Site identification and general characteristics.

Term Definitions

DEP_ID

Site or deposit identification number within this database, used as a key linking all tables containing information about the site.
A unique 12-digit system generated sequence number which references records of information pertaining to a mineral property. Textual values of no more than 12 characters.

Record Type

(REC_TP) General characteristics of the record: Site, Plant, District, Deposit, or Region record.

Development Status

(DEV_ST) Category term describing operations at the time the deposit record was entered or this field was last modified: Occurrence, Prospect, Producer, Past Producer, Plant, or Unknown. Occurrence: ore mineralization found in outcrop, shallow pits, or isolated drill hole. Grade, tonnage, and extent of mineralization are unknown. No production and little or no activity since discovery other than routine claim maintenance. Prospect: development beyond the occurrence stage such as surface trenching, adits, shafts, drill holes, geophysics, geochemistry, or geological mapping. Enough data has been gathered to estimate grade and tonnage. Producer: a mine that was in production at the time the data was entered, includes intermittent and seasonal producers. Past Producer: a former producer that was closed at the time of data entry with no known plans to re-open. Plant: a mineral processing plant such as a smelter, refiner, beneficiation plant, active or inactive.

Options

Status of development of the resource or operation. Textual values of no more than 25 characters.

Occurrence

Ore mineralization in outcrop, shallow pit or pits, or isolated drill hole. Grade, tonnage, and extent of mineralization essentially unknown. No production has taken place and there has been no or little activity since discovery with the possible exception of routine claim maintenance.

Prospect

A deposit that has gone beyond the occurrence stage. That is subsequent work such as surface trenching, adits, or shafts, drill holes, extensive geophysics, geochemistry, and/or geologic mapping has been carried out. Enough work has been done to at least estimate grade and tonnage. The deposits may or may not have undergone feasibility studies that would lead to a decision on going into production.

Producer

A mine in production at the time the data was entered. An intermittent producer that produces on demand or seasonally with variable lengths of inactivity is considered a producer.

Past Producer

A mine formerly operating that has closed, where the equipment or structures may have been removed or abandoned.

Plant

A processing plant (smelter, refiner, beneficiation, etc.) that may or may not be currently producing at the time of data entry. A plant will have no geological information associated with it.

Unknown

At the time of data entry, either the development status was unknown or the data source this record came from did not specify this value.

Deposit Type

(DEP_TP) Short genetic or morphological terms indicating the geological origin or form of the mineralization. Generally less specific than a formal deposit model.

Plant Type

(PLANT_TP) General type of processing plant.

Plant Subtype

(PLANT_IDENT) Subtype of processing plant such as gravity, flotation, crush.

Operation Type

(OPER_TP) General category of operation at this site or proposed for it, such as surface, underground, leach, processing plant

Options

Type of operation existing or proposed at the site. Textual values of no more than 30 characters.

Surface

Open-pit or open-cast mine in which the overburden is completely removed and the sides of the mine are typically terraced away from the center. The overburden and ore are usually transported out of the pit in trucks. Includes quarry operations which are often open at the front as well, and strip mines which are open at both ends.

Underground

The opening to the mine is small relative to the size of the workings. The opening is usually called a shaft or adit. The ore is transported out of the mine in cars, buckets, on conveyor belts, etc.

Surface-Underground

Both surface and underground operations are present

Placer

A stream-sediment or beach-sand mine.

Offshore

Underwater mining operation such as for Mn nodules.

Well

The product is extracted through a borehole. Water, oil, and gas are the most common products, but includes solution-mining or in-situ leaching in which liquid solvent is circulated underground to extract the material.

Processing Plant

No ore extraction at the site, only a mill, smelter, etc.

Leach

Ore or concentrate is placed on an impervious pad, and a solvent is percolated or forced through the heap. The desired mineral or solute is dissolved into the leachate, from which it is more easily refined.

Brine Operation

The product, usually a type of salt, produced from a well or open pan.

Geothermal

Energy extracted from heat stored in the earth.

Unknown

Unknown or undetermined by evaluator

Mining Method

(MIN_METH) Predominant mining method used at this site, such as open pit, open stope, strip-level.

Milling Method

(MILL_METH) Predominant milling method used at this site, such as gravity or flotation

First Year Of Production Modifier

(YFP_BA) Modifier for year of first production (YR_FST_PROD). Before (<) or after (>) the specified date.

First Year Of Production

(YR_FST_PRD) The year ore was first produced at this site.

Last Year of Production Modifier

(YLP_BA) Modifier for year of last production (YR_LST_PROD). Before (<) or after (>) the specified date.

Last Year Of Production

(YR_LST_PRD) The year ore was last produced at this site. Optional modifier is YLP_BA.

Discovery Method

(DISC_METH) The most important method or feature used in the discovery of economic minerals at this site, such as drilling or geochemical anomaly.

Year Discovered Modifier

(DY_BA) Modifier for the year the deposit was discovered (DISC_YR). Before (<) or after (>) the specified date.

Year Discovered

(DISC_YR) The year the deposit was discovered.

Production Years

(PROD_YRS) The range of years this site was producing. May indicate more than one range, such as 1900-1915, 1918-1939, 1945 to present.

Discovered By

(DISCR) The name of the company, organization, or person most closely involved in the discovery of this deposit.

MAS ID

(MAS_ID) The unique 10 digit SEQuence number of this record within the MAS database.

