The Alaskan., 1929-01-11

cabin after putting in a hard shift in the tunnel. Jack dropped down
 on big rock with the remark: Let's
 take five, Larry have been trying
 to think, and I cannot walk and think at the same time-sort of a. Isingle track mind, I guess you would call it. Larry dropped down near b., picked up piece of quartz float iying on the trail and mechanically began breaking it between two rocks, then examining the fresh surface for "colors." Don't try to think too hard
 on an empty stomach, Jack Doctor
 says it's bad for the digestion. We'll, 10 ahead and get it off your chest"
 What I don't understand, Larry is why quartz is so often associated W ith valuable ores. It seems to be
 pretty we'll understood by everybody that quartz and ore are almost uni versally associated but I have never heard anyone attempt to explain "hy. Take ore of the eastern sports men who come aout here hunting in
 tie summers. Now, if one of these f,llows was crawling along on | idge to get a pot shot at a bunch Inf sheep and he should suddenly
 crawl across a quartz ledge he would
 immediately forget all about getting
 il shot at the sheep and begin look
 ing for gold"
 "Some but not all of them, Jack.
 have seen some of these hunters
 who would rather get themselves a nice sheep head than be President
 ot the First National Bank back in their home town.'
 Your lodging my question, Larry
 Either you're hungry or for once I
 taye found subject which that
 irish mind Of yours is afraid to wran- slo with"
 ''I'll admit that I am good and nungry but don't figure for minute that you have me stuck" Larry re- tofted. When I took the short Curse that winter at the College we talked about that subject quite bit. Putting the explanation into my own words it is something like this: The original home of the ore minerals is in these igneous intru- ems. such as granite and mazonite. These intrusjons were once deeper in the earth and were in a molten condition. The geologists call these molten areas by the term magmas. | These magmas contain the chemical clements which rocks are composed of and they also contain minor amounts of such metals as copper, lead, silver, gold, etc. One magmas | may be particularly rich in gold, an- other in copper and some of them have only very small | quantities of the valuable metals. \ Now one of these magmas may be forced into some area of overlying older rocks If the molten material breaks thru to the surface the lava will be quickly chilled and freeze as fife grained volanic rocks such as rhyolite, and basalt. The quick does not give any metals which may be present time to col ect together and they will occur scattered as small traces through the antire mass. Now, on the other land, if this intrusion gets within nile or so of the surface and most f it does not break through the { 'verlying rocf rocks, it will take this irea of molten rocks years to cool town and freeze. It will naturally tart freezing from the outer edge nd the time will be sufficient for Le heavier metals to sink deeper .. nd collect more or less together. !. IS the magma chills it is known !. cientifc fact, that the darker rock i. orming minerals, such as mica and .