1. Mineral Resources
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National Geochemical Database: Concentrate

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   U.S. Geological Survey, 2016, National Geochemical Database: Concentrate: U.S. Geological Survey.

   Online Links:

   • https://mrdata.usgs.gov/ngdb/concentrate/

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -174.58554758
   East_Bounding_Coordinate: 151.85333333
   North_Bounding_Coordinate: 71.04151751
   South_Bounding_Coordinate: -46.86777778
   

3. What does it look like?

   https://mrdata.usgs.gov/ngdb/concentrate/ngdbconc-large.png (PNG)

   Schematic map showing sample density in the conterminous US, (768 x 512 pixels)

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 25-Sep-1964

   Ending_Date: 24-Aug-2007

   Currentness_Reference:

   Dates samples were submitted for analysis

5. What is the general form of this data set?

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Entity point (143350)
   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in decimal degrees. The horizontal datum used is World Geodetic System 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
      
7. How does the data set describe geographic features?

   datadxny

   Data dictionary, explaining tables and fields (Source: USGS)

   id

   Record ID.

   Row identifier within datadxny table. Integer values. Integer of width 8. (Source: this data release)

   Range of values
   Minimum:	1
   Maximum:	74
   Resolution:	1

   tblorder

   Table order.

   Order in which this table should appear in some presentations. Integer values. Integer of width 8. (Source: this data release)

   Range of values
   Minimum:	1
   Maximum:	4
   Resolution:	1

   tblname

   Table name.

   Name of the table. Textual values of no more than 20 characters. (Source: this data release) Text as used by the database management system

   number

   Ordinal position.

   Order in which this field occurs in the database. Integer values. Integer of width 8. (Source: this data release)

   Value	Definition
   (no value)	The table row describes the table as a whole rather than one of its fields

   Range of values
   Minimum:	1
   Maximum:	30
   Resolution:	1

   label

   Field label.

   Label of the field in the database. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   (no value)	The table row describes the table as a whole rather than one of its fields

   Field name as used internally in the database software

   category

   Category.

   General category of information provided by the contents of the field. Textual values of no more than 50 characters. (Source: this data release)

   Value	Definition
   (no value)	The table row describes the table as a whole rather than one of its fields
   Sample identification	Names, numbers, or other identifiers of the samples
   Processing information	Characteristics of the handling, processing, or analysis of the samples
   Geographic location	Information indicating the location from which the sample was collected
   Site characteristics	Information describing the environment from which the sample was taken
   Sample characteristics	Descriptive characteristics of the sample itself
   Chemical analysis	Results of analysis of the sample, typically quantitative
   Metadata	Information used to organize the data in this collection

   short_desc

   Short description.

   Descriptive name of the field used in some presentations, not constrained by rules affecting the label. Textual values of no more than 40 characters. (Source: this data release)

   Value	Definition
   (no value)	The table row describes the table as a whole rather than one of its fields

   description

   Description.

   Longer description of the purpose and contents of the field or table. Textual values of no more than 4096 characters. (Source: this data release) Plain text, not abbreviated

   link

   Link.

   URL providing more information about the field. Textual values of no more than 96 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 67 records have no value for link.

   origin

   Origin of field.

   Abbreviation of an organization, data set, or other entity responsible for defining the field. Textual values of no more than 12 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 67 records have no value for origin.

   sqltype

   SQL type.

   Data type of the field as used in the database. Textual values of no more than 8 characters. (Source: this data release)

   Value	Definition
   (no value)	the table row describes an entire table rather than a single field
   integer	Field contains integer values
   character varying	Field contains character values of varying length
   double precision	Field contains floating-point values

   dbftype

   DBF field type.

   Data type of the field when expressed in DBF. Textual values of exactly 1 character. (Source: this data release)

   Value	Definition
   C	character data
   N	numeric data

   width

   Field width.

   Field width when expressed in DBF. Integer values. Integer of width 8. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 4 records have no value for width.

   Range of values
   Minimum:	1
   Maximum:	4096
   Resolution:	1

   prec

   Precision.

   Precision of the field (places to right of decimal) when expressed in DBF, only for numeric fields. Integer values. Integer of width 8. (Source: this data release)

   Value	Definition
   (no value)	The field contains character data, or the row describes the table as a whole rather than an individual field

   Range of values
   Minimum:	0
   Maximum:	6
   Resolution:	1

   units

   Units of measure.

   Units of measure of the field values. Textual values of no more than 64 characters. (Source: this data release)

   Value	Definition
   (no value)	The field contains character data, the units are specified in a separate field of the table, or the row describes the table as a whole rather than an individual field

   main

   Sample location, characteristics, and general methods of collection and analysis (Source: USGS)

   lab_id

   Lab ID.

   Unique identifier assigned to each submitted sample by the Sample Control Officer of the analytical laboratory that received the sample. Textual values of no more than 10 characters. (Source: this data release) Alphanumeric identifiers without intrinsic scientific significance

   field_id

   Field ID.

   Field identifier assigned by the sample collector, sometimes modified or truncated when keypunched to fit the available field width. Textual values of no more than 16 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 4 records have no value for field_id.

   Alphanumeric identifiers without intrinsic scientific significance

   job_id

   Job ID.

