# Help! Tricky geology question **URL:** \ **Category:** Factual Questions\ **Created:** [November 13, 2001, 3:35am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058 "2001-11-13T03:35:19Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![TonyD](https://avatars.discourse-cdn.com/v4/letter/t/e274bd/32.png) [@TonyD](https://boards.straightdope.com/u/TonyD)\ **Post date:** [November 13, 2001, 3:35am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/1 "2001-11-13T03:35:19Z")
I’m in the process of writing a paper for my intro geology class and I’m having a few problems. The topic seems easy enough…“Choose at least 5 minerals and describe what they show about igneous and metamorphic rock formation”. I’ve been searching the internet and geology textbooks and have found volumes of information, but none of it directly applies to my situation. I know I have to include texture, composition, etc to discribe various aspects of a rock, but with my limited knowledge I’ve been unable to put it all together. Any help would be GREATLY appriciated. ---
**Author:** ![TonyD](https://avatars.discourse-cdn.com/v4/letter/t/e274bd/32.png) [@TonyD](https://boards.straightdope.com/u/TonyD)\ **Post date:** [November 13, 2001, 3:36am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/2 "2001-11-13T03:36:53Z")
I should also state that it’s important to include Bowen’s Reaction Series. ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [November 13, 2001, 3:52am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/3 "2001-11-13T03:52:26Z")
IANA geologist, but I think a good starting point would be: 1. Do you know what “igneous” and “metamorphic” means? Yes? 2. Okay, then pick your five minerals. List them. Then tell how each one illustrates either “igneous” properties or “metamorphic” properties. I’m sorry, that’s the best I can do. I can’t write your paper for you. ☹ If I had to pick 5 minerals, I’d pick: –quartz. –granite. –obsidian. –marble. –basalt. Then tell how each one is either igneous or metamorphic. I have no clue what Bowen’s Reaction Series is, but I can go look it up on Google. [http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry32.html](http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry32.html) > **[Home | Science](https://uwaterloo.ca/science/)** > > As an integral part of Canada’s most innovative university, the Faculty of Science is a global leader and a preferred destination for those seeking to engage in world-class basic and applied research. We take this valuable research strength and... [http://maps.unomaha.edu/Maher/geo117/bowens.html](http://maps.unomaha.edu/Maher/geo117/bowens.html) It has something to do with crystallization? How long is this paper supposed to be? Are you a geology major, or is this just filling a “sciences” requirement? ---
**Author:** ![Rysdad](https://avatars.discourse-cdn.com/v4/letter/r/7cd45c/32.png) [@Rysdad](https://boards.straightdope.com/u/Rysdad)\ **Post date:** [November 13, 2001, 3:59am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/4 "2001-11-13T03:59:31Z")
I’d pick: Pumice (igneous) Pahoehoe (igneous) Slate (metamorphic) Marble (metamorphic) Quartzite (metamorphic) ---
**Author:** ![Ringo](https://avatars.discourse-cdn.com/v4/letter/r/779978/32.png) [@Ringo](https://boards.straightdope.com/u/Ringo)\ **Post date:** [November 13, 2001, 4:13am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/5 "2001-11-13T04:13:09Z")
I am a geophysicist, but I’m not going to write your paper for you either; you might want to search (you are familiar with [Google](http://www.google.com)?) for the **rock cycle** and take note of the conditions of formation within such of both igneous and metamorphic rocks. Pay heed to the environmental conditions, such as heat and pressure. ---
**Author:** ![TonyD](https://avatars.discourse-cdn.com/v4/letter/t/e274bd/32.png) [@TonyD](https://boards.straightdope.com/u/TonyD)\ **Post date:** [November 13, 2001, 4:45am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/6 "2001-11-13T04:45:40Z")
Thanks a lot for everyone’s help. I think I should clearify a few things…I wasn’t very clear in my OP. I definitely don’t want anyone to write the paper for me, I’m just having some trouble fitting all of this together. I guess I need resources outlining various observable traits. Like say what the abundance of a certain mineral says about the composition of the magma or protolith. For some reason I’m having serious problems relating my limited knowledge of minerals to the formation of rocks. > [@](#): > > Are you a geology major, or is this just filling a “sciences” requirement? I’m just finishing up my science requirements…I had no idea I would have this much trouble with an intro course ---
