- Email: [email protected]
Beryllium in deep-seated crustal rocks
702
Notes
by COMPSTONet aE. (1970) for the Apollo 11 intqsertal basalts now becomes 3.71 & O-1 b.y. in good agreement with the results of PAPANASTASSIOUand WASSERBURG (1970).
of the difference in *%r concentration between the 1969 and 1972 calibrations of Rb-Sr 1 can be attributed to evaporation. It appears that the fused RbCl used in the original shelf sohtion contained l-8 per cent more Rb than the stoichiometric proportion, presumably due to the substitution of Cl by lighter anions such as F or 0. All
Ackwwkdg men&-We thank J. C. RODDICK,M. W. MAXON 8nd D. J. MILLARfor assist8noe with mass-spectrometry.
REFERENCES CATANZABO E. J., MV~PHY T. J., GARNERE. L. and SHIELDSW. R. (1969) Absolute isotopic abundance rrrtioand 8tomic weight of terrestritrlrubidium.J. Res. Nat. Rur. Stand. 73A (Phy8. andChem.) 6,511-516. COTKPSTON W., CH~SPELLB. W., ARBIIENsP. A. and VERNONM. J. (1970) The chemistry and 8ge of Apollo 11 luner msterial. Proc. Apollo 11 LumarSci. Conf.(editor A. A. Levinson), Vol. 2, pp. 1007-1027. Perg8mon. COWP~TON W., VERNONM. J., B-Y H., RTJDOWSKI R., GRAYC. Y., Waaa: N., CEAPPELL B. W. 8nd EAYX M. J. (1972) Age and petrogenesisof Apollo 14 bsaalts (8bStmCt). In LuwScaence 111 (editor C. Wetkins), pp. 161-163. Lunar %entx Contr. No. 88. DECAL C. (1963) Itwrganic ThermogmvimetticAnaiyai8, 2nd Ed. Elsevier, New York. MWTHY V. R., E~ENEENN. M., JAEN BosMrwo and COSOIOM. R. (1972) Rb-Sr ages, trace elements, and speculations on luner differentiation (abatmct). In tinor gcience 111 (editor C. Wetkins), pp. 571-672. Lunar Science Contr. No. 88. PAPANMTASBIOU D. A., WASSERBUBU G. J. and B-TT D. S., (1970) Rb-Sr ages of lunar rooks from the Se8 of Trenquillity. Earth Plant. Sci. Letter8 &l-19. PAP~AST~SSXOUD. A. and Wksslsa~oaa G. J. (1971) Rb-Sr ages of igneous rocks from the Apollo 14 mission and the 8ge of the Fra Mauro Formetion. E&h. Planet. Sci. Letter8 12, 36-48. SHIELDSW. R., G-R E. L., HEDGE C. E. and GOLDICHS. S. (1963) Survey of Rbes/Rbe7 ratios in minerele. J. &aphye. Rss. 68, 2331. TAT~~XOTOM., HEDQEC., DOE B. R. 8ndUwsus D. (1972) U-Th-Pb and Rb-Sr measurements on some Apollo 14 lunar samples. Pmt. Apollo 14 Lunar Sci. Conf. (editor A. A. Levinson), Vol. 2 (in press). &ochlmica et Comxxhimlca Acta.1973.vol.37,pp.702to 708. Pergamon Preaa.Printed inNorthern Ireland
Beryllium
in deeg-mhd
orustal rocks
G. P. SIQEINOLFI Istituto di Minemlogia e Petrologia, UniversitB di Modena, 41100 Modene, Itely
(Received 0 June 1972; acceptedin revisedform 12 September1972) &&&-In the gmnulites of the Brazilian shield, beryllium decreeees in the order: intermediate granulites, basic grsnulites, gmnitic gmnulites. Two hypotheses Bpeput forward for this peculiar distribution: (1) isochemicel beheviour during metamorphism of the original sediment, where Be w8e more 8bundant in p&tic th8n in 8ren8ceous rocks; (2) dehydration reactions 8nd/or partial melting, with removel of 8 Bebe8ring mobilizate, affecting the granitic more then t,heintermediate or b&o gmnulitee.