   Laboratory batch identifier assigned by the Sample Control Officer of the analytical laboratory for each batch of samples received. Textual values of no more than 10 characters. (Source: this data release) Alphanumeric identifiers without intrinsic scientific significance

   submitter

   Submitter.

   Name of the individual(s) who submitted the sample in a batch to the laboratory for analysis; not necessarily the sample collector. Textual values of no more than 80 characters. (Source: this data release) Names, unabbreviated

   date_collect

   Date collected.

   Date sample was collected, as reported by submitter, mm/dd/yyyy. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 142689 records have no value for date_collect.

   While dates are generally formatted as month/day/year, the number of digits in these components varies, and some values are expressed as a range

   date_submitted

   Date submitted.

   Date sample was submitted to Sample Control for initial database processing prior to sample prep and analysis, mm/dd/yyyy. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 3578 records have no value for date_submitted.

   Generally these dates follow the format month (2 digit) / day (2 digit) / year (4 digit)

   project_name

   Project name.

   Project name, if known, that funded the collection and analysis of submitted samples. Textual values of no more than 80 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 77095 records have no value for project_name.

   Names, typically unabbreviated, sometimes with question marks

   state

   State.

   Abbreviation of state from where the sample was collected; only used within the United States. Textual values of no more than 2 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 6443 records have no value for state.

   Formal codeset
   Codeset Name:	U.S. Postal Service abbreviations for states and territories
   Codeset Source:	Post Office Department Publication 59, Abbreviations for Use with ZIP Code, October 1963, revised 1969.

   country

   Country.

   Country from where the sample was collected. Textual values of no more than 32 characters. (Source: this data release) Place or area names, mostly unabbreviated, including bodies of water.

   lat_wgs84

   Latitude (WGS84).

   Latitude coordinate of sample site converted, if necessary, to the WGS84 datum, reported in decimal degrees. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-49.81222222
   Maximum:	74.90833333
   Units:	decimal degrees

   long_wgs84

   Longitude (WGS84).

   Longitude coordinate of sample site converted, if necessary, to the WGS84 datum, reported in decimal degrees. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-179.36667
   Maximum:	179.9425
   Units:	decimal degrees

   datum_orig

   Original datum.

   Original reference datum, when recorded, for the latitude and longitude coordinates of the sample site. Values in (parentheses) are a best estimate for original datum values that were not recorded. Textual values of no more than 64 characters. (Source: this data release)

   Value	Definition
   European 1950	European 1950 (which variant is not specified)
   Indonesian 1974	Indonesian 1974
   NAD27	North American Datum of 1927
   NAD83	North American Datum of 1983
   SAD69	South American Datum 1969
   WGS84	World Geodetic System 1984

   lat_orig

   Original latitude.

   Original latitude coordinate of sample site as supplied by the sample submitter, reported in decimal degrees. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-49.81222222
   Maximum:	74.90833333
   Units:	decimal degrees

   long_orig

   Original longitude.

   Original longitude coordinate of sample site as supplied by the sample submitter, reported in decimal degrees. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-179.36667
   Maximum:	179.9425
   Units:	decimal degrees

   coord_prec_est

   Precision of coordinate location.

   Estimated precision of coordinates that were originally supplied by the sample submitter, reported to the nearest second, minute, degree, foot, or meter. Textual values of no more than 32 characters. (Source: this data release) Explanatory text, not abbreviated

   depth

   Depth.

   Depth from the surface at which the sample was collected; units are specified by the submitter. Textual values of no more than 80 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 142731 records have no value for depth.

   locate_desc

   Location description.

   Sample location description as supplied by the sample submitter. Textual values of no more than 256 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 134649 records have no value for locate_desc.

   Explanatory text, not abbreviated

   sample_source

   Sample source.

   Sample source, parent material, or indication of the land cover. Textual values of no more than 40 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 22341 records have no value for sample_source.

   Short descriptive terms for the environment, not abbreviated, in some cases expressed as a set of closely related terms separated by slash to mean "or".

   method_collected

   Method of collection.

   Method used to collect the sample. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 33637 records have no value for method_collected.
   channel	material taken from a trench or linear excavation
   composite	material combined from several discrete takings
   other	collection method not one of those described by this field
   single/grab	material from a single act of taking at a single location
   sngl/cmpst/chnl	collection may have been single, composite, or channel
   unknown	collection method not known

   primary_class

   Sample type.

   Sample media primary classification. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   sediment	unconsolidated earth materials, typically deposited by streams or other bodies of water
   soil	unconsolidated earth materials developed in place from pre-existing surficial material
   miscellaneous	other earth materials possibly including pulverized rock

   secondary_class

   Sample type.

   Sample media secondary classification. All values in the concentrate dataset equal CONCENTRATE. Textual values of no more than 64 characters. (Source: this data release)

   specific_name

   Specific name.

   Specific name or description of material that was submitted. Textual values of no more than 40 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 15909 records have no value for specific_name.

   Text indicating material, not abbreviated

   addl_attr

   Notes on sample.

   Comment field that includes submitter supplied comments and text for additional attributes that are no longer maintained separately. Textual values of no more than 256 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 7443 records have no value for addl_attr.

