Help with geochemistry report?

Question

hello everyone

i dont want answers but rather help, just a few questions as i dont quite understand the questions being asked.

I have to write about the element "Titanium" and answer the bellow questions

1. Describe the main primary and secondary mineralogy of this element.

2. What is the extent of mobility of this element in groundwaters under oxidizing conditions? What are the main ligands and complexes responsible for this mobility?

3. How is this element transported in primary mineralizing solutions (hydrothermal conditions)?

what i dont understand is in question 1

what is exactly is "primary" and "secondary" mineralogy??

and for question 2 and 3. can someone dumb down the questions as im getting confused trying to get the correct meaning out of it all

thanks

Answer 1

Primary minerals are the minerals that occur in the rock when the rock forms.  Secondary minerals are the minerals that result from later reactions, such as weathering or hydrothermal alteration.  A metamorphic mineral can be considered as either primary or secondary, depending on whether you are considering the metamorphism as the altering event or prior to the altering event (a metamorphic rock can be altered by later hydrothermal activity).

Basically, primary minerals are the minerals that are present before some event, and secondary minerals are the minerals that are present after the event.  The primary mineralogy changes into some secondary mineralogy during the event.

For the second question, the amount of an element that will be taken into solution by a passing fluid (water in this case) is very much unique to the element.  For metals, some (copper for example) are very mobile under oxidizing conditions, and others (iron for example) are very mobile under reducing conditions.  pH is also usually an important factor.

The amount of an element or metal that can go into solution can be increased by the presence of other compounds or elements in the fluid.  This is because the metal ion will join together with these other compounds in addition to floating around as a naked ion.  Chloride ion is a common complexing agent that will increase the amount of a metal that the solution can carry.  Sulfate, sulfide, bicarbonate, hydroxide, and other such anions also can form complexes with metal or other cations.  Complexes increase the effective solubility of a specie-you get more of the metal in solution if it complexes with other things on top of running around in the water by itself.

The third question applies to water-dominant fluids that are at high temperatures (as much as 350°C).  Most metals exist primarily as chloride complexes in hydrothermal solutions (iron, lead, zinc, copper, gold, silver), but some metals, like titanium and aluminum, are weakly soluble even in hydrothermal solutions.  Generally, these weakly soluble metals are present in the rock from the start, and are not added to or removed from the rock during alteration, at least not in any significant amounts.  The secondary minerals that form during alteration are produced by the removal of other elements rather than by addition of the metal itself, for these metals.

This of course is why there are not any real deposits of aluminum and titanium from hydrothermal activity, in contrast to the main base and precious metals (lead zinc copper gold silver), all of which are typically added to the rock during alteration.

Aluminum and titanium ores are generally produced by the leaching of everything else, or by simple physical transport of titanium minerals to form titanium rich sediments.

I don't think I dumbed it down. Sorry.  Hope it helps anyway.

Answer 2

1. Primary mineral : Rutile and Ilmenite

Secondary minerals : the various weathering products of rutile and ilmenite

By "Primary" it is indicated that they crystallized directly from an igneous source, say, a magma. By "secondary", it is meant that they have been produced from a primary mineral under various weathering, erosion, sedimentation or even metamorphic processes. So alteration products are always secondary, even when the make the entire mass of a secondary rock.

for question 2 and 3, please follow the link below :

http://books.google.co.in/books?id=FF0x5...