The mud tank carbonatite is unusual with the low Th/U. with a high zircon content…I would like to read your paper and get the explanation…the petrogenesis of carbonatites is not necessarily a single process as different source rocks are involved…These rocks are fascinating not only for the rare minerals and economic importance but also because of the petrogenesis… I don’t understand much it other than high C02 and carbonate/silicate liquid immiscibility within a small field of PT conditions.
Question for you that you can skip if you don’t want to answer: are you a geochemist or petrologist? A PhD in the geosciences? I’m just an amateur with an interest in rocks… that interest is sincere as I have attended two of the last Goldschmidt meetings and will be going to Chicago for the third… I find them very enjoyable… Some but not all of it is over my head… qualitatively I can understand all of it but quantitatively some it is over my head… I need formal study and am contemplating getting a degree in geology. I’m retired so it’s possible except for my age making my memory slow…
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The zircon content is not high at Mud Tank but thanks to at least a mile depth of erosion the initial zircon content in gravels was extremely high. Also, as Mitchell has pointed out, carbonatites are a mixed bag: and as Chakhramouradian has emphasised, cannot be treated like silicate rocks. To answer your question, I studied geology fifty years ago and have returned to it in my retirement because it keeps Alzheimers at bay. Also, it is relatively simple to research. All it needs is a pick and shovel and a suitable location to test the body and the brain.
As a Colored Gem Merchant I love that the diamond market is finally getting its “comeuppance”. After screwing over the retail buyer for over a Century with monopolistic price fixing, I enjoy the turmoil. .
I need to get formal training and a degree in geology myself now that I am retired. I have to also return to my petrology textbooks and buy updated versions. Isotope geochemistry has advanced so far that every element can be isotopically separated… this has lead to an explosion of data… I am attending the annual geochemical society Goldschmidt meetings… they are very enjoyable, even though some of it is beyond my limited self training…I am well aware that not all carbonatites are created the same. but the deep earth processes that created all of them are highly unusual… They are not a good place to look for gems in general but have highly unusual mineralogies…I friend of mine, now retired, when a professor of geology, wrote a paper about two belts of alkalic igneous rocks trending east west across the northern and southern tiers of the US… the thesis was the foundering of the Farallon plate and opening of a slab window at the north and south edges of the plate, allowing for kimberlitic metasomatism of the asthenospheric mantle and genesis of alkalic rocks. My original home was Honolulu, now many years ago. Why numerous small volume unsaturated alkalic monogenetic eruptions occured on the northern Hawaiian islands after 2 million years of extinction of the main tholeiitic shields drove my curiosity. The iconic landmark of Diamond Head is a nephelinite tuff cone. All of the eruptions show enrichment in incomptible elements but are depleted by eNd…one of them brought up garnet eclogite… peridotite xednoliths are common in most… No single model can explain all of the isotopic aspects for these eruptions, nor the trace element signatures in entirety. One that came close is still incomplete. The simple hotspot model in a simple system as the Hawaiian Islands is far more complicated than it seems on the surface.
As mentioned before, I have no formal training in geochemistry… just a lot of reading driven by curiosity and an intellectual adventure grown out of my old rock hounding days… getting formal training is a necessity if I am to pursue this further.
please see my post above… I messed up in trying to direct it to you
My advice is to forget the formal training and simply understand the modern analysis methodology. Modern geology should be about simplification away from the early “butterfly collection” days of rocks being named after their investigators, and also whole-of-rock analyses. The problem now is a thicket of data that comes out of LA-CPMS and other instruments, with geologists who publish it in unnecessary and infinite detail. I must confess I am an analytical chemist with a PhD in organic chemistry and therefore in comparison find geology to be an inexact science concerned with complex mixtures of unideal molecules. However, I am plugging on because it’s fun.
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Fun for me too… PhD work is detailed by nature of being academic. Every element is now being separated by isotopic composition and ratios… it’s all technology driven as expensive equipment becomes more sensitive… My own field in medical…and molecular biological… advances are all technology driven in these area also. Inexact science certainly applies to medical science.
I will keep struggling to learn more exactly because it is fun…having retired from medicine gives me more time to pursue other interests that are fun and not work…
Regrettably, the high cost of instrumentation means that scientists like me find it expensive to decipher what we find. Not only that, but a lot of the past literature is hard to access without paying for full article access. Fortunately, some journals now print public access papers which helps. What I find most insulting is the arrogance of some geologists who assume that since you are not a geologist you do not really understand science. This illustrates the unfortunate compartmentalisation that modern science has fallen into. Specialisation is fine but too much leads to loss of creativity and new ideas.
