Bisbee daily review., 1918-01-20

Geology Of tue War7,en
 District
By ]. B. PENNY.

low dotted line. By the end of this time the old land surface was almost all under water. so that the next for nations to be deposited were lime StoneS-SoO feet of Ahrigo. 800 feet of Martin. 500 feet of E.ScahrOwsa and S0e0 feet Of NacO. making a total Of of lSoO feet. or $500 feet Of sediments altosether. a little over a mile. To lay down a mile Of sediments on the bottom of the sea takes some time. From actual measurements of the amount Of silt deposited by such riv- CTS as the Mississippi and the Ganges over a long pericd figures have been arrived at for the time necessary tO deposit enc foot. This varies rom 1900 10 5000 years: so that Co deposit $500 feet it would take rom 7.sSO.OQO years o 15.9o0.0O0 years. This Is prob ably low. because most of the seji- ments are hmestones. which deposit much slower than sands and silts. The probability is that the tine was much greater than the higher figure. or say se.000.0OO years
 After all these sediments had been deposited a big crumpling in the earth's crust took place. and this part of the earth was showed up out or , the sea. As most of the sediments had become hard and compact. instead of being bent or folded. they were all broken up by faults. One Of the largest Of the breaks or faults was the Dividend fault. shown by the red line. the south side being dropped about 5000 feet The land surface after this faUlting was then about as shown by the red line. Just aitsr this. the Sacramento Hin porphyry came up. eating into both sides 0f tas fault This wSs followed by the orc | solutions, which made our present ore bodies. Then followed long period of erosion or wearing down Of this old land surface. until it finally took the form shown by the brown line, nearly where we are now. To wear down thrOush mile of sediments takes the same time as to deposit a mile. so that this period probably , represents another s00O0,e00 or SO years,
 Then followed ano;ter sinking Ot the whole area under the sea, and 4s00 feet of CrCtacerous s;andstone's Shaies and hmeStOnes were deposited, This took from 5.o00.eOO to 9.00o.0O0 years more. Then followed a second crumpling of the eartks crust and this part of the world was egain thrown up. The land Mas then about as shown by the blue line. From then URt1 now tais has bsSn ste Niiiy worn doNa unGl Sll but nere remnant ot the Cre,a cer0US sediments are iets at the extreme right Of tSe illustration This took another 5000 900 tO 9.O0o.. co years.
 To summar:ze: The tctal tine wc know anvta.ne sbou;. that k. rom the old scnist land surface time up tO now represents time Cf at least 5e.. OC0OOO years The time since the orss were put where they are now up to the present date is at least So,oo0.. eco years, When We take into con. SideratiOn the fact that the known history Of man Onlt goes back 1000 years. or only time enough Co wear down about four feet of land, you can get an idea Of the enormous time that has elapsed since these ores we are mining we're put into the ground.
 The old idea os the condition Of the earthS interior was thSt it was so hot that |; vas tn liquid or molten state. This has been proved by as- ,ronomy and mechanics to probably be net the case. 10 Is new considered probable that the pressure eXertel ny the solid crust is en0Ggh Co keep ;he rocks inside nom ulel,ing. u. how ever. the pressure for any reason ts removed. these rocks become melted immediately and force their way up. sometimes tO the surface, as in vol canoes.
 The earth was originally probably a similar body tO the sun; that iS. eN- ;remely hot lt Is constantly cooling. and in doing this Is continually shrink iEg. As it shrinks the crust tends Go Csumple ur into ridge and iuyrOVs. We an ere familiar with the cr9aipiins which t>ScS place in the skia of an apple s 'C interior of the apple dries al d shrinSs. This crumplins IS what produces mountains and seas. lt the crumpling is violent enough Co produce cracks it takes off the press ure from the hot interior, and part ot it melts up and forces it's way up into the cracks. These molten rocks are volcanic rocks as we meet them today. The examples here are the Juniper Tat granite and the granite pOrphyry.
 These volcanic rocks are some times accompanied by steam and hot gases and sometimes not. If hot gases come with them they are called wet intrusions" II not. they are called dry intrusions" The wet intrusions have the most effect on the rocks they meet. The hot gases under very high pressure dissolve large amounts of metals and sulphur, which they bring up and deposit as ore bodies if they have dissolved valuable metals, or only pyrite if iron is dissolved.
 A dry intrusion. on the other hand. has very little effect. except little