703
N0t.M
INTRODUCTION
of beryllium and the mechanisms which regulate its distribution in magmatic processes have been sufficiently discussed. Little is known, on the other hand, of the geochemistry of beryllium in metamorphic formations, particularly in high-grade metamorphic rocks. Recently, some authors (HURLEY, 1968 ; LAMBERT and HEIER, 1968) pointed out that high-grade metamorphic rocks are present in the lower Earth’s crust. The present work deals with the distribution of beryllium in a granulite terrain in the Precambrian Brazilian shield, contributing to some extent to the knowledge of this element in the lower crust. Detailed petrographic descriptions, general geochemical trends followed by main and trace elements and discussion on the role of metamorphism in the redistribution of elements are reported in previous works ( SICWINOLFI, 1970,197 1). They are granulitic rocks in which medium- to high-pressure types predominate; their most probable ages are 1900-2100 m.y. Beryllium was determined (in 62 samples) by flameless A.A. spectroscopy using the Perkin-Elmer heated graphite atomizer HGA 70 and Model 303 spectrophotometer. The detailed procedure is described by SIQHINOLFI (1972). Precision (about 10 per cent) and accuracy checks were carried out on USGS standard rocks. THE BEEAVIOUR
GENERALDISTRIBUTION OF BEBYLLZUBI IN THE Gm TERR&IN Table 1 reports the average Be content in the whole terrain and in some single rock types subdivided according to the SiO, content. Figure 1 shows the distribution of beryllium on a histogram as plotted by BEUS (1961). The average content of 2.1 Table 1. BeryIlium in various geologid environmente
Range
ppm Average
n
04-64 0.6-3-7 04F3.4
2.1 1.6 1.7
62 9 11
This work This work This work
1.2~0.4 0.6-4.5
2.6 13
25 17
This work This work
0.9 1.6 5.5 4.5
22 7
SANDELL(1962) SANDELL(1962) HORMANN(1967) BEUS (1961)
Beryllium in whole SmmIlita terrain a&d: SiOs > 70% sub-acid: SiO, 66-70% intermediate: SiO, 56-65x basic: SiO, < 56% Subsilicic rocks Dioritse Gra’Xlites biotite granites muscovite and twomicas granites A.lkalic rocks Pelagic clays Bedeposited clays Platform sands schists Gneisses Amphibolites Earth% crust n = number of samples. 22
I-30
l-50
10.0
11.4 6.0
50
2.6 2
5 26
4 3
20
2-3
2.8
6
BEUS (1961) SEAWE and BERNOLD(1964) HORBUNN(1967) MEILBILL et cr2.(1960) BEUS (1966) HIIWT (1962) BEUS (1966) BEUS (1966) SLEPNEV(1959) TAYLOR ( 1964)
704
Fig. 1. Distribution
of beryllium in gmnuiitic
rocks.
1Ogruithmic scale aa a function of frequency (log Z:
Be concentrations
iu s
arithmetio mean).
