LIFORNIA JUNE 1991 OLOG In This Issue CALIFORNIA UNDERWATER MINING CONFERENCE ...... 122 e GEOLOGY MINES AND GEOLOGY OF FORT IRWIN ...... 123 TAMARACK TUFF ...... 130 HELP YOUR STUDENTS GET EXCITED ABOUT EARTH SCIENCE ...... 138 A PUBLICATION OF THE DEPARTMENT OF CONSERVATION DMG RELEASES ...... 139 DIVISION OF MINES AND GEOLOGY SP 107 MINERAL COMMODITY REPORT-BENTONITE ...... 139 OFR 91-07 PRINCIPAL FACTS AND SOURCES FOR State of California PETE WILSON Governor 1528 LAND GRAVITY STATIONS ON SAN FRANCISCO QUAD ...... 140 INLAND GEOLOGICAL SOCIETY CALL FOR PAPERS ...... 140 The Resources Agency DOUGLAS P. WHEELER BOOK REVIEWS ...... 141 Secretary for Resources MAIL ORDER FORM ...... 141 Department of Conservation EDWARD G. HEIDIG CALIFORNIA GEOLOGY SUBSCRIPTION FORM ...... 142 Director MEMORIAL, JOSEPH F. POLAND: 1908-1991 ...... 144 Division of Mines & Geology JAMES F. DAVIS State Geologist

CALIFORNIA GEOLOGY staff

Technical Editor: Don Dupras Assistant Editor: lena Tabilio Cover Photo: Paleozoic metamorphic rocks, northeastern Graphics and Design : louise Huckaby Avawatz Mountains. The Avawatz Mountains have been Publications Supervisor: Jeff Tambert uplifted thousands of feet since the Miocene. The geologist is standing on an upthrown block of Paleozoic meta­ Printed: Department of General Services Office of State Printing sedimentary rock.

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Publications and Information Office: 660 Bercut Drive, Sacramento, CA 95814-0131 Public Information: 916-445-5716 Underwater Mining Conference Los Angeles Office: 107 South Broadway, Room 1065 Los Angeles, CA 90012-4402 (Telephone: 213-620-3560) The 22nd International Underwa­ coastline. This forum is sponsored by ter Mining Conference will be held the University of Wisconsin Sea Pleasant Hill Office: 380 Civic Drive, Suite 100 Pleasant Hill, CA 94523-1997 from September 29-0 ctober 2, 1991 Grant Institute in cooperation with (Telephone: 415-646-5920) in Kahuku, Hawaii. This forum for the Ocean Basins Division of the

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122 CALIFORNIA GEOLOGY JUNE 1991 Mines and Geology of Fort Irwin San Bernardino County, California

By JOHNS. RAPP, Geologist and LARRY M. VREDENBURGH, Geolog ist

INTRODUCTION Ibex Pass Kingston he examination of mines and mining /\r.CY).,R ange T prospects at Fort Irwin was done /"-~ (~ concurrently with Division of Mines and Geology (DMG) regional geologic mapping and other mineral resource N studies in the region. Mapping, field Fort Irwin checking, and geologic data of the Fort Irwin region were collected between January 1982 and May 1990 . DMG l conducted an investigation of the mineral resource potential of the Fort MILES Irwin region to develop geologic and 10 15 20 mineral information in a region of California where very little published mineral resource information exists . This article was adapted from an unpublished DMG Special Report that will be entitled The m inera l resource potential, geology, and abandoned mines of Fort Irwin, San Bernardino County, California.

Figure 1. Location map of the Fort Irwin region .

LOCATION AND ACCESS Fort Irwin is located in the central Mojave Desert, approximately 40 miles north of Barstow (Figure 1). The Fort Irwin National Training Center employs approximately 5 ,800 civilian workers (in­ house U.S. Government documents, 198 7) . Part of the southern boundary of Death Valley National Monument is fewer than 3 miles north of the Fort, and the National Aeronautic and Space Administration's (NASA) Goldstone satellite tracking faci lity is located just west of Fort Irwin.

Photo 1. M-60 tank heading east from Bicycle Lake. Photos by authors.

CALIFORN IA GEOLOGY JUNE 199 1 123 Fort Irwin is an important military training center that serves each branch of the armed services. Tens of thousands of American soldiers recently sent to Saudi Arabia received much of their desert warfare training at Fort Irwin . Civilian access is not permitted during training exercises. The main entrance of Fort Irwin, and the only authorized entry point, is on Fort Irwin Road.

DESERT LAND USE DECISIONS The Mojave Desert is a vast region with substantial mineral, energy, and agricultural resource potential. Thou­ sands of Californians live, work, and vacation in the desert.

One of the most important desert land proposals pending before Congress involves the expansion of the Fort Irwin National Training Center (Fort Irwin) by Photo 2. Salt Basin prospect. The Salt Basin playa deposits are truncated and displaced by 370,000 acres of Federal (public), State, slivers of the Death Valley fault zone. These disrupted beds are underlain by basal conglom­ and private land . Fort Irwin now covers erate and breccia, and overlain by Plio-Pleistocene fanglomerate•. The brown clay-rich salt 636,457 acres, and is one of the most beds contain layers of salt and gypsum, and nodules of celestite. active military training centers in the United States.

The Department of Defense would larger training area is required . Some The National Park Service (NPS) like to conduct larger and more compre­ environmental groups, miners, and proposed that Death Valley National e hensive military field exercises at Fort others question the need for additional Monument be expanded to include the Irwin . Military planners believe that a military land in the desert. Owls Head Mountains, the Quail Mountains, the northern Avawatz Mountains, and the southern part of the Amargosa River Valley. The expansion would make the Monument contiguous with the northern boundary of Fort Irwin. The Monument expansion plan is designed to protect scenic and wildlife values of the southern Death Valley region.

This proposal however, is opposed by the mining community and various outdoor recreation groups. Many exploration geologists believe that the Fort Irwin region has good mineral resource potential. There are several dozen old mines and prospects within Fort Irwin, and hundreds of mineral location notices have been filed in the outlying region. Many of the new location notices have been filed in the proposed Fort expansion area.

Photo 3. Cave Spring, northern Avawatz Mountains. Cave Spring is located adjacent to Cave Spring Road, just north of the Avawatz Pass summit. It was a well known geographic feature and watering hole from 1880 to 1920. In 1891 the outpost at Cave Spring consisted of a stone corral and a ruined hut. By 1991 all that remained at the Spring were rudimentary foundations and "tunnel dwellings." Ephemeral springs issue from weathered andesite flows that have been broken and displaced by movement along the Garlock fault zone. *Bolded terms are in Glossary on page 129.

124 CALIFORNIA GEOLOGY JUNE 1991 Fort Irwin. It passed through Red Pass, skirted just north of Bitter Spring, and turned south through Spanish Canyon at Alvord Mountain. Mexican-American trade continued from 1829 to 1848. John C. Fremont and Kit Carson were the most famous early Americans to use the Old Spanish Trail. In April 1844, while traveling northward on the Trail, Fremont and his men had a bloody encounter with Indians at Bitter Spring. Bitter Spring was one of the most important Indian rest and watering spots.

Mormon immigrants discovered placer gold near the Salt Springs Hills in December of 1849, just east of the Amargosa River, where the river changes course to the west. Early prospectors traced placer gold from the Salt Springs Hills to its source, the Photo 4. Mining camp ruins , south of Avawatz Pass. A few ston e ruins still exist within Fort Amargosa lode gold deposit. The Irwin , although many of these turn-of-the-century mining structures were di smantled and Amargosa mine, which produced about destroyed by military and civilian visitors several decades ago. These ruins are not identified $300,000 in gold (Nolan, 1936, p. 52), or documented in the literature. The Army has diligently attempted to protect archeological was worked intermittently from the mid- sites since 1980, especially well-documented American Indian sites like Bitter Spring. 1800s to 1902. During the 1860s, a route was established from the town of Visalia, across the Sierra Nevada through GEOMORPHOLOGY Walker Pass, the northern part of Fort Irwin by way of Leach Lake, then to the The terrain of Fort Irwin is mostly Amargosa mine. barren and rocky, with rugged moun­ tains that are separated by dry lakebeds and broad alluvial fans. A variety of cacti, desert shrubs, and grasses grow in the region and are abundant near the few isolated springs. Alluvial terraces and bajadas sustain sparse perennial vegetation, and the broad playas are completely barren. Pale brown dune sand collects on the leeward sides of sharp ridges and ravines. Strong desert winds winnow poorly sorted fanglomerate terraces, leaving a mosaic of angular reddish­ brown clasts called "desert pavement." Although it is called desert pavement, these iron-stained clasts are generally ineffective in supporting off-road vehicles because they often conceal deep, unconsolidated, wind-blown sand.

HISTORY The mountain passes and valleys of Fort Irwin were well traveled by early Photo 5. Much of the tuffaceous country rock in the Fort Irwin region is weathered, bleached, Californians. The Old Spanish Trail, and friable. Rock exposures near Goldstone and the northern Avawatz Mountains exhibit structural and lithologic features of a volcanic center. A sample of altered meta-volcanic rock which was a lucrative trade route from the Old Shadey mine, wh ich is located near Cave Spring, assayed 3.06 ounces of silver between Santa Fe and Los Angeles, and traces of gold. The sample also contained high concentrations of arsenic, copper, passed through the southeastern part of molybdenum, lead, anti mony, and zinc.

CALIFORNIA GEOLOGY JUNE 1991 125 Avawatz Mountains in 1872, and Frank Denning discovered gold at Denning Spring in 1884 (Mining and Scientific Press, A 1884, p. 262). Gold was discovered in the Paradise Range and - at Goldstone in the 1880s. Silver mines in the Avawatz Mountains and Soda Mountains were recording production in the late 1880s, and gold was discovered near Quail Spring before the turn of the century.

Several small mining camps sprang up in and near Fort Irwin . Crackerjack was the original camp of the Avawatz Pass area, and one of the few that lasted more than a few months. A post office was established in February, 1907, and a weekly newspaper, Crackerjack News, appeared a few months later. Regular automobile stage service connected Crackerjack with Silver Lake for a one-way fare of $15.00.