Academics are academics no matter what field they are in. It’s still publish or perish. It’s also internicine intra and inter departmental politics. A meta-analysis of scientific papers found that 10% were junk science with poor methadology and unsupported conclusions. Money or the lack thereof is always the issue. Grants have all dried up… In my former field of medical science, research is skewed by money from big drug companies. But at least some money is there. The cost of buying and running a mass spect is on the same order of magnitude of buying and running an MRI machine… except that MRI machines produce revenue… mass spect doesn’t. I was quoted a while ago that a rock sample could be analyzed by a private contract lab for 2,000 USD per sample… any study to be valid would require a dozen samples or more…the cost is prohibitive. Nonetheless, all of science is now technology driven. Technology is advancing faster than applications. Technology is also very expensive. Medical science and clinical appplications are costing so much in the USA that the national expenditure on health care is unsustainable. It keeps rising exponentially with costs outrunning revenue. Revenue has it’s limits.
Your comments on how expensive it is to get an rock analysis is cogent. So are your comments on finding open sourced references. I am an associate memeber of the America Geophysical Union, which for a nominal annual fee, included in membership, I get open sourced articles from Geochemistry, Geophysics, Geosystems. Other reference articles that are not open source I either have to go thru interlibrary loan at our local university or be content to read the abstract. I’m not willing to pay 40 USD to read a single paper…
I know what academics can be like… I was in it for a short time. I could have pursued an academic career with my subspecialty skill set but being in academics even for a short time was distastful. I have some regrets but going into private practice set me up for retirement with enough savings to maintain my lifestyle, I retired completely as of the first of this year and have no regrets. I’m not looking back at all.
Studying geology and rock collecting were hobbies pursued life long until I had too many rocks to deal with. I need to downsize and get rid of stuff. Finding pretty rocks was too difficult although I do have few museum quality specimens which I will donate to a university mineral and rock musuem. But I want them on display and not shuttered in a box in a store room… My interest shifted into the science behind the rocks. I studied geochemistry on my own but realize that I need to study it more systematically in a structured environment to make the most sense out of it… ie, going back to school and getting a degree as a non traditional student. My interest is purely entertainment. Some people watch sports and I study rocks… but today is the Superbowl game in the USA… I will be watching it… I’ve been going to the annual Goldscmidt Geochemical Socieity meetings since 2021. A lot of it is over my head, but at least on the conceptual, if not the quantitative level, I can understand most of the presentations. It’s been a spectator sport for me. I have no intention for pursing a second career at my age…Dowinsizing and moving south to a warmer climate is my priority. Collecting papers and not physical objects, storing them on a computer solves a small part of the junk accumulation problem.
My other interest centers around foreign languages. I have and will be doing a lot of travel this year. I like to speak the language of my host country. I am already conversationally fluent in French and am learning Spanish to visit Spain and Latin America. However my time is limited. Given my age I don’t know how long I will be able to enjoy life and keep up with life long learning.
I recommend specialising in one limited area otherwise there are too many loose ends to follow. I am lucky in that I can get LA-CPMS and sample prep for about A$180 an hour, so about eight samples cost A$1,500 for about twelve elements. Still, it’s an expensive hobby.
Maybe you should visit Australia. No language difficulties and there are plenty of interesting minerals if you know where to look. I can only help you with info on zircon but I have friends who are into opal and gold detecting.
My interest in stones is because I want to sell off my collection. I’m trying to find some gauge of valuation which is difficult. I have stopped doing jewelry making as a hobby and have a hoard of loose stones. Getting rid of precious metals is easy… I can send them to a refiner. loose cut stones is a real problem. but keep getting distracted by the science of minerals.
My interest in rocks is more broad based. I like the academic stuff and want to know more about it.
I’d also love to travel to Australia someday. What’s holding me back is that I have other travel plans for this and next year and hate long plane rides…Even first class is a pain on long flights besides prohibitibely expensive. Fares to Australia for the continental US are as high as 10K USD for first class.
Lucky you. I always travel cattle class because that saves money for my research. Maybe I should have done medicine or finance instead of pure science. Too late now.
I would have to go in cattle class also… just too expensive to go transpacific. I’m retired and don’t have megabucks to spend.