How do I make different minerals and rocks and where do they come from/ where are they located?

Question

Ok, Geo 101 student here, Let me say we have only covered plate tectonics, minerals and igneous rocks. Use plain English please, my college textbook doesn't.

Ok this question is directly from the study guide my geology teacher gave me. I assume he is askinf how are different minerals and rocks made, where do they come from and where are they located.

Answer 1

I don't understand your question. I am a degreed geologist and geologic engineer (Colorado School of Mines). If you can explain your question better, perhaps I can help. Are you asking a question regarding the mechanics of the formation of various types of minerals and rocks? Are we discussing igneous rocks only?

addition: Being as you said you have studied igneous rocks, I'll concentrate on that situation only. Please remember that simplified answers are not totally accurate.

With igneous rocks, we start with a "pool" of magma that has been "intruded" toward the earth's surface. The initial factor, determining what minerals or rocks will form, is the chemical composition of the magma. Then, other factors and the interplay of these factors work together to determine what get's formed. The rate of the cooling of the magma plays a major factor. Rapid cooling doesn't allow enough time for minerals to separate out. Slower cooling allows minerals such as plagioclase, orthoclase, hornblende, micas, quartz, etc. to separate out into individual crystals. This will lead to the formation of granite for example. Even slower cooling will allow larger crystal formation and lead to the formation of a pegmatite. The depth and pressure, that the magma is under, will also be factors that help determine what minerals and rocks form. Then the interplay of cooling rate versus pressure will help determine what minerals and rocks form.

I'm running out of time and room to continue to answer you. Perhaps Tom-PG will take over and add on to my answer. Don't worry if he "corrects" something I said. I tried to simplify my answer and that leads to inaccuracies. Perhaps Tom can explain a little about extrusives or near extrusives such as basalts, gabbro's, diorites, etc.

Answer 2

Also a registered professional geologist, and likewise, I don't understand the question.

There are so many processes and dynamics involved. Igneous and magmatics create one type of rocks, sedimentary are made from the parts and pieces of other rocks, metamorphics are a heat, warp, and rework resulting in completely different rocks.


EDIT:
Spiritual.... did such a fine job, its going to be hard to expound. Its really difficult to tell where the study guide is pointing you. As was pointed out, in igneous rocks, key factors are chemical concentrations in the magma, confinement of the magma, and rate of cooling. Also, if the magma is expressed on the surface, then other processes take place with totally different results, such as basalt.

My advise... seek out the TA and ask for some direction. That is what they are there for. It is absolutely imperative you understand the basics now as everything you learn now will be built upon later. Ask lots of questions and DON"T FALL BEHIND.

I do geology (and GIS) every day and it is a continual learning experience. Make sure to also include GIS in your studies. Your best shot at a job depends on it.

Unfortunately, igneous rocks are not my strong point. I wish I could be of more help.

Are we close?