Avawatz City was located 1.5 miles east of Crackerjack, and 2.5 miles from Cave Springs. According to Van Dyke (1977), Avawatz City originated when eight men from Crackerjack ran a Chinese camp cook out of town with the legal authority of

Photo 6. New Deal mine located in the Owls Head Mountains, approximately 2 miles north of Fort Irwin. Also known as the Owls Hole mine and the Owls Head mine, it was originally developed as an open-pit mine in 1914. One report estimates that about 4,000 tons of manganese ore was produced at the New Deal mine from 1916 through 1956. Trask (1950) reports 480 tons. The ore averaged 19 to 43 percent manganese and contained much hematite.

Cave Spring was an important way station for borax wagons from 1882 through 1887. The first shipment through Avawatz Pass came from the short-lived Eagle Borax Works, which was located at Bennett's Well in Death Valley. Borax was hauled from Death Valley through Avawatz Pass, to the Sante Fe Railroad siding at Daggett (Paher, 1973, p. 9). A fraudulent mining claim was filed by a desert entrepreneur at Cave Spring when the borax wagons began rolling. Teamsters were charged 25 cents per man and animal for each night of rest and water. The spring was abandoned when borax mining shifted from the Death Valley region to Calico, and travel through Avawatz Pass diminished.

Mineral prospectors came to the Fort Irwin region looking for gold and silver in the mid-1800s. It is very likely that the Photo 7. Fault-controlled vein at the Tungate mine. The Tungate gold mines of Red Pass, the Avawatz Mountains, and the quartz vein is discontinuous and relatively free of accessory Granite Mountains were discovered during this period. The minerals, including sulfides. The high-angle Tungate fault is roughly parallel to the nearby Garlock fault zone. Later northeast-trending Desert Cave mining district was established by 1880, and the faults distorted the mineralized Tungate fault. No gold was observed first mining claims were recorded within the Fort as early as in hand specimens, but channel-cut samples of vein quartz assayed 1872 (Quinn, 1981, p. 19). Silver was discovered in the from 0.009 to 0.08 ounces of gold per ton , plus traces of silver.

126 CALIFORNIA GEOLOGY JUNE 1991 of the region vary in mineral composi­ tion and may contain tungsten ore (scheelite), gold, iron ore, manganese ore, and calc-silicate minerals (wollasto­ nite) that are used in ceramics and composites. Various accessory minerals also occur.

Undiscovered low-grade epithermal gold/silver deposits may be concealed under broad exposures of Tertiary volcanic rocks in the region. Miocene zeolite, clay, and saline deposits are among the youngest and most valuable undeveloped mineral deposits of the region.

VOLCANOGENIC GOLD DEPOSITS Tertiary, volcanogenic, gold and silver-bearing veins occur in several places along the northern border of Fort Photo 8. Tiefort Mountain quarry. This aggregate quarry is located on the north slope of the Irwin . Epithermal deposits may be Tiefort Mountains, 3 miles east of Bicycle Lake. It was developed by an independent present in the Goldstone region west of contractor in about 1980, and produced aggregate base materials and concrete aggregate for numerous Army road and utility construction projects. The mine was idle in 1990. the Fort, but there is little supporting documentation. Emplacement of mineralized epithermal veins depends on three fundamental factors: a suitable volcanic source, receptive host rocks, an unwritten District ordinance prohibit­ Most of the old workings and historic and an effective subsurface hydro­ ing the permanent residence of persons references of the Fort Irwin region relate thermal system. Fort Irwin , and its of Chinese descent. San Bernardino to Mesozoic calc-silicate skarn and surrounding area, appear to have all County authorities worked out a plan auriferous quartz vein deposits. Skarns three characteristics. that permitted the cook to return to Crackerjack, but division among local residents over the issue resulted in the creation of a new town, Dry Camp. Dry Camp later became Avawatz City (Van Dyke, 1977, p. 25-26).

CURRENT MINING Other than aggregate borrow pits, mining has not been permitted within Fort Irwin since about 1941. However, mines and quarries dot the countryside of the surrounding area. Most historic activity in the area involved precious metal mining. Today, industrial minerals and construction materials are the principal commodities being mined in the region.

MINERAL RESOURCE POTENTIAL The Fort Irwin region has undevel­ oped mineral resource potential. Precambrian talc deposits and gold­ bearing quartz veins in the Avawatz Photo 9. Midway Green quarry is located about 3 miles north of Dunn Siding. Th e quarry is currently operated by Calico Rock Milling Company. Metamorphic bedrock is drilled, blasted, Mountains are among the geologically and transported by truck to the company plant in Barstow where it is crushed, screened, and oldest mineral deposits of the region. sold as decorative rock.

CALIFORNIA GEOLOGY JUNE 1991 127 The most favorable areas for epithermal gold/silver deposits are in the northern Avawatz Mountains, the area immediately east of Goldstone Space Tracking Facility, the region northwest of Calico and the Red Pass Range. Each of these areas has broad expanses of Tertiary volcanic and sedimentary rocks.

MESOZOIC SKARN DEPOSITS Small, mostly concealed, iron ore and calc-silicate skarn deposits exist through­ out the Fort Irwin region. The most likely place to discover new iron or manganese skarn deposits of economic importance is the eastern and northern Avawatz Mountains where massive plutons of quartz monzonite come into contact with pre-Mesozoic carbonate roof pendants. Undiscovered iron ore and manganese deposits may exist, but regional gravity and magnetic data Photo 10. Red Pass Lake, southeast Fort Irwin. Red Pass Lake appears to have occupied a suggest that no major deposits lie hidden large area west and southwest of the Red Pass Range during the Pleistocene Epoch. Regional uplift has tilted the Tertiary section of Red Pass Lake to the west, thus confining the beneath the surface. Holocene lakebed (usually dry) to its western limit against volcanic hills with in Fort Irwin.

A relatively small iron and manganese ore deposit could be hidden somewhere in the region because Mojave Desert tains, Granite Mountains, Quail Moun­ assumed that ore grades, depending on iron and manganese skarn deposits tend tains, Paradise Range, and the Alvord the mining methods, might range from to be small. Although small, these skarn Mountains. Only those mineral veins 0.10 to 1.0 troy ounces of gold per ton. deposits are large enough to supply iron that have been exposed by tectonic uplift Also based on limited field data, it is ore to the portland cement industry of and erosion have been observed, assumed that vein widths would range southern California. Brightly colored prospected, and developed. Most of the from a few inches wide to a few yards rock from these skarns can also be existing mines were discovered more wide. Veins could range from a few marketed for decorative rock and than 80 years ago because of gossan yards to half-mile or more in length. specialty uses. exposures. Unless concealed vein There may be fault-brecciated zones with deposits have imposed an obvious complex veins and more broadly GOLD-BEARING QUARTZ geochemical signature to overlying rocks mineralized areas. It is reasonable to Cretaceous poly-metallic, sulfide­ and colluvium, they are likely to remain assume that undiscovered mineralized bearing, quartz veins occur throughout hidden for the foreseeable future. veins of the Fort Irwin region could the Fort Irwin region. Auriferous quartz produce 100,000 ounces of gold. veins have been mined within Fort Irwin , The volume and economic value of CONSTRUCTION MATERIALS and similar well-documented gold undiscovered mineralized vein deposits occurrences have been mined in the in the Fort Irwin region are difficult to The crushed stone mineral resource area surrounding the Fort. estimate because of the scarcity of potential of Fort Irwin is limited by detailed geologic mapping and relevant potentially high transportation costs. Mineralized veins intrude, and appear mineral information. It is especially Until recently, it would have been to be derived from , Mesozoic quartz difficult to predict the occurrence and unrealistic to consider developing large monzonite plutons that intrude meta­ grade of auriferous quartz veins. scale stone quarries in the remote Fort morphic roof pendants. Most of the However, if known mineral occurrences Irwin region. However, continuous mineralized roof pendants appear to be are representative of undiscovered and suburban development of greater Los Paleozoic meta-carbonate rocks, hidden quartz veins, the volume and Angeles has already pushed eastward quartzite, siliceous meta-volcanic rocks, economic value of these undiscovered into the western Mojave Desert. It has and quartz-mica schist. mineralized quartz veins must be become extremely difficult to acquire relatively small. and develop mineral properties west of Undiscovered Mesozoic poly-metallic, the San Gabriel Mountains, and it may sulfide-bearing, quartz veins undoubtedly Based on limited assay data and now be reasonable to consider develop­ exist in the northern Avawatz Moun- mineral production statistics, it is ment of remote desert stone quarries.

128 CALIFORNIA GEOLOGY JUNE 1991 Fort Irwin and the surrounding desert Colorful Tertiary volcanic rock from effort, the Division of Mines and region has billions of tons of common the Pickhandle and Jackhammer Geology, the U.S. Bureau of Mines, the stone that is suitable for dimension formations are marketed extensively in U.S. Bureau of Land Management, and stone, construction aggregate, and the Barstow region. Similar, colorful, the U.S. Geological Survey have invested decorative rock. Rock types that have tuffaceous volcanic rocks are exposed in much time and effort into developing a potential commercial value--given a the Goldstone area, northern Avawatz body of mineral resource and economic viable market and transportation Mountains, near Bitter Spring, and in information. Hopefully, this enhanced options-include a wide variety of the Red Pass area. mineral information will be used by Paleozoic metamorphic rocks, Mesozoic federal decision-makers in laying out the granitic rocks, and Cenozoic volcanic CONCLUSIONS future of California's Mojave Desert. rocks. It is unlikely that the mineral resource REFERENCES potential of the Fort Irwin region will be Non-folia ted Paleozoic metamorphic Nolan, T.B., 1936, Metalliferous resources rock types, such as marble, feldspathic developed during the 20th century. Fort Irwin plays an important role in main­ and non-ferrous metal deposits: Mineral hornfels, and quartzite make excellent taining the national defense, and mining resources in the region around Boulder construction aggregate materials, Dam: U.S. Geological Survey, 871 , p. 52. is generally incompatible with intensive decorative rock, and dimension stone. military training. In the 1980s, federal Paher, S.W. , 1973, Death Val ley's ghost Foliated metamorphic rock often makes towns: Las Vegas, Nevada Publications. land-use decisions were heavily influ­ attractive flagstone , decorative rock, and enced by political action coalitions Quinn, R. , 1981, An historic overview of the dimension stone. The best target areas Fort Irwin region: U.S. Army, contract no . concerned for the environment and for Paleozoic metamorphic rock deposits C5201 0(80), unpublished in-house report. recreational assets of the desert region. include the Alvord Mountains, the Trask, P.O ., 1950, Manganese in California: northern and eastern Avawatz Moun­ California Division of Mines, Bulletin 152. In the next decade, important desert tains, Owls Head Mountains, and the Van Dyke, D. , 1977, Crackerjack-once upon land-use decisions will be made by the Soda Mountains. a desert, in G.L. Moon, editor, Life on the United States Congress. To assist in this Mojave River Valley: Mojave River Valley Museum Association, Barstow, California.