MRDS ID

(MRDS_ID) The unique 7-place alpha-numeric identifier for the record in old MRDS before the merger with MAS/MILS in 2002. Records containing both MAS_ID and MRDS_ID are actually former MAS/MILS records – the MRDS_ID was assigned by USBM staff to show which MAS records had MRDS counterparts.

Significance

(SIG) Indicates whether the deposit has world-class significance. The criteria is total endowment of contained commodity, which includes all past production and reserves. Each commodity is considered separately, commodities cannot be combined to arrive at a significant size. The tonnage thresholds are from the deposit model grade-tonnage studies. As of 6/2008, the field contains many entries that were classified as significant under less strict rules.

Production Size

(PROD_SIZE) Production size – Large, Medium, Small, Yes, No. From old MRDS, no guidelines were established for the size categories, which may have referred to the rate of production as opposed to the total cumulative production.Note: Information not available for this record. 194976 records have no value for PROD_SIZE.

Options

A broad characterization of the magnitude of production at the site. The precise meanings of this field have changed over time and are lost to history; it is clear in retrospect that two different categorizations were used, a three-fold set based on magnitude (Small, Medium, Large) and a simple indicator (Yes or No), with some records showing U for unknown. Modern specialists would prefer that such a categorization take into account the type of deposit and commodity at the site, but there is no evidence that approach was taken in assigning values to this field.

Y

Yes, production has occurred

N

No, production has not occurred

S

Small ammount of material produced (we do not know what criteria are used to make this determination)

M

Medium ammount of material produced (we do not know what criteria are used to make this determination)

L

Large ammount of material produced (we do not know what criteria are used to make this determination)

U

Production statistics were not known to the reporters

Site Commodity Type

(SITE_COMMOD_TYPE) Metallic, non-metallic, or both, reflects the type of commodities at the site, drawn from the commodity table.

Options

Type of commodities present: metallic (M), non-metallic (N), or both (B). Textual values of no more than 1 characters.

M

Metallic commodity

N

Non-metallic commodity

B

Commodity used in metallic and non-metallic forms

(no value)

Information not available for this record. 34 records have no value for COM_TYPE.

Primary Commodities

(COMMOD1) Primary commodities present, a comma-separated list. Commodity qualifiers follow each commodity, delimited by a hyphen. Textual values of no more than 128 characters.Note: Information not available for this record. 22335 records have no value for COMMOD1.

Secondary Commodities

(COMMOD2) Secondary commodities present, a comma-separated list. Commodity qualifiers follow each commodity, delimited by a hyphen. Textual values of no more than 128 characters.Note: Information not available for this record. 285184 records have no value for COMMOD2.

Tertiary Commodities

(COMMOD3) Tertiary commodities present, a comma-separated list. Commodity qualifiers follow each commodity, delimited by a hyphen. Textual values of no more than 128 characters.Note: Information not available for this record. 239278 records have no value for COMMOD3.

Deposit Size

(DEPOSIT_SIZE) Deposit size – Large, Medium, or Small. The tonnage of the deposit including all production, reserves, and resources. From old MRDS (former MAS/MILS records lack this field). Size categories from Guild, P. W., and others, compilers, 1981, PRELIMINARY METALLOGENIC MAP OF NORTH AMERICA: U.S. Geological Survey Map, scale 1:5,000,000.

Mineral Area Name

(MIN_AREA_NAME) The name of a mineralized area as defined by deposits of similar geological model and environment, for instance the “Boulder Tungsten Area”. Related information is stored in the districts table and in the tectonic setting table.

Latitude

(LATITUDE) Geographic latitude of the site, WGS84 if needed). Real numbers stored in double precision.Note: Information not available for this record. 4033 records have no value for LATITUDE.

Range of values

-76.6667 to 80

Longitude

(LONGITUDE) Geographic longitude of the site, WGS84 if needed). Real numbers stored in double precision.Note: Information not available for this record. 4033 records have no value for LONGITUDE.

Range of values

-178.8167 to 179.54917

Host Rock Type Code

(HROCK_CODE) Integer number(s) indicating the type of host rocks. Textual values of no more than 40 characters. (Source: Rock names, their hierarchical relationships, and definitions appear to be derived from Bruce Johnson’s simplified classification of lithology for geologic map units, “LithClass 6”. However the numerical codes given here are not part of that work.)Note: Information not available for this record. 236050 records have no value for HROCK_CODE.

1

(Unconsolidated Deposit) Dominantly unsorted and unstratified drift, generally unconsolidated, deposited directly by and underneath a glacier without subsequent reworking by meltwater

2

(Unconsolidated Deposit > Alluvium) A general term for clay, silt, sand, gravel or similar unconsolidated detrital material, deposited during comparatively recent geologic time by a stream or other body of running water, as a sorted or semi-sorted sediment.

3

(Unconsolidated Deposit > Beach Sand)A loose aggregate of unlithified mineral or rock particles of sand size forming a beach (the relatively thick and temporary accumulation of loose water-borne material that is in active transit along, or deposited on, the shore zone between the limits of low water and high water)

4

(Unconsolidated Deposit > Dune Sand) A type of blown sand that has been piled up by the wind into a sand dune, usually consisting of rounded mineral grains, commonly quartz, having diameters ranging from 0.1 to 1 mm

5

(Unconsolidated Deposit > Loess) A widespread, homogeneous, commonly nonstratified, porous, friable, slightly coherent, usually highly calcareous, fine-grained blanket deposit, consisting predominantly of silt with subordinate grain sizes ranging from clay to fine sand.

