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Drift Composition and Surficial Geology of the Trutch Map Area (94G), Northeastern British Columbia

Geological Survey of Canada Open File D3815

Heavy Mineral Analysis of 45 Tills, Northeastern British Columbia

Recommended Citation:
Paré D.1
2000: Heavy Mineral Analysis of 45 Tills, Northeastern British Columbia in Drift composition and surficial geology of the Trutch map area (94G), northeastern British Columbia, J.M. Bednarski (comp.); Geological Survey of Canada Open File D3815

1D. Paré,Consorminex Inc.,11-1695 Atmec, Gatineau, Québec, Canada (819) 669-2820, fax (819) 669-2775 (Email: cmx@consorminex.com)


Contents

Introduction
Description of Selected Minerals
Results; 98BJB (45 samples) series

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Introduction

The analyses were done on the 63-250µm, 3.3 s.g. heavy mineral fraction of 45 sediment samples, mounted in epoxy cement on 1 x 3 inch glass slides by the staff of the Sedimentology Lab, 601 Booth, G.S.C., Ottawa.

A Zeiss, Stemi SR, stereoscopic microscope with polar and Nicol, in conjunction with a petrographic microscope, were used to count the heavy minerals. The ribbon method was used to count 300 grains. A computer program was used to enter the data by keyboard in the same manner as a Swift blood cell counter.

A preliminary scan of all the slides was done to before the classification for counting was prepared. The data is presented as a spread sheet.

Description Of Selected Minerals

No attempt is made here to interpret the data. However selected minerals from the classification are described for the following reasons:

  1. to describe the variation within a mineral group
  2. to allow comparisons with other heavy mineral studies
  3. to point out minerals that should be verified using SEM, microprobe, or XRD
  4. to describe the level of difficulty in identifying individual heavy minerals.

Pyrite

With the exception of the first and last sample, very few grains of fresh pyrite were observed. The two goethite covered pyrite classes, however, consist of grains that are covered by a very thin coat of goethite and the fresh pyrite can be seen through the goethite or directly, where the goethite has flaked off.

Hematite

This class includes grey and red hematite. Some red hematite grains were difficult to distinquish from red goethite. When this was the case, the mineral was counted as goethite.

Ilmenite

The common, dull grey, variety of ilmenite was counted separately from the black, high lustre ilmenite (the grains are very similar to those in the image).

Chromite

Grains were observed in only one sample, 98BJB0043.

Rutile

Consists mostly of dark red to almost black variety. A separate class for bright orange rutile, was used (the red rutile resembled the darker grains in this image).

Anatase

Most of the grains are light blue, a few are tan or washed out yellow. It is unusual to see so many anatase grains in a suite of samples.

Leucoxene

Some samples were unusually rich in leucoxene. Sample 98BJB0043 contains 7%. It is very rare for a till(?) to contain so much leucoxene. The sample is also rich in other resistant minerals such as zircon, rutile, chromite, and garnet.

Barite

Barite is very plentiful and is the dominant mineral in many of the samples. The mineral was counted using three classes. Since the bondaries between these classes, colourless, cloudy, and stained, are not sharp, the percentages reported in the table are not very precise. However, there are important variations in the abundance of the various barites from one sample to another. In these cases, the classification may be useful.

Kyanite

Kyanite is absent all samples. It is important to point out that care has to be taken in identifying kyanite in these samples as it can resemble colourless, tabular barite.

Goethite

The goethite class consists of 1) pale yellow to dark brown earthy to varnished grains, 2) red botryoidal and fossiliferous, earthy grains, 3) black, varnished, irregular and botryoidal, 4) euhedral grains after pyrite. Many of the grains classified as pseudomorhs after pyrite may have only thin coats of goethite; it is impossible to say. With the two goethite covered pyrite classes, there are six classes of goethite and it may be convenient to combine some or all of these classes (this goethite is similar to those in the image; note pseudomorph after pyrite in right bottom corner).