Glossary

bajada: A broad continuous alluvial slope extending from the base of mountain ranges into inland basins. It forms by the coalescence of a series of alluvial fans .

calc-silicate skarn: Rocks composed largely of calcium-bearing silicate minerals. Calc-silicate skarn minerals are derived from carbonate rocks into which large amounts of silica, alumina, iron, and magnesium have been introduced by adjacent igneous intrusions.

colluvium: A general term for loose and incoherent clastic deposits, usually deposited by gravity at the foot of a steep slope. In desert regions, such as Fort Irwin, bajadas form along the lower slopes of mountain ranges from the uniform coalescing of alluvial fans and colluvium .

epithermal deposits: Form within fissures and other rock voids through deposition of silica, calcite and other minerals at geologically shallow depths. Ore minerals are brought to the surface by means of ascending hot water solutions. Geologists divide the family of epithermal ore deposits into a fantastic array of "ore models,'" each with its own geochemical and mineralogical attributes.

fanglomerate: A sedimentary rock made of slightly waterworn heterogeneous fragments deposited in an alluvial fan and later cemented into a firm rock.

gossan: An old mining term that describes a cap of silica and iron oxide which commonly overlies sulfide-bearing ore deposits. Sulfide minerals exposed to atmospheric conditions tend to oxidize and liberate sulfuric acid. The acid then dissolves parts of the host rock and leaves a lattice of acid-resistent silica and iron oxides.

playa: A dry, vegetation-free, flat area at the lowest part of an undrained desert basin :X:

CALIFORNIA GEOLOGY JUNE 1991 129 TAMARACK TUFF A Devonian Submarine Pyroclastic Flow Deposit In The Northern Sierra Nevada Plumas and Sierra Counties

By JUNE L. LEGLER, Geolog ist San Jose State University ELWOOD A. BROOKS, Geolog ist Californ ia State University, Hayward and JOHN S. LULL, Geolog ist U.S. Geological Su rvey, Menlo Park

INTRODUCTION he Sierra Nevada, dominantly com­ T posed of Mesozoic plutonic rocks, also contains a variety of metamor­ phosed volcanic and sedimentary rocks into which the plutons were intruded. Pre-intrusive rocks largely have been eroded in the central and southern Si­ erra, leaving only scattered remnants, referred to as roof pendants and screens. The northern part of the range contains more of the older rocks and some of the best exposures are found just west of Yuba Pass and north of Highway 49 in Plumas and Sierra coun­ ties. The popular Sierra Buttes-Lakes Basin area, located within the Gold Lake and Sierra City 7 .5-minute quadrangles N (Figure 1), is underlain almost entirely by Paleozoic volcanic and marine sedimen­ tary rocks. GEOLOGIC SETTING ! The Paleozoic section in the Sierra Buttes-Lakes Basin area includes a strati­ graphic unit formally designated the Si­ erra Buttes Formation (McMath , 1966; Hanson and Schweickert, 1986). These Upper Devonian (Anderson and others, 197 4) rocks are mostly silicic to interme­ 0 10 20 diate volcanic deposits, interbedded with phosphatic black chert or siliceous argil­ lite and intruded by dikes and sills . The more silicic volcanic rocks are noted for Figure 1 . General location map of the Sierra Buttes-Lakes Basin area, abundant, large (to 1/ 2 inch) quartz phe­ Sierra and Plumas counties. nocrysts and an absence of mafic phe­ nocrysts. These quartz-bearing rocks 1892; Turner, 1895). The Sierra Buttes The Paleozoic island arc and overly­ were called "quartz porphyry" in early Formation and other units in the Paleo­ ing deposits were accreted to the North descriptions of Sierran geology (Diller, zoic section have been identified geo­ American continent during the Late Ju­ chemically as the remnants of a volcanic rassic Nevadan orogeny (Hannah and Bolded terms are in Glossary on page 137. island arc (Brooks and Coles, 1980). Verosub, 1980; Schweickert, 1981).

130 CALIFORNIA GEOLOGY JUNE 1991 Figure 2. Outcrop map of the Tamarack tuff between Sardine Lakes and Lakes Basi n, Sierra, and Plumas counties. Dashed line is the approxi­ mate limit of the Sierra Buttes Formation. Tips of arrows indicate sites shown in photos. Triangle shows the proposed vent site. Base map compiled from portions of Gold Lake and Sierra City 7.5- minute quadrangle topographic maps.

This tectonic event produced a northwest-strik­ ing , east-dipping orientation of the strata. The rocks are thoroughly recrystallized and meta­ morphosed to low grade, and locally are strongly foliated. Nevertheless, primary textural features of the rocks are preserved well enough in most places to provide the data for the inter­ pretations which follow.

Tamarack Tuff A significant portion of the Sierra Buttes Formation in the Sierra Buttes-Lakes Basin area consists of a particularly distinctive meta­ andesitic layer, which we refer to informally as the Tamarack tuff (Legler, 1983; Legler and Brooks, 1983; Brooks and Legler, 1989), named for the two small lakes near the south­ ern outcrops (Figure 2). Because of its relative resistance to erosion, the Tamarack tuff is we ll exposed for about 11 km (7 mi.) along strike (Figure 2), forming prominent ridges or the steep walls of glacial valleys. Unlike most of the other volcanic rocks in the Sierra Buttes For­ mation, the Tamarack tuff lacks the character­ istic large quartz phenocrysts. Fresh rock sur­ faces are greenish, reflecting the presence of metamorphic minerals such as chlorite and epi­ dote, and are unexceptional in appearance. However, the weathered surface of the tuff is spectacular; a work of abstract geologic art in which the vivid rusty-red matrix forms a back­ ground that is mottled by irregular whitish pumice fragments of various sizes and bizarre shapes (Photos 1 and 2).

Although the Tamarack tuff can be identified as a volcanic rock by its relict texture, the ap­ pearance of the weathered tuff is unlike that of other volcanic rocks in the Sierra Buttes For­ mation. Our analysis reveals that these peculiar rocks are a pyroclastic flow deposit produced by an explosive submarine eruption.

FIELD OBSERVATIONS

Outcrop Appearance of the Tamarack Tuff The freshly broken rock is light to dark green and aphanitic so that few features are discernible even with a hand lens. Weathered surfaces reveal the blocks and coarse lapilli

CALIFORNIA GEOLOGY JUNE 1991 131 (collectively referred to as "clasts" from Some "clasts" are actually rounded those on clasts are common on matrix this point on) set in a matrix of fine lap­ xenoliths of quartz porphyry or angular lapilli. Those ash-sized matrix particles illi and ash. The clasts, determined from fragments of chert that underlie the which are visible without a microscope thin-section analysis to be pumice, Tamarack tuff. The weathered appear­ have subequant blocky and ovoid shapes. weather to light gray-green, cream, or ance of these siliceous xenoliths is simi­ Overall, the appearance of the matrix is gray-white·smooth surfaces. In contrast, lar to true clasts but usually the xenoliths reminiscent of shredded paper clippings the weathered rusty-red matrix is have discrete edges and are more and confetti. mottled with dark red, shallow, irregular rounded. Although in some cases, the The texture of matrix particles is less pits and pale-rimmed, angular raised edge of the xenolithic core cannot be uniform than that of clasts. Lighter col­ patches. readily discerned against matrix ored areas of matrix fragments look simi­ Shapes and Textural lar to clasts, being Characteristics smooth and chert­ of Fragments like, but the dark, reddish patches of The pumice the matrix have a clasts have odd rough, granular shapes, including appearance, com­ ovoid, lensoid, pletely unlike clast spindle-shaped, surfaces. Linea­ amoeboid, ribbon­ tions are visible in like, and irregular larger grains, and sinuous forms. some contain ap­ Most clasts have parent vesicles, ragged outlines filled with chlorite with numerous or quartz. inflections and wispy terminations Distribution and (Photos 1 and 2) . Thickness Less frequently, and unrelated ei­ Based on geo­ ther to size or graphic distribu­ shape, clasts have tion, internal fea­ sharply-defined tures, and chemi­ perimeters. cal composition, the exposures of Photo 1. Outcrop surface of Tamarack tuff at Tamarack Lakes exposures. Lightly The pumiceous colored clasts display a variety of shapes and sizes and are aligned in long dimension. Tamarack tuff be­ nature of the The deposit appears bimodal (large clasts in finer-grained matrix) and lacks multiple tween Sierra clasts is not appar­ layering. The map case in the lower right is 12 inches wide. Photos by authors. Buttes and Lakes ent in outcrop, Basin are thought because the visible to represent a textural features are not characteristic of (Photo 2), making it difficult to recognize single depositional unit. Most gaps in pumice. Most clasts are uniformly apha­ the fragment as foreign . outcrop can be attributed to Pleistocene nitic and chert-like due to post-deposi­ glacial erosion or cover. However, a 4 tional silicification. Clasts are more resis­ Xenoliths are usually less than 1 0 km (2 1/ 2 mi.) hiatus exists west of Up­ tant than the matrix and stand out in em (5 in .) in average diameter and gen­ per Salmon and Gold Lakes (Figure 2), relief on outcrop surfaces, rather than erally decrease in size and abundance where the projected stratigraphic posi­ weathering to cavities, as expected for upward through the lowermost 10 tion of the tuff is occupied mostly by pumice. Many clasts bear lineations (due meters (33 feet) of tuff. Xenoliths are heterolithologic tuff-breccia and tur­ either to flow lamination or to collapse rare higher in the unit. In places, xeno­ bidites . The tuff-breccia contains large under compression) which appear in the liths occur only in the basal few inches. blocks of Tamarack tuff and probably field to be fine stratification rather than The resulting mixed zone identifies the records erosion of the original deposit by pumiceous texture. Some clasts have approximate base of the unit when the later submarine debris flows. Therefore, hollow cores with a few ghost-like, contact itself is unexposed. we think the original distribution of the spherical vesicles up to 2 mm in diam­ tuff was continuous for the entire 11 km eter. All vesicles are filled with quartz Shapes of smaller lapilli in the matrix (7 mi.) of present exposure. and/or chlorite, but those that are large (Photo 2) include a variety of subequant enough to identify with a hand lens are polygons, triangles, ovoids, and ribbon­ The thickness of the Tamarack tuff too sparse to indicate pumiceous tex­ like forms. Rarely, the larger matrix frag­ has been estimated from the outcrop ture. The vesicularity of these rocks is ments have sinuous shapes like those of map because no section could be mea­ mostly visible on the microscopic scale. some clasts. Ragged edges similar to sured in the field. The outcrop at Tama-