6

(Unconsolidated Deposit > Volcanic Ash)A fine pyroclastic material (under 2.0 mm in diameter). The term usually refers to the unconsolidated material

7

(Unconsolidated Deposit > Colluvium) A general term applied to any loose, heterogeneous, and incoherent mass of soil material and/or rock fragments deposited by rainwash, sheetwash, or slow, continuous downslope creep, usually collecting at the base of gentle slopes or hillsides.

8

(Unconsolidated Deposit > Till)Dominantly unsorted and unstratified drift, generally unconsolidated, deposited directly by and underneath a glacier without subsequent reworking by meltwater

9

(Unconsolidated Deposit > Glacial Sediment) Stratified glacial drift deposited by, or reworked by running water, or deposited in standing water

10

(Unconsolidated Deposit > Peat) An unconsolidated deposit of semicarbonized plant remains in a water saturated environment, such as a bog or fen, and of persistently high moisture content (at least 75 percent).

11

(Unconsolidated Deposit > Coral) A hard calcareous substance consisting of the continuous skeleton secreted by coral polyps for their support and habitation and found in single specimens growing plant-like on the sea bottom or in extensive, solidified accumulations (coral reefs).

12

(Unconsolidated Deposit > Clay, Mud) A loose, earthy, extremely fine-grained, natural sediment composed primarily of clay-size or colloidal particles and characterized by high plasticity and by a considerable content of clay minerals.

13

(Unconsolidated Deposit > Silt) A loose aggregate of unlithified mineral or rock particles of silt size (1/256 to 1/16 mm); an unconsolidated deposit consisting essentially of fine-grained clastic particles.

14

(Unconsolidated Deposit > Sand) A loose aggregate of unlithified mineral or rock particles of sand size (1/16 to 2 mm); an unconsolidated deposit consisting essentially of medium-grained clastic particles.

15

(Unconsolidated Deposit > Gravel) A loose accumulation of rock fragments composed predominantly of more or less rounded pebbles and small stones.

16

(Unconsolidated Deposit > Sand And Gravel) A loose aggregate of unlithified mineral or rock particles of sand size (1/16 to 2 mm); an unconsolidated deposit consisting essentially of medium-grained clastic particles, plus a loose accumulation of rock fragments composed predominantly of more or less rounded pebbles and small stones.

17

(Unconsolidated Deposit > Brine) Saline waters containing high amounts of Na, Ca, K, Cl, and other soluble elements.

18

(Unconsolidated Deposit > Seafloor) The surface of the rock or sediments at the bottom of the sea.

19

(Sedimentary Rock) A rock resulting from the consolidation of loose sediment that has accumulated in layers

20

(Sedimentary Rock > Clastic Sedimentary Rock) A composed principally of broken fragments that are derived from preexisting rocks or minerals and that have been transported some distance from their place of origin.

21

(Sedimentary Rock > Clastic Sedimentary Rock > Mudstone) A general term that includes claystone, siltstone, shale, and argillite, and that should be used only when the amounts of clay-sized and silt-sized particles are not known or specified, or cannot be precisely identified.

22

(Sedimentary Rock > Clastic Sedimentary Rock > Mudstone > Claystone) An indurated rock having more than 67 percent clay-sized minerals.

23

(Sedimentary Rock > Clastic Sedimentary Rock > Mudstone > Bentonite) A soft, plastic, porous, light-colored rock composed essentially of clay minerals of the montmorillonite (smectite) group plus colloidal silica, and produced by devitrification and accompanying chemical alteration of a glassy igneous material, usually a tuff or volcanic ash

24

(Sedimentary Rock > Clastic Sedimentary Rock > Shale) A laminated, indurated rock having more than 67 percent clay-sized minerals.

25

(Sedimentary Rock > Clastic Sedimentary Rock > Shale > Black Shale)A dark, thinly laminated carbonaceous shale, exceptionally rich in organic matter (5 percent or more carbon content) and sulfide (esp. iron sulfide, usually pyrite), and often containing unusual concentrations of certain trace elements (U, V, Cu, Ni).

26

(Sedimentary Rock > Clastic Sedimentary Rock > Shale > Oil Shale) A kerogen-bearing, finely laminated brown or black sedimentary rock that will yield liquid or gaseous hydrocarbon on distillation.

27

(Sedimentary Rock > Clastic Sedimentary Rock > Argillite) A compact rock derived either from mudstone or shale, that has undergone a somewhat higher degree of induration than mudstone or shale but is less clearly laminated than shale and without its fissility, and that lacks the cleavage distinctive of slate.

28

(Sedimentary Rock > Clastic Sedimentary Rock > Siltstone) An indurated silt having the texture and composition of shale but lacking its fine lamination or fissility; a massive mudstone in which silt-sized particles predominate over clay-sized particles.

29

(Sedimentary Rock > Clastic Sedimentary Rock > Sandstone) A medium-grained clastic sedimentary rock composed of abundant sand-sized fragments, which may have a finer-grained matrix (silt or clay), and which is more or less indurated by a cementing material

30

(Sedimentary Rock > Clastic Sedimentary Rock > Orthoquartzite) A clastic sedimentary rock that is made up almost exclusively of quartz sand (with or without chert), that is relatively free of or lacks a fine-grained matrix; a quartzite of sedimentary origin, or a &quot;pure quartz sandstone&quot;.

