Cherry Hill Deposit

Site Name

Primary: Cherry Hill Deposit
Secondary: Manzanita
Secondary: Empire
Secondary: In Between
Secondary: West End
Secondary: Central
Secondary: Cerise
Secondary: Buckeye
Secondary: Gold Mountain
Secondary: Montezuma
Secondary: Wide Awake

---

Commodity

Primary: Mercury
Primary: Gold
Secondary: Silver
Tertiary: Arsenic
Tertiary: Sulfur
Tertiary: Thallium
Tertiary: Antimony

---

Location

State: California
County: Colusa
District: Sulphur Creek District

---

Land Status

Land ownership: BLM Administrative Area
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.
Administrative Organization: Clear Lake Management Area

---

Holdings

Not available

---

Workings

Not available

---

Ownership

Owner Name: None

Owner Name: Homestake Mining Company

---

Production

Not available

---

Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: Hot Spring
Operation Type: Surface-Underground
Discovery Year: 1863
Years of Production:
Organization:
Significant: Y
Deposit Size: S

---

Physiography

Not available

---

Mineral Deposit Model

Model Name: Hot-spring Au-Ag

---

Orebody

Form: Irregular

---

Structure

Type: L
Description: Abbott-Coyote Peak Fault Zone, Resort Fault, Wilbur Springs Antiform (Structure)

Type: R
Description: Stony Creek Fault

---

Alterations

Alteration Type: L
Alteration Text: Gold mineralization occurred during alternating periods of carbonate-dominant and silica-dominant fluids (Nelson and others, 1993). Fluid-inclusion studies by Pearcy and Petersen (1990) indicated a steady decrease in temperature through the paragenetic sequence from 190 to 100?C. They concluded that the hot-springs currently depositing gold and mercury reflect the waning stages of the hydrothermal system. They resolved twelve stages of vein mineralization and three major wall-rock alteration events as follows (minerals listed are for wall-rock alteration): Stage I: adularization; adularia, sericite, chalcedony, pyrrhotite Stages II-XI: silicic-carbonate; dolomite Stage XII: argillic; smectite-illite, pyrite, marcasite, cinnabar; at least 150-180 meters deep advanced argillic; allophane, gypsum, native sulfur, jarosite Wall-rock alteration in stages I and XII was strong, while alteration in stages II-XI was weak. Gold mineralization occurred during stages V, VI, and IX; cinnabar in Stages VII, XI, and XII; and iron sulfides are found in veinlets in every stage with one exception. In stage XII, pyrite occurs in the wallrock but not in the veinlets. Alteration began at about 0.56 ? 0.14 Ma (K-Ar, adularia), corresponding to Clear Lake volcanism. The mudstone, hardened by adularization and silicification, became dark, chert-like, and brittle. Subsequent deformation resulted in a meshwork of fractures in which gold mineralization occurred.

---

Rocks

Name: Serpentinite
Role: Host
Description: detrital
Age Type: Host Rock
Age Young: Early Cretaceous
Age Old: Late Jurassic

Name: Sandstone
Role: Host
Age Type: Host Rock
Age Young: Early Cretaceous
Age Old: Late Jurassic

Name: Siltstone
Role: Host
Age Type: Host Rock
Age Young: Early Cretaceous
Age Old: Late Jurassic

Name: Mudstone
Role: Host
Age Type: Host Rock
Age Young: Early Cretaceous
Age Old: Late Jurassic

---

Analytical Data

Not available

---

Materials

Ore: Electrum
Ore: Cinnabar
Ore: Miargyrite
Ore: Pyrargyrite
Gangue: Marcasite
Gangue: Pyrite
Gangue: Dolomite
Gangue: Magnesite
Gangue: Adularia
Gangue: Opal
Gangue: Chalcedony
Gangue: Quartz
Gangue: Pyrrhotite

