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Geochemistry

 

The SIGÉOM geochemistry database includes chemical analyses of rock and secondary environment samples.

Database

Database Architecture

The SIGÉOM geochemistry database is divided into two layers or attribute tables:

  • Rock samples
  • Sediment samples (secondary environment samples)

In each of these two layers, data is contained in an entity class (main table) to which several related tables are attached, as in the following examples: (You can consult the data models for these layers here).

This type of relational structure makes it possible to obtain complete information and avoid overwriting data, as in the case of a sample reanalysis. Complete information, including all relationships between tables, is only available in ArcGIS File Geodatabase (FGDB) and Geopackage (GPKG) files.

In the case of GPKG format, we recommend the use of the QGIS software to view the data. A turnkey SIGEOM_geopackage.qgz is included with every SIGÉOM à la carte download. Table relationships are pre-established. For more information, visit this page (coming soon).

 

 

 

This relational table structure can prove difficult to manipulate. Therefore, it’s important to note that a simplified table for analysis results is always included with the downloaded file in FGDB format. For this purpose, you will need to import into your project the point files “R1E01_ECHANTILLON_ROCHE_RESULTAT” or “R1E02_ECHANTILLON_SEDIMENT_RESULTAT” as appropriate. This table details all analytical techniques for the analyzed geochemical elements. At the end of the table, the most relevant results (best analytical technique or most recent analysis) are listed.

Information provided in other formats, such as Shapefile (SHP) and Comma-Separated Values (CSV), is incomplete. In fact, these files only present the results deemed most relevant. This means that it is impossible to know which method was used for analysis, or to see if several analyses were carried out using different methods.

Information About the Database

Information Specific to Rock Samples

Field
[FGDB and GPKG][SHP and CSV]		 Information
Type of Rock Sample
[CODE_TYPE_ECHN_ROCH]
[CODE_ECHN]
Type Code Description
Government data G Geochemical analyses carried out or requested by the Ministère or the federal government. They may also have been commissioned by the Ministère for partnership projects with universities. Some data have been entered from the Ministère’s reports, particularly older data from before 1980. Since 2016, a strict quality control process has been in place for analyses carried out on behalf of the Ministère.
Manual compilation C Geochemical analyses manually compiled from works outside the Ministère (companies, university works, etc.). Samples with a « Descar » project number correspond to samples from the database compiled by Jean Descarreaux. It should be noted that Géologie Québec only performs quality control on data transfer (extraction). Possible errors may be found in the source documents. Géologie Québec is not responsible for errors in these documents. Certain data may be deleted if they appear to be erroneous (e.g., an overt location error).
Artificial intelligence compilation I Geochemical analyses manually compiled from works outside the Ministère (companies, university works, etc.). The compilation work was carried out using reports in PDF format from the EXAMINE record holdings. The data was extracted and classified using artificial intelligence. It should be noted that Géologie Québec only performs quality control on data transfer (extraction). Possible errors may be found in the source documents. Géologie Québec is not responsible for errors in these documents. Certain data may be deleted if they appear to be erroneous (e.g., an overt location error).
Numeric data from assessment work S Geochemical analyses obtained from statutory work reports submitted directly by the companies in numeric format. Therefore, there was no manual or automated compilation of data. It should be noted that Géologie Québec only performs quality control on data transfer (extraction). Possible errors may be found in the files submitted. Géologie Québec is not responsible for errors in these files. Certain data may be deleted if they appear to be erroneous (e.g., an overt location error).
Data source not specified N Geochemical analyses from unknown sources.
Unique Sample Number
[NUMR_ECHN_UNIQ]
[NUMR_ECHN]

Corresponds to the unique sample identification number assigned by the SIGÉOM. This number is made up of 10 digits and normally begins with the sampling year. For numbers starting with:

  • 6666: manually compiled analyses (type C)
  • 5555: analyses compiled by artificial intelligence (type I)
Sample Number Rock Geologist
[NUMR_ECHN_ROCH_GEOLG]
[N/A]

Corresponds to the original sample number assigned on site by the geologist.

  • Sample taken by a geologist from the Ministère:

    The number is generally composed of the following elements:

    • the last two digits of the observation year;
    • the geologist’s initials;
    • the outcrop number;
    • an alphabetical code (corresponding to the lithology of the géofiche) and a sequential number corresponding to the sample number taken for the same lithology.