Hornblende

Hornblende was very rare to absent in the samples and the few grains present were difficult to identify. Samples 98BJB0002 and 98BJB0029 are therefore interesting as the hornblende is relatively plentiful and easy to identify (this hornblende is also very similar but without the blue grains).

Clinopyroxene, orthopyroxene, and hypersthene

Most of the pyroxene grains had to be verified under crossed polars. Hypersthene was counted separately from orthopyroxene.

Epidote

Most of the epidote grains consisted of an easily recognised, classic, pistachio yellow-green, epidote (typical epidote seen in sample). Unlike samples from the shield, very few grains were observed. As with hornblende however, sample 98BJB0002 stands out as an exception with 4.7% epidote.

Garnet

The garnet are colourless to pink almandine/pyrope (purple of Gwynn and Dreimanis) solid solution series. Its abundance is also extremely variable in the samples (The garnets in the sample resemble the garnet in the top, right corner).

Staurolite

Only one grain of staurolite was found (98BJB0002). It is probably useful to keep in mind that staurolite is associated with metamorphism (very similar to staurolite in samples).

Monazite

Monazite is absent in most samples and the 1 or 2 grains that show up in a few of the samples is far from helpful. It is, however, a consolation that, along with clinopyroxene, this is the only mineral osbserved in the suite, whose variation is so low as to be unhelpful.

Zircon

Zircon is easily recognised in these sediments and the variation of abundance is substantial (e.g. these images are very similar to zircons and rounded zircons in the samples).

Contamination

Most of the samples had silvery, shavings of metal, probably aluminium. Samples where these shavings were particularly plentiful are marked with a p in the table.