---

Comments

Comment (Geology): Introduction In the northern Coast Ranges, mercury, gold, and silver have been mined since the 1860?s. A few gold deposits are known to be closely associated with mercury mines. The McLaughlin Mine represents the only known large-volume, world-class gold deposit in the Coast Ranges. It and the Cherry Hill deposit, in the Sulphur Creek (Wilbur Springs) District 14 miles to the north, originated in hot-spring environments within the Clear Lake volcanic field. This field is the northernmost and most recent of a NNW-trending chain of Neogene-Holocene volcanic fields that follow and cut across a regional fold and thrust belt better known for petroleum and mercury resources than for gold. The McLaughlin, Cherry Hill, and other hydrothermal systems within the Clear Lake and adjoining Sonoma volcanic fields formed by extensional and compressional tectonics, high heat flow, and intermediate-silicic magmatism (Griscom and others, 1993). The McLaughlin deposit has been well studied. In contrast, the Cherry Hill deposit has received much less attention because of its apparently smaller size and thus less economic interest. Three of the most recent summaries of geologic and geochemical characteristics of the deposit are those by Nelson and others (1993), Pearcy and Petersen (1990), and Peters (1991). Basically, the Cherry Hill deposit formed by deposition within a hot-spring system, remnants of which are still active. Regional Tectonics and Structure The northern Coast Ranges have experienced several deformational episodes (i.e., Mesozoic compression and Neogene-Holocene intermittent dextral translation, transtension and transpression, and volcanism). The resulting complicated structure of the northern Coast Ranges is defined primarily by a broad region of numerous, closely spaced, generally north-northwest-trending faults, folds, ridges, and pull-apart basins (Hearn and others, 1988; Namson and Davis, 1988). A secondary system of short (less than a quarter mile) faults trends east-west (Jennings, 1994). In the Clear Lake region, the NNW-trending structures exceed one mile in length; some represent active components of the San Andreas Fault system. Since the Mesozoic, the development of the northern Coast Ranges has been dominated by the tectonic interaction of three major plates: the North American, Farallon, and Pacific. During this time, the Farallon Plate has been subducting beneath the North American Plate (Thorkelson and Taylor, 1989). Seafloor sediments, exotic terranes, and ophiolites that failed to subduct were accreted to the continental margin. The accreted material formed several packages of north-trending lithotectonic belts. The Coast Ranges are composed of a package of the three westernmost belts. From east to west, they are Great Valley Sequence (forearc basin sedimentary rocks), Coast Range Ophiolite, and Franciscan Complex (thick accretionary prism of sedimentary and volcanic rocks). The Coast Range Ophiolite is an assemblage of serpentinized ultramafic rocks, mafic intrusions, and submarine volcanic rocks. The ophiolite is tectonically dismembered. In some localities, it occurs as a serpentinite-matrix melange (Hopson and others, 1981). In a few areas, large lenses of sedimentary serpentinite, presumably derived from subjacent ophiolite, are interbedded with lower Cretaceous and Miocene sediments. The Franciscan Complex and Great Valley Sequence are coeval and formed on opposite sides of the subduction zone. With time, these marine deposits were progressively compressed and uplifted in a fold and thrust belt. Once uplifted, this over-thickened package may have become gravitationally unstable leading to collapse through extensional faulting (Platt, 1986).

Comment (Deposit): Overall, the deposit consists of a northwest-trending irregular distribution of small veinlets in hydrothermally altered rock, part of which is concealed by alluvium deposited along Sulphur Creek. Classification of this deposit as a hot-spring type is based on the presence of young sinter deposits associated with pervasive silicification and strong near-surface argillic alteration (Pearcy and Petersen, 1990). Other evidence includes mineral textures in the veins indicative of open-space filling. In addition, active hot springs in this area are currently depositing gold and mercury. This activity is considered to be the waning vestiges of a more robust earlier period (0.56 ? 0.14 Ma) of hydrothermal activity when most of the mineralization occurred (Pearcy and Petersen, 1990; Rytuba, 1993).

Comment (Commodity): Commodity Info: Electrum, the primary ore mineral, has a high Hg content. Pearcy and Petersen (1990) measured an average of 5.2 wt. % for 30 samples, with Stage VI electrum carrying up to 15 wt. % Hg. Gangue for the electrum is most commonly quartz and chalcedony, and, to a lesser extent, dolomite. Gold is restricted to veins only; it is not disseminated in the wall rock. Hydrocarbons (bitumen and oil) are present in the veins.

Comment (Commodity): Ore Materials: Electrum, cinnabar, miargyrite, pyargyrite

Comment (Commodity): Gangue Materials: Quartz, chalcedony, opal, adularia, magnesite, dolomite, pyrite, pyrrhotite, marcasite

Comment (Environment): The region is characterized by rugged, narrow valleys and NW-trending ridges with peaks up to 6,000 ft. in elevation that parallel the regional structure. At the deposit, the elevation ranges from about 1,300 feet to over 2,000 feet. The Mediterranean climate delivers approximately 30 inches of rain per year, 90% of which falls between October and April. The area supports a mixed oak woodland-grassland. The deposit is cut by Sulphur Creek, which flows west to east through a flat-floored alluviated valley surrounded by hills of moderate relief. Several hot springs feed into Sulphur Creek, producing water that is variegated and pungent with the odor of sulfur. There is no habitation in the immediate area of the deposit, although a resort/retreat is present at Wilbur Springs about a mile to the east.

Comment (Economic Factors): Based on its 1977 drilling results, Homestake Mining Company considered the deposit uneconomic. Although numerous high-grade (typically >0.3 opt, some >1.0 opt) veins were intersected, they are widely separated. Homestake Mining has relinquished all of its landholdings in the district. Total gold production from the Manzanita and Cherry Hill mines is estimated at 3,000 oz (Nelson and others, 1993).