   Text may contain identifiers, description, place names, or feature types

   geologic_age

   Geologic age.

   Geologic age of the sample (or possibly the parent material) as supplied by the submitter. Textual values of no more than 64 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 130035 records have no value for geologic_age.

   Geologic periods, sometimes specified as a range of periods using hyphen

   stratigraphy

   Stratigraphy.

   Stratigraphic formation name as supplied by the submitter. Textual values of no more than 256 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 141335 records have no value for stratigraphy.

   Formation names (sometimes abbreviated) or stream names

   mineralization

   Mineralization.

   Indication of or type of mineralization associated with the sample. Textual values of no more than 40 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 142983 records have no value for mineralization.

   Short descriptive text indicating general form or process of mineral concentration, not abbreviated

   sample_zone

   Sample zone.

   Soil horizon zone from which the soil sample was collected. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143283 records have no value for sample_zone.

   Plain text, but the soil horizons themselves are indicated in symbolic form such as C or A, but there are a variety of unusual designations.

   horizon

   Soil horizon.

   Indication of how well defined the sampled soil horizon was at the collection site. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143347 records have no value for horizon.

   Plain descriptive text, unabbreviated.

   saline

   Saline.

   Indication of whether the sampled soil was saline or non-saline. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143349 records have no value for saline.

   Plain descriptive text, unabbreviated.

   organics

   Organics.

   Indication of whether the sampled soil was highly organic or not. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143350 records have no value for organics.

   Plain descriptive text, unabbreviated.

   ferritic

   Ferritic.

   Indication of whether the sampled soil was ferritic (iron rich), highly ferritic, or non-ferritic. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143337 records have no value for ferritic.

   Plain descriptive text, unabbreviated.

   drainage

   Drainage.

   Indication of whether the sampled soil was well drained or poorly drained. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143349 records have no value for drainage.

   Plain descriptive text, unabbreviated.

   prep

   Preparation.

   Description of sample preparation procedures used prior to analyzing the sample. Textual values of no more than 256 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 45899 records have no value for prep.

   Descriptive text, may include program name such as NAWQA to indicate adherence to program preparation protocols

   mesh_size

   Sieve mesh size.

   Mesh size used or final size fraction that was analyzed. Textual values of no more than 64 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 86348 records have no value for mesh_size.

   Descriptive text, may include procedural details such as "dry sieved"

   collection_protocol

   Collection protocol.

   Standard or published protocol used for collecting and preparing the sample. Textual values of no more than 64 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143350 records have no value for collection_protocol.
   NAWQA sediment collection protocol	Collection procedures followed guidelines of the National Water Quality Assessment program

   previous_job_id

   Previous job ID.

   Previous laboratory batch identifier, used when a sample was resubmitted in a new batch for further analyses. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143350 records have no value for previous_job_id.

   Alphanumeric identifier without further scientific significance

   previous_lab_id

   Previous lab ID.

   Previous laboratory-assigned Unique identifier, used when a sample was resubmitted for further analyses and given an new Lab ID. Textual values of no more than 20 characters. (Source: this data release)

   Value	Definition
   (no value)	Information not available for this record. 143350 records have no value for previous_lab_id.

   Alphanumeric identifier without further scientific significance

   chemistry

   All chemical analyses recorded for the sample, with analytical method, measured values, and qualifiers to indicate where a measured value was outside the reliable determination limits of the method (Source: USGS)

   rec_id

   This field contains the unique sequence number by which the given analysis can be related to the corresponding record in the master database from which these records were drawn. Consequently this value would be used to identify records that required correction in the master database, if necessary.

   Integer values. Integer of width 8. (Source: this data release)

   Range of values
   Minimum:	45289
   Maximum:	52354719
   Resolution:	1

   lab_id

   Lab ID.

   Unique identifier assigned to each submitted sample by the Sample Control Officer of the analytical laboratory that received the sample. Textual values of no more than 10 characters. (Source: this data release) Alphanumeric identifiers without intrinsic scientific significance

   species

   Chemical species.

   Element, oxide, compound, or property that was determined or measured by the laboratory. Textual values of no more than 40 characters. (Source: this data release)

   Value	Definition
   Li	Lithium
   Be	Beryllium
   B	Boron
   C_tot	Carbon (total)
   C_org	Carbon (organic)
   C_crb	Carbon (carbonate)
   F	Fluorine
   Na	Sodium
   Mg	Magnesium
   Al	Aluminum
   Si	Silicon
   P	Phosphorus
   S	Sulfur
   K	Potassium
   Ca	Calcium
   Sc	Scandium
   Ti	Titanium
   V	Vanadium
   Cr	Chromium
   Mn	Manganese
   Fe	Iron
   Co	Cobalt
   Ni	Nickel
   Cu	Copper
   Zn	Zinc
   Ga	Gallium
   Ge	Germanium
   As	Arsenic
   Se	Selenium
   Rb	Rubidium
   Sr	Strontium
   Y	Yttrium
   Zr	Zirconium
   Nb	Niobium
   Mo	Molybdenum
   Ru	Ruthenium
   Rh	Rhodium
   Pd	Palladium
   Ag	Silver
   Cd	Cadmium
   In	Indium
   Sn	Tin
   Sb	Antimony
   Te	Tellurium
   I	Iodine
   Cs	Cesium
   Ba	Barium
   La	Lanthanum
   Ce	Cerium
   Pr	Praseodymium
   Nd	Neodymium
   Sm	Samarium
   Eu	Europium
   Gd	Gadolinium
   Tb	Terbium
   Dy	Dysprosium
   Ho	Holmium
   Er	Erbium
   Tm	Thulium
   Yb	Ytterbium
   Lu	Lutetium
   Hf	Hafnium
   Ta	Tantalum
   W	Tungsten
   Re	Rhenium
   Os	Osmium
   Ir	Iridium
   Pt	Platinum
   Au	Gold
   Hg	Mercury
   Tl	Thallium
   Pb	Lead
   Bi	Bismuth
   Th	Thorium
   U	Uranium
   SplWtAu	Weight of sample used for gold analysis
   SplWtFA	Weight of sample used for fire assay analysis