132 CALIFORNIA GEOLOGY JUNE 1991 rack Lakes is more than 100 meters Even though the tuff is a submarine blocks are found in the southern out­ (325 feet) thick. The Deer Lake outcrop, deposit, its contact with adjacent rocks is crops. The distribution of sizes in clasts 3 km (2 mi.) north, has a present thick­ not depositional everywhere. Quartz indicates the tuff is polymodal, rather ness of at least 150 meters (485 feet). porphyry apparently was intruded along than bimodal. The tuff appears to pinch out 10 km (6 the lower contact in places. Also, it is mi.) north of Tamarack Lakes, near possible that some overlying rocks were The whitish pumice clasts are fou nd Long Lake. Due to compaction and sub­ intruded after deposition of the tuff and throughout the section in varying abun­ sequent erosion, the present thickness is other units. Fragments of tuff, that could dance, making up from a few percent to probably less than the original thickness. have been incorporated either by intru- 80 percent of the rock by volume. Over- all , concentration of clasts approxi­ Features typical mates 20 percent. of the Tamarack Pumice clasts are tuff are best seen inversely graded, in two areas. The and increase in Tamarack Lakes number upward locality has mag­ (Photo 3), except nificent displays of at the northern­ clasts and matrix most exposures, features, upper where clasts are and lower contacts evenly distributed. of the unit, inter­ Xenoliths, con­ nal stratification, versely, are nor­ and primary orien­ mally graded and tation of clasts. found mostly near The Deer Lake the base of the area contains rep­ deposit. resentative ex­ amples of sorting, The average size ranges and size, variation in shapes of clasts, size, and concentra­ and provides a tion of clasts de­ vertical section crease along strike through the Photo 2. A close-up view of the Tamarack tuff weathered surface. Wispy ends and from south to deposit. hazy edges of the clasts with irregular shapes are typical of the deposit. Many of the north. The matrix contrasting darker matrix fragments of various shapes are flow aligned. The "clast" in fragments also de­ Contact the upper left is a quartz-porphyry xenolith which has a concentric halo of matrix Relationships fragments. Photo width is 10 inches. crease in grain size and become better The lower con- sorted from south tact, exposed at the north and south end sion or by erosion, were found in the to north. The matrix appears to be sorted of the Deer Lake outcrop, west of Long quartz porphyry and felsic lava which compositionally; the ratio of pumice Lake, and at several places north of and overlie the tuff. grains to vitric granules increases in the east of Tamarack Lakes, is sharply de­ matrix from south to north and upward fined. Underlying rocks include massive Size Distribution, Stratification, and in the deposit. The matrix at the north­ and brecciated quartz porphyry, chert, Alignment of Clasts ernmost outcrop consists almost entirely and pillowed and massive flows of The tuff appears superficially to be of bits of pumice. andesitic lava. Chert and quartz por­ bimodal. We attempted to confirm the phyry xenoliths occur in the tuff near the grain-size distribution by determining the Except for two places, the Tamarack lower contact. Lava-flow xenoliths were average dimensions of fragments. Be­ tuff is a single, thick bed. At Tamarack not found , but the lava and tuff are simi­ cause the finest material is recrystallized, Lake, for about 40 meters (130 feet) of lar in appearance and lava fragments individual matrix particles cannot be dis­ lateral extent, the tuff deposit consists of may have been overlooked. criminated completely. Those fragments a 75-meter (240-feet) thick inversely­ The upper contact is not so well ex­ which are visible show that the matrix graded bed overlain by a second 2-meter posed as the lower, but is sharp where consists of all sizes of dust, ash, and lap­ (7-feet) thick inversely-graded layer. Else­ visible east of Tamarack Lake, southwest illi to 3 em (1+ in. ). The pumice clasts where at the Tamarack Lake outcrop, of Deer Lake, and west of Long Lake. can be measured accurately and mostly the bed is overlain along 50 meters (165 Overlying rocks include silicic (dacite?) range from 3 to 40 em (1+ to 16 in.) in feet) of its upper contact by a fine­ lava , quartz porphyry breccia, other average diameter. A few individual clasts grained, clast-free layer averaging 25 em pyroclastic flow deposits, and chert. to 2 meters (6.6 feet) and zones with (10 in .) thick. This thin fine-grained layer abundant large (>50 em or 20 in.) appears to be recrystallized vitric ash

CALIFORNIA GEOLOGY JUNE 1991 133 which may or may not be related to the The rocks have been devitrified and smaller than 0.01 mm cannot be identi­ tuff. The absence of a second layer in metamorphosed to prehnite-pumpel­ fied reliably within the metamorphic other areas is puzzling; it could have lyite or low greenschist facies mineral fabric. been removed by erosion, or the assemblages. The present rock is a very second layer may have been only locally fine-grained (less than 0.01 mm diam­ The matrix originally consisted prima­ deposited. eter), foliated aggregate of albite, quartz, rily of pumice fragments, grains of non­ chlorite, epidote, calcite, sphene, pyrite, vesicular glass, and interstitial glassy dust Alignment of long axes of both clasts and sericite, prehnite and pumpellyite, (now chlorite). Pumice, which makes up and matrix grains, which appears to be and actinolite (in approximate order of a few percent to nearly all of the matrix, primary orienta­ is identical to clast tion, has been pre­ pumice. Glass served in some grains are sagittate areas. Sinuous, or cuneiform splin­ elongate, and large ters and angular, ovoid clasts are equant granules. aligned with the Cuspate or Y­ bedding plane at shaped glass the Tamarack shards, typically Lakes locality found in subaerial (Photos 1 and 3). vitroclastic de­ Alignment of adja­ posits, were seen cent matrix frag­ in only two thin ments suggests sections. The rarity that the clasts of these classic were oriented by shapes is probably laminar flow. Sev­ due to the lack of eral other outcrop large vesicles surfaces show whose broken alignment of long walls would pro­ axes of matrix par­ duce the shards. ticles, which is considered the Sparse perlitic result of turbulent Photo 3. A ridge formed by the resistant Tamarack tuff. This outcrop shows flow cracks occur both flow because align­ alignment of large clasts and inverse grading. The tree is about 3 meters (1 0 feet) high. within individual ment is neither clasts or matrix parallel to bedding grains and con­ nor to metamor- tinue across grains. phic foliation . abundance). Pervasive foliation is present Other devitrification features, including locally. Despite recrystallization and ori­ axiolitic structures, spherulites, and PETROGRAPHIC FEATURES entation of metamorphic minerals, relict "snowflake texture," (an intergrowth of Petrographic studies were conducted primary features are readily discernible. quartz and feldspar which develops in by the senior author on 96 thin sections devitrified collapsed pumice) (Anderson , cut from 76 samples of tuff. Microscopic Primary Textures 1969), are present, but rare. study of the rocks was critical to deter­ Originally, the Tamarack tuff was Several kinds of nonmetamorphic mine the abundance of glass, pumice, predominantly glassy and highly vesicu­ deformation were identified. Collapsed and the paucity of lithic components in lar, with little crystallization. Both matrix pumice occurs in several samples, indi­ the Tamarack tuff. In outcrop, pumice and clasts generally have less than 1 per­ cated by streakiness in the mosaic and by clasts cannot easily be distinguished from cent microphenocrysts of quartz, plagio­ snowflake texture. Some pumice vesicles chert fragments or small lava pillows clase, and magnetite, and less than 1 are flattened parallel to adjacent grain present in adjacent breccia deposits, ex­ percent of the tuff is made up of lithic boundaries. Recurved and flattened glass cept where phosphate nodules are fragments. shards and granules molded against present in the chert or where chilled other grains are present in two samples margins are found on the pillows. Other­ The conspicuous lightly colored taken from near the base of the deposit. wise, thin sections are necessary to see clasts consist of pumice containing sphe­ the mosaic of quartz in the chert, the roidal vesicles less than 0 .1 mm in diam­ Primary Minerals lesser abundance of vesicles, and greater eter (Photo 4) . Vesicles make up at least abundance and size of plagioclase 50 percent of the pumice clasts, but this Sparsely scattered microcrystals in microlites. Microlites are found in pil­ figure probably represents the lower limit the Tamarack tuff consist of whole and low lava fragments and are distinguished of vesicularity. Vesicles now are filled broken e uhedral bipyramidal quartz from pumice clasts. with quartz and/or chlorite and those phenocrysts and plagioclase microlites.