Comment (Geology): The Cherry Hill and nearby West End ore bodies are truncated on the east and west by subparallel NW-trending faults. These faults are subparallel to the Resort Springs Fault, the Wilbur Springs Structure, and the regional grain and generally show reverse, dextral slip. A conjugate NNE-trending system of discontinuous, dip-slip faults (including the Abbott-Coyote Peak Fault zone) are locally important ore controls, especially at the intersection with NW-trending faults. Veins are numerous but often widely spaced, sub-horizontal to shallow dipping (< 30?), and very thin (typically <1 cm). At Cherry Hill, the spacing between veins averages about 2 meters. The largest reported thickness is about 40 cm (Nelson and others, 1993). Veins are typically composed of crustiform clear to milky quartz and amber to brown quartz, which contains petroleum. Froth-vein textures and vugs filled with petroleum are common. Some high-grade veins consist of coarse gold in a matrix of petroleum with only traces of quartz gangue (Nelson and others, 1993). At the Wide Awake Mine, gold is present in the sedimentary serpentinite (Nelson and others, 1993). Hydrothermal alteration of the country rock is pervasive in places, particularly around the Manzanita, Cherry Hill, West End, and Wide Awake mines. An early adularization-silicification phase was overprinted locally by a later argillic-advanced argillic phase. Formation of the gold-bearing veins took place between these two major phases of alteration. Pearcy and Petersen (1990) concluded that there was a lack of complete correspondence between the presence of gold and locations of specific alteration or geochemical anomalies.

Comment (Geology): Regarding development of transform structures and magmatism in the northern Coast Ranges during the Cenozoic, a spreading ridge initially separated the Farallon and Pacific plates. While the Farallon Plate progressively subducted under the North American Plate, the Pacific Plate and intervening ridge approached the North America continent. The ridge system was locally offset and generally oblique to the subduction zone. Because of the geometry and motion between the plates, a proximal portion of the ridge moved into the subduction zone. At this location, subduction ceased and the North American and Pacific plates made contact. This event marked the birth of a triple junction. This contact essentially bisected the Farallon Plate into two smaller plates, the Juan de Fuca and Cocos plates. The new triple junction marked the point where the two new plates and the Pacific Plate met. However, it was short-lived. As subduction continued, the area of contact between the Pacific and North American Plates lengthened. What was a single triple junction split into two, joined by an incipient transform fault, the proto-San Andreas Fault. With time, the transform lengthened and the triple junctions separated farther. The growth of this proto-San Andreas Fault created a gap, or window, behind the subducting slab as it descended beneath the North American Plate. This window was increasingly enlarged and represented a region on the North American Plate-side of the proto-San Andreas Fault where the process of subduction was no longer operable. The path of the northward-migrating triple junction (Mendocino Triple Junction) is delineated by the San Andreas Fault (Dickinson, 1981, 1997; Atwater, 1970, 1989). A northward-younging sequence of Neogene-Holocene volcanic fields is thought to represent the surficial expression of a progressive upwelling of asthenosphere into the enlarging slab window. In the southern Coast Ranges, the volcanic fields are located along the San Andreas proper. However, in the north, starting just south of San Francisco Bay, the San Andreas Fault splays out into three codominant active strands. The western strand, the main San Andreas Fault, extends directly to the current position of the Mendocino Triple Junction. The volcanism shifted inboard along the eastern splays of the San Andreas system, which include the Bartlett Springs and Collayomi faults. It then extended northward to its current position just north of the Clear Lake volcanic field (Thorkelson and Taylor, 1989; Dickinson, 1981, 1997; Griscom and others, 1993). Debate exists concerning the interaction of the San Andreas Fault and the triple junction and is beyond the scope of this discussion. As the Mendocino Triple Junction and the track of volcanism migrated northward, localized transtension due to wrench faulting accompanied the strike-slip tectonics and produced a N-S string of pull-apart basins. This Neogene faulting as well as inherited Mesozoic structures controlled the locus of shallow magmatism and hydrothermal activity associated with the slab window. The most recent volcanic rocks, the Clear Lake Volcanics and Sonoma Volcanics, and their associated intrusions and hot- spring deposits, are localized within active pull-apart basins along the Collayomi and Bartlett Springs faults (Griscom and others, 1993).