   unit

   Units of measure.

   Unit of measurement associated with the accompanying concentration value. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   g	grams
   pct	percent by weight
   ppm	parts per million by weight

   qvalue

   Measured value.

   Qualified concentration value for the associated Species and reported in the associated Unit. Values less than the lower limit of determination are negative while values greater than the upper limit of determination have a .1111 suffix. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-10000
   Maximum:	940000

   qualifier

   Qualifier of measurement.

   Qualifier (L, N, G, <, or >) for censored data. Only used in the All Chemistry tables. Textual values of no more than 1 characters. (Source: this data release)

   Value	Definition
   L	The measured value was less than the lower limit of determination by the method
   N	The chemical species was not detected by the method
   G	The measured value was greater than the analytical method's upper determination limit
   (less-than symbol)	The measured value was less than the lower limit of determination by the method
   (greater-than symbol)	The measured value was greater than the upper limit of determination by the method
   (no value)	The measured value is within the range of values for which the analytical method is considered valid.

   amethod

   Analytical method.

   Analytical method code (abbreviation) for the method used to determine the associated Species. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   AA_CV	Mercury by cold-vapor atomic absorption spectrometry after multi-acid digestion and solution.
   AA_CV_WO	Mercury by wet oxidation and cold-vapor atomic absorption spectrometry ("flameless"); HNO3-H2SO4-HClO4 digestion, Hg aerated to silver screen, amalgamator heated in furnace, Hg vapor measured in AAS.
   AA_FE	Sodium and potassium by flame emission spectrometry (flame photometry) after HF-HClO4 dissolution or LiBO2 fusion.
   AA_F_AZ_H2O2_P	Silver, arsenic, bismuth, cadmium, copper, molybdenum, lead, antimony and zinc by flame atomic absorption spectrometry after partial digestion with HCl-H2O2-KI, ascorbic acid and selective organic extraction with Aliquat 336-MIBK.
   AA_F_Fuse	Major and minor elements by flame atomic absorption spectrometry after LiBO2/Li2B4O7 fusion digestion.
   AA_F_Fuse_P	Molybdenum and antimony by flame atomic absorption spectrometry after K2S2O7 (Mo) or NH4I (Sb) fusion, partial acid digestion, and selective organic extraction with Aliquat 336-MIBK.
   AA_F_HBr	Gold and tellurium by flame atomic absorption spectrometry after HBr-Br2 digestion and selective organic extraction with Aliquat 336-MIBK.
   AA_F_HCl_OE_P	Antimony by flame atomic absorption spectrometry after NH4I fusion, digestion with HCl, and selective organic extraction with Aliquat 336-MIBK.
   AA_F_HF	Major and minor elements by flame atomic absorption spectrometry after multi-acid digestion with HF.
   AA_F_HNO3_P	Silver, bismuth, cadmium, cobalt, copper, nickel, lead and zinc by flame atomic absorption spectrometry after partial digestion with hot HNO3.
   AA_GF_HBr	Gold and tellurium by graphite furnace atomic absorption spectrometry after HBr-Br2 digestion and selective organic extraction with Aliquat 336-MIBK.
   AA_GF_HF	Arsenic, gold, bismuth, indium, antimony, tellurium and thallium by graphite furnace atomic absorption spectrometry after multi-acid digestion with HF and selective organic extraction with Aliquat 336-MIBK.
   AA_HG_Acid	Selenium by flow injection or continuous flow hydride generation-atomic absorption spectrometry after digestion with HNO3-HCl-H2SO4-KMnO4.
   AA_HG_HF	Arsenic, antimony, selenium and tellurium by flow injection or continuous flow hydride generation-atomic absorption spectrometry after multi-acid digestion with HF.
   AA_TR	Mercury by thermal release and atomic absorption spectrometry after heating (Vaughn-McCarthy method).
   AES_AR_P	Major and minor elements by inductively coupled plasma-atomic emission spectrometry after partial digestion with aqua regia.
   AES_AZ_P	Silver, arsenic, gold, bismuth, cadmium, copper, molybdenum, lead, antimony and zinc by inductively coupled plasma-atomic emission spectrometry after partial digestion with HCl-H2O2.
   AES_HF	Major and minor elements by inductively coupled plasma-atomic emission spectrometry after digestion with HF-HCl-HNO3-HClO4.
   CB_IRC	Carbon and sulfur by infrared detection after combustion.
   CB_TC	Total carbon and organic carbon by thermal conductivity detection after combustion.
   CB_TT	Sulfur by iodometric titration after combustion.
   CM_Acid	Bromine by colorimetry after acid digestion.
   CM_Acid_P	Arsenic by modified Gutzeit apparatus confined-spot method colorimetry after partial digestion in KOH-HCl and chemical separation.
   CM_Fuse	Major and minor elements by colorimetric spectrophotometry after fusion digestion.
   CM_Fuse_P	Molybdenum and antimony by colorimetry after partial digestion by K2S2O7 fusion (Mo) or NaHSO4 fusion-HCl digestion (Sb, rhodamine B).
   CM_HF	Major and minor elements by colorimetric spectrophotometry after multi-acid digestion with HF.
   CM_HNO3_P	Copper, lead and zinc by colorimetry after partial digestion with HNO3.
   CM_HSF	Fluorine by chemical separation and colorimetric spectrophotometry; chemical separation to fluorosilicic acid (H2SiF6), converted to silicomolybdate, reduced to Mo blue.
   CM_PC_P	Uranium by paper chromatography after partial digestion with HNO3.
   CM_SDDC	Arsenic by colorimetric spectrophotometry after digestion in HF-aqua regia and chemical separation with SDDC.
   CM_ST_P	Tungsten by colorimetry after partial digestion with carbonate sinter.
   CP	Organic carbon, carbonate carbon and totals by computation.
   DN	Uranium and thorium by delayed neutron activation counting.
   ES_Q	Major and minor elements by quantitative emission spectrography.
   ES_SQ	Major and minor elements by semi-quantitative emission spectrography.
   FA_AA	Gold, silver and platinum group elements by graphite furnace atomic absorption spectrometry after PbO fire assay chemical separation.
   FA_DC	Gold by direct current plasma-atomic emission spectroscopy or atomic absorption spectrophotometry after PbO fire assay chemical separation.
   FA_ES	Gold and platinum group elements by direct-current arc quantitative emission spectrography after PbO fire assay chemical separation.
   FA_MS	Platinum group elements by inductively coupled plasma-mass spectrometry after NiS fire assay chemical separation.
   FL_HF	Beryllium, tin and uranium by fluorometry after multi-acid digestion with HF.
   GV	Density, moisture and weight by gravimetry; ash or loss on ignition by weight loss after heating at 900 degrees C.
   ISE_Fuse	Chloride, fluoride and iodide by ion specific electrode after fusion digestion.
   MS_HF	Major and minor elements by inductively coupled plasma-mass spectrometry after HF-HCl-HNO3-HClO4 digestion.
   NA_LC	Major and trace elements by long count instrumental neutron activation analysis; no digestion/extraction necessary.
   NA_SC	Major and trace elements by short (abbreviated) count instrumental neutron activation analysis; no digestion/extraction necessary.
   VOL	Carbon dioxide or carbonate carbon by evolution after acid decomposition; aka ""gasometric"" or ""manometric"".
   WDX_Fuse	Major and minor elements by wavelength-dispersive X-ray fluorescence spectrometry after LiBO2 fusion digestion.