134 CALIFORNIA GEOLOGY JUNE 1991 Quartz commonly is embayed or frac­ Fisher and Schmincke, 1984). These in­ Combinations of laminar and turbu­ tured. Most quartz crystals are less than clude andesitic composition, vitroclastic lent flow are typical in pyroclastic flows 0.5 mm across but range in size to 2.0 textures, an abundance of pumice, in­ (Sparks, 1976; Fisher, 1983). Clasts mm and are visible in outcrop. Plagio­ verse grading of pumice blocks, normal locally are aligned by laminar flow at clase microlites are generally between grading of lithic fragments, conformity Tamarack Lakes. Elsewhere at that out­ 0.01-0.05 mm in length, but range to with adjacent bedded units, large areal crop and at Deer Lake outcrop, random 1.5 mm, with the notched terminations extent, poor sorting, polymodal grain-size orientations of elongated clasts and flow and hollow centers that are common in distribution, and stratification which com­ lineations record the turbulence which quenched crystals. Quartz and plagio­ prises a single very thick bed with or with­ would be expected by rapid ejection and clase are subequally distributed in the out an overlying, much thinner layer. deposition of a mass flow of exploded rock. tephra. The ir­ regular lower con­ CHEMICAL tact at Tamarack COMPOSITION Lakes and the size Compositions and number of of 4 7 whole-rock xenoliths suggest samples, compris­ turbulent corrosion ing 13 matrix and of the underlying quartz porphyry. clast pairs (col­ lected from the Turbulence in the same outcrop), 14 flow is the prob­ clasts, and seven able cause of cha­ matrix samples, otic incorporation were determined of chert into the by x-ray fluores­ base of the tuff at cence analysis Long Lake and is (Legler, 1983; a likely contributor Legler and Brooks, to the geometry of 1983; Brooks and clasts (see below). Turbulence also Legler, 1989). occurs during sub­ Si02 ranged from 50.5 percent to aqueous sediment 6 7.1 percent and flows , but the re­ sulting deposits averaged 59.8 Photo 4. Photomicrograph, plane polarized light, showing the lower limit of vesicularity usually have fining­ percent in matrix (about 50 percent) of the pumice fragments. Vesicles average less than 0.1 mm in upward patterns samples which are diameter, are filled mostly with quartz with lesser chlorite and are deformed by considered the metamorphic foliation. The horizontal field of view is 2.5 mm (0.1 in.). that are lacking in least altered. Silica the tuff. in clasts ranged from 65.1 percent The adjacent to 84.9 percent and averaged 71.8 per­ Several lines of evidence infer that pillow lavas and little-disrupted chert cent. The difference in silica content be­ the Tamarack tuff originated from a lenses, which conformably underlie and tween clasts and matrix is attributed to single explosive eruption in a submarine overlie the tuff in places, attest to sub­ silica infilling of abundant vesicles in the environment. The great variety of shapes marine deposition of the tuff. Further­ clasts and does not necessarily indicate of fragments with irregular boundaries more, small size of vesicles in pumice original differences in rock chemistry. and many inflection points indicates brec­ and near-absence of broken-bubble glass Analytical results indicate an andesitic ciation by explosion, rather than by hy­ shards, such as in the tuff, are character­ composition for the Tamarack tuff. dro-quenching or other means (Walker istics attributed to suppression of vesicle and Croasdale, 1972; Honnorez and development under high hydrostatic DISCUSSION Kirst, 1976). Also , the sparsity of larger pressures (Heiken, 1974). Origin by Submarine Pyroclastic Flow microlites or microphenocrysts in the tuff and the presence of quench crystals are The absence of multiple layers within The Tamarack tuff displays a number consistent with rapid cooling during ex­ the deposit suggests that a single epi­ of characteristics which have been de­ plosion. These features are evidence that sode of eruption and deposition oc­ scribed for both subaerial and subaque­ the tuff did not develop as a hydrobrec­ curred. The two-layer sequence found at ous pyroclastic flow deposits erupted ciated lava flow , such as the adjacent Tamarack Lakes is similar to descrip­ and deposited under various conditions andesitic isolated-pillow breccia that has tions of other single eruptions, and sub­ (Ross and Smith, 1961; Francis and abundant, large microlites. marine pyroclastic flow deposits (Fiske Howells, 1973; Sparks and others, and Matsuda, 1964; Niem, 1977). Fur­ 1973; Sparks, 1976; Sheridan, 1979; thermore, the lack of turbidite sequences

CALIFORNIA GEOLOGY JUNE 1991 135 in the tuff implies that the erupted mate­ during eruption and transport of the sively and moved by turbulent and lami­ rial moved not as a water-fluidized cur­ flow. Pumice often has a lower viscosity nar flow for at least 11 km (6.6 mi.) , rent, but as a gas/grain mass flow and greater plasticity than associated producing a deposit over 100 meters wherein the gas pressures excluded sig­ non-vesicular material because of the (325 feet) thick. This mass flow appears nificant invasion and disintegration by high gas concentrations in the pumice to have originated at a vent near what is water. The abundance of delicately an­ (Ross and Smith, 1961). Ross and Smith now the southern end of the deposit. gular and irregular shapes throughout state that viscosity also derives from the deposit indicates that abrasion was composition and temperature of the Pale, weathered, chert-like clasts, not extensive during transport, nor is it glass, but even slight variations in gas which give the Tamarack tuff its distinc­ likely that the material was reworked content can lead to rapid changes in vis­ tive outcrop appearance, are pumice after deposition. cosity. When pumice collapses under blocks and lapilli. Extremely fine vesicu­ pressure, some of the trapped gases larity, contorted shapes resulting from Volume of the Deposit may go back into solution, which de­ plastic deformation during eruption, creases viscosity and increases plasticity transport, and deposition, and subse­ The volume of the Tamarack tuff is of the glass. quent silicification have disguised the na­ within the range for other known pyro­ ture of the peculiar pumice fragments. clastic flow deposits (Fisher and In a pyroclastic eruption, the blobs of Schmincke, 1984). The thickness now glass which separate from the erupting Sparse evidence suggests that weld­ averages about 100 meters (328 feet), mass would mold and distort during ex­ ing may have occurred at the base of the which is less than the original. Assuming trusion. Deformation could continue un­ deposit and possibly stratigraphically that the gap in outcrop west of Salmon til cooling and loss of gases froze the higher in those portions of the deposit Lakes is the result of later disruption, the blob to a rigid, pumiceous glass. If some near the vent. Evidence for welding is tuff extended for at least 11 km (7 mi.) re-solution occurred during impacts of inconclusive and still under investigation, in one direction. Present orientation in­ tumbling in the turbulent mass, the pe­ but includes some petrographic features hibits assessing the width of the deposit, riod of plastic behavior would be ex­ associated with subaerially deposited but the broad Deer Lake outcrop pro­ tended. Many of the contorted clasts welded tuffs. Weak welding would ac­ vides a lower limit of 650 meters (2 , 130 probably formed during turbulent extru­ count for the initial preservation of the feet) of width. The present exposures, sion and shortly thereafter. Tamarack tuff. therefore, reveal a minimum of 0.7 km3 (0.2 mi. 3) of material in the deposit. Clast shapes suggest that fragments Although explosive submarine erup­ Since many pyroclastic flow deposits in the tuff remained plastic and were tions should be common in oceanic vol­ have equidimensional areal extent (Ross molded additionally during transport and canic arcs, few submarine pyroclastic and Smith, 1961; Sheridan, 1979), it is deposition. Flattened vesicles, collapsed flow deposits have been described. Such more reasonable to assume that the pumice, and vesicles deformed against deposits are often disrupted by currents width was equal to the length, in which adjacent fragments could develop only or subsequent eruptions soon after depo­ case the volume would approximate 12 while the glass was plastic and these oc­ sition. Older deposits which survive this km3 (2.9 mi.3). cur at considerable distances from the vigorous submarine activity may become inferred vent. Delicate protrusions and altered beyond recognition during subse­ Possible Vent Location feathery edges are found on fragments quent tectonic events or destroyed by Thickness and distribution of the de­ several miles from the implied vent and erosion. Similar modern deposits can be posit, along with sorting and rounding of probably did not form only during erup­ studied only by dredge samples and drill the fragments, suggest a south-to-north tion. It seems unlikely these features cores which give an incomplete picture direction of transport of the Tamarack would have survived abrasion during of their extent and fabric. The opportu­ tuff from a vent site south of Tamarack transport over that distance. These frag­ nity to study the Tamarack tuff subma­ Lakes. A plug south and west of Tama­ ile features must have formed during rine pyroclastic flow deposit is as unique rack Lakes (Figure 2) , consisting of rocks transport by tearing of still-plastic blobs as its outcrop appearance. The docu­ similar in composition to the tuff and to or after deposition from compression of mentation of significant criteria for iden­ the underlying andesitic pillow breccias, the plastic mass. tifying the tuff may aid in the recognition is speculated to be the eruptive center. of other such ancient deposits. However, talus and glacial debris unfor­ SUMMARY OF FINDINGS tunately mask any confirming field evi­ AND THEIR SIGNIFICANCE ACKNOWLEDGMENTS dence. The Tamarack tuff is a devitrified and D. Harwood and S. Silva, both with recrystallized andesitic tephra deposit Origin of Unusual Clast Geometry the United States Geologic Survey in with textural and structural features typi­ Menlo Park, reviewed this paper and The unusual shapes of clasts are cal of pyroclastic flow deposits. Petro­ offered suggestions for additional investi­ thought to result from two factors: great graphic and field evidence indicates sub­ gations on the tuff. Field work was sup­ plasticity of the pumice (indicated by marine eruption and deposition. Tex­ ported by a grant from the Geological elongation of vesicles and alignment of tures, fragment morphology, stratifica­ Society of America. plagioclase microlites) and turbulence tion, and orientation of components show that the tuff was ejected explo-

