BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250804T011446EDT-2910UUflh8@132.216.98.100 DTSTAMP:20250804T051446Z DESCRIPTION:The Department of Earth and Planetary Sciences Presents: \n\n  \n\nDr. Daniel Gregory\n\nDepartment of Earth Sciences \n\nUniversity of T oronto\n\n \n\nOctober 6\, 2023 \n\n11:00 am \n\nIn-person: FDA room 232  \n\n \n\nFrom economic geology to ocean chemistry: the wide range of infor mation that can be obtained from a humble pyrite grain\n\nAbstract:\n\nPyr ite incorporates a portion of the trace elements dissolved in the fluids f rom which it formed. Thus trace element analysis of pyrite grains can give us information of these past fluids with applications as varied as unders tanding changes in ocean chemistry to identifying ore deposit type. We hav e analysed over 1400 pyrite grains from sedimentary rocks through geologic time using laser ablation ICPMS. Periods in geologic time when several tr ace elements are enriched in pyrite match with times where whole rock anal yses of redox sensitive trace elements also show enrichments. This suggest s that pyrite chemistry\, like these traditional whole rock studies\, can be used to understand changes in ocean chemistry and the atmosphere throug h Earth history. In this presentation we evaluate the efficacy of this by investigating nano-scale zoning of pyrite framboids from euxinically forme d pyrite\, the most likely pyrite to retain the trace element signature of the water column from which it formed.\n\nPyrite also incorporates trace elements from hydrothermal fluids. Because pyrite forms in many different deposits and those deposits have different fluid compositions pyrite chemi stry should be a viable way to identify ore deposit type. This is importan t as near surface deposits are increasingly exploited and new\, large depo sits will be found at deeper and deeper depths. This requires deeper drill ing and increased costs\, thus we must get as much information from each d rill hole as possible. If pyrite can be utilized to identify ore deposit t ype it will allow for application of geological models early in an explora tion program enhancing efficiency of the drilling. In this study we presen t almost 4\,000 LA-ICPMS trace element analyses of pyrite from 84 differen t deposits (including porphyry\, hydrothermal breccia\, IOCG\, SEDEX\, VHM S\, orogenic gold\, and skarn) and unmineralized sedimentary pyrite format ions. These data are used to train a Random Forest data learning algorithm to identify ore deposit signatures based on the trace element composition of the pyrite associated with them.\n\n \n DTSTART:20231006T150000Z DTEND:20231006T160000Z SUMMARY:Seminar Speaker: Dr. Daniel Gregory URL:/eps/channels/event/seminar-speaker-dr-daniel-greg ory-351077 END:VEVENT END:VCALENDAR