   parameter

   Parameter.

   The suggested field name for a Species_Unit_Method column in crosstabbed chemistry tables. These field names concatenate the Species and Unit fields, and includes the general analytical method (first part of the amethod field). Textual values of no more than 32 characters. (Source: this data release) Concatenation of species, unit, and the characters of the amethod field to the left of the first underscore.

   tblname

   Table name.

   Textual values of no more than 16 characters. (Source: this data release)

   Value	Definition
   Chem_ES	Chemical analyses by emission spectroscopy
   Chem_ICPAES	Chemical analyses by inductively-coupled plasma atomic emission spectroscopy
   Chem_ICPMS	Chemical analyses by inductively-coupled plasma mass spectroscopy
   Chem_NAA	Chemical analyses by neutron activation analysis
   Chem_Other	Chemical analyses of "totally" digested samples by methods other than those identified by other values of this field.
   Chem_XRF	Chemical analyses by either energy dispersive or wavelength dispersive X-ray fluorescence
   Partial_A2Z	Chemical analyses of partially digested samples using HCl with H2O2, KI, or both
   Partial_AqReg	Chemical analyses of partially digested samples using aqua regia
   Partial_Other	Chemical analyses of partially digested samples using other digestion procedures

   bestvalue

   Best analytic value for each element obtained by selecting the most reliable analytic methods from among those that were performed on the sample (Source: USGS)

   rec_id

   Record ID.

   Integer values. Integer of width 8. (Source: this data release)

   Range of values
   Minimum:	1
   Maximum:	4287923
   Resolution:	1

   lab_id

   Lab ID.

   Unique identifier assigned to each submitted sample by the Sample Control Officer of the analytical laboratory that received the sample. Textual values of no more than 10 characters. (Source: this data release) Alphanumeric identifiers without intrinsic scientific significance

   species

   Chemical species.