136 CALIFORNIA GEOLOGY JUNE 1991 REFERENCES Anderson, T.V. , Woodard, G.D., Strathouse , Francis, E.H., an d Howells, M.F., 1973, fornia, in Bailey, E. H., editor, Geology of M., and Twichell, M.K., 1974, Geology of Transg ressive welded ash-flow tuffs northern California: California Division of a Late Devonian fossil locality in the Si­ among the Ordovician sediments of NE Mines and Geology Bulletin 190, p. 173- erra Buttes Formation, Dugan Pond, Si ­ Snowdonia, N. Wales : Journal of the 184. erra City quadrangle, California: Geologi­ Geological Society, v. 129, p. 621 -641 . Niem , A.A ., 1977, Mississippian pyroclastic cal Society of America Abstracts with Hannah, J.L., and Verosub, K.C. , 1980, Tec­ flow and ash fall deposits in the deep ma­ Programs, v. 6, p. 139. tonic impl ication s of remagnetized upper rine Ouachita flysch basin, Oklahoma and Anderson, J.E. , Jr. , 1969, Development of Paleozoic strata of the northern Sierra Arkansas: Geological Society of America snowflake texture in welded tuff, Davis Nevada, California: Geology, v. 8, p. 520- Bulletin, v. 88 , p. 49-61 . Mountains, Texas: Geological Society of 524. Ross, C.S. , and Smith, R.L., 1961 , Ash flow Am erica Bulletin, v. 80, p. 2075-2080. Hanson, A.A., and Schweickert, A.A., 1986, tuffs: their origin, geologic relations, and Brooks, E.R., and Coles, D.G., 1980, Use of Stratigraphy of mid-Paleozoic island-arc identification: U.S. Geological Survey Pro­ immobile trace elements to determine rocks in part of the northern Sierra Ne­ fessional Paper 366, 54 p. original tectonic setting of eruption of vada, Sierra and Nevada counties, Cali­ Schweickert, A.A. , 1981 , Tectonic evolution metabasalts, northern Sierra Nevada, fornia: Geological Society of America of the Sierra Nevada range, in Ernst, California: Geological Society of America Bulletin , v. 97 , p. 986-998. W.G. , editor, The geotectonic evolution of Bul letin, pt. 1, v. 91 , p. 665-671 . Heiken, G., 1974, An atlas of volcanic ash: California: Prentice Hall, Incorporated, p. Brooks, E.R., and Legler, J.L., 1989, An un­ Smithsonian Contributions to Earth Sci­ 87-131. usual Devonian subaqueous pyroclastic­ ences, no . 12, 101 p. Sheridan, M.F., 1979, Emplacement of pyro­ flow deposit in the northern Sierra Ne­ Honnorez, J., and Kirst, P., 1976, Subma­ clastic flows : a review: Geological Society vada, Sierra County California: Geologi­ rine basaltic volcanism : Morphological of America Special Paper 180, p. 125-136. cal Society of America Abstracts with parameters for di scriminating Programs, v. 21 , no. 5, p. 59 . Sparks, R.S.J., 1976, Grain size variations in hyaloclastites from hyalotuffs: Bulletin ignimbrites and implications for the trans­ Diller, J.S., 1892, Geology of the Taylorsville Volcanologique, v. 39, no . 3, p. 441-465. port of pyroclastic flows : Sedimentology, v. region of California: Geological Society of Legler, J.L. , 1983, A su bmarine pyroclastic 23, p. 147-188. America Bulletin, v. 3, p. 359-364. flow deposit in the Sierra Buttes Forma­ Sparks, R.S.J., Self, S., and Walker, G.P.L., Fiske, R.S., and Matsuda, T., 1964, Subma­ tion, northern Sierra Nevada, California: 1973, Products of ignimbrite eruptions: rine equivalents of ash flows in the M.S. thesis, California State University, Geology, v. 1, p. 115-118. Towika Formation, Japan: American Hayward, 149 p. Journal of Science, v. 262, p. 76-106. Turner, H.W., 1895, The age and succession Legler, J.L. , and Brooks, E.R., 1983, A sub­ of the igneous rocks of the Sierra Nevada, Fi sher, R.V. , 1983, Flow transformations in marine pyroclastic flow in the Devonian California: Journal of Geology, v. 3, p. sediment gravity flows: Geology, v. 11 , p. Sierra Buttes Formation, Sierra and 385-414. 273-274. Plumas counties, California: Geological Walker, G.P.L., and Croasdale, R., 1972, Fi sher, R.V., and Schmincke , H.U., 1984, Society of America Abstracts with Pro­ grams, v. 15, no . 5, p. 330. Characteristics of some basaltic Pyroclastic rocks: Berlin, Germany, pyroclastics: Bulletin Volcanologique, Springer-Verlag, 473 p. McMath, V.E., 1966, Geology of the Taylors­ v. 35 , p. 303-317. ville area, northern Sierra Nevada, Cali-

Glossary axiolitic: A rock texture in which needle-like crystals radiate mafic: Dark-colored iron and magnesium bearing minerals from a central axis rather than from a point. or a rock composed primarily of these minerals. bimodal: A grain or fragment size distribution having two microlite: Minute crystals, usually of tabular or prismatic sizes occurring with greatest frequency. shape. euhedral: A mineral grain completely bounded by its own prehnite-pumpeUyite facies: Similar to greenschist facies regularly developed crystal faces. but containing the minerals prehnite and pumpellyite. felsic: A term applied to igneous rocks containing abundant tephra: A general term for all fragmental volcanic material light-colored minerals primarily quartz and feldspar. ejected during an eruption and transported through the air. greenschist facies: Metamorphic mineral assemblage turbidite: A sedimentary rock deposited from a sediment­ represented by albite + epidote + chlorite + actinolite and laden current and characterized by graded-bedding, characteristic of low-grade regional metamorphism. moderate sorting and well-developed layering in a fixed heterolithologic: Clastic rocks containing fragments of sequence. different rock types. vitric: Pyroclastic material containing more than hydrobrecciated: Broken into fragments by contact with 75 percent glass particles. water. vitroclastic: A pyroclastic rock structure characterized by inversely graded: A sedimentary structure in which grain fragmented bits of glass. or fragment size increases upwards within a bed. volcanic island arc: A generally curved linear belt of lapiUi: Volcanic fragments that range in size from volcanic islands located above a subduction zone. 2 to 64 mm. xenolith: A foreign inclusion in an igneous rock. X'

CALIFORNIA GEOLOGY JUNE 1991 137 A Page For Teachers

Help Your Students Get Excited About Earth Science

Help for planning activities is Earth Science Research Activi­ necticut Avenue, NW, Washington, DC difficult to find, say many science ties, by James Scannell. Published in 20009, (202) 328-5800: $16.50 plus teachers and volunteers. This source 1988, this book is one of four in the $2.50 postage/handling. list was compiled to help you stimulate series, Explorations in Science. It interest in your earth science students. contains 50 ready-to-use individual and How to Construct a Paper Model group enrichment activities for grades 8- Showing the Motion That Occurred Earth Science Investigations, 12. Each has been tested and includes a on the San Andreas Fault During edited by Margaret A. Oosterman and teacher's guide and answer key. Order the Lorna Prieta, California, Mark T. Schmidt. The American from Alpha Publishing Company, 1910 Earthquake of October 17, 1989, Geological Institute (AGI) published this Hidden Point Road, Annapolis, MD is available from the U.S. Geological collection of activities for grades 8-12 in 21401, (301) 757-5404: spiral-bound Survey, Books and Open-File Reports fall 1990. The 26 activities were book, 273 pages, $35 plus $3.50 Section, Box 25425, Denver, CA developed by teachers, reviewed by postage/handling. 80225, (303) 236-7476: USGS Open­ scientists and tested with students. Each File Report 89-640A, $1.50 for paper hands-on exercise provides the con­ Resources for Earth Science copy, $4.50 for microfiche. cepts, vocabulary, and worksheets, plus Teachers 1991 lists 43 sources of an answer key when applicable. Order earth science reference and enrichment Oceanography for Landlocked from AGI , 4220 King Street, Alexan­ materials including catalogs, publications Classrooms, for teachers of grades 7- dria, VA 22302, (703) 379-2480: lists , teacher packets, books, and 12, contains easy-to-follow lessons and spiral-bound book, 231 pages, $34.95 journals. To get a copy, contact the activities written by marine educators plus $4 postage/handling. American Geological Institute (AGI), from high schools and universities. National Center for Earth Science Order from National Association of Inside Hawaiian Volcanoes, a 25 Education, 4220 King Street, Alexan­ Biology Teachers, 11250 Roger Bacon minute color video, illustrates techniques dria, VA 22302 (703) 379-2480. Drive #19, Reston, VA 22090, (703) for monitoring Hawaiian volcanoes. The 471-1134: $15 plus $2 postage/ video, aimed at audiences of all ages, Earthquakes: A Teacher's handling. includes spectacular eruption footage. Package for K-6, a six-unit book, was Subsurface features are depicted by developed by the National Science Water in Your Hands, an imagina­ cutaway views, models, and computer Teachers Association (NST A) with a tive 16-page booklet, uses cartoon graphics. Noted volcano cinematogra­ grant from the Federal Emergency characters to help children (grades 4-6) pher Maurice Kraft produced the video Management Agency (FEMA). It is a develop awareness of water quality and in collaboration with the U.S. Geological complete earthquake curriculum management problems. The instructor's Survey and the Smithsonian Institution. containing activities, lesson plans, line guide includes activity masters, back­ Orders must include check or money masters, and background information. ground information, implementation order made out to Smithsonian Institu­ Order from FEMA, Earthquake Pro­ suggestions, optional activities, and tion. Send to Richard S. Fiske, Natural gram, Marilyn MacCabe, 500 C Street, sources of additional information . Order History Building 119, Smithsonian SW, Washington, DC 20472: one free from Soil and Water Conservation Institution, Washington, DC 20560, copy to schools (while supplies last). Society, 7515 N.E. Ankeny Road, (202) 357-1384: videotape, VHS Order additional copies from NST A Ankeny, lA 50021-0764, (515) 289- format $20.00, PAL format $25.00. (address below): $15 plus $2.50 2331 or (800) THE-SOIL single copies postage/handling. $2, discounts on bulk orders. The teacher's guide for Inside Hawaiian Volcanoes contains Earth: The Water Planet, a book Reprinted with permission from questions and lab exercises. Order from of readings and activities for middle­ Blueline (v. 24, no. 1, spring 1991), the U.S. Geological Survey (address grade teachers, resulted from a joint newsletter of the Association of Earth above): USGS Open File Report 89- project of Horizon Research, Inc. , and Science Editors. X 685, $3.50 for paper copy, $4.00 for AGI. Order from NSTA, 1742 Con- microfiche.

