Analytical Suite Metadata

GSC OF 5117 compilation of granitoid rock analyses



GSC Open File 5117 is a compilation of geoscience data for the Cape Smith Belt in the north of the Ungava Peninsula.  Analytical data for granitoid intrusive rocks were merged together from several different sources, including MSc and PhD theses, to produce a single data file.  Analytical metadata are largely absent.

General Methodology:

GSC Open File 5117 included compilations of lithogeochemical data as part of a larger compilation of geoscience data for the Cape Smith Belt.  The data were merged together from several different sources, some of which were previously unpublished.  A limited amount of metadata on analytical methods is provided in OF 5117, which indicates that the data were obtained over a period of several years, in several different laboratories, by different methods.  The compilation should be used with great caution, especially for the trace element data.  Information on detection limits was lost in the compilation process.  Values below detection are not identified as such.  The different methods would have had varying detection limits for the same quantities, but it is impossible to determine which values are actually below detection.  For example, for Picard’s data published in ET 87-14, values that were originally reported as below detection are reported in this compilation as simply the detection limit.  For example, “<5 ppm” is reported as “5 ppm”.  The data files contain many values of ‘0”.  It is not clear whether these represent missing data or values below detection.  They are treated here as “missing data”.  OF 5117 states that the measurement units for the trace elements are all in ppm, but for some quantities (Ag, Au, Pd, Pt), the measured values may be in ppb, or a combination of both ppm and ppb, depending on the data source.  In some cases, apparently high values for ultra-trace quantities may be reflecting the removal of the “<” symbol from a “below detection” measurement; for example < 15 ppm Au may become simply 15 ppm Au.  INAA data frequently have variable detection limits for the same element, further confusing the situation.

Fe is expressed in different formats.  Many analytical techniques cannot distinguish between Fe2+ and Fe3+.  In XRF analysis, Fe is conventionally reported as Fe2O3 (or Fe2O3T, for total).  Fe2+ can be measured by titration, and may then be reported as FeO.  This then allows one to calculate a “true” value for Fe3+, or Fe2O3 (or Fe2O3V, for vrai (true in French)).  Sometimes, Fe is reported as FeOT rather than Fe2O3T.  Note that the different conventions for reporting Fe will have an effect on the total sum of the major oxides.  Theoretically, this sum should be slightly less than 100.  But reporting Fe entirely as Fe2O3 rather than a mix of Fe2O3 and FeO may lead to sums of greater than 100.

Fe calculations

Using atomic weights of Fe = 55.845(2) and O = 15.9994(3), we obtain molecular weights for Fe2O3 = 159.688 and 2(FeO) = 143.689.  This gives a conversion factor of 159.688 / 143.689 = 1.1113.

We can then use the expressions:

  • Fe2O3T – FeO * 1.1113 = Fe2O3V
  • Fe2O3T = FeOT * 1.1113

 

 

Instrument: unstated

Sample material: solid

Sample weight: unstated


Analytical Technique:

Hierarchical classification

Technique >> Other >> Multiple

Children

None


Analytical Decomposition:

Hierarchical classification

Multiple

Children

None


Analytical Methods:

IndexMethod OrderMethod IDQuantityDetection Limit
1  5371     SiO2 
2  5372     TiO2 
3  5373     Al2O3 
4  5374     Fe2O3T 
5  5378     MnO 
6  5379     MgO 
7  5380     CaO 
8  5381     Na2O 
9  5382     K2O 
10  10  5383     P2O5 
11  11  5389     LOI 
12  12  5395     Cr_ppm 
13  13  5397     Ni_ppm 
14  14  5396     Co_ppm 
15  15  5393     Sc_ppm 
16  16  5394     V_ppm 
17  17  5398     Cu_ppm 
18  18  5437     Pb_ppm 
19  19  5399     Zn_ppm 
20  20  5427     W_ppm 
21  21  5403     Rb_ppm 
22  22  5404     Cs_ppm 
23  23  5406     Ba_ppm 
24  24  5405     Sr_ppm 
25  25  5425     Ta_ppm 
26  26  5424     Nb_ppm 
27  27  5423     Hf_ppm 
28  28  5422     Zr_ppm 
29  29  5421     Y_ppm 
30  30  5440     Th_ppm 
31  31  5441     U_ppm 
32  32  5407     La_ppm 
33  33  5408     Ce_ppm 
34  34  5400     Nd_ppm 
35  35  5411     Sm_ppm 
36  36  5412     Eu_ppm 
37  37  5414     Tb_ppm 
38  38  5416     Ho_ppm 
39  39  5419     Yb_ppm 
40  40  5420     Lu_ppm 

Associated Analytical Packages:

IndexPackage IDPackage Name
1  257     GSC OF 5117 granitoid rocks lithogeochemical compilation
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