org/licenses/by-nc/3.0/us/
Permanent URL: http://hdl.handle.net/10066/8842

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Citation

Herz-Thyhsen, Ryan. "Diagenetic Analysis of Carbonates within the Dinwoody Formation at the Black Tail Creek Locality". 2012. Available electronically from http://hdl.handle.net/10066/8842.

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http://creativecommons.org/licenses/by-nc/3.0/us/ Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by-nc/3.0/us/

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