    Example: 22DB1003-A1

  • Sample from sources other than the government (company, university, etc.):

    Original sample number entered in an EXAMINE record holdings report.

    Example: 126501
Notes
[COMN_ECHN_ROCH]
[COMN_ECHN]

Additional comments or notes related to a rock sample. It can also be used to indicate document references not included in the EXAMINE record holdings.

It can also be used to:

  • Indicate borehole identifier when sample origin is “Diamond drilling”;
  • Indicate certificate of analysis number (e.g., CER:A16-08999);
  • Indicate project number, geologist’s name, rock type, etc.
Provenance
[CODE_ENTT_GEOMT]
[CODE_ENTT]

This field is used to specify from which geological entity or environment the rock sample was taken.

Type Code Description
Compilation outcrop AC The sample was taken from an outcrop that was compiled from maps or historical reports. In some cases, these data are taken from previous works by the Ministère or from assessment work reports.
Géofiche outcrop AG The sample comes from an outcrop observed on site, for which the geological information has been entered in the SIGÉOM database.
Erratic boulder BE The sample comes from an erratic boulder.
Ore body CM The sample comes from a mineralized zone.
Rock sample ER The sample comes from an in-place outcrop.
Diamond drilling FD The sample comes from a diamond drilling.
Overburden drilling FM The sample comes from a rock located beneath Quaternary deposits and sampled during drilling.
Non-metallic deposit GNM The sample comes from a mineralized zone containing a non-metallic substance.
Construction materials and industrial stone PI The sample comes from a site for construction materials or industrial stone.
Showing, Anomalous and Significant Values
[ERO_VAL_INDIC],[ERO_VAL_ANOMA],[ERO_VAL_SIGNI]
[ERO_INDIC],[ERO_ANOMA],[ERO_SIGNI]

Showing, anomalous and significant values are automatically detected by the metallic substances system. For more information on determining these values, click here (coming soon).

Information Specific to Sediment Samples (Secondary Environment Samples)

Field
[FGDB and GPKG]
[SHP and CSV]		 Information
Sediment Sample Type
[CODE_TYPE_ECHN_SEDM]
[CODE_ECHN]
Type Code Description
Undefined 00 Geochemical analyses of an unknown-type sample.
Water 01
02
03
04
05
06
07		 Geochemical analyses of a water sample:

 

 

  • 01 : Undifferentiated groundwater
  • 02 : Surface water
  • 03 : Spring water
  • 04 : Well water
  • 05 : Overburden drill water
  • 06 : Rock drill water
  • 07 : Drill water

Water analyses are rare in the SIGÉOM database and date back many years. Géologie Québec no longer performs this type of analysis. Other databases are therefore probably more useful for obtaining water quality data.
Lake-bottom sediments 20 Geochemical analysis of a lake-bottom sediment sample. These analyses cover most of Quebec. The western part of the James Bay region was not surveyed, as the marine clay deposits present in the area were likely to provide an unrepresentative bedrock signal. Regarding analysis methods, the reader is referred to the various reports accompanying each survey. In most cases, however, samples were dried, crushed and homogenized before being analyzed by inductively coupled plasma mass spectrometry (ICP-MS) after dissolution in aqua regia (0.5 g aliquots).
Stream sediments 30
31

Geochemical analyses of a stream sediment sample:

  • 30 : Undifferentiated stream sediment
  • 31 : Stream sediment, heavy minerals
Soil 40
41
42
43
44
45
46
47
48
49		 Geochemical analysis of a soil sample:

 

 

  • 40 : Undifferentiated soil
  • 41 : Soil, horizon O
  • 42 : Soil, horizon AO
  • 43 : Soil, horizon A
  • 44 : Soil, horizon AB
  • 45 : Soil, horizon B
  • 46 : Soil, horizon BC
  • 47 : Soil, horizon C
  • 48 : Soil, horizon C, heavy minerals
  • 49 : Soil, horizon C, clay collected from drilling
Fine fraction of till 60
61
62
63
64
65
66
67
68		 Geochemical analyses of the fine fraction (<63 µm) of till:

