Show s GOVE TON r Geological Survey Makes an al Ex Exhaustive Examination of o oThe The Nevada Camp HOT WATER CAUSED VEINS J 11 limo llio ComMock Co I I 1 1 l And 11 nil lie th I Minos i 1 I Around roii II mid Do Io 1 1 Ia La Mur Idaho Maho Tho Tine United State States GeologIcal survey lurey gives Elves out the ti following report upon the formation of ot the tho Tonopah Mining dis district In Nevada Neada and also ulso of the econ economic untIe Value of lt Ihl deposits leps Its H It I Is In Interesting to note that Geologist purr who manic lado the examination of ot the Ule dis tritt trel lads finds u a I very vr lIO resemblance between It I and the deposits of ot the thc Corn Com stock stok Me lode and 11 the LIme De Do La L L Mar Idaho mines 11 nil nes The fhe report though length r li Is of ot no ItO fO much Interest to tn the tho mining raining public of Salt Lake Ulic that U It I It l given In full tul The Tho geological problem presented Inthis In III this district coull culI have been solvent only tidy bj by I u a I trained since the tine Igneous rooks rocks that carry the vein deposits have bean be 1 largely covered by ly practically barren hews Hows of more recent Tha fhe very careful and thor thoro thorough ough U l study Luly of or the district which Mr Ir has made can cnn hardly full fail tul to bo ho 1 hoof of grout practical value to the miner miller I IlS I ae as lS well Vill ai as n of interest to LI the of ot ore deposIts depo The value nd interest of or the text are aI enhanced by b tho addition of ot 78 Illustrations tu which In topographic timid and ud geologic maps some of ot them In colors diagrams plans of or veins and anil faults faul geologic aunt and eros cros sections views of characteristic arid and Ild lt tie tic le landscape features The rocks of ot the tho mining joining district ann aro annall oil all ni of ot immediate volcanic origin with wil the exception of ot n a B s of ot tutlA represent the th accumulations tion of flue Mno volcanic detritus In lii a I Ter Tertiary TerI Tertiary ton I age lige I probably Miocene Pliocene Tile The g t of If this volcanic ol ep epoch och as at ut Tonopah were nn sun Two have been dl dis distinguished the younger or earlier earler an deste aunt the later inter which Is slightly II more basic than the earlier eruption of or and 1111 of occurred nt at In Intervals for tor a long tong time and produced of ot the formations mapped mape which Include tuffs and ancl flows Hows Th structure Is HO so complicated that HIt no General cross cros sections have been mode Some Somo Interesting Information on oil 01 his lis however been obtain obtained ed ent ll chIefly ehlen from froni mine working The most Important mineral mineraI veins oc occur occur cur clr In the tine early and do not rocks Too Tie extend Into the lie overlying ion wa ts IU probably caused c by b hot ascending waters water Immediately after oter the earlier earler eruption The Th jirl primary mary oes have a ii 1 of or quartz ad a ulula 1111 some and carbon carbonates ate ates timid and Ind contain sliver sitter sulphides such as is and silver gold gohl In Iii a II yet ot undetermined undetermined mined form Comm Irle oral ond sumo some galena Falena and anni blonde blende The depth of oxidation Is Irregular In tho the ore oro of or off ort t tn f oxidized zone no urn lD Important Calles changes in III n the amount of pf gold gaul or slIver silver ns os com corn compared pared with wih the tho primary ore have hae taken pilco lare The he ore ure near nor the surface Is not nota a 1 truly trimly oxidized mixture of ot original sul sui sulphides lul anti and el together with wih sulphides chlorides anti ox oxIdes Ides des Secondary sulphides s include ar nr argentite and amid 1111 A series of ot vein of or Importance commercially t within the Tonopah dis triet wan a 11 formed after the tho eruption of me tine of or the member of the rh dtp Cite th These ThEse eln may lay luia ba I lP but bul are arc usual usually ally illy al of 01 low lot grade ralle or Dr barren They fee fre frequently fr contain a II greater proportion of gold thi tho the veins vein ind antt have hrc other r distinguishing charac en A St l B i of ot veins of still lew le Importance Importance tance w vs 11 s formed titter after the eruption of ot one Ole of tt If the later hater members of ot the tine rh o oll ll a which up Ioro omo onno of or the hills hilis neat near leur Tonopah One of theme thane Mount Ararat Ararata IL a 1 denuded volcanic neck Is I traversed values by Iw t reins carry car very nr little lart Pa I of the thc curlier cler 1 I its in ro altered Tho iho maximum effect of ot the th waters which caused those e alter Iter alterations aton nit the formation of ot tho the mineral er along their circulation channels Thu ho of these processes li Is hj by h the detailed study of or nn an analyses al se of ft specimens The con cn dUBlon l I IA drawn that t lit the time mineralizing waters w wee rc charged changed with wih an nut 11 excess of or silks und and i of potash h to together together gether Keher with wih alIve gold nr or 11 coper lead zinc anti and ld selenium that te also 1150 Contained carbonic add lell tail and tn with wih come chlorine and fluorIne but that they the were noticeably di M lent In III Iron The alteratIon n of the later by I thermal water Is t also n fly y comparison of ot and by micro sc plc ile It IH is II concluded that that the waters produced the alteration were charged with carbonic acid and hydrogen find end contain contained ed oll Iron Irn and limo lime The two theories of or thu tha origin or ln of hot springs amid Ald nun are by I Mr tr Spur Spurn Spurr In connection Ion tion with the tho th Tonopah phenomena The lo meaning of tho the nature of or the metals metal In Inthe Inthe the th Tonopah veins Is also The Tho conclusion I 1 Is reached that IhM the wa waters a toes which produced the veins vein wore Were largely lava below blow given oft off of from the tho congealing cong |