**Author:** ![Geobabe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/geobabe/32/3908_2.png) [@Geobabe](https://boards.straightdope.com/u/Geobabe)\ **Post date:** [November 13, 2001, 4:51am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/7 "2001-11-13T04:51:24Z")
For metamorphic rocks particularly, many minerals form only under very specific conditions. There are polymorphs with the same chemical composition but different crystal form, depending on temperature and pressure; for example andalusite, sillimanite and kyanite. And to the rest of y’all, learn the difference between rocks and minerals. 😉 ---
**Author:** ![Geobabe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/geobabe/32/3908_2.png) [@Geobabe](https://boards.straightdope.com/u/Geobabe)\ **Post date:** [November 13, 2001, 5:03am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/8 "2001-11-13T05:03:34Z")
Oh, and here are some lists of geoscience web resources --some of these may be too advanced for an intro course, but check em out and see if they’re useful to you: [The Virtual Geosciences Professor](http://www.uh.edu/~jbutler/anon/anonfield.html) [Yahoo List: Earth Sciences](http://dir.yahoo.com/Science/Earth_Sciences/) [Geoscience Links from Galaxy](http://galaxy.einet.net/galaxy/Science/Geosciences.html) [The Hub: Earth Science Internet Resources](http://www.connect.slb.com/index.cfm?id=id13158) ---
**Author:** ![Ringo](https://avatars.discourse-cdn.com/v4/letter/r/779978/32.png) [@Ringo](https://boards.straightdope.com/u/Ringo)\ **Post date:** [November 13, 2001, 5:06am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/9 "2001-11-13T05:06:49Z")
OK **'babe** , I’ll fire off the top of my head that a rock is a naturally occuring bound aggregate of minerals. And our OP is concerned with the minerals that compose the rocks of igneous or metamorphic origin. He’s probably given up on us for the night before the paper’s due anyway. ---
**Author:** ![TonyD](https://avatars.discourse-cdn.com/v4/letter/t/e274bd/32.png) [@TonyD](https://boards.straightdope.com/u/TonyD)\ **Post date:** [November 13, 2001, 5:30am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/10 "2001-11-13T05:30:12Z")
Nope, I’m still here. Thanks a lot for all your responses…I really appriciate it. It’s a little late so you’ll have to excuse my writing. I think the best way to describe my problem (and from what I can tell the entire class’s problem) is to use an example: olivine. If I happen to find a rock, that I determine to be igneous, with a high concentration of olivine I can assume that it formed at a higher temperature than say amphibole (at least I believe I can assume this because as the melt cools the now forming olivine crystals will sink to the bottom). If the rock formed at lower temps, the olivine would have become unstable, yes? I guess I’m just seeing if I’m on the right track. ---
**Author:** ![Geobabe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/geobabe/32/3908_2.png) [@Geobabe](https://boards.straightdope.com/u/Geobabe)\ **Post date:** [November 13, 2001, 12:04pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/11 "2001-11-13T12:04:54Z")
Guess I should have said, _the rest of y’all except for **Ringo** _. 😛 ---
**Author:** ![Duck\_Duck\_Goose](https://avatars.discourse-cdn.com/v4/letter/d/50afbb/32.png) [@Duck\_Duck\_Goose](https://boards.straightdope.com/u/Duck_Duck_Goose)\ **Post date:** [November 13, 2001, 2:37pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/12 "2001-11-13T14:37:47Z")
A Rock is a big ugly chunk. A Mineral is a shiny pretty little chunk glued to a piece of cardboard, with an explanatory caption. Hope this helps. 😃 ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [November 13, 2001, 3:50pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/13 "2001-11-13T15:50:02Z")
\*Originally posted by Duck Duck Goose \* > [@](#): > > A Rock is a big ugly chunk. 'Cept to a geologist. We think they’re all gorgeous. 🙂 What Geobabe said about rocks vs minerals. And here’s a site that might help. [http://www.geolab.unc.edu/Petunia/IgMetAtlas/mainmenu.html](http://www.geolab.unc.edu/Petunia/IgMetAtlas/mainmenu.html) Good luck. It’s an **awesome** science! ---
**Author:** ![Ethilrist](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ethilrist/32/4604_2.png) [@Ethilrist](https://boards.straightdope.com/u/Ethilrist)\ **Post date:** [November 13, 2001, 4:08pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/14 "2001-11-13T16:08:13Z")
> [@](#): > > \*Originally posted by lieu \* > \*\*\*Originally posted by Duck Duck Goose \* > > > [@](#): > > > > A Rock is a big ugly chunk. > > 'Cept to a geologist. > We think they’re all gorgeous. :)\*\* So would **Geobabe** be redundant? 🙂 ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 13, 2001, 4:09pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/15 "2001-11-13T16:09:32Z")