Results


Percent proportion, heavy minerals, >3.3 s.g., 63-250µm, 300 grain count of grains mounted in epoxy (1"X2" petrographic slides).
SAMPLE PY Pg Pr HM IL Ib CM RU Ro AT LX BA Bc Bs KY GO Gf Gb Gp HB CP OP HY EP GA ST MZ ZR ZA UK Al
98BJB0001 0.0 0.3 0.0 1.0 6.7 8.3 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.0 44.7 0.0 0.0 0.0 1.0 0.0 1.0 29.0 1.3 5.0 0.0 0.0 0.0 0.0 1.0  
98BJB0002 0.3 0.7 0.0 6.3 1.7 5.0 0.0 0.3 0.0 0.0 1.0 0.0 0.0 0.0 0.0 30.3 4.0 0.0 0.0 4.0 0.0 1.3 13.7 4.7 25.7 0.3 0.0 0.3 0.0 0.3  
98BJB0003 0.0 3.7 0.3 1.3 1.7 0.0 0.0 0.3 0.0 0.0 1.3 43.7 4.0 1.0 0.0 32.7 0.0 0.0 3.7 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 2.0 3.0 0.0  
98BJB0004 0.0 1.7 0.0 0.0 1.0 0.3 0.0 0.0 0.0 0.0 0.0 41.0 11.0 2.0 0.0 37.3 0.0 0.0 2.3 0.0 0.0 0.0 0.3 0.0 0.7 0.0 0.0 0.0 1.3 0.0  
98BJB0005 0.0 2.3 8.0 1.7 0.0 0.0 0.0 0.0 2.0 0.0 2.3 21.3 0.7 5.0 0.0 37.7 0.0 0.0 4.0 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.3 1.7 6.3 1.0  
98BJB0006 0.0 0.3 0.3 1.3 0.0 0.0 0.0 0.3 0.0 0.0 0.7 7.3 1.0 0.3 0.0 80.0 0.3 0.0 4.3 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.3 0.3 1.0 0.0  
98BJB0007 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 1.0 0.0 2.0 0.0 87.7 0.0 0.0 3.0 0.3 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 2.7 0.7  
98BJB0008 0.0 4.3 0.7 0.7 0.7 0.0 0.0 0.0 0.0 0.3 1.7 6.3 2.7 2.7 0.0 27.7 47.0 0.3 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 1.7 0.0 p
98BJB0009 0.0 0.3 0.0 1.7 0.0 0.0 0.0 0.0 0.7 0.0 1.0 6.3 1.0 1.3 0.0 78.3 4.3 0.3 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 1.7 0.3  
98BJB0010 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.3 1.0 3.0 0.0 0.0 0.0 0.0 64.7 0.3 0.0 16.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 12.7 1.0  
98BJB0011 0.0 0.3 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 73.0 0.0 3.3 21.7 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.7  
98BJB0012 0.0 1.3 0.7 0.7 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 66.3 0.0 6.0 23.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.7  
98BJB0013 0.0 0.3 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 0.0 60.0 16.3 4.0 0.0 19.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 p
98BJB0014 0.0 0.0 0.3 1.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 16.3 64.3 0.7 0.0 13.7 0.0 0.0 2.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 p
98BJB0015 0.0 0.0 0.3 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 18.7 51.7 0.0 0.0 23.0 0.0 0.0 5.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.3 0.0 p
98BJB0016 0.0 0.0 0.0 0.3 0.0 0.3 0.0 0.0 0.0 0.0 0.7 7.7 2.3 13.3 0.0 69.0 0.0 0.0 3.0 0.0 0.7 0.0 0.3 0.0 0.0 0.0 0.0 0.0 2.3 0.0  
98BJB0017 0.0 0.3 4.3 0.0 0.7 0.0 0.0 0.0 0.0 0.0 0.0 39.3 12.3 1.3 0.0 33.0 0.0 0.0 8.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0  
98BJB0018 0.0 4.3 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 11.3 23.7 10.0 0.0 39.3 0.7 0.0 10.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 p
98BJB0019 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.3 9.3 34.3 1.3 0.0 42.7 0.0 0.0 11.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 p
98BJB0020 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 21.0 65.7 2.3 0.0 9.0 0.0 0.0 1.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  
98BJB0021 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 13.7 76.7 2.7 0.0 5.0 0.0 0.0 1.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  
98BJB0022 0.7 2.3 0.3 1.3 0.0 0.0 0.0 0.0 0.3 0.0 0.0 10.7 23.3 5.7 0.0 50.0 0.0 0.0 2.7 0.0 0.3 0.0 0.0 0.0 0.7 0.0 0.0 0.0 0.7 1.0 p
98BJB0023 0.3 55.6 0.7 2.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 4.0 4.0 1.3 0.0 21.0 0.0 0.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.0 0.7 p
98BJB0024 0.0 0.7 0.0 2.3 0.0 0.0 0.0 0.7 0.0 0.3 1.7 8.7 20.7 3.3 0.0 51.0 0.0 0.0 2.7 0.0 0.0 0.0 0.0 0.0 1.3 0.0 0.0 1.7 5.0 0.0  