   Element, oxide, compound, or property that was determined or measured by the laboratory. Textual values of no more than 8 characters. (Source: this data release)

   Value	Definition
   Li	Lithium
   Be	Beryllium
   B	Boron
   C_tot	Carbon (total)
   C_org	Carbon (organic)
   C_crb	Carbon (carbonate)
   F	Fluorine
   Na	Sodium
   Mg	Magnesium
   Al	Aluminum
   Si	Silicon
   P	Phosphorus
   S	Sulfur
   K	Potassium
   Ca	Calcium
   Sc	Scandium
   Ti	Titanium
   V	Vanadium
   Cr	Chromium
   Mn	Manganese
   Fe	Iron
   Co	Cobalt
   Ni	Nickel
   Cu	Copper
   Zn	Zinc
   Ga	Gallium
   Ge	Germanium
   As	Arsenic
   Se	Selenium
   Rb	Rubidium
   Sr	Strontium
   Y	Yttrium
   Zr	Zirconium
   Nb	Niobium
   Mo	Molybdenum
   Ru	Ruthenium
   Rh	Rhodium
   Pd	Palladium
   Ag	Silver
   Cd	Cadmium
   In	Indium
   Sn	Tin
   Sb	Antimony
   Te	Tellurium
   I	Iodine
   Cs	Cesium
   Ba	Barium
   La	Lanthanum
   Ce	Cerium
   Pr	Praseodymium
   Nd	Neodymium
   Sm	Samarium
   Eu	Europium
   Gd	Gadolinium
   Tb	Terbium
   Dy	Dysprosium
   Ho	Holmium
   Er	Erbium
   Tm	Thulium
   Yb	Ytterbium
   Lu	Lutetium
   Hf	Hafnium
   Ta	Tantalum
   W	Tungsten
   Re	Rhenium
   Os	Osmium
   Ir	Iridium
   Pt	Platinum
   Au	Gold
   Hg	Mercury
   Tl	Thallium
   Pb	Lead
   Bi	Bismuth
   Th	Thorium
   U	Uranium
   SplWtAu	Weight of sample used for gold analysis
   SplWtFA	Weight of sample used for fire assay analysis

   unit

   Units of measure.

   Unit of measurement associated with the accompanying concentration value. Textual values of no more than 8 characters. (Source: this data release)

   Value	Definition
   g	grams
   pct	percent by weight
   ppm	parts per million by weight

   qvalue

   Qualified value.

   Qualified concentration value for the associated Species and reported in the associated Unit. Values less than the lower limit of determination are negative while values greater than the upper limit of determination have a .1111 suffix. Real numbers stored in double precision. (Source: this data release)

   Range of values
   Minimum:	-10000
   Maximum:	940000

   amethod

   Analytical method.

   Analytical method code (abbreviation) for the method used to determine the associated Species. Textual values of no more than 32 characters. (Source: this data release)

   Value	Definition
   AA_CV	Mercury by cold-vapor atomic absorption spectrometry after multi-acid digestion and solution.
   AA_CV_WO	Mercury by wet oxidation and cold-vapor atomic absorption spectrometry ("flameless"); HNO3-H2SO4-HClO4 digestion, Hg aerated to silver screen, amalgamator heated in furnace, Hg vapor measured in AAS.
   AA_FE	Sodium and potassium by flame emission spectrometry (flame photometry) after HF-HClO4 dissolution or LiBO2 fusion.
   AA_F_Fuse	Major and minor elements by flame atomic absorption spectrometry after LiBO2/Li2B4O7 fusion digestion.
   AA_F_HBr	Gold and tellurium by flame atomic absorption spectrometry after HBr-Br2 digestion and selective organic extraction with Aliquat 336-MIBK.
   AA_F_HF	Major and minor elements by flame atomic absorption spectrometry after multi-acid digestion with HF.
   AA_GF_HBr	Gold and tellurium by graphite furnace atomic absorption spectrometry after HBr-Br2 digestion and selective organic extraction with Aliquat 336-MIBK.
   AA_GF_HF	Arsenic, gold, bismuth, indium, antimony, tellurium and thallium by graphite furnace atomic absorption spectrometry after multi-acid digestion with HF and selective organic extraction with Aliquat 336-MIBK.
   AA_HG_Acid	Selenium by flow injection or continuous flow hydride generation-atomic absorption spectrometry after digestion with HNO3-HCl-H2SO4-KMnO4.
   AA_HG_HF	Arsenic, antimony, selenium and tellurium by flow injection or continuous flow hydride generation-atomic absorption spectrometry after multi-acid digestion with HF.
   AA_TR	Mercury by thermal release and atomic absorption spectrometry after heating (Vaughn-McCarthy method).
   AES_HF	Major and minor elements by inductively coupled plasma-atomic emission spectrometry after digestion with HF-HCl-HNO3-HClO4.
   CB_IRC	Carbon and sulfur by infrared detection after combustion.
   CB_TC	Total carbon and organic carbon by thermal conductivity detection after combustion.
   CB_TT	Sulfur by iodometric titration after combustion.
   CM_Acid	Bromine by colorimetry after acid digestion.
   CM_Fuse	Major and minor elements by colorimetric spectrophotometry after fusion digestion.
   CM_HF	Major and minor elements by colorimetric spectrophotometry after multi-acid digestion with HF.
   CM_HSF	Fluorine by chemical separation and colorimetric spectrophotometry; chemical separation to fluorosilicic acid (H2SiF6), converted to silicomolybdate, reduced to Mo blue.
   CM_SDDC	Arsenic by colorimetric spectrophotometry after digestion in HF-aqua regia and chemical separation with SDDC.
   CP	Organic carbon, carbonate carbon and totals by computation.
   DN	Uranium and thorium by delayed neutron activation counting.
   ES_Q	Major and minor elements by quantitative emission spectrography.
   ES_SQ	Major and minor elements by semi-quantitative emission spectrography.
   FA_AA	Gold, silver and platinum group elements by graphite furnace atomic absorption spectrometry after PbO fire assay chemical separation.
   FA_DC	Gold by direct current plasma-atomic emission spectroscopy or atomic absorption spectrophotometry after PbO fire assay chemical separation.
   FA_ES	Gold and platinum group elements by direct-current arc quantitative emission spectrography after PbO fire assay chemical separation.
   FA_MS	Platinum group elements by inductively coupled plasma-mass spectrometry after NiS fire assay chemical separation.
   FL_HF	Beryllium, tin and uranium by fluorometry after multi-acid digestion with HF.
   GV	Density, moisture and weight by gravimetry; ash or loss on ignition by weight loss after heating at 900 degrees C.
   ISE_Fuse	Chloride, fluoride and iodide by ion specific electrode after fusion digestion.
   MS_HF	Major and minor elements by inductively coupled plasma-mass spectrometry after HF-HCl-HNO3-HClO4 digestion.
   NA_LC	Major and trace elements by long count instrumental neutron activation analysis; no digestion/extraction necessary.
   NA_SC	Major and trace elements by short (abbreviated) count instrumental neutron activation analysis; no digestion/extraction necessary.
   VOL	Carbon dioxide or carbonate carbon by evolution after acid decomposition; aka ""gasometric"" or ""manometric"".
   WDX_Fuse	Major and minor elements by wavelength-dispersive X-ray fluorescence spectrometry after LiBO2 fusion digestion.