standard deviation C % = 45.5) is slightly lower than the crustctleetimate of TAYLOR(1964). The Be distribution in the various types of granulites differs markedly (see Table 1) from that in magmatic rocks: there beryllium tend8 to increz18eregularly from basic to acid rocks, showing a maximum accumulation in the latest differentiate8 such as granitic pegmatites or in alkalic rocks. SHAWX and BERNOLD (1964, 1966) found a close relationship in magmatic rock8 between beryllium and silica. In the granulite terrain beryllium in general does not appear to be signiflcantly correlated either with the silica content (see Fig. 2) or with the alkalic character of the rocks. On the contrary, the maximum Be content is found in the more diffuse ‘intermediate’ type, while rocks of granitic composition appear to have very low Be contents, both in comparison with magmatic rocks showing the 8ame acidity, and in comparison with basic granulites. Furthermore, detailed ob8ervations of the result8 show that the Be distribution can be regulated by several Merent factors, such 88 spatial localization within the terrain or the peculiar chemical or mineralogical character of the rock. For example, some anomalous high Be content8 are found sporadically in samples showing alkalic tendency or in hornblende- or in biotite-rich rocks. ppm (rehkive
Be DISTRIBUTION AND HIGH-GRADEMETAMORPHISM: POSSIBLEINTERPRETATIONS Conclusion8 of preceding works (SIGEINOLFI,1970, 1971) on the same granulite terrain based on geochemical data such as K/Rb values, Li content, etc., lead the author to consider granulites as unmelted residuals of partial melting proce88es. These residuals would be deprived of some granitophile elements through depletion8 in a migrating melt phltse and/or through dehydration reactions. Owing to it8 high mobility in fluid compounds, particularly fluorine-rich fluids, beryllium would al80 be moved, at least partially, from granulitic residuals. The results of this work make it difficult to assert that noticeable Be depletions from the granulitic rocks have
705
NOtee
Fig. 2. Variations of beryllium iu gwsulitee
88
8
function of the 8ilio& camkant.
occurred. Acid graxmlites behave abnormally showing Be levels markedly lower in oomparison with other rooks of granitic oomposition. On the basis of theee observatioae two hypotheses c&cerning possible relationships between Be distribution and metamorphism can be considered: (a) high-grade metamorphism hae not notably affected the Be distribution: in this case the at&al levels of beryllium in the vtious rock typea merely represent features of the origimxl material. AB a sedimentary sequence, as shown by many obeervations, is the most probable original material of this terrain, the aotual distribution of beryllium reflects the fact that, in aedimtmte,pelitic rooks normally oontain higher Be levels than more silicic arenaceous rocks (eee Table 1). (b) A *bution of beryllium within the same gram&e terrain ocaurred, analogous with other mobile elements, following fluid phases, so that local concentrations or depletions of beryllium were caused by local chemico-physical conditions. The low Be levels in ‘granitic’ granulite~ in this IXM would be the results of dehydration reaotiona and/or partial melting proce~~a which obviously &eot granitic material more than intermediate or b&c rocks. REFERENCES BEUS A. A. (1961) Distribution of beryllium in granites. Uwchemtiq (USSR) (English Transl.) 6, 432-437. BEVB A. A. (lfM3) Uc&w&q/ of &uy&utn. Freeman. HURSTD. %f. (1862) The geo&m&q of modern wdimente from the Uulf of Park-II. The location end diataibution of trace elements. &o&k. Ckwwc&m. A&x $6, 1147-1187. H&XANN P. K. (1989) Handbook of @iochemistry. II-l. BwyUiwa. Springer. HURLEY P. M. (1968) Aboolute abundance and distribution of Rb, K and Sr in the Ikth. G’wchk Uoanwch&n. Acta 88,273-283. LAMB- I. B. and HEIEB K. 8. (1908) Gteochemicsl iuveatigatione of deep-seated rocks in the u&r&an Shield. Lithoa 1, 30-&i3. MkUULL J. R., LYDENE. F. X., HONDAM. and ARNOLDJ. R. (1960) Sedimentery geochemistry of the beryllium isotopes. &whim. Cosmochim. Acta 18, 108-129.