Comment (Development): Historic Activity The early history of these mines is sparingly reported by the State Mining Bureau and its successor, the Division of Mines and Geology. Cherry Hill and Manzanita mines were discovered in 1863. These mines were worked primarily for gold until 1892. A Monticello and Hughes Mill was constructed in 1883. In 1888, ore was trammed to a 10-stamp mill where sodium amalgam and bluestone were used as charges. The total gold production from these mines is estimated at 3,000 ounces (Nelson and others, 1993). By 1892, mercury had become the primary interest. Mining consisted mostly of minor surficial workings and some short drifts. The mines were patented in 1893 and worked intermittently until 1916. In 1917, Cerise Gold Mining Company assumed ownership of the Cherry Hill and Manzanita mines, which were combined as the Cerise Mine. The mine operated for one year, producing a small amount of gold. An 8,000' long pipeline was extended from Bear Creek to the mines in 1920. At that time, underground workings in the Cerise Mine consisted of 1,000' of tunnels, 300' of which intersected ore. In 1922, Cherry Hill Gold Mining Company assumed ownership, although there was no production for seven years. In 1929, ownership changed to H.M. Newhall and Company, which leased to various operators, including the Shanjay Quicksilver Mining Company from 1930-31 and the Western Mergers Company from 1932-33. Mining of mercury continued until 1943. Recent Activity In 1977, Homestake Mining Company, through a drilling project, delineated a small deposit in the area of the Cherry Hill, West End, and Wide Awake mines. Mineralization extends throughout the area between the mines (Nelson and others, 1993). Homestake controlled part of the property until 2000 when it sold it s remaining interests. Pearcy and Petersen (1990) mapped gold, silver, mercury, antimony, thallium, and arsenic anomalies. The patterns of the anomalies follow a NW trend, subparallel with the regional trend of the Wilbur Springs structure and its associated faults. The patterns broaden at the center of the area where the NW-trending structures intersect with NE-trending structures of Abbott-Coyote Peak Fault. Silver showed the weakest anomalies, with maximum concentrations of 5.5 ppm. Gold had a wider distribution than silver, with a maximum concentration of 17 ppm. Mercury had the widest distribution and greatest anomalies, reaching 6,000 ppm. The areas of highest mercury concentration are thought to be areas of highest fluid flow. There is no significant correspondence between any of the trace element anomalies and the location of active hot springs. The present-day springs do not represent the locus for the dominant mineralization but are only peripheral to the central anomaly. Today, the site still has open workings, mine dumps, and scattered equipment. Some of the workings are fenced off, but still accessible.

Comment (Geology): Associated with the three main lithologic units described above are deposits of sedimentary serpentinite. Such deposits are present in the Wilbur Springs quadrangle, near the Cherry Hill deposit. There, lenses of sedimentary serpentinite are found interbedded in the upper Knoxville Formation (locally named the Stony Creek Formation) of the Great Valley Sequence. The origin of these enigmatic masses has been controversial. They may represent brecciated ophiolite, landslide deposits, or diapirs or protrusions from serpentine mud volcanoes. Recent studies of active mud volcanism in the Mariana subduction complex may provide clues to relationships in the Coast Ranges. The mud volcanoes erupt slab-derived fluids, serpentinite mud, and blocks of blueschist (Fryer, 1992; Fryer and others, 1999; Carlson, 1981a, b; 1984a, b; McLaughlin and others, 1980; Bailey and others, 1964; Phipps, 1992). Interpretations vary regarding the process by which the fault-bounded portions of Coast Range Ophiolite came to reside between the two sedimentary units. Seismic reflection profiles reveal a stack of detached ophiolite-like slabs encased in fault-bounded wedges that underlie most of the eastern margin of the Coast Ranges. The uppermost, subsurface ophiolitic slab produces a prominent magnetic anomaly. It is shaped like an airfoil and measures about 600 km along strike, 10-20 km wide, and about 4 km deep (Griscom and others, 1993). A 3-km-deep geothermal exploration well near the Manzanita Mine in the Sulphur Creek District corroborates the seismic data. It revealed two layers of ophiolite separated by melange and overlain by Great Valley Sequence (McLaughlin and others, 1990). Over the past decade, two structural models have been used to explain the above relationships of the ophiolite with the surrounding sedimentary units. One model suggests that imbricate thrusting produced the stack of wedges and ophiolite slabs. This process inserted Coast Range Ophiolite between the Great Valley Sequence and Franciscan Complex. The other model proposes that the ophiolite slid beneath both units, as the leading edge of the subducting slab of oceanic crust, until it locked up. Eventually the locked ophiolite broke off the oceanic slab, and subduction resumed at a lower level. The wedges are interpreted as abandoned accretionary prisms. The continued subduction drove outboard Franciscan sediments beneath the ophiolite. This process would indicate a cycle of ophiolite generation and wedge abandonment. Later extensional faulting, as mentioned above, exhumed the slab of ophiolite. The first model requires that the bounding faults are thrusts. Conversely, the second model requires them to be normal faults. The kinematics and significance of these faults remains unresolved. Field evidence seems ambiguous and may represent a more complicated history. Tectonic blocks of blueschist, which are thought to have formed deep in the subduction zone, crop out in the Franciscan Complex. Proponents of extensional dynamics have suggested that these blocks were brought up from depth by normal faulting (Platt, 1986; Jayko and others 1987). To the south, Harms and others (1992) determined the timing of such extension in the Diablo Range to about 60-70 Ma. Conversely, Ring and Brandon (1994) suggested that exhumation could be accomplished by both out-of-sequence faulting in the upper plate and erosion. Their model negates the need for extension. Namson and Davis (1988), who conducted structural studies in the southern Coast Ranges, concluded that the Franciscan Complex was thrust eastward over itself, Coast Range Ophiolite, and lower Great Valley Sequence, which developed a series of east-dipping backthrusts that form the tectonic wedge geometry.