31

(Sedimentary Rock > Clastic Sedimentary Rock > Calcarenite) A clastic sedimentary rock that is made up predominantly of recycled carbonate particles of sand size; a consolidated calcareous sand

32

(Sedimentary Rock > Clastic Sedimentary Rock > Arkose) A feldspar-rich sandstone, commonly coarse-grained and pink or reddish, that is typically composed of angular to subangular grains that may be either poorly or moderately well sorted. Quartz is usually the dominant mineral, with feldspars constituting at least 25 percent.

33

(Sedimentary Rock > Clastic Sedimentary Rock > Wacke) A &quot&dirty&quot& sandstone that consists of a mixed variety of unsorted or poorly sorted mineral and rock fragments and of an abundant matrix of clay and fine silt; specif. an impure sandstone containing more than 10 percent argillaceous matrix.

34

(Sedimentary Rock > Clastic Sedimentary Rock > Graywacke) a dark gray, firmly indurated, coarse-grained sandstone that consists of poorly sorted angular to subangular grains of quartz and feldspar, with a variety of dark rock and mineral fragments embedded in a compact clayey matrix having the general composition of slate and containing an abundance of very fine-grained illite, sericite, and chloritic minerals.

35

(Sedimentary Rock > Clastic Sedimentary Rock > Conglomerate) A coarse-grained clastic sedimentary rock, composed of rounded to subangular fragments larger than 2 mm in diameter typically containing fine-grained particles in the interstices, and commonly cemented by calcium carbonate, iron oxide, silica, or hardened clay

36

(Sedimentary Rock > Clastic Sedimentary Rock > Sedimentary Breccia) A breccia (coarse-grained clastic rock composed of angular broken rock fragments held together by a mineral cement or a fine-grained matrix) formed by sedimentary processes

37

(Sedimentary Rock > Clastic Sedimentary Rock > Olistostrome) A sedimentary deposit consisting of a chaotic mass of intimately mixed heterogeneous materials (such as blocks and muds) that accumulated as a semi-fluid body by submarine gravity sliding or slumping of unconsolidated sediments.

38

(Sedimentary Rock > Clastic Sedimentary Rock > Lake Sediments)Sediments laid on the floor of a lake, usually coarse grainde near shore and rapidly changing to fine-grained clay and limesone in deeper water.

39

(Sedimentary Rock > Carbonate) A sedimentary rock composed of more than 50 percent by weight carbonate minerals

40

(Sedimentary Rock > Carbonate > Limestone) A sedimentary rock consisting chiefly (more than 50 percent by weight or by areal percentages under the microscope) of calcium carbonate, primarily in the form of the mineral calcite.

41

(Sedimentary Rock > Carbonate > Dolomite) A carbonate sedimentary rock of which more than 50 percent by weight or by areal percentages under the microscope consists of the mineral dolomite

42

(Sedimentary Rock > Mixed Clastic/Carbonate Rock) An undivided mixture of clastic and carbonate sedimentary rocks.

43

(Sedimentary Rock > Mixed Clastic/Volcanic Rock) An undivided mixture of clastic and carbonate sedimentary rocks.

44

(Sedimentary Rock > Phosphorite) A sedimentary rock with a high enough content of phosphate minerals to be of economic interest.

45

(Sedimentary Rock > Chemical Sediment) A sedimentary rock composed primarily of material formed directly by precipitation from solution or colloidal suspension or by the deposition of insoluble precipitates

46

(Sedimentary Rock > Chemical Sediment > Evaporite) A nonclastic sedimentary rock composed primarily of minerals produced from a saline solution as a result of extensive or total evaporation of the solvent.

47

(Sedimentary Rock > Chemical Sediment > Salt) An evapotite primarily composed of sodium chloride.

48

(Sedimentary Rock > Chemical Sediment > Chert) A hard, extremely dense or compact, dull to semivitreous, microcrystalline or cryptocrystalline sedimentary rock, consisting dominantly of interlocking crystals of quartz less than 30 cm in diameter.

49

(Sedimentary Rock > Chemical Sediment > Iron Formation) A chemical sedimentary rock, typically thin-bedded and/or finely laminated, containing at least 15 percent iron of sedimentary origin, and commonly but not necessarily containing layers of chert

50

(Sedimentary Rock > Chemical Sediment > Exhalite) A chemical sedimentary rock, usually containing oxide, carbonate, or sulfide as anions, and iron, magnesium, base metals, and gold as cations, formed by the issuance of volcanically derived fluids onto the sea floor or into the sea

51

(Sedimentary Rock > Coal) A readily combustible rock containing more than 50 percent by weight and more than 70 percent by volume carbonaceous material, formed by compaction and induration of variously altered plant remains

52

(Sedimentary Rock > Diatomite) A light-colored,soft, friable, siliceous sedimentary rockconsisting chiefly of opaline frustules of the diatom.

53

(Volcanic Rock (Aphanitic)) A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the Earth’s surface, either ejected explosively or extruded as a lava. The term includes near-surface intrusions that form a part of the volcanic structure.

54

(Volcanic Rock (Aphanitic) > Glassy Rock) Extrusive rock having a texture which is similar to that of glass or quartz and developed as a result of rapid cooling of the lava without distinct crystallization.

55

(Volcanic Rock (Aphanitic) > Glassy Rock > Obsidian) A black or dark-colored volcanic glass, usually of rhyolite composition, characterized by conchoidal fracture

56

(Volcanic Rock (Aphanitic) > Glassy Rock > Vitrophyre) Any porphyritic igneous rock having a glassy groundmass.