706
xotes
SANDELLE. B. (1962) The beryllium content of igneous rocks. Qeochim. Cosmochim. acta 2, 211-216. SHALE D. R. and BERNOLD S. (1964) Distribution of beryllium in igneous rocks. U.S. Beol. Surv., Prof. Paper 501-B, 100-104. SEAWE D. R. and BERNOLD S. (1966) Beryllium content of volcanic rocks. U.S. Geol. Sure. Bull. 1214-C, 11. SIQKCNOLFI G. P. (19’70) Investigations into the deep levels of the continental crust: petrology and chemistry of the granulite facies terrains of Southern Bahia (Brazil). Atti Sot. Tosc. SC. Nat. &fern. A17, 327-341. SIOHMOLPI G. P. (1971) Investigations into deep crustal levels: fractionating effecta and geochemical trends related to high-grade metamorphism. f_Jwchim. Coemochim. Acta 35, 10061021. SIOEINOLIFI G. P. (1972) Determination of beryllium in standard rock samples by flameless A. A. spectroscopy. Atomic Absorption Newektter II, 96-98. SLEPNEYY. S. (1969) The characteristics of distribution of some rare elements in metamorphio rocks, granites, and rare metal pegmatites of the Sayan Mountains. Ueochemietry (USSR) (English Transl.) 4, 312-314. TAYLOR S. R. (1964) Abundance of chemical elements in the continental crust: a new table. Qeochim. Coemochim. Acta aS, 1273-1285. Oeochlmica et Coamochlmica Aeta,1973.Vol. 97, pp. 706to 708. Pergamon Pm.
Trace elements
in finesfrom
the
Apoh
PrIntedin Northern Ireland
15 deep dpill
PHILIP A. HELMKE, KAREN M. TELANDEB, CHARLES K. WEISS and L-Y A. BASEIN Department of Chemistry, University of Wisconsin-Madison, (Received 22 August 1972: accepted in rev&&form
53706, U.S.9.
10 October 1972)
Al&&--No systematic variations in concentrations with depth were found for lOtrace elements in samplea from the Apollo 15 deep drill. Presence of a sign&ant amount of KREEP is indiceted.
SAMPLESof fines ( < 1 mm) from the bottom of the Apollo 16 deep drill core and from each junction between the six 42.5 cm long segments of the drill stem were analyzed for Ag, Co, Cr, Cs, Cu, Ga, Hf, Rb, SC and Zn by neutron activation. Prooedures used were adapted from our earlier work (-KIN et al., 1970 ; ALLEN eb al., 1970). The samples weighed approximately 50 mg each ctnd were splits of approximately 2 g, sieved samples used for biomedical testing. The results of the analyses are shown in Fig. 1. The indicated analytical uncertainties are based mainly on counting statistics. The samples were subjected to a minimum of kndling in our laboratory prior to neutron irradiation. Each plastic vial was removed from its inner T&on@ bag and opened inside a cleaned stainless steel and luoite cabinet in an air atmosphere. The contents were transferred immediately into weighed, cleaned quartz tubes. The tubes were weighed with$he samples in them and sealed off. Exposure time between opening the plastic vials and sealing the quartz tubes ranged from 5 to 16 minutes. The samples were irradiated for 7 hours at a neutron flux of approximately lOls n/cmz/ sec.
Notes
by COMPSTONet aE. (1970) for the Apollo 11 intqsertal basalts now becomes 3.71 & O-1 b.y. in good agreement with the results of PAPANASTASSIOUand WASSERBURG (1970).
of the difference in *%r concentration between the 1969 and 1972 calibrations of Rb-Sr 1 can be attributed to evaporation. It appears that the fused RbCl used in the original shelf sohtion contained l-8 per cent more Rb than the stoichiometric proportion, presumably due to the substitution of Cl by lighter anions such as F or 0. All
Ackwwkdg men&-We thank J. C. RODDICK,M. W. MAXON 8nd D. J. MILLARfor assist8noe with mass-spectrometry.
REFERENCES CATANZABO E. J., MV~PHY T. J., GARNERE. L. and SHIELDSW. R. (1969) Absolute isotopic abundance rrrtioand 8tomic weight of terrestritrlrubidium.J. Res. Nat. Rur. Stand. 73A (Phy8. andChem.) 6,511-516. COTKPSTON W., CH~SPELLB. W., ARBIIENsP. A. and VERNONM. J. (1970) The chemistry and 8ge of Apollo 11 luner msterial. Proc. Apollo