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#geochemistry

1 post1 participant0 posts today
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bse

Aqueous #geochemistry this semester! We've moved from simple fluid-mineral equilibria to more complex models. As a teaching tool, I developed with help of our Uni's IT folks, an online portal to #USGS model software, WEB-PHREEQ. Anyone can use this.

Of course the students download the more capable desktop version for their projects (also, yes, I know there are more advanced portals out there). #geology

ndsu.edu/webphreeq/

www.ndsu.eduWelcome to Web-phreeq - aqueous geochemical modelingPHREEQC, low temperature aqueous geochemistry, modeling, modelling, web-phreeq, wateq, water, Department of Geosciences, North Dakota State University, Fargo, ND, USA.
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Ele Willoughby, PhD

Happy birthday to #geochemist Charles David Keeling (1928 - 2005) whose decades long observations of CO2 in air samples from Mauna Loa Observatory were some of the 1st direct data to show the human contribution to greenhouse effect & global warming. The ‘Keeling Curve’ (in copper & red) shows both the seasonal variations (the wiggles) & the strong upward trend with time as the greenhouse gas built up in the atmosphere. 🧵

Linocut portrait of Keeling in teal with geochemical sampling tools with the Keeling curve in copy and axes (vertical: CO2 fraction micro-mol/mol from 325 to 400 and horizontal: Year 1960 to 2000).
#linocut#printmaking#climateChange
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Bill Minarik

Jonathan O'Neil of the University of Ottawa telling the story of the Hadean mantle and crust from the few scraps of rocks left to us from that time. Short- and long-lived isotopic systems constrain the timing and processes of the Earth's first crust. The second keynote at the Geotop annual meeting, hosted at ÉTS.

Jonathan O'Neil of the Univ. Ottawa introducing the ancestry of Earth's crust.
A slide illustrating the radioactive decay of isotopes present at the Earth's formation.
#UOttawa#ETS_Montreal#Geotop
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Chris Rowan

This seems to be the latest round in the eternal battle between the #geophysics data which strongly suggests whole mantle convection (and for quite some time, if ideas about the origin of all the weird junk at the core-mantle boundary are correct) and the #geochemistry data which suggests long-lived and distinct mantle reservoirs - authors here are in latter camp #geology #tectonics
phys.org/news/2023-07-proof-ea

Phys.orgNew proof that Earth's plate tectonics recently underwent a fundamental changeBy Science X
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Preston MacDougall

The expression “Old as the hills” means really, really old when you’re referring to #JackHills in Western Australia.

How old are they? They’re so old that isotopic analysis of zircon rocks 🪨 found there indicate that they were formed BEFORE tectonic activity on Earth 🌏 began! 👉 si.edu/newsdesk/releases/earth

This fascinating result of #geochemistry agrees with the second oldest rocks on Earth from the Canadian Shield.

Smithsonian InstitutionEarth’s Oldest Minerals Date Onset of Plate Tectonics to 3.6 Billion Years Ago | Smithsonian InstitutionScientists led by Michael Ackerson, a research geologist at the Smithsonian’s National Museum of Natural History, provide new evidence that modern plate tectonics, a defining feature of Earth and its unique ability to support life, emerged roughly 3.6 billion years ago. Earth is the only planet known to host complex life and that ability is partly predicated on another feature that makes the planet unique: plate tectonics. No other planetary bodies known to science have Earth’s dynamic crust, which is split into continental plates that move, fracture and collide with each other over eons.
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Geo-Nerd

#Mineral identification entered a new era when #geochemistry came to the fore. But some #crystals were real head-scratchers.

#Tourmaline is what we like to affectionately call a "trash-can mineral". It feels like every element under the sun finds a way to worm into its crystal structure. Mineralogists quickly grew frustrated with pinning down the chemistry.

"[On] the whole the chemistry of it is more like a medieval doctor’s prescription than the making of a respectable mineral." -John Ruskin

Elbaite with green termination fading into a pink base. Print from 1873 with text below reading "Crystal of Tourmaline - Exact Size"
Continued thread
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Susie Leopold l

"This idea does remain robust because the two volcanoes can still "feel" one another through stress effects. They don't have to be directly connected for this to happen. An example model of this process was published in 2012: nature.com/articles/ngeo1….https://www.nature.com/articles/ngeo1612"

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#MaunaLoa #MaunaLoaEruption #Kilauea #KilaueaEruption #Geochemistry
twitter.com/USGSVolcanoes/stat

TwitterUSGS Volcanoes🌋 on Twitter“@ominologist @waitwutf This idea does remain robust because the two volcanoes can still "feel" one another through stress effects. They don't have to be directly connected for this to happen. An example model of this process was published in 2012: https://t.co/gWrMeGGZ2h.”
Continued thread
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Susie Leopold l

"If you'd like some detailed background reading on the topic, one of the classic papers on the subject is royalsocietypublishing.org/doi"

(3/4)

#MaunaLoa #MaunaLoaEruption #Kilauea #KilaueaEruption #Geochemistry
twitter.com/USGSVolcanoes/stat

Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering SciencesIntershield geochemical differences among Hawaiian volcanoes: implications for source compositions, melting process and magma ascent paths | Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences As Hawaiian volcanoes develop, their lavas systematically change in composition and isotopic ratios of Sr, Nd and Pb. These trends provide important constraints for understanding plume-related volcanism as a volcano migrates away from the hotspot. There ...
Continued thread
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Susie Leopold l

Answer:
"There are geochemical trends that separate Hawaiian volcanoes - the Kea and Loa trends. Mauna Loa is on the Loa trend and Kilauea is on the Kea trend. Isotopic geochemical signals provide evidence for a bilateral hotspot plume that feeds the two trends."

(2/4)

#MaunaLoa #MaunaLoaEruption #Kilauea #KilaueaEruption #Geochemistry
twitter.com/USGSVolcanoes/stat

TwitterUSGS Volcanoes🌋 on Twitter“@ominologist @waitwutf There are geochemical trends that separate Hawaiian volcanoes - the Kea and Loa trends. Mauna Loa is on the Loa trend and Kilauea is on the Kea trend. Isotopic geochemical signals provide evidence for a bilateral hotspot plume that feeds the two trends.”
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