57

(Volcanic Rock (Aphanitic) > Glassy Rock > Pumice) A light-colored vesicular glassy rock commonly having the composition of rhyolite.

58

(Volcanic Rock (Aphanitic) > Pyroclastic Rock) Clastic rock material formed by volcanic explosion or aerial expulsion from a volcanic vent.

59

(Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff) Consolidated or cemented volcanic ash.

60

(Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff > Welded Tuff) A glass-rich pyroclastic rock that has been indurated by the welding together of its glass shards under the combined action of the heat retained by particles, the weight of the overlying material, and hot gasses.

61

(Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff > Ash-Flow Tuff) A tuff deposited by an ash flow or gaseous cloud; a type of ignimbrite. It is a consolidated, but not necessarily welded deposit.

62

(Volcanic Rock (Aphanitic) > Pyroclastic Rock > Ignimbrite) The deposit of a pyroclastic flow.

63

(Volcanic Rock (Aphanitic) > Pyroclastic Rock > Volcanic Breccia (Agglomerate))A pyroclastic rock that consists of angular volcanic fragments that are larger than 64 mm in diameter and that may or may not have a matrix

64

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock) A light-colored, fine-grained or aphanitic extrusive or hypabyssal rock, with or without phenocrysts and composed chiefly of quartz and feldspar.

65

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Alkali Rhyolite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) between 20 and 60 and P/(P+A) less than 10.

66

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) between 20 and 60 and P/(P+A) between 10 and 35.

67

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyodacite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) between 20 and 60 and P/(P+A) between 35 and 65.

68

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Dacite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) between 20 and 60 and P/(P+A) greater than 65.

69

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Alkali Trachyte) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, and P/(P+A) less than 10.

70

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Trachyte) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, and P/(P+A) between 10 and 35.

71

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) between 5 and 20 and P/(P+A) between 35 and 65.

72

(Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Latite) A volcanic rock defined in the QAPF diagram as having Q/(Q+A+P) less than 5 or F/(F+A+P) less than 10, and P/(P+A) between 35 and 65.

73

(Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock) A solidified body of volcanic rock having approximately equal light- and dark-colored minerals in its mode

74

(Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Trachyandesite) A volcanic rock defined modally by Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, P/(A+P) between 65 and 90, and M less than 35.

75

(Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite) A volcanic rock defined modally by Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, P/(A+P) greater than 90, and M less than 35

76

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock) A solidified body of volcanic rock having abundant dark-colored minerals in its mode

77

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Trachybasalt) A volcanic rock defined modally by Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, P/(A+P) between 65 and 90, and M greater than 35.

78

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt) A volcanic rock defined modally by Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, P/(A+P) greater than 90, and M greater than 35.

79

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt > Tholeiite) A silica-oversaturated basalt, characterized by the presence of low-calcium pyroxenes in addition to clinopyroxene and calcic plagioclase. Olivine may be present in the mode, but neither olivine nor nepheline appear in the norm.

80

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt > Hawaiite) A basalt in which the normative and modal feldspar is andesine, and with soda:potash ratio greater than 2:1. It generally, but not always, lacks normative quartz, and commonly contains normative and modal olivine.

81

(Volcanic Rock (Aphanitic) > Mafic Volcanic Rock > Basalt > Alkaline Basalt)A basalt with nepheline and/or acmite in the CIPW norm.

82

(Volcanic Rock (Aphanitic) > Alkalic Volcanic Rock) A volcanic rock that contains more sodium and/or potassium than is required to form feldspar with the available silica.

83

(Volcanic Rock (Aphanitic) > Alkalic Volcanic Rock > Phonolite) A volcanic rock defined in the QAPF diagram as having F/(F+A+P) between 10 an 60, and P/(P+A) less than 10.

84

(Volcanic Rock (Aphanitic) > Alkalic Volcanic Rock > Tephrite (Basanite)) A volcanic rock defined in the QAPF diagram as having F/(F+A+P) between 10 an 60, and P/(P+A) greater than 90.

85

(Volcanic Rock (Aphanitic) > Komatiite (Ultramafite)) A volcanic rock with color index (M) greater than or equal to 90

86

(Volcanic Rock (Aphanitic) > Volcanic Carbonatite) A rock of apparent volcanic origin composed of at least 50 percent carbonate minerals

87

(Plutonic Rock) A rock formed at considerable depth by crystallization of magma and/or by chemical alteration. It is characteristically medium- to coarse-grained, of granitoid texture.

88

(Plutonic Rock > Aplite) A light-colored igneous rock characterized by a fine-grained allotriomorphic-granular (i.e. aplitic) texture.