   summary

   Related analyses.

   Summary of all analyses for the total concentration of a single element in a samples; analyses are listed in order of 'Best Value'. Used only in the bestvalue table. Textual values of no more than 256 characters. (Source: this data release) List of the values of concentration and analytical method drawn from fields of the chemistry table where lab_id and chemical species matches the row.

   parameter

   Parameter.

   The suggested field name for a Species_Unit column in crosstabbed chemistry tables. These field names concatenate the Species and Unit fields. Textual values of no more than 32 characters. (Source: this data release) Concatenation of chemical species and unit fields, separated by underscore

   mthd_parameter

   Method parameter.

   The suggested field name for an AMethod column in crosstabbed chemistry tables. Textual values of no more than 32 characters. (Source: this data release) Concatenation of chemical species field value and "_Mthd"

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • U.S. Geological Survey
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   Steven M Smith

   Southwest Region

   Geologist

   U.S. Geological Survey

   Box 25046 Mail Stop 973

   Denver Federal Center

   Denver, CO
   

   USA

   303-236-1192 (voice)

   303-236-3200 (FAX)

   smsmith@usgs.gov

Why was the data set created?

The National Geochemical Database is a curated repository intended to contain all geochemical analyses carried out by and for geological studies conducted by the U.S. Geological Survey. Sample characteristics, including the location from which the sample was taken, and characteristics of the location and nearby geographic area, are included as well as analytical determinations of the concentration of elements and other chemical species. The work of USGS is strongly concentrated in earth sciences, so most of the analyses are of inorganic components. Likewise as a US Federal government organization, the work of USGS focuses on areas governed by the United States. Samples are located throughout the world, but most of the samples come from the US.

How was the data set created?

1. From what previous works were the data drawn?
2. How were the data generated, processed, and modified?

   Date: 2016 (process 1 of 2)

   Chemical analyses were carried out by USGS laboratories or by other organizations contracted by USGS to carry out those analyses, over a period of decades; these results begin in the 1960s and continue to this day.

   Much of the data now in the NGDB had been previously compiled into other collections such as PLUTO and RASS. Those older databases are now subsumed into the NGDB and the concentrate sample analyses they contained are represented here.

   This process occurred over many decades, and the current compilation has reached maturity in 2016.

   Date: 2016 (process 2 of 2)

   The Best Value data set is a subset of data that represents one "best value" per species for each of its samples.

   This data set was created by ranking analytical methods, taking into account factors which vary between methods. These include weight of sample analyzed, method of decomposition of the sample during the preparation for analysis, sensitivity and accuracy of the instrument used in each method, upper and lower limits of detection for a given element by a given method, the age of the method and stage of its development when a specific analysis was performed, and the exact analytical laboratory and equipment used. The dataset was populated, species by species, first with detected values, from the highest ranked analytical method to the lowest, and then with non-detect values, from the lowest to the highest. Each "best value" per species per sample has a value, an analytical method code for that value, and a summary of one or more possible values from which the "best value" was derived.