98BJB0025 0.0 0.0 0.0 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 4.0 14.3 0.3 0.0 59.7 0.0 0.0 13.3 0.0 0.0 0.0 0.0 0.0 1.3 0.0 0.0 0.0 4.7 0.0 p
98BJB0026 0.3 0.0 0.0 1.3 0.0 0.0 0.0 1.3 0.0 0.0 5.3 0.0 0.0 0.0 0.0 64.7 0.0 8.3 3.0 0.3 0.0 0.0 0.0 0.0 2.3 0.0 0.0 2.3 9.7 1.0  
98BJB0027 0.0 0.3 0.0 1.0 0.0 0.0 0.0 1.0 0.0 0.0 2.7 0.0 0.0 0.0 0.0 75.3 0.0 7.0 3.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 9.0 0.3 p
98BJB0028 0.0 0.0 0.0 1.7 2.7 0.0 0.0 1.7 0.0 0.0 2.7 1.3 0.0 0.0 0.0 70.7 0.0 7.3 4.0 0.0 0.0 0.0 0.0 0.0 1.7 0.0 0.0 1.3 5.0 0.0 p
98BJB0029 0.0 0.0 0.0 1.3 2.7 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.3 0.0 0.0 66.0 0.7 2.3 0.0 3.0 0.0 4.3 0.3 1.0 15.3 0.0 0.0 0.0 0.0 1.7 p
98BJB0033 0.0 0.3 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.7 10.0 25.0 2.0 0.0 59.0 0.0 0.7 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 1.3 0.0 p
98BJB0034 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 41.3 40.3 1.0 0.0 12.3 0.0 0.0 4.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 p
98BJB0035 0.0 0.3 0.0 0.7 1.0 0.0 0.0 1.3 0.0 0.0 0.3 0.0 2.7 0.0 0.0 77.7 0.3 0.7 11.3 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.0 3.3 0.0 p
98BJB0036 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.7 0.3 0.0 0.0 0.0 0.0 39.7 0.0 0.3 56.3 0.0 0.0 0.0 0.0 0.0 0.7 0.0 0.7 0.0 0.3 0.3  
98BJB0037 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 44.3 46.0 1.0 0.0 5.7 0.0 0.0 2.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  
98BJB0038 0.0 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 47.7 41.0 0.3 0.0 8.3 0.0 0.0 2.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0  
98BJB0039 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 35.7 57.0 0.7 0.0 6.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0  
98BJB0040 0.0 0.0 0.0 0.0 0.3 0.3 0.0 0.0 0.0 0.0 0.0 2.7 1.7 0.0 0.0 75.0 0.0 0.0 18.3 0.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.7 0.0  
98BJB0041 0.0 0.0 0.0 0.3 0.7 0.0 0.0 0.0 0.0 0.3 1.7 7.7 54.3 1.7 0.0 23.7 0.0 0.0 2.7 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.3 5.0 1.3  
98BJB0042 0.0 0.0 0.0 0.3 1.0 0.3 0.0 0.0 0.0 0.3 0.3 0.0 0.7 0.3 0.0 84.0 0.0 0.3 11.3 0.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.0 0.3 0.3  
98BJB0043 0.0 0.0 0.0 4.7 5.0 1.3 1.0 0.0 1.7 0.7 7.0 0.0 0.7 0.3 0.0 29.7 0.0 0.3 0.3 0.7 0.0 0.3 0.0 1.0 20.7 0.0 0.0 11.0 13.0 0.7  
98BJB0044 0.3 2.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 6.0 21.0 0.0 0.0 52.0 0.3 0.0 12.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.7 2.7 0.0 p
98BJB0045 0.0 0.0 0.0 4.0 0.0 0.0 0.0 0.0 0.0 1.3 1.7 0.0 0.0 0.0 0.0 50.0 0.0 0.0 16.0 0.3 0.0 0.0 0.0 0.3 0.0 0.0 0.0 5.3 20.7 0.3  
98BJB0046 0.0 0.3 0.0 6.0 0.0 0.0 0.0 0.0 0.0 0.0 1.3 0.0 0.0 0.0 0.0 78.7 0.0 0.0 11.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.0 1.0  
98BJB0048 0.3 0.3 0.0 0.7 0.3 0.0 0.0 0.0 0.0 0.0 0.7 4.7 32.3 0.0 0.0 39.7 0.0 0.0 13.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.0 5.7 0.0  
98BJB0050 34.7 39.7 0.0 1.0 8.0 1.7 0.0 0.0 0.0 0.0 0.7 1.3 4.3 0.3 0.0 4.7 0.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.3 2.0 0.0  
PY=pyrite; Pg=pyrite, goethite covered; Pr=pyrite, red goethite covered; HM=hematite, grey; IL=ilmenite, grey; Ib=ilmenite, black; CM=chromite; RU=rutile, red; Ro=rutile, candy orange; AT=anatase; LX=leucoxene; BA=barite, colourless; Bc=barite, milky; Bs=barite, stained; KY=kyanite; GO=yellow to brown; Gf=goethite, red botryoidal and fossiliferous; Gb=goethite, black, varnished; Gp=goethite after euhedral pyrite; HB=hornblende; CP=clinopyroxene; OP=orthopyroxene; HY=hypersthene; EP=epidote; GA=garnet, pink; ST=staurolite; MZ=monazite; ZR=zircon; Za=zircon, rounded; UK=unknown and unidentifiables; Al=aluminum shaving, p=present

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