 

 

  • 60 : Fine fraction of undifferentiated till
  • 61 : Fine fraction of till collected by pionjar
  • 62 : Fine fraction of till collected by reverse circulation
  • 63 : Fine fraction of till collected by rotosonic
  • 64 : Fine fraction of till collected with an auger or shovel
  • 65 : Fine fraction of basal till
  • 66 : Fine fraction of basal till collected by pionjar
  • 67 : Fine fraction of basal till collected by reverse circulation
  • 68 : Fine fraction of basal till collected by rotosonic
Heavy fraction of till 70
71
72
73
74
75
76
77
78
79		 Analyses géochimiques de la fraction lourde du till :

 

 

  • 70 : Heavy fraction of undifferentiated till
  • 71 : Heavy fraction of till collected by pionjar
  • 72 : Heavy fraction of till collected by reverse circulation
  • 73 : Heavy fraction of till collected by rotosonic
  • 74 : Heavy fraction of till collected with an auger or shovel
  • 75 : Heavy fraction of basal till
  • 76 : Heavy fraction of basal till collected by pionjar
  • 77 : Heavy fraction of basal till collected by reverse circulation
  • 78 : Heavy fraction of basal till collected by rotosonic
  • 79 : Heavy fraction of till >177 microns
Light fraction of till 80
81
82
83
84
85
86
87
88
89		 Geochemical analyses of the light fraction of till:

 

 

  • 80 : Light fraction of undifferentiated till
  • 81 : Light fraction of till collected by pionjar
  • 82 : Light fraction of till collected by reverse circulation
  • 83 : Light fraction of till collected by rotosonic
  • 84 : Light fraction of till collected with an auger or shovel
  • 85 : Light fraction of basal till
  • 86 : Light fraction of basal till collected by pionjar
  • 87 : Light fraction of basal till collected by reverse circulation
  • 88 : Light fraction of basal till collected by rotosonic
  • 89 : Light fraction of till >177 microns
Coarse fraction of till 90 90 : Geochemical analyses of the coarse fraction (>177 microns) of till
Unique Sample Numbers
[NUMR_ECHN_UNIQ]
[ECHN_UNIQ]

Corresponds to the sample identification number assigned by SIGÉOM. This number is made up of 10 digits and often begins with the year of sampling.
Depth
[PROF_SEDM]
[PROF]

Depth (in meters) at which the sample was taken. For most samples, the depth is measured from the surface of the soil. In the case of lake-bottom sediments, this value corresponds to the water depth at the sampling site.
pH
[PH]
[PH]

The pH of a sediment is measured by adding demineralized water to part of the sample. It is carried out no later than the day after sampling. The usual procedure is as follows:

  1. Using a spatula, scoop out a sample of approximately 3.5 cm3 (1.5 x 1.5 x 1.5 cm) and place it in a small porcelain crucible.
  2. Add demineralized water until the material is slightly oversaturated with water.
  3. Stir thoroughly and break up all concretions.
  4. Let it rest for about five minutes.
  5. Measure with pH meter and combination electrode. E.g.:

    Instrument –> Fisher Accumet 150 (portable) pH/Meter cat. 13-637-15.
    Electrode –> Standard Combination Electrode Model Pin Terminal combination cat. 13-639-100. Fisher catalog.

  6. Carefully lower the electrode into the solution (with minimal movement) to avoid damaging it. Make sure to submerge the sensor tip, wait a few seconds for the instrument to stabilize, and record the pH value on the 0.1-unit scale.
  7. Clean crucibles thoroughly with demineralized water between each preparation.
  8. After completing the day’s readings, cover the reservoir hole on top of the electrode with the provided rubber. Clean the instrument thoroughly, following the instrument’s cleaning instructions. The instrument should be calibrated before each series of determinations to achieve an accuracy of 0.1 pH unit.
  9. The KCl solution supplied with the instrument may need to be added to the electrode sometimes.
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Project Number
[NUMR_PROJ_SEDM]
[PROJ_SEDM]

A project number is assigned to each secondary environment geochemistry survey (e.g., lake-bottom sediment survey or stream sediment survey). This number is often recorded in reports. It can also be viewed on the interactive map via the “Ministry geoscientific works” tab.
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