74 



California Division of Mines and Geology 



Bull. 197 



nous, and dolomitic. Similar limestone occurs to the 

 southeast in SE'X sec. 18 and NE'X sec. 19, along the 

 crest of the Panoche Hills. Impure limestone and 

 other marly beds of the Tulare Formation also are 

 reported in Little Panoche V^alley and elsewhere to 

 the north (Briggs, 1953, p. 48-49) and in N% sec. 30 

 to the south (Anderson and Pack, 1915, p. 210). Analy- 

 ses of limestone from sec. 30 are given in table 15. 



Table 15. Chemical analyses of limestone of the Tulare 

 Formation, Panoche Hills, Fresno County. 



Samples from Samples from 



sec. 18 ' sec. W " 



Oxide Marlife I Marlife 2 #1 #2 



SiOa 12.30% H.JO% 19.84% 9.74% 



AI2O3 8.20 .v. 10 4.97 2.76 



FejOj 1.30 0.80 1.95 1.65 



MgO 8.80 16.00 5.28 1.85 



CaO 32.90 25.30 34.06 45.48 



NajO 0.50 0.30 ND ND 



K2O 0.30 0.20 ND ND 



PjO, 0.05 0.03 ND ND 



SO3 ND ND none none 



Ignition loss 



(CO2+H2O) R20 37^ 29^ 35>» 



Total 98.55 99,73 95.95 97.42 



ND=Not done. 

 • Samples Marlife 1 and 2 were collected by Earl W. Han and analyzed by 

 Lydia Lofgren, Division of Mines and Geology, March 1963, Marlife I 

 is soft, crumbly, represents 2 feet of thickness near center 1K-14S-11E; 

 Marlife 2 is from moderately hard, thm ledge in NW'/J8-14S-1 IE, 



•• Anderson and Pack (1915, p, 210) samples arc from N'/, J0-14S-11E, Sam- 

 ple #1 is typical of marl bed 15-20 feet thick; #2 is from thin, hard 

 limestone bed (analyst, George Steiger), 



Development of the Marlife deposit consists of sev- 

 eral shallow pits or broad trenches from which materi- 

 al was quarried in NWI4 and center of sec. 18. A few 

 prospect pits and trenches are located within 2 miles 

 to the southeast along the crest of the hills. Quarrying 

 of the thin marl horizon and removal of overburden 

 were conducted using a tractor-powered carryall. The 

 marl was delivered to a nearby hammer mill, where it 

 was pulverized, and subsequently delivered to points 

 in the San Joaquin Valley for sale as agricultural lime- 

 stone (Logan, etal., 1951, p. 507-508). The production 

 pits have estimated maximum dimensions of 400 feet 

 long, 100 feet or more wide, and 5 to 10 feet deep. It 

 is estimated that roughly 30,000 to 40,000 tons of marl 

 and soil overburden were excavated. Probably over 

 half of this was processed as agricultural lime. Accord- 

 ing to the California Department of Agriculture (Spe- 

 cial Publications 231, 236, 239, 244, 247, 251), partial 

 analyses of the commercial marl varied from 33.75% 

 to 48.47% CaCOa during the 1948-1953 period. Appar- 

 ently some soil was admixed with the marl during 

 excavation, as these analyses are lower in equivalent 

 CaO than sample analyses shown in table 15. Future 

 value of the Marlife deposit and similar marl deposits 

 of Panoche Hills appears to be limited to agricultural 

 uses. There is no record of commercial production 

 since about 1953. 



NORTHERN SANTA LUCIA DISTRICT (C-3) 



This district encompasses the northern half of the 

 Santa Lucia Range and the smaller Sierra de Salinas 

 to the northeast. It lies totally within Monterey 

 County (plate IC). Much of the northern Santa Lucia 

 Range district is rugged and rather remotely situated 

 with respect to major lines of transportation. The 

 northeast side of the district is served by a railroad and 

 highway along the Salinas \'alley. The southwest side, 

 where most deposits are located, is served only by a 

 winding highway along the precipitous Pacific Coast. 

 The nearest major marketing center is the San Fran- 

 cisco Bay Area 100 to 150 miles to the north. 



The oldest and most important carbonate deposits 

 are crystalline limestone and dolomite associated with 

 schist, gneiss, quartzite, and other metamorphic rocks 

 of the pre-Cretaceous Sur Series. This metamorphic 

 unit has been intruded by granitic rocks of probable 

 Late Cretaceous age. Upper Cretaceous, Tertiary, and 

 (^aternary sedimentary rocks flank and locally over- 

 lie the crystalline basement. Except for impure dolo- 

 mite of the Miocene Monterey Formation and an uni- 

 dentified shell deposit, none of the sedimentary rocks 

 has been of economic interest. No limestone or dolo- 

 mite deposits are known from the Francisca rocks 

 southwest of the Sur-Nacimiento fault zone. Uplift 

 and erosion in recent geologic time have exposed the 

 crystalline basement rocks over a broad region in the 

 northern part of the range. Faulting and folding have 

 severely deformed the range, and the older crystalline 

 rocks in particular are brecciated and sheared in many 

 places. 



The great bulk of carbonate rock in the northern 

 Santa Lucia Range is confined to a 3-mile wide, north- 

 west-trending belt in the Coast Ridge area (Hart, 

 1966b, p. 61-62). The belt is more or less defined by 

 the Sur-McWay (Nacimiento) fault zone on the 

 southwest and the Palo-Colorado and Coast Ridge 

 faults on the northeast (Jennings and Strand, 1958). 

 Carbonate rocks also are found west of Junipero Serra 

 Peak and elsewhere in the range but in much smaller 

 concentrations. The general distribution and loca- 

 tions of the known carbonate deposits, based largely 

 on the work of Trask (1926), Reiche (1937), and 

 Fiedler (1944), are shown in figure 5. Most of the 

 deposits are much smaller than indicated and 

 generally consist of multiple small lenses and beds of 

 carbonate rock associated with various noncarbonate 

 rock. 



Although a few deposits are relatively pure lime- 

 stone, most carbonate bodies are mixtures of lime- 

 stone and dolomite, the former predominating. Much 

 of the Sur Series limestone is white to light blue gray 

 and fine to very coarse crystalline, with local concen- 

 trations of graphite crystals 1 or 2 mm across. Near 

 intrusive contacts, the limestone shows development 

 of a wide variety of calcium and magnesium silicates. 

 Silica also is present as quartz. Dolomite occurs both 



