Silver and thallium contents of rocks

C3eochlmlca et C!oamochlmim

Acta.

1080. Vol.

10, pp. 139 to 146.

Pergamon

GEOCHEMICAL

silver

Press Ltd.

Printed

In Northern

Ireland

NOTES

contents of rocks

and thallium

PEIO~ to the recent study of HAXAQUCHI and KIJRODA(1959) little information has been available on the distribution of silver in igneous rocks. In order to attain the necessary analytical sensitivity, these investigators used a procedure involving ohemical enrichment followed by spectrochemical analysis (HAMAC+UCEL-I and KWODA, 1957). We have recently determined silver in some rooks by neutron-activation analysis and feel that our results may be of interest. In our analytical method both silver and thallium were determined in 1 g samples. Full details of the procedure will be published elsewhere. In Table 1 are shown our results for the standard granite G-1 from Weaterley, Rhode Island, and for the standard diabase W-l from Centreville, Virginia. The data for thallium Table 1. Silver and thallium analyses of the standard granite G-l and standard diabaae W-l G-l Silver content (w.m.)

0.047 0.046 0.048 0.036 0.038 0.037 0.044 0.042 0.043 av. 0.042

W-l

I Thallium content (p.p.m.1

I

1.3 1-l l-2 l-4 1.0 1-5 1.0 1.5 1.4 av. 1.3

Silver content @p.m.) 0.055 0.055 0.058 0.068 0.057 0.058 RV. 0.057

Thallium content @p.m.) 0.15 0.17 0.17 0.18 0.17 0.16 av. 0.17

appear to be independently confirmed by results obtained by the ion-exchange and spectrographic technique of EDQE et al. (1959), namely l-3 p.p.m. Tl in G-1 and 0.1 p.p.m. Tl in W-l (AHREYS,private communication). Table 2 records the results obtained by us for the silver and thallium contents of a series of rocks supplied by Dr. J. R. BUTLER, Department of Geochemistry, Imperial College, London. The arrangement corresponds to the geological differentiation succession of the rocks in the Insch Mass, (mostly gabbro), Aberdeen&ire. In general the silver contents reported here seem to be similar to those found by HAICAQUCECI and KURODA (1959) in corresponding Japanese rocks. This helps to provide some 139

Geochemicalnotes Table 2. Silver and thallium in rocks of the Insch Mass, Aberdeenshire

-

Sample no. (Dept. of Geology, Imperial College, London) 3722(H63)

Rock

i

Silver found @p.m.)

Location

-__--Peridot&e

IV &ope of Hill of Barra

y

! I

0.030 0.028 0.030 0.028

3724(H67)

Pyroxenitic peridotite

As above

0.086 0.078

3732(H56)

Olivine gabbro

NE top of Gallow Hill, Leslie

0*03’ 0.041 0.038 0.042 0.44 O-46 0.47 0.43

3645(H107

3731(H51)

Thallium folmd (p.p.m.)

Syenogabbro

Syenite

S slope of Gallow Hill

SW slope of Callow Hill

0*040 0.032 0.039 0.038 0.040 0.036 0.033

/

; : ; i ; j j j 1 1 i

1.03 1.06 1.04 1.04

0.047 0.043 0.046 0.048 0.046 0.045 O-047 0.045 0.31 0.28 0.26 0.26 o-34 0.26 0.31

further justification for their calculation of the erustal abundance of silver as 0.08 p.p.m. In addition, our analytical results for thallium can be correlated quite well with the data obtained by other workers for similar rock types @RAW, 195’7). D. F. C. Momrs

R. A. KILLICK

Department of Chemistry Brmnel College of Technology London, W.3 R~F~~E~~Es

EDQE R. A., SROOXS R. R., ABXBNS L. H. and AMDUFT.ERS. (1959) Combined use of ion-exchange enrichment and spectroohemical analysis for the determination of trace constituents in silicate rocks. Cfeochirn.et Coamochim. Acta 16, 337-341. HAMAQUCXIII. and KURODA R. (1957)Determination of traces of silver in silicate rocks. J. Chem. Sot. Japan, 78, 1666-1671. IIAXAWXBI H. and KUEODA R. (1959) Silver oontent of igneous rooks. Geochim. et Cosmochim. Aei%zX7,44-52. SEAW D. M. (1957) The geochemistry of gallium, indium, thallium-a review. Phy&s and Chemi&y of the Earth 2, 104-211. Pergamon Press, London. 140