89

(Plutonic Rock > Porphyry) An igneous rock of any composition that contains conspicuous phenocrysts in a fine-grained groundmass

90

(Plutonic Rock > Porphyry > Lamprophyre) A group of porphyritic igneous rocks in which mafic minerals form the phenocrysts; feldspars, if present, are restricted to the groundmass

91

(Plutonic Rock > Pegmatite) An exceptionally coarse-grained igneous rock, with interlocking crystals, usually found as irregular dikes, lenses, or veins, esp. at the margins of batholiths

92

(Plutonic Rock > Granitoid) A general term for all phaneritic igneous rocks dominated by quartz and feldspars

93

(Plutonic Rock > Granitoid > Alkali-Granite (Alaskite)) A plutonic rock defined in the QAPF diagram as having Q between 20 and 60 and P/(A+P) less than 10

94

(Plutonic Rock > Granitoid > Granite) A plutonic rock defined in the QAPF diagram as having Q between 20 and 60 and P/(A+P) between 10 and 65

95

(Plutonic Rock > Granitoid > Granite > Peraluminous Granite) A granite with aluminum oxide greater than sodium oxide + potassium oxide + calcium oxide; typical accessories include: muscovite, biotite, corundum, topaz, garnet

96

(Plutonic Rock > Granitoid > Granite > Metaluminous Granite) A granite with aluminum oxide greater than sodium oxide + potassium oxide, but with aluminum oxide less than sodium oxide + potassium oxide + calcium oxide; typical accessories include: hornblende, epidote, melilite, or biotite + pyroxene

97

(Plutonic Rock > Granitoid > Granite > Subaluminous Granite) A granite with aluminum oxide approximately equal to sodium oxide + potassium oxide; typical accessories include: olivine, orthopyroxene, clinopyroxene

98

(Plutonic Rock > Granitoid > Granite > Peralkaline Granite) A granite with aluminum oxide less than sodium oxide + potassium oxide; typical accessories include: soda pyroxene and soda amphibole[

99

(Plutonic Rock > Granitoid > Granodiorite) A plutonic rock defined in the QAPF diagram as having Q between 20 and 60 and P/(A+P) between 65 and 90

100

(Plutonic Rock > Granitoid > Tonalite) A plutonic rock defined in the QAPF diagram as having Q between 20 and 60 and P/(A+P) greater than 90

101

(Plutonic Rock > Granitoid > Tonalite > Trondhjemite) A tonalite with color index (M) less than 15; composed essentially of sodic plagioclase, quartz, sparse biotite, and little or no alkali feldspar

102

(Plutonic Rock > Granitoid > Alkali Syenite) A plutonic rock defined in the QAPF diagram as having Q/(Q+A+P) less than 20 or F/(F+A+P) less than 10, and P/(P+A) less than 10

103

(Plutonic Rock > Granitoid > Quartz Syenite) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20 and P/(A+P) between 10 and 35

104

(Plutonic Rock > Granitoid > Syenite) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20 and P/(A+P) between 35 and 65

105

(Plutonic Rock > Granitoid > Quartz Monzonite) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20 and P/(A+P) between 65 and 90, and plagioclase more sodic than An50

106

(Plutonic Rock > Granitoid > Monzonite)A plutonic rock defined in the QAPF diagram as having Q less than 5 or F/(F+A+P) less than 10, and P/(A+P) between 35 and 65

107

(Plutonic Rock > Mafic Intrusive Rock)An igneous rock composed chiefly of one or more dark ferromagnesian minerals. An exception is made for anorthosite, which occurs in association with mafic rocks.

108

(Plutonic Rock > Mafic Intrusive Rock > Quartz Monzodiorite) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20 and P/(A+P) between 65 and 90, and plagioclase more sodic than An50

109

(Plutonic Rock > Mafic Intrusive Rock > Quartz Monzogabbro) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20 and P/(A+P) between 65 and 90, and plagioclase more calcic than An50

110

(Plutonic Rock > Mafic Intrusive Rock > Monzodiorite) A plutonic rock defined in the QAPF diagram as having Q less than 5 or F/(F+A+P) less than 10, and P/(A+P) between 65 and 90, and plagioclase more sodic than An50

111

(Plutonic Rock > Mafic Intrusive Rock > Monzogabbro) A plutonic rock defined in the QAPF diagram as having Q less than 5 or F/(F+A+P) less than 10, and P/(A+P) between 65 and 90, and plagioclase more calcic than An50

112

(Plutonic Rock > Mafic Intrusive Rock > Quartz Diorite) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20, P/(A+P) greater than 90, and plagioclase more sodic than An50

113

(Plutonic Rock > Mafic Intrusive Rock > Quartz Gabbro) A plutonic rock defined in the QAPF diagram as having Q between 5 and 20, P/(A+P) greater than 90, and plagioclase more calcic than An50

114

(Plutonic Rock > Mafic Intrusive Rock > Diorite) A plutonic rock defined in the QAPF diagram as having Q between 0 and 5 or F/(F+A+P) less than 10, P/(A+P) greater than 90 and plagioclase more sodic than An50

115

(Plutonic Rock > Mafic Intrusive Rock > Diorite > Diabase) A plutonic rock whose main components are labradorite and pyroxene and which is characterized by ophitic texture

116

(Plutonic Rock > Mafic Intrusive Rock > Gabbro) A plutonic rock defined in the QAPF diagram as having Q between 0 and 5 or F/(F+A+P) less than 10, P/(A+P) greater than 90 and plagioclase more calcic than An50

117

(Plutonic Rock > Mafic Intrusive Rock > Gabbro > Norite) A plutonic rock satisfying the definition of gabbro, in which pl/(pl+px+ol) is between 10 and 90 and opx/(opx+cpx) is greater than 95.

118

(Plutonic Rock > Mafic Intrusive Rock > Gabbro > Troctolite) A plutonic rock satisfying the definition of gabbro, in which pl/(pl+px+ol) is between 10 and 90 and px/(pl+px+ol) is less than 5.

119

(Plutonic Rock > Mafic Intrusive Rock > Anorthosite) A plutonic rock defined in the QAPF diagram as having Q between 0 and 5, P/(A+P) greater than 90, and M less than 10. A group of monomineralogic plutonic igneous rocks composed almost entirely of plagioclase feldspar.