Comment (Workings): Numerous shallow cuts and adits dot the area. Details of underground workings are scarce and are derived from historic reports (1888-1939) of the California Mining Bureau and its successor, the Division of Mines and Geology. Prior to 1921, the Cerise Mine (the Manzanita and Cherry Hill mines combined) consisted of 1,000' of tunnels, 300' of which penetrated ore. In 1929, a glory hole at the Manzanita Mine was connected to underground workings by pipe. Ore was trammed by hand to the portal and hauled by horse to the mill bin several hundred feet away. At that time, the mine produced sixty-five to eighty ore carts (1,200 lbs.) of mercury ore daily. The generally friable ore was screened without crushing. Coarse reject from the screen was dumped onto the hillside. Fines were concentrated on tables and hauled by sled to the retorting plant one quarter-mile away near Sulphur Creek. The plant contained seven retorts each capable of processing 250 lbs. of ore per day. Workings at the Wide Awake Mine consisted of a 470'-deep shaft with levels at 190, 290, and 390'. The longest stope (390') was on the 190 level. On the 290' level, a heavy seep yielded about a half a barrel of oil in 24 hours. An adit and associated dump are present at the West End Mine. Moisseeff (1966) reported shallow depleted stopes and a small shaft with associated dump at the Cherry Hill Mine.

Comment (Identification): The area of the mining district just west of Wilbur Springs contains several mercury mines, some with gold shows. The mines with known historic gold production are Cherry Hill and Manzanita. Gold is also present at the West End and Wide Awake mines. The Manzanita Mine was also a substantial producer of mercury. The Manzanita and Cherry Hill mines at one time were grouped together as the Cherry Hill Mine, formerly known as the Cerise Mine. The Wide Awake Mine was formerly known as the Buckeye Mine. All of these historic mines are closely spaced and any modern mining operation would work them as a group. Accordingly, they are described here collectively as the Cherry Hill Deposit.

Comment (Location): Location point selected as adit symbol at Manzanita Mine on Wilbur Springs 7.5-minute quadrangle map. Locations of the Empire and Central mines on the Wilbur Springs 7.5-minute quadrangle conflict with those shown in the geologic literature. The deposit is accessible by two dirt roads from State Highway 20 to the south (permission for access is required because much of the land is private property).

Comment (Geology): In the Clear Lake area, several lines of geophysical, geochemical, and geologic evidence suggest that a NE-trending zone of extension cuts across NW-trending structures. The zone extends from the Collayomi Fault in the west to at least the Bartlett Springs Fault in the east. Farther east, NE-trending structures in the Sulphur Creek District seem to be related to the zone. The Clear Lake and Sonoma volcanics occur within and may be genetically related to this zone also (Stanley and others, 1997). Overall, the zone of extension corresponds with a NE-trending basement structure proposed by Griscom and others (1993), which trends N70E and is defined by the alignment of magnetic and gravity anomalies and the alignment of the Geysers geothermal field, the Sonoma and Clear Lake volcanics, and the Sutter Buttes volcano. The gold deposits at McLaughlin and Cherry Hill lie above the intersection of the proposed structure and the contact between Coast Range Ophiolite and Great Valley Sequence. Also, above this intersection is a possible local window in the ophiolite slab, indicated by an anomalous magnetic low. These deep structures may have been important in the development of the ore deposits (Griscom and others, 1993). Hot Springs-Type Mineral Deposits Several hot-springs-type mineral deposits are present within the Clear Lake and Sonoma volcanic fields. Some, including Cherry Hill, are still hydrothermally active. Hydrothermal activity at the McLaughlin Mine persisted from about 1.0 to 0.5 Ma (Dean Enderlin, Homestake Mining Company, personal communication, 1999). Sulphur Bank Mine, at Clear Lake, is in an active vapor-dominated hydrothermal system, which continues to deposit mercury, but not precious metals. Precious-metal deposition is restricted to water-dominated hydrothermal systems, such as at Cherry Hill, where hot springs are actively depositing gold and mercury (Rytuba, 1993). Local Geology The Cherry Hill deposit is hosted mostly in mudstone, siltstone, and sandstone of the Upper Jurassic-Lower Cretaceous Stony Creek Formation, a basal unit of the Great Valley Sequence equivalent to the Knoxville Formation found farther south at the McLaughlin deposit. Gold is also hosted in serpentinite melange that is interpreted to be interbedded in the Stony Creek Formation. The host rocks at Cherry Hill appear to be one level higher in the imbricate stack described above. The Cherry Hill deposit appears to have developed in a smaller, lower-temperature, and less-vigorous system than the McLaughlin deposit. Here, in contrast to the McLaughlin deposit, no large sinter terraces or explosion breccias formed (Nelson and others, 1993). Cherry Hill is situated in a pervasively fractured region on the nose of a SE-plunging antiform known as the Wilbur Springs Structure. The relationship here between the Coast Range and the Stony Creek faults is complicated and has been interpreted differently by different workers (compare McLaughlin and others, 1989; Lawton, 1956; and Rich, 1971). The Wilbur Springs Structure interrupts the regional trend of the Stony Creek Fault. North of Cherry Hill, the Coast Range Fault trends N10-15?W and to the south it trends N40?W. The Stony Creek Fault is a near-vertical zone of intensely sheared serpentinite 10-15 Km wide. The Resort Fault, located just east of the deposit, is the most prominent local structure and may be the youngest. Wilcox (1978) proposed a third major fault zone, the Abbott-Coyote Peak Fault Zone, which trends NE across the Cherry Hill vicinity. The intersection of these regional structures has made the local structure very complicated.

---

References

Reference (Deposit): Bailey, E.H. and others, 1964, Franciscan and related rocks and their significance in the geology of western California: California Division of Mines and Geology Bulletin 183, 177 p.

Reference (Deposit): Berger, B.R., 1986, Descriptive model of hot-spring Au-Ag, in Cox, D.P. and Singer, D.A., editors, Mineral deposit models: U.S. Geological Survey Bulletin 1693, p. 143-144.

Reference (Deposit): Boalich, E.S., 1921, Mines and mineral resources, Colusa County: California State Mining Bureau Eighteenth Report of the State Mineralogist, v. 17, p. 43-47.

Reference (Deposit): Fox, K.F., Jr., 1983, Tectonic setting of Late Miocene, Pliocene, and Pleistocene rocks in part of the Coast Ranges north of San Francisco, California: U.S. Geological Survey Professional Paper 1239, 33 p.

Reference (Deposit): Forstner, W., 1903, The quicksilver resources of California: California State Mining Bureau Bulletin 27, p. 81-89.

Reference (Deposit): Fryer, P., 1992, Volcanoes of the Marianas: Scientific American, v. 266, no. 2, p. 46-52.

Reference (Deposit): Fryer, P. and others, 1999, Mariana blueschist mud volcanism: Implications for conditions within the subduction zone: Geology, v. 27, p. 103-106.

Reference (Deposit): Griscom, A. and others, 1993, Regional geophysical setting of gold deposits in the Clear Lake region, California, in Rytuba, J.J., editor, Active geothermal systems and gold-mercury deposits in the Sonoma-Clear Lake volcanic fields, California: Society of Economic Geologists Guidebook Series, v. 16, p. 289-310.

Reference (Deposit): Harms, T.A. and others, 1992, Kinematic evidence for extensional unroofing of the Franciscan Complex along the Coast Range Fault, northern Diablo Range, California: Tectonics, v. 11, no. 2, p. 228-241.

Reference (Deposit): Carlson, C., 1984a, Depositional environments and sedimentary facies of foliate serpentinite breccias, Wilbur Springs, in Carlson, C., editor, Depositional facies of sedimentary serpentinite: Selected examples from the Coast Ranges, California: Society of Economic Paleontologists and Mineralogists Field Trip Guidebook No. 3, Tulsa, Oklahoma, p. 113-116.

Reference (Deposit): Carlson, C., 1984b, Stratigraphic and structural significance of foliate serpentinite breccias, Wilbur Springs, in Carlson, C., editor, Depositional facies of sedimentary serpentinite: Selected examples from the Coast Ranges, California: Society of Economic Paleontologists and Mineralogists Field Trip Guidebook No. 3, Tulsa, Oklahoma, p. 108-112.

Reference (Deposit): Chapman, R.H. and others, 1982, Gravity, structure, and geothermal resources of the Calistoga area, Napa and Sonoma counties: California Geology, v. 35, no. 8, p. 175-183.

Reference (Deposit): Hearn, B.C., Jr., and others, 1988, Tectonic framework of the Clear Lake basin, California: Geological Society of America Special Paper 214, p. 9-20.

Reference (Deposit): Dickinson, W.R., 1981, Plate tectonics and the continental margin of California, in Ernst, W.G., editor, The geotectonic development of California (Rubey volume 1), Prentice-Hall, Englewood Cliffs, New Jersey, p. 1-28.

Reference (Deposit): Carlson, C., 1981b, Upwardly mobile melanges, serpentinite protrusions, and transport of tectonic blocks in accretionary prisms: Geological Society of America Abstracts with Programs, v. 13, no. 2, p. 48.