138 CALIFORNIA GEOLOGY JUNE 1991 DMG Releases

SPECIAL PUBLICATION 107 MINERAL COMMODITY REPORT­ Fu ller's earth is not produced in Califor­ include fil tering agents for beer and Bentonite and Fuller's Earth. By Michael nia at this time. The most productive wine, ingredients in cosmetics, medi­ A. Silva and Daniel T. Eyde. 1990. bentonite deposits in California are in cines, paints, inks and adhesives , and 37 p. $5.00 San Benito, lnyo, and San Bernardino additions to ceramic and tile mixes to counties. increase flow. Mineral commodity reports describe the availability and demand for industrial Bentonite is used for a variety of In 1988, according to the U.S. minerals in California, the United States, commercial applications in many Bureau of Mines, California produced and the world. Part I consists of United industries. Sodium bentonite is used in 2,200,000 tons of clay worth over States and worldwide mineral statistical well drilling operations; it functions as a $31,000,000. Bentonite production information and analysis adopted directly sealant, conditions the drill hole and was reported at 137,000 tons worth from the U.S. Bureau of Mines "Mineral holds the drill hole open, and aids in $10,000,000 (this production accounts Commodity Summaries." Part II bringing up drill-hole cuttings. Bentonite for 6 percent of clay by volume, yet discusses the geology and production is also used as a impermeable li ner for almost one-third of the value of the clay and marketing of industrial minerals in landfills and waste water ponds, and as a produced in California during 1988). California. binder for foundry molds and iron ore The majority of bentonite mined was pellets. Calcium bentonite is used as an non-swelling and is used mainly for pet Special Publication 107 describes adsorbent for removing impurities from adsorbents, oil and grease adsorbents, significant occurrences of bentonite and mineral and vegetable oils. Calcium and animal feed additives. Most of the fuller 's earth in California by county. and sodium bentonites also absorb pet swelling bentonite is used for paint, inks , Bentonite is any clay that is composed wastes (cat li tter) and are used for cosmetics, and other similar high value­ dominantly of a smectite clay mineral. removing grease and oils from fl oors added materials. In turn, smectite is a class or group of and driveways. Bentonite is heated Although bentonite reserves are large clay mi nerals, formerly called the mont­ and expanded to produce lightweight and the United States is self-sufficient in morillonite group, that posses swelling aggregate that is commonly used in this commodity, environmental issues, properties and high cation-exchange skyscrapers. Both types are added to conflicting land use, and competition for capacities. Smectite clay minerals animal feed for trace element retention public lands have adversely affected include montmorillonite, hectorite, and are used to carry pesticides. saponite, and nontronite. Fuller's earth mining costs. These increased costs have is a bentonite that has absorbing, Specially treated bentonite or made imported materials, especially from decolorizing, and purifying properties. chemically unique bentonite is used Mexico, more attractive in some market for specialty products. Specialty uses areas)<:

Th e Newberry hectorite mine operated by Rheox, Incorporated (formerly N.L. Indus­ tries). Hectorite is a colloidal, gel-forming type of bentonite clay used for pharmaceuti­ cals, cosmetics, and clarification of wine. Note the characteristi ­ cally intense white color of hectorite. Photo by John Clinkenbeard.

CA LIFOR NIA GEOLOGY JU NE 1991 139 DMG Releases (continued)

OFR 91-07

OFR 91-07 PRINCIPAL FACTS AND SOURCES FOR 1528 Make check or money order payable to the LAND GRAVITY STATIONS ON THE SAN FRANCISCO 1' BY Division of Mines and Geology. 2' QUADRANGLE, CALIFORNIA. By Rodger Chapman.

Gravity data are frequently used in studies of local and regional Geologic Information geology. For example, these data can be used to investigate and Publications Office geologic structures such as subsurface folds , fau lts, and possible 660 Bercut Drive sources of groundwater or mineral resources. Many multi-purpose Sacramento, CA 95814-0131 geologic studies that include gravity measurements have been (916) 445-5716 made in the San Francisco area. These earlier data were used to (Reference copies, over-the-counter sales, produce maps of the area showing contoured gravity values. pre-paid mail orders) Additional work has either been done or is currently underway in the area. These new data will be combined with the older data to San Francisco Bay Regional Office make new, more detailed maps of the area. OFR 91-07 com­ 380 Civic Drive , Suite 100 bines and documents the older data to provide investigators with Pleasant Hill, CA 94523-1921 the information in a convenient form. It is intended that this (415) 646-5920 report wi ll enable investigators to readily find the sources of data (Reference copies and over-the-counter sales) they need so that they can ascertain data accuracy and usefulness. Southern California Regional Office OFR 91-07 has ten tables of gravity data arranged by sources, 107 South Broadway, Room 1065 information on the reduction processes used, the base stations Los Angeles, CA 90012-4402 used, and the sources of the data. Maps showing the location of (213) 620-3560 most of the gravity stations are included. Copies of OFR 91-07 (Reference copies only}~ may be purchased by check or money order for $8.00.

L Inland Geological Society Call for Papers

The Inland Geological Society invites Abstract deadline: December 1, 1991 technical papers for its newest volume Manuscript deadline: March 1, 1992 entitled "Quaternary Faulting and Related Phenomena in the Inland and Desert Areas of Southern California" to be published in June 1992. This For more information, contact: geographically large and varied region Gary S. Rasmussen consists of most of southern California IGS Publications Committee Chair with the exception of the coastal areas. 1811 Commercenter W. Only high quality, original papers will be San Bernardino, CA 92408 considered. This publication will be (714) 888-2422~ similar to the Society's previous volume entitled "Landslides in a Semi-Arid Environment. " Any topic related to faulting is encouraged.

140 CALIFORNIA GEOLOGY JUNE 1991 Book Reviews Books reviewed in this section are not available for purchase from DMG.

Astronomy THE CELESTIAL PLANISPHERE, Universe as it looked more than 12 figures of mythology and is not due to Poster of the Universe as it appears in billion years ago. The opportunity to be their imagined resemblance; instead, the Northern and Southern hemi­ so easily informed about the immense­ areas of the sky were dedicated in honor spheres. Compiled and designed by ness of the Universe is a tribute to the of mythical figures and the familiar Tomas Filsinger. 1990. Available from: science of astronomy. pictures of these figures were then fitted Celestial Arts, P.O. Box 7327, Berke­ to the patterns of bright stars more than ley, CA 94707. Poster is 24 inches x 36 The constellations, such as the 12 2000 years ago. The patterns of stars inches. A 28-page manual is included. familiar constellations of the Zodiac, are we see today may not necessarily be $14.95 (add $2.25 for postage and imaginary figures superimposed on the what the ancients saw. The designation handling for 1 to 10 posters). patterns of stars we see at night. Many of constellations to specific areas of the constellations were invented thousands night sky helps account for the lack of This planisphere projection of the of years ago. The invention of the obvious resemblance between star Universe during the year 2000 includes constellations probably results from patterns and the mythical figures they a polar projection from the Northern symbolic representations of prominent represent. Hemisphere connected to a polar projection from the Southern Hemi­ sphere. It shows galaxies, galactic ,------clusters, quasars, constellations, plan­ 1 MAIL ORDER etary nebulae, meteor showers, planets Complete address form on next page. I Indicate number Price includes in our solar system (other than Earth), of copies. postage and sales tax . black holes, and stars; pulsars, super­ I • giants, red giants, neutron stars, white I BULLETINS dwarfs, and supernovas. This poster is __ B174 Pumice, pumicite, and volcanic cinders in California. 1956 ...... $4.00 I __ B197 Limestone, dolomite, and shell resources of the Coast Ranges province. 1978 .... $8.00 coated with a phosphorescent paint that I __ B198 Urban geology master plan for California. 1973 ...... $6.00 allows the stars, galaxies, and other __ B199 Basic geology of the Santa Margarita area, San Luis Obispo County. 1976 ...... $9.00 represented bodies in the cosmos to I SPECIAL REPORTS glow in the dark after being illuminated I SR73 Economic geology of the Panamint Butte quadrangle and Modoc district. by a light source; the Milky Way galaxy, lnyo County, California. 1963 ...... $4.00 containing 40 billion stars, is a promi­ SR88 Geology of the Queen of Sheba lead mine, Death Valley, lnyo County, nent feature. The accompanying manual California. 1965 ...... $3.00 SR96 Geologic reconnaissance of the Slate Range, San Bernardino and lnyo counties, includes descriptive information on how California. 1968 ...... $4.00 to understand and interpret the poster. __ SR119 Landsliding in marine terrace terrain , California. 1975 ...... $3.00 Also included are astronomical tables, a __ SR142Geology and slope stability in selected parts of the Geysers geothermal area brief history of celestial astronomy, and (Sonoma County) , California. 1980 ...... $8.00 definitions of astronomical terms such as SPECIAL PUBLICATIONS pulsars and nebulae. SP49 California jade, a collection of reprints. 1976 ...... $4.00 SP57 Proposed earthquake safety programs and activities of the Department of Conservation, fiscal years 1982 through 1986. 1980 ...... $4.00 As we gaze at the celestial bodies in SP69 An annotated bibliography of geothermal information published or authored by the night sky, we see into the past. The staff of the California Division of Mines and Geology. 1984 ...... $4.00 nearest stars to Earth other than the Sun SP81 Mineral commodity report- sodium sulfate. 1985 ...... $3.00 SP83 Mineral commodity report - sodium carbonate. 1985 ...... $3.00 are more than four light-years away. SP84 Mineral commodity report - phosphate rock. 1985 ...... $3.00 Light from the Magellanic Clouds-or SP86 Foothill counties mining handbook. 1985 ...... $6.00 galaxy cluster-can be seen with the __ SP1 07 Mineral commodity report: bentonite and fuller's earth. 1991 . (NEW) ...... $5.00 naked eye in the Southern Hemisphere CALIFORNIA GEOLOGY and takes 150,000 years to reach Earth. __ 1 year (12 issues)...... $10.00 Scientists using the latest technologies __ 2 years (24 issues) ...... $20.00 can hear the echo of the big bang and I Each back issue ...... $1 .25 are seeing the far reaches of the I Specify volume and month ...... I List of Available Publications ...... Free I TOTAL AMOUNT ENCLOSED ...... $__ _ L ______~YMENTMUST~NCLUD~WITHORDE~ ------

CALIFORNIA GEOLOGY JUNE 1991 141 • • • • • more Books

Energy Geochemistry

ALTERNATIVE ENERGY ing systems, power storage and manage­ OXIDE ZONE GEOCHEMISTRY. SOURCEBOOK. 1991. Available from: ment, and conservation and purification By Peter A. Williams. 1990. Available Real Goods Trading Corporation. 966 systems. from: Prentice Hall, Prentice Hall Mazzoni Street, Ukiah, CA 95482. 398 Building, Englewood Cliffs, NJ 07632. p., $14.00, paper cover. This is not only a how-to guide, but a 286 p. $109.95, hard cover. Price does catalogue as well. The 1991 edition not include sales tax, postage, and The 1991 edition of this sourcebook contains over 2,000 environmentally handling. and catalogue focuses on energy conscience, energy-efficient products education and contains a comprehensive such as an electric refrigerator which Oxide zones form by the weathering collection of energy-sensible technolo­ uses one tenth the power of an ordinary of sulfide minerals near the surface of gies. With this book readers can plan refrigerator, and compact fluorescent the Earth. Sulfide minerals in turn form independently powered homes that lights that produce four times the light of from silicate melts or by precipitation maintain their accustomed comfort incandescent li ghting and last twenty from geothermal water from silicate levels. It demystifies solar, wind, and times as long. This catalogue is a blend melts. Oxidized mineral zones are an hydro-electric technologies, deals of renewable energy supply options and important source of metallic ores and practically with energy conservation, illustrates efficient ways to use the have been mined for many centuries. and features complete step-by-step energy. Reviewed by Max Flanery. These metallic oxide zones are the instructions for installing power genera!- primary source of base metals such as copper, lead, and zinc. Other important metallic ore deposits in these zones include tin, iron, and tungsten. Most of ------, the spectacular museum specimens ADDRESS FORM FOR ALL ORDERS come from these oxide zones. Please print or type