3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

1. How well have the observations been checked?
   
2. How accurate are the geographic locations?
   Uncertainty of the point locations is exprssed, where this could be determined, in the field coord_prec_est. The information provided there accounts for the common and officially accepted practice, in years past, of specifying sampling locations by the southeast corner of the map quadrangle from which the sample was taken, and other indications that the original coordinates were expressed with limited precision. Yes, we know that accuracy and precision are not the same thing.
3. How accurate are the heights or depths?
   Sample depth is given as reported by the original investigator, and the compiler had no independent way to check those values.
4. Where are the gaps in the data? What is missing?
   Currently 3,998 of the samples described in the database have no analytical results recorded.
   In general, chemical analyses were carried out to pursue specific scientific objectives of a research project. Consequently there are no samples for which results were determined for every possible chemical analysis described in this database. Some analyses were rarely performed, and some were commonly performed. The table below shows, of the 143,350 samples, how many include an analysis, by any method, of each chemical species, with the proportion of samples (expressed as percent) for which an analysis of that chemical species was reported.

     Species  Samples Percent analyzed
   ------------------------------------
          Ag   135708 94.0%
          Al     4195  2.0%
          As   134231 93.0%
          Au   132742 92.0%
           B   131439 91.0%
          Ba   131200 91.0%
          Be   134104 93.0%
          Bi   134321 93.0%
          Ca   130776 91.0%
       C_crb      207  0.0%
          Cd   134548 93.0%
          Ce     3831  2.0%
          Co   134562 93.0%
       C_org      207  0.0%
          Cr   134218 93.0%
          Cs        6  0.0%
       C_tot      218  0.0%
          Cu   134751 94.0%
          Dy     2022  1.0%
          Er     2020  1.0%
          Eu     4062  2.0%
           F      710  0.0%
          Fe   131874 91.0%
          Ga    15270 10.0%
          Gd     2111  1.0%
          Ge    16624 11.0%
          Hf     3881  2.0%
          Hg     6482  4.0%
          Ho     2343  1.0%
           I        1  0.0%
          In     5157  3.0%
          Ir     2891  2.0%
           K     2811  1.0%
          La   130646 91.0%
          Li     4106  2.0%
          Lu     2133  1.0%
          Mg   131583 91.0%
          Mn   131644 91.0%
          Mo   134306 93.0%
          Na    14050  9.0%
          Nb   130684 91.0%
          Nd     2570  1.0%
          Ni   134610 93.0%
          Os     1765  1.0%
           P    15136 10.0%
          Pb   134799 94.0%
          Pd    20358 14.0%
          Pr     2067  1.0%
          Pt    20425 14.0%
          Rb        6  0.0%
          Re     3890  2.0%
          Rh     2939  2.0%
          Ru     2874  2.0%
           S      155  0.0%
          Sb   134112 93.0%
          Sc   121086 84.0%
          Se       16  0.0%
          Si     1488  1.0%
          Sm     2346  1.0%
          Sn   133663 93.0%
     SplWtAu     7031  4.0%
     SplWtFA      412  0.0%
          Sr   130369 90.0%
          Ta     4571  3.0%
          Tb     2125  1.0%
          Te     5452  3.0%
          Th   105098 73.0%
          Ti   133064 92.0%
          TI      340  0.0%
          Tl     5168  3.0%
          Tm     2130  1.0%
           U     6117  4.0%
           V   131878 91.0%
           W   135388 94.0%
           Y   131662 91.0%
          Yb     2578  1.0%
          Zn   135654 94.0%
          Zr   129836 90.0%
   

5. How consistent are the relationships among the observations, including topology?
   The samples described in the database were collected by a wide variety of researchers over a long period of time, and the analyses conducted on those samples were carried out for varying purposes. In addition, the sample preparation and analytical methodology varied through time as the technology available changed. The result is that samples may not be directly comparable due to differences in sampling procedure, preparation, analytical instrumentation, or choice of chemical species to analyze.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: none
Use_Constraints: none

1. Who distributes the data set? (Distributor 1 of 1)
   
   Peter N Schweitzer

   USGS Geology, Energy, and Minerals Science Center

   Geologist

   12201 Sunrise Valley Drive

   Reston, VA
   

   USA

   703-648-6533 (voice)

   703-648-6252 (FAX)

   pschweitzer@usgs.gov
2. What's the catalog number I need to order this data set?
3. What legal disclaimers am I supposed to read?

   This database has been approved for release by the U.S. Geological Survey (USGS). Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review. Furthermore, the database is released on condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from its authorized or unauthorized use.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Geochemical analyses of concentrate samples with site characteristics in format WMS (version 1.3.0)
     Network links:	https://mrdata.usgs.gov/services/ngdbconc?request=GetCapabilities&service=WMS&version=1.3.0

     Data format:	Simple shapefile with a url to the full report for each location, with all attribute data as included CSV files in format shapefile (version 1.0) Size: 52
     Network links:	https://mrdata.usgs.gov/ngdb/concentrate/ngdbconc-csv.zip

     Data format:	Simple shapefile with a url to the full report for each location, with all attribute data as included CSV files in format CSV (version 1.0) Size: 52
     Network links:	https://mrdata.usgs.gov/ngdb/concentrate/ngdbconc-csv.zip

   • Cost to order the data: none

Who wrote the metadata?

Dates:

Last modified: 30-Dec-2020

Metadata author: