Evaporites Through Phanerozoic Time: Using GeoDeepDive, Macrostrat, and Geochemical Modeling to Investigate and Model Changes in Seawater Chemistry
| dc.contributor.author | Kumpf, Benjamin | |
| dc.contributor.supervisor | Coogan, Laurence | |
| dc.contributor.supervisor | Husson, Jon | |
| dc.date.accessioned | 2024-04-23T20:48:51Z | |
| dc.date.available | 2024-04-23T20:48:51Z | |
| dc.date.issued | 2024 | |
| dc.degree.department | School of Earth and Ocean Sciences | |
| dc.degree.level | Master of Science MSc | |
| dc.description.abstract | Marine evaporites provide a unique insight to the variation in paleo-seawater chemistry throughout the Phanerozoic Era which in turn provides information about various geologic processes and earth history. This study examines changes in paleo-ocean chemistry and evaporite mineralogy by utilizing GeoDeepDive and Macrostrat to derive records of evaporite occurrences and abundance throughout the Phanerozoic. This study provides a more comprehensive list of epsomite and sylvite evaporites, and their temporal occurrence, than has been available to date (Appendix 1). Changes observed in the abundance of epsomite, sylvite, halite, calcium sulfate and dolomite help contextualize changes in paleo-seawater composition and global sea-level fluctuations. Normalizing marine calcium sulfate occurrences to calcium sulfate and halite occurrences (RAC) shows a distinct difference in the abundance of calcium sulfate-bearing evaporites before and after the Mid-Devonian. Prior to the Mid-Devonian the RAC was highly variable and after this it stabilized. Changes in the RAC were evaluated using batch evaporation modeling attempts in PHREEQC that suggest the main drivers of increased calcium sulfate relative to halite could be caused by increases in the product of Ca2+ and SO42- which could constrain the assumption of a constant product of Ca2+ and SO42- used in the calculation of seawater chemistry through fluid inclusion analyses. The occurrence and temporal abundance of marine evaporites yields unique insights into the role of global sea-level and its relationship to evaporites and their formation. Evaporite abundance tends to increase during periods where there is significant continental flooding following a decrease relative sea level, then relative sea-level subsequently decreases again. The RAC tends to be elevated when global sea-level is decreasing and lower when sea-level has stabilized or is increasing. Dolomite abundance compared to these global evaporite records suggest that dolomite is primarily formed during continental flooding and less likely during widespread evaporite formation. | |
| dc.description.scholarlevel | Graduate | |
| dc.identifier.uri | https://hdl.handle.net/1828/16395 | |
| dc.language | English | eng |
| dc.language.iso | en | |
| dc.rights | Available to the World Wide Web | |
| dc.subject | Geology | |
| dc.subject | Earth | |
| dc.subject | Ocean | |
| dc.subject | Seawater Chemistry | |
| dc.subject | GeoDeepDive | |
| dc.subject | Macrostrat | |
| dc.title | Evaporites Through Phanerozoic Time: Using GeoDeepDive, Macrostrat, and Geochemical Modeling to Investigate and Model Changes in Seawater Chemistry | |
| dc.type | Thesis |