Bisbee daily review., 1918-01-20
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gases either come up with the DOT phyry or just after If they come up with the pOrphyry the contacts will be either ore or pyrite- If the gases come up later they may come up al the contacts or may come up through some other nearby crack or crushed zone In this case the contacts may be barren. and the ore or pyrite al some distance away The hot gases usually come up just after the intru- sion as all familiar with present vol canoes know Geysers and hot springs almost always follow an eruption Oi Mount Vesuvius. Mount Etna, Mount Pelee and other active volcanoes
 As I have just stated. ores are car ried by the hot gases coming up with wet iIsuUsiOns-" They are pGt down in two ways: Q) in open cracks or faults. when they are called veins; and. t2) as replacements of other rocks, either sediments or volcanic rocks Replacement means that the msieria, forming the original rock Is dissolved by the gases, and at the same time sulphide ore takes the place of the dissolved material
 Here in Bisbee most of our ore bodies are replacement ore bodies, usually replacing limestone, but also replacing porphyry las in Sacramento Hill and in some Of the ore bodies in the Lowell. Gardner and Sacramento mines)- The ores in these ore bodies were al sulphide ore bodies originally, and where they are now, We cali them primary ores
 We all know that part of the rain water sinks into the earth through cracks This water goes down to a certain depth and then stops This level is called the water level Of the district This ground water" dis solves air, which contains oxygen We are all familiar with this fact from the bubbles rising from water when we heat it, just before it reaches boil ing point This dissolved air will oxidize ore and change it into car bOnate and oxide ores. if it is gwen 2 chance.
 When we consider again that dur ing the two land ages since the ores were put in there has been twenty =A-----1A -N6-C ---1-C OA AI01 A0A N-AA1 ground water to act. you can see that it is really remarkable that we have anything left but oxide ores. and gOs- sans GOsssBs are the result Of the action Of ground water on sulphides Of iron and copper, where the copper has not only been Oxidized but car ried away, and deposited somewhere else
 After the original primary sulI hide ores are Oxidized. they are called -en- riched' ores, depending on whether the original sulphides have been changed to glance or oxide ores
 The oldest rock in the district is the Pinal Schist. Ehioh made up Jne old original land surface This Schist is a uetamOrphic rock, made up of quartz grains and mineral called seri- cite, a kind of mica The rock has been so completely altered that there is no evidence what il was before it was altered
 The first sedimentsry rock to be deposited was the BaIsa quartzite which is 40 feet thick This was originally a sandstone, which has been compressed by the weight of the over lyIng sediments into a quartZite-
 Above this comes 7SS feet of AbrisO limestone This limestone is a very impure limestone. with a number Of beds of shale and sandstone The shale was deposited originally as mud This limestone has also been changed by the pressure of the over lylDg sediments. so that it now con sists of thin beds of limestone. shale and thin seams of mineral called cpl dOte- This epidOte on the surface looks like cherL UnGergrOund il Is greenish- The Abrigo limestone can De told from all others by the thin beds usually each bed Is not more than couple of inches thick. by its impurity- and by the absence Of fossil shells.
 At the top of the Abrigo limestone comes a white cuartzsse pea varying in thickness from a half a foot 10 10 feet thick This Is Ehs- ~e cali the capping qUsrJzite
 Above the czpping quartzite comes BIO to go feet Of martin limestone. a compact dark grey to nearly black limestone. fairly pure. and with nun bers Of beds made up of fossil shells. about half inch in oIame7er.
 Above the Martin limestone comes 4ss feet of very pure coarse crystal line Esca brOsa limestone, the purest limestone we have. In this limestone there ls considerable cnert or flint Ehica cones as rounded nOdules in the beds
 Above the EscabrOsa comes S.g0e feet of NscO limestone. very much Ike the EscabrOsa. except that there are some impure shady beds. usually pink Tn color and there IS more flint f IS The NacO that covers almost the whole surface south of Mule Gulch- Practically all the shafts start in this for T.nstion-
 Alter the NacO had been laid down trere followed the first upheavaI. ana the intrusion of the DOryhyry and long age or wearing down. or erosion. Alter mat the xhole area again sank. and we had deposited over a very un- even land surface the Glaune con EiOmerste- This cOlglOmerate is made up of schist. limestone. porphy- TT, quartzite and granite bOulders. all Jumbled together The town of War ren Is built on glance cOnglOmerate-
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