Reference (Deposit): Carlson, C., 1981a, Sedimentary serpentinites of the Wilbur Springs area -a possible Early Cretaceous structural and stratigraphic link between the Franciscan Complex and the Great Valley Sequence: Master's thesis, Stanford University, 105p.

Reference (Deposit): Dickinson, W.R., 1997, Tectonic implications of Cenozoic volcanism in coastal California: Geological Society of America Bulletin, v. 109, p. 936-954.

Reference (Deposit): Donnelly-Nolan, J.M. and others, 1993, The Geysers-Clear Lake area, California: Thermal waters, mineralization, volcanism, and geothermal potential: Economic Geology, v. 88, p. 301-316.

Reference (Deposit): Enderlin, D.A., 1993, Epithermal precious metal deposits of the Calistoga mining district, Napa County, California, in Rytuba, J.J., editor, Active geothermal systems and gold-mercury deposits in the Sonoma-Clear Lake volcanic fields, California: Society of Economic Geologists Guidebook Series, v. 16, p. 52-76.

Reference (Deposit): Irelan, W., Jr., 1888, Colusa County: California State Mining Bureau Eighth Report of the State Mineralogist, v. 8, p. 157-159.

Reference (Deposit): Hopson, C.A. and others, 1981, Coast Range ophiolite, western California, in Ernst, W.G., editor, The geotectonic development of California: Prentice-Hall, Englewood Cliffs, New Jersey, p. 418-510.

Reference (Deposit): Ring, U. and Brandon, M.T., 1994, Kinematic data for the Coast Range Fault and implications for exhumation of the Franciscan subduction complex: Geology, v. 22, no. 8, p. 735-738.

Reference (Deposit): Rytuba, J.J., 1993, Epithermal precious-metal and mercury deposits in the Sonoma and Clear Lake volcanic fields, California, in Rytuba, J.J., editor, Active geothermal systems and gold-mercury deposits in the Sonoma-Clear Lake volcanic fields, California: Society of Economic Geologists Guidebook Series, v. 16, p. 38-51.

Reference (Deposit): Thompson, J.M., 1993, Chemical and isotopic constituents in the hot springs along Sulphur Creek, Colusa County, California, in Rytuba, J.J., editor, Active geothermal systems and gold-mercury deposits in the Sonoma-Clear Lake volcanic fields, California: Society of Economic Geologists Guidebook Series, v. 16, p. 190-206.

Reference (Deposit): Thorkelson, D.J. and Taylor, R.P., 1989, Cordilleran slab windows: Geology, v. 17, no. 9, p. 833-836.

Reference (Deposit): Wakabayashi, J. and Unruh, J.R., 1995, Tectonic wedging, blueschist metamorphism, and exposure of blueschists: Are they compatible?: Geology, v. 23, no. 1, p 85-88.

Reference (Deposit): Vredenburgh, L.M., 1982, Tertiary gold bearing mercury deposits of the Coast Ranges of California: California Geology, v. 35, no. 2, p. 23-27.

Reference (Deposit): Wilcox, R.E., 1978, Report on the geology of Cherry Hill: Homestake Mining Company unpublished report, 30 p.

Reference (Deposit): Whitney, J.D., 1865, Geology - Report of progress and synopsis of the field work from 1860 to 1864: Geological Survey of California, Volume 1, 498 p.

Reference (Deposit): Miscellaneous field reports on Manzanita Mine (File Number 332-0899, CDMG Mineral Resources Files, Sacramento). Also see References 16124 and 16532 for the Cherry Hill Mine in the Anaconda collection at the University of Wyoming.

Reference (Deposit): Sherlock, R.L. and others, 1995, Origin of the McLaughlin Mine sheeted vein complex: Metal zoning, fluid inclusion, and isotopic evidence: Economic Geology, v. 90, p. 2156-2181.

Reference (Deposit): Stanley, W.D. and others, 1997, Tectonic controls on magmatism and geothermal resources in the Geyers-Clear Lake region, California: Integration of new geologic, earthquake tomography, seismicity, gravity, and magnetotelluric data: U. S. Geological Survey Open File Report 97-95, 40p.

Reference (Deposit): Ransome, A.L. and Kellogg, J.L., 1939, Quicksilver resources of California: California Journal of Mines and Geology, v. 35, p. 353-486.

Reference (Deposit): Rich, E.I., 1971, Geologic map of the Wilbur Springs Quadrangle, Colusa and Lake counties, California: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-538, scale 1:48,000.

Reference (Deposit): Lawton, J.E., 1956, Geology of the north one-half of the Morgan Valley quadrangle and the south one-half of the Wilbur Springs quadrangle, California: Stanford University, Ph.D. dissertation, 223 p.