120

(Plutonic Rock > Alkalic Intrusive Rock)A plutonic rock that contains more sodium and/or potassium than is required to form feldspar with the available silica

121

(Plutonic Rock > Alkalic Intrusive Rock > Nepheline Syenite) A plutonic rock defined in the QAPF diagram as having F/(F+A+P) between 10 and 60, and P/(P+A) less than 50; composed essentially of alkali feldspar and nepheline

122

(Plutonic Rock > Ultramafic Intrusive Rock) A general name for plutonic rock with color index (M) greater than or equal to 90

123

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite) A plutonic rock with M equal to or greater than 90 and ol/(ol+opx+cpx) greater than 40

124

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Dunite) A plutonic rock with M equal to or greater than 90 and ol/(ol+opx+cpx) greater than 90

125

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Harzburgite) A plutonic rock with M equal or greater than 90, ol/(ol+opx+cpx) greater than 40, and cpx/(ol+opx+cpx) less than 5.

126

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Wherlite) A plutonic rock with M equal or greater than 90, ol/(ol+opx+cpx) greater than 40, and opx/(ol+opx+cpx) less than 5.

127

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Lherzolite) A plutonic rock with M equal or greater than 90, ol/(ol+opx+cpx) greater than 40, and opx roughly equal to cpx.

128

(Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Kimberlite) A porphyritic alkalic peridotite containing abundant phenocrysts of olivine and phlogopite, and possibly geikielite and chromian pyrope, in a fine-grained groundmass of calcite and second-generation olivine and phlogopite.

129

(Plutonic Rock > Ultramafic Intrusive Rock > Pyroxenite) A plutonic rock with M equal to or greater than 90 and pyroxene/(ol+pyroxene) greater than 90.

130

(Plutonic Rock > Ultramafic Intrusive Rock > Pyroxenite > Clinopyroxenite) A plutonic rock with M equal to or greater than 90 and cpx/(ol+opx+cpx) greater than 90.

131

(Plutonic Rock > Ultramafic Intrusive Rock > Pyroxenite > Orthopyroxenite) A plutonic rock with M equal to or greater than 90 and opx/(ol+opx+cpx) greater than 90.

132

(Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite) A plutonic rock with M equal to or greater than 90 and hbl/(hbl+px+ol) greater than 90.

133

(Plutonic Rock > Intrusive Carbonatite)A plutonic rock composed of at least 50% carbonate minerals.

134

(Metamorphic Rock) A rock derived from pre-existing rocks by mineralogical, chemical, and/or structural changes, essentially in the solid state, in response to marked changes in temperature, pressure, shearing stress, and chemical environment, generally at depth in the earth’s crust.

135

(Metamorphic Rock > Hornfels) A fine-grained rock composed of a mosaic of equidimensional grains without preferred orientation and typically formed by contact metamorphism.

136

(Metamorphic Rock > Metasedimentary Rock) A sedimentary rock that shows evidence of having been subjected to metamorphism

137

(Metamorphic Rock > Metasedimentary Rock > Meta-Argillite) An argillite that has been metamorphosed.

138

(Metamorphic Rock > Metasedimentary Rock > Slate) A compact, fine-grained metamorphic rock that possesses slaty cleavage and hence can be split into slabs and thin plates

139

(Metamorphic Rock > Metasedimentary Rock > Quartzite) A granoblastic metamorphic rock consisting mainly of quartz and formed by recrystallization of sandstone or chert by either regional or thermal metamorphism.

140

(Metamorphic Rock > Metasedimentary Rock > Marble) A metamorphic rock consisting predominantly of fine- to coarse-grained recrystallized calcite and/or dolomite, usually with a granoblastic, saccharoidal texture

141

(Metamorphic Rock > Metavolcanic Rock) A volcanic rock that shows evidence of having been subjected to metamorphism.

142

(Metamorphic Rock > Metavolcanic Rock > Felsic Metamorphic Rock) A metavolcanic rock having abundant light-colored minerals, typically quartz and feldspar

143

(Metamorphic Rock > Metavolcanic Rock > Felsic Metamorphic Rock > Meta-Rhyolite) A low-grade, felsic metavolcanic rock with preserved evidence of its original rhyolitic character

144

(Metamorphic Rock > Metavolcanic Rock > Felsic Metamorphic Rock > Keratophyre) All salic extrusive and hypabyssal rocks characterized by the presence of albite or albite-oligoclase and chlorite, epidote, and calcite, generally of secondary order.

145

(Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock) A metavolcanic rock having abundant dark-colored minerals, typically feldspar, amphibole, and/or pyroxene

146

(Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Meta-Basalt) A low-grade, mafic metavolcanic rock with preserved evidence of its original basaltic character

147

(Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Spilite) An altered basalt, characteristically amygdaloidal or vesicular, in which the feldspar has been albitized and is typically accompanied by chlorite, calcite, epidote, chalcedony, prehnite, or other low-temperature hydrous crystallization products characteristic of a greenstone.

148

(Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Greenstone) A field term applied to any compact, dark-green, altered or metamorphosed basic igneous rock (e.g. spilite, basalt, gabbro, diabase) that owes its color to the presence of chlorite, actinolite, or epidote.

149

(Metamorphic Rock > Phyllite) A metamorphosed rock, intermediate in grade between slate and mica schist. Minute crystals of graphite, sericite, or chlorite impart a silky sheen to the surfaces of cleavage (or schistosity).