Yes, most of y’all (meaning, except for **Geobabe** , **lieu** , and the former beatle, **Ringo** ), _please_ learn the difference between rocks and minerals! It pains me! I am a geologist, and like the other geologists and non-geologists here I’m not going to write your paper for you, but in referencing Bowen’s Reaction Series(\*), you’ve answered your own question. Here’s the hint: every mineral in a rock is significant in that it says something about the conditions in which the rock formed, whether it’s pressure, temperature, oxygen fugacity, silica activity, or etc. Usually especially when combined with data from another mineral phase present. (\*)By the way, whilst in Boston last week for the GSA meeting, I picked up a copy of _N.L. Bown and Crystallization-Differentiation: The Evolution of a Theory_ by Davis Young. It’s a history of Igneous Petrology! Who wants to read it next? Anyone? Anyone? ---
**Author:** ![lieu](https://avatars.discourse-cdn.com/v4/letter/l/c2a13f/32.png) [@lieu](https://boards.straightdope.com/u/lieu)\ **Post date:** [November 13, 2001, 4:40pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/16 "2001-11-13T16:40:10Z")
Fugacity. Is that from the Sopranos? ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 13, 2001, 5:21pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/17 "2001-11-13T17:21:09Z")
Nah, but **Leucocratic** was in _The Godfather_. As in: “Leucocratic sleeps with the fishes.” (Every time I teach IgMetPet, I tell that joke and every year fewer people get it…) ---
**Author:** ![Geobabe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/geobabe/32/3908_2.png) [@Geobabe](https://boards.straightdope.com/u/Geobabe)\ **Post date:** [November 13, 2001, 10:38pm UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/18 "2001-11-13T22:38:59Z")
> [@](#): > > \*Originally posted by Ethilrist \* > \*\* > > > [@](#): > > > > \*Originally posted by lieu \* > > \*\* > > > > > [@](#): > > > > > > \*Originally posted by Duck Duck Goose \* > > > A Rock is a big ugly chunk. > > > > 'Cept to a geologist. > > We think they’re all gorgeous. :)\*\* > > So would **Geobabe** be redundant? 🙂 \*\* 😃 > [@](#): > > _Originally posted by Pantellerite \* > \*\*I am a geologist, and like the other geologists and non-geologists here I’m not going to write your paper for you, but in referencing Bowen’s Reaction Series(_), you’ve answered your own question. Here’s the hint: every mineral in a rock is significant in that it says something about the conditions in which the rock formed, whether it’s pressure, temperature, oxygen fugacity, silica activity, or etc. Usually especially when combined with data from another mineral phase present.\*\* My esteemed colleague here has said what I would have had I not been about to be late for work this morning. Seriously. Your answer is to be found in the Bowen Series, Grasshopper. > [@](#): > > \*\*(\*)By the way, whilst in Boston last week for the GSA meeting, I picked up a copy of _N.L. Bown and Crystallization-Differentiation: The Evolution of a Theory_ by Davis Young. It’s a history of Igneous Petrology! Who wants to read it next? Anyone? Anyone? \*\* You just love making me squeal, don’t you? ---
**Author:** ![Yossarian](https://avatars.discourse-cdn.com/v4/letter/y/9de0a6/32.png) [@Yossarian](https://boards.straightdope.com/u/Yossarian)\ **Post date:** [November 14, 2001, 12:04am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/19 "2001-11-14T00:04:25Z")
> [@](#): > > \*Originally posted by Geobabe \*You just love making me squeal, don’t you? \*\* Hey, it’s what us Hard-Rock Igneous Petrology types do best! And if you _really_ want to squeal, check out my soon-to-be-issued article in the Journal of Volcanology and Geothermal Research (volume 111, pages 155-182, I think; due to be released in December) on the origins of a quartz trachyte-rhyolite suite by combined crustal melting, magma mixing, and fractional crystallization. Talk about squealing! Petrogenesis gets me every time… ---
**Author:** ![Geobabe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/geobabe/32/3908_2.png) [@Geobabe](https://boards.straightdope.com/u/Geobabe)\ **Post date:** [November 14, 2001, 12:54am UTC](https://boards.straightdope.com/t/help-tricky-geology-question/93058/20 "2001-11-14T00:54:46Z")
Oooh. Ooh. OOH! **Pantellerite** , you’re _dreamy_… So where is Intro Boy, anyway? Are we helping at all, or just making you more confused? [Next page](https://boards.straightdope.com/t/help-tricky-geology-question/93058.md?page=2)