Reference (Deposit): Logan, C.A., 1929, Colusa County, Sulphur Creek District: California Division of Mines and Mining Report 25, p. 288-290.

Reference (Deposit): McLaughlin, R.J. and others, 1980, Structure of Late Mesozoic rocks in the core of the Wilbur Springs Antiform, northern Coast Ranges, California: Geological Society of America Abstracts with Programs, v. 12, no. 3 , p. 119.

Reference (Deposit): McLaughlin, R.J. and others, 1989, Geologic map and structure sections of the Little Indian Valley-Wilbur Springs Geothermal Area, Northern Coast Ranges, California: U. S. Geological Survey Miscellaneous Investigations Series Map I-1706, scale 1:24,000.

Reference (Deposit): McLaughlin, R.J. and others, 1990, Geologic map and structure sections of the Little Indian Valley-Wilbur Springs geothermal area, northern Coast Ranges, California: U. S. Geological Survey Miscellaneous Investigations Series Map I-1706, scale 1:24,000.

Reference (Deposit): Moisseeff, A., 1966, The geology and geochemistry of the Wilbur Springs quicksilver district, Colusa and Lake counties, California: Stanford University, Ph.D. dissertation, 214 p.

Reference (Deposit): Namson, J.S. and Davis, T.L., 1988, Seismically active fold and thrust belt in the San Joaquin Valley, California: Geological Society of America Bulletin, v. 100, no. 2, p. 257-273.

Reference (Deposit): Nelson, C.E., 1987, Gold deposits in the hot springs environment, in Schafer, R.W. and others, editors, Bulk mineable precious metal deposits of the western United States: Symposium Proceedings of the Geological Society of Nevada, p. 417-432.

Reference (Deposit): Nelson, G.C. and others, 1993, Gold and mercury deposits in the Sulphur Creek district, California, in Rytuba, J.J., editor, Active geothermal systems and gold-mercury deposits in the Sonoma-Clear Lake volcanic fields, California: Society of Economic Geologists Guidebook Series, v. 16, p. 262-269.

Reference (Deposit): Jayko, A.S. and others, 1987, Attenuation of the Coast Range Ophiolite by extensional faulting, and nature of the Coast Range ?Thrust?, California: Tectonics, v. 6, no. 4, p. 475-488.

Reference (Deposit): Jennings, C. W., 1994, Fault activity map of California and adjacent areas with locations and ages of recent volcanic eruptions: California Division of Mines and Geology, Geologic Data Map No. 6, scale 1:750,000.

Reference (Deposit): Northey, G.V., 1913, Concentration of cinnabar ores: Engineering and Mining Journal, v. 96, no. 17, p. 783-784.

Reference (Deposit): Pearcy, E.C. and Petersen, U., 1990, Mineralogy, geochemistry and alteration of the Cherry Hill, California, hot-spring gold deposit: Journal of Geochemical Exploration, v. 36, p. 143-169.

Reference (Deposit): Peters, E.K., 1991, Gold-bearing hot spring systems of the northern Coast Ranges, California: Economic Geology, v. 86, p. 1519-1528.

Reference (Deposit): Phipps, S.P., 1992, Late Cenozoic wedging and blind thrusting beneath the Sacramento Valley and eastern Coast Ranges, in Erskine, M.C. and others, editors, Field guide to the tectonics of the boundary between the California Coast Ranges and the Great Valley of California: American Association of Petroleum Geologists, Pacific Section, p. 63-84.

Reference (Deposit): Phipps, S.P. and Unruh, J.R., 1992, Crustal-scale wedging beneath an imbricate roof-thrust system: Geology of a transect across the western Sacramento Valley and northern Coast Ranges, California, in Erskine, M.C. and others, editors, Field guide to the tectonics of the boundary between the California Coast Ranges and the Great Valley of California: American Association of Petroleum Geologists, Pacific Section, p. 117-140.

Reference (Deposit): Platt, J.P., 1986, Dynamics of orogenic wedges and the uplift of high-pressure metamorphic rocks: Geological Society of America Bulletin, v. 97, no. 9, p. 1037-1053.

Reference (Deposit): Bradley, W.W., 1916, The counties of Colusa, Glenn, Lake, Marin, Napa, Solano, Sonoma, Yolo: California State Mining Bureau 14th Report of the State Mineralogist, p. 173-370.

Reference (Deposit): Atwater, T., 1989, Plate tectonic history of the northeast Pacific and western North America, in Winterer, E.L. and others, editors, The eastern Pacific Ocean and Hawaii: Geological Society of America, The Geology of North America, Vol. N, p. 21-72.

Reference (Deposit): Atwater, T., 1970, Implications of plate tectonics for the Cenozoic tectonic evolution of western North America: Geologic Society of America Bulletin, v. 81, no. 12, p. 3513-3536.

---

California Gold

"Where to Find Gold in California" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in California. Read more: Where to Find Gold in California.