150

(Metamorphic Rock > Schist) A strongly foliated crystalline rock, formed by dynamic metamorphism, that can be readily split into thin flakes or slabs due to the well developed parallelism of more than 50 percent of the minerals present, particularly those of the lamellar or elongate prismatic habit, e.g. mica and hornblende.

151

(Metamorphic Rock > Schist > Greenschist) A schistose metamorphic rock whose green color is due to the presence of chlorite, epidote, or actinolite; a common product of low-grade regional metamorphism of pelitic or basic igneous rocks

152

(Metamorphic Rock > Schist > Blueschist) A schistose metamorphic rock with a blue color owing to the presence of sodic amphibole, glaucophane, or crossite, and commonly mottled bluish-gray lawsonite; characteristic of metamorphism in areas of unusually low thermal gradient, such as subduction zones

153

(Metamorphic Rock > Schist > Mica Schist) A schist whose essential constituents are mica and quartz, and whose schistosity is mainly due to the parallel arrangement of mica flakes.

154

(Metamorphic Rock > Schist > Pelitic Schist) A schistose metamorphic rock derived by metamorphism of an argillaceous or a fine-grained alluminous sediment.

155

(Metamorphic Rock > Schist > Quartz-Feldspar Schist) A schist whose essential constituents are quartz and feldspar and having lesser amounts of mica and/or hornblende

156

(Metamorphic Rock > Schist > Calc-Silicate Schist) A metamorphosed calcareous rock, commonly derived from argillaceous limestone or calcareous mudstone, containing calcium-bearing silicates such as diopside and wollastonite, with a schistose structure produced by parallelism of platy minerals

157

(Metamorphic Rock > Schist > Amphibole Schist) A schist whose essential constituent is amphibole with lesseramounts of feldspar, quartz, and/or mica

158

(Metamorphic Rock > Granofels) A medium- to coarse-grained granoblastic metamorphic rock with little or no foliation or lineation.

159

(Metamorphic Rock > Gneiss) A foliated rock formed by regional metamorphism, in which bands or lenticles of granular minerals alternate with bands or lenticles in which minerals having flaky or elongate prismatic habits predominate. Generally less than 50 percent of the minerals show preferred orientation.

160

(Metamorphic Rock > Gneiss > Felsic Gneiss) A gneissic rock dominated by light-colored minerals, commonly quartz and feldspar

161

(Metamorphic Rock > Gneiss > Felsic Gneiss > Granitic Gneiss) A gneissic rock with a general granitoid composition

162

(Metamorphic Rock > Gneiss > Felsic Gneiss > Biotite Gneiss) A granitic gneiss in which the dominant mafic mineral is biotite

163

(Metamorphic Rock > Gneiss > Mafic Gneiss) A gneissic rock dominated by dark-colored minerals, commonly biotite and hornblende

164

(Metamorphic Rock > Gneiss > Orthogneiss) A gneissic rock formed from an igneous parent

165

(Metamorphic Rock > Gneiss > Paragneiss) A gneissic rock formed from a sedimentary parent

166

(Metamorphic Rock > Gneiss > Migmatite) A composite &quot&mixed rock&quot& composed of igneous or igneous-appearing and metamorphic portions

167

(Metamorphic Rock > Amphibolite) A crystalloblastic rock consisting mainly of amphibole and plagioclase with little or no quartz.

168

(Metamorphic Rock > Granulite) A metamorphic rock consisting of even-sized, interlocking mineral grains less than 10 percent of which have any obvious preferred orientation.

169

(Metamorphic Rock > Eclogite) A granular rock composed essentially of garnet (almandine-pyrope) and sodic pyroxene (omphacite).

170

(Metamorphic Rock > Greisen) A pneumatolytically altered granitic rock composed largely of quartz, mica, and topaz.

171

(Metamorphic Rock > Skarn (Tactite)) A rock of complex mineralogic composition formed by contact metamorphism and metasomatism of carbonate rocks. It is typically coarse-grained and rich in garnet, iron-rich pyroxene, epidote, wollastonite, and scapolite.

172

(Metamorphic Rock > Serpentinite) A rock consisting almost wholly of serpentine-group minerals derived from the hydration of ferromagnesian silicate minerals such as olivine and pyroxene.

173

(Tectonite) A rock whose fabric reflects the history of its deformation.

174

(Tectonite > Tectonic Melange) A melange produced by tectonic processes.

175

(Tectonite > Cataclasite) A fine-grained, cohesive cataclastic rock, normally lacking a penetrative foliation or microfabric, formed during fault movement.

176

(Tectonite > Phyllonite) A rock that macroscopically resembles phyllite but that is formed by mechanical degradation (mylonitization) of initially coarser rocks.

177

(Tectonite > Mylonite) A compact, chert-like rock without cleavage, but with a streaky or banded structure, produced by the extreme granulation and shearing of rocks that have been pulverized and rolled during overthrusting or intense dynamic metamorphism.

178

(Tectonite > Flaser Gneiss) A dynamically metamorphosed rock in which lenses or layers of original or relatively unaltered granular materials are surrounded by a matrix of highly sheared and crushed material, giving the appearance of a crude flow structure

179

(Tectonite > Augen Gneiss) Gneissic rock containing augen (large lenticular mineral grains or mineral aggregates having the shape of an eye in cross section)

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Site identification and general characteristics

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