PAYMENT MUST BE INCLUDED WITH ORDER This book combines much of the knowledge and recent research about NAME ______the complex geochemistry and mineral­ ADDRESS ______ogy in oxide zones. Oxygen dissolved in groundwater is a powerful oxidizing CITY ______agent, particularly when heated. The oxygen/ water solution reacts with many STATE ______ZIP ______common minerals to produce strong solvents, such as carbonic acid, hydro­ TOTALAMOUNTENC~L~O~S~E~D~: $~=====- chloric acid, and sulfuric acid. Over CALIFORNIA GEOLOGY SUBSCRIPTIONS geologic time, such chemical reactions have produced significant metallic oxide 0 1 yr. $10.00 0 2 yrs. $20.00 (Individu al issues are $1.25 each) zones peripherally to the original sulfide deposits. This book is designed for NEW SUB SCRIPTIO N: Allow 60 days for delivery of fi rst issue. geochemists, mineralogists, environmen­ tal chemists, and researchers in ground­ 0 RENEWAL: To receive your magazine conti nuou sl y, send in renewal 60 days before expiration date shown on your add ress label. (Example: EXP9112 means water or soil contamination by heavy that the subscription expi res on receipt of December 1991 issue.) Please metals. An extensive bibliography is enclose address label from past issue. Without an add ress label , re newal included and is listed by topic at the end subscriptions will take 3 to 4 months to process. of each chapter. CALIFORNIA GEOLOGY renewals on ly: fill in information from your maili ng label or attach a label from a past issue. 1.0. # ______EXPlR. DATE ____ _

0 GIFT: (G ift card from ------Gol d Mining

0 ADDR ESS CHAN GE: Send us an old address label and your new add ress. STAKE YOUR CLAIM! How to Find Allow two issues to reflect address change. Gold and Stake a Mining Claim. By Mark G. Silva. 1990. Available from: Your order/subscription cannot be processed unless correct amount is remitted. All Foreign and Cana­ High-Grade Publications, Box dian orders must be paid with an International Money Order or Draft payable in United States funds to : 995, Division of Mines and Geology. Address all orders to : DIVISION OF MINES AND GEOLOGY, P. 0. Aptos, CA 95001. 105 p. $14.95 Box 2980, Sacramento, California 95812-2980. (California residents add 6 3/ 4% sales · ------~ tax) plus $2.00 shipping, paper cover.

142 CALIFORNIA GEOLOGY JUNE 1991 • • • • • more Books

Over 10 million ounces of gold are at depth and at the surface. Geologists Mother Lode Geology expected to be produced in 1990 from interested in igneous processes also 4 7 states. Mineral exploration and wanted to determine actual causes of the YOSEMITE AND THE MOTHER mining are possible on over 440 million structural features seen in volcanic and LODE GOLD BELT: Geology, Tecton­ acres of public land. Beginning gold plutonic rocks in the field. The working ics, and the Evolution of Hydrothermal hunters will find most of their basic hypothesis is that knowledge of these Fluids in the Sierra Nevada of California. questions answered in this step-by-step structural features can be combined with Edited by Leslie A. Landefeld and guide to locating potential gold deposits mineral, textural, trace element con­ Geoffrey G. Stone. 1990. Available and filing a legal claim to the property. tents, and isotope ratios of specific from: Publications Committee, Pacific The book also includes standard claim elements to yield information about the Section AAPG, P.O. Box 631, Ventura, forms, lists of pertinent State and temperatures and pressures at which CA 93002. 200 p. $21.50 (including Federal agencies, sources of government magma forms, how magma forms, how shipping and handling), paper cover. information and gold prospecting clubs, the magma gets to the surface or is Make check payable to: Publications magazines, videos, and organizations. emplaced at depth, and the nature of the Pacific Section AAPG. conduits from magma chambers to centers of eruption. One of the many The discovery of gold in 1848 forever changed the landscape and history of History reasons the knowledge of magma transport and storage is important to California. Placer mining, hydraulic HISTORIC SPOTS IN CALIFORNIA. geologists is that it leads to an under­ mining, hard rock mining, and dredge Fourth Edition. Revised by Douglas E. standing of the behavior of volcanoes mining served to remove millions of Kyle. 1990. Available from: Stanford and volcanic eruptions. ounces of gold from the Sierra Nevada. University Press, Stanford, CA 94305- The quest for gold has not stopped. 2235. 617 p. $49.50, hard cover; This book is a collection of articles by Mother Lode mining activity has $19.95, paper cover. specialists in the fields of continuum returned after a 30-year hiatus following mechanics, fluid dynamics, computa­ World War II. More than 230,000 This book guides the reader or tional fluid dynamics, heat transfer, ounces of gold have been mined since traveler on a county-by-county tour of experimental high-pressure geophysics, 1985. Today, geologists continue to historical California landmarks. Mileage seismology, seismic tomography, study the structural, stratigraphic, and and specific locations are given. Each volcanology, geodesy, field geology, and chemical processes that formed the county's chapter proceeds in a chrono­ structural geology. These specialists Mother Lode in order to locate additional logical vein, beginning with geography, discuss theoretical approaches to basic gold ore deposits. Additionally, geologic continuing with Indian life , early Spanish geologic questions about magma investigations and mining operations are settlements, and moving on through movement and storage. They then carried out within a framework of local history into the twentieth century. Not compare their theoretical work with government and public concerns as well intended as a history book per se, it actual field evidence to see how well the as State and Federal permitting require­ does highlight historic landmarks and theory explains what is observed in the ments. gives a chronicle of each. Mining field. They also compare their theoreti­ landmarks can be located quickly by cal work with indirect observations. For This field guide is adapted from the consulting the index under "Mines" and example, magma bodies can frequently annual meeting of the American "Mining Camps." Counties impacted by be detected by analyzing; (1) bulging of Association of Petroleum Geologists the late 1800s gold rush receive detailed the Earth's surface, (2) clustering of (held in San Francisco in June 1990) and attention and include buildings and other small earthquakes, (3) attenuation of is organized into two parts. Part 1 landmarks from this era. seismic signals through magma cham­ contains three road logs that sample the bers, and (4) differences in seismic geologic and mining history of the velocity along specific paths around and Mother Lode from Yosemite to Coloma. through magma chambers (a system The road log stops describe the tectonic Igneous Geology known as seismic tomography). and structural forces that formed the MAGMA TRANSPORT AND gold deposits within the Mother Lode. STORAGE. Edited by Michael P. Ryan. While this is an advanced text, the Part 2 contains articles covering the 1990. John Wiley & Sons, Inc., 605 discussions include interesting and geology, mineral land classification, and Third Avenue, New York, NY 10158, productive treatment of some of the mine permitting procedures within the 420 p. , $310.00, hard cover. Earth's most fascinating phenomena. Foothills Metamorphic Belt. Part 2 also The concepts presented in this book includes descriptions of six mines; Pine Over recent decades geologists advance our understanding of many Tree-Josephine, Harvard, Royal­ became increasingly aware of the need parameters controlling magma move­ Mountain King, Carson Hill , Gold Cliff, to understand how magma (molten rock ment and storage. Reviewed by Dale and Lincoln .X: charged with gases) moves and behaves Stickney.

CALIFORNIA GEOLOGY JUNE 1991 143 STATE OF CALI FORNIA SECOND CLASS POSTAGE PAID THE RESOURCES AGENCY AT SACRAMENTO, CALIFORNIA DEPARTMENT OF CONSERVATION CALIFORNIA GEOLOGY DIVISION OF MINES AND GEOLOGY P.O. BOX 2980 SACRAMENTO, CALIFORNIA 95812-2980 USPS 350 840 ADDRESS CORRECTION REQUESTED

MEMORIAL Joseph F. Poland 1908-1991

oseph Fairfield Poland, an internationally recognized J authority of land subsidence, died June 4, 1991 at the age of 83. Poland earned his bachelor's degree in geology from Harvard University in 1929 and his master's degree from Stanford University in 1935. His friends point out that he had one of the longest graduate careers on record. Although he completed his doctoral studies and oral examinations at Stanford in the late 1930s, Poland lacked a written dissertation when he joined the U.S. Geological Survey in 1940. It was not until 1981, when his former co­ workers at the Survey submitted 40 years of research papers and reports, did Poland receive his doctorate from Stanford University.

While at Stanford, Poland became interested in ground­ water. In 1940 he joined the U.S. Geological Survey's Ground Water Branch in Long Beach and later transferred to the Survey's Sacramento office where he directed a research program on land subsidence caused by groundwater withdrawal.

After retiring from the Survey in 197 4, Poland continued working as a groundwater consultant. One of his many accomplishments was the explanation of why Venice, Italy was sinking; he became known to the Italians as the "healer" and "savior" of the city. Over several years of observation, Poland determined that the Santa Clara Va lley was sinking Dr. Poland standing at the approximate point of maximum at an average rate of 4 inches per year due to extensive ground subsidence in the San Joaquin Valley. Subsidence of groundwater pumping. He also made many contributions approximately 30 feet occurred from 1925 to 1977 due to from his investigations of sea water intrusion into coastal aquifer compaction caused by groundwater pumping. Signs aquifers of California, investigations of subsidence in the San indicate the former elevations of the land surface in 1925, Joaquin Valley, and investigations of subsidence in the 1955, and 1977. Photo taken in December 1977. Photo by Wilmington-Long Beach harbor area. X Richard Ireland, courtesy of the U.S. Geological Survey.

144 CALIFORNIA GEOLOGY JUNE 1991