Analytical Suite Metadata

GSC OF 5117 compilation of volcanic rock analyses



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  The data were merged together from several different sources, some of which were previously unpublished.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 Fe 2+ and Fe 3+.  In XRF analysis, Fe is conventionally reported as Fe 2O 3 (or Fe2O3T, for total).  Fe 2+ can be measured by titration, and may then be reported as FeO.  This then allows one to calculate a “true” value for Fe 3+, or Fe 2O 3 (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 Fe 2O 3 rather than a mix of Fe 2O 3 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 Fe 2O 3 = 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

Decomposition >> Multiple

Children

None


Analytical Methods:

Index Method Order Method ID Quantity Detection Limit
1  5371     SiO2  
2  5372     TiO2  
3  5373     Al2O3  
4  5374     Fe2O3T  
5  5375     Fe2O3V  
6  5376     FeO  
7  5377     FeOT  
8  5378     MnO  
9  5379     MgO  
10  10  5380     CaO  
11  11  5381     Na2O  
12  12  5382     K2O  
13  13  5383     P2O5  
14  14  5384     Total_Dry  
15  15  5385     S  
16  16  5386     CT_CO2  
17  17  5387     C_Tot  
18  18  5388     H2O  
19  19  5389     LOI  
20  20  5390     Total_LOI  
21  21  5391     Li_ppm  
22  22  5392     Be_ppm  
23  23  5393     Sc_ppm  
24  24  5394     V_ppm  
25  25  5395     Cr_ppm  
26  26  5396     Co_ppm  
27  27  5397     Ni_ppm  
28  28  5398     Cu_ppm  
29  29  5399     Zn_ppm  
30  30  5400     Ga_ppm  
31  31  5401     As_ppm  
32  32  5402     Se_ppm  
33  33  5403     Rb_ppm  
34  34  5404     Cs_ppm  
35  35  5405     Sr_ppm  
36  36  5406     Ba_ppm  
37  37  5407     La_ppm  
38  38  5408     Ce_ppm  
39  39  5409     Pr_ppm  
40  40  5410     Nd_ppm  
41  41  5411     Sm_ppm  
42  42  5412     Eu_ppm  
43  43  5413     Gd_ppm  
44  44  5414     Tb_ppm  
45  45  5415     Dy_ppm  
46  46  5416     Ho_ppm  
47  47  5417     Er_ppm  
48  48  5418     Tm_ppm  
49  49  5419     Yb_ppm  
50  50  5420     Lu_ppm  
51  51  5421     Y_ppm  
52  52  5422     Zr_ppm  
53  53  5423     Hf_ppm  
54  54  5424     Nb_ppm  
55  55  5425     Ta_ppm  
56  56  5426     Mo_ppm  
57  57  5427     W_ppm  
58  58  5428     Rh_ppm  
59  59  5429     Ir_ppb  
60  60  5430     Pd_ppb  
61  61  5431     Pt_ppb  
62  62  5432     Ag_ppm  
63  63  5433     Au_ppb  
64  64  5434     Cd_ppm  
65  65  5435     Tl_ppm  
66  66  5436     Sn_ppm  
67  67  5437     Pb_ppm  
68  68  5438     Sb_ppm  
69  69  5439     Te_ppm  
70  70  5440     Th_ppm  
71  71  5441     U_ppm  

Associated Analytical Packages:

Index Package ID Package Name
1  256     GSC OF 5117 volcanic rocks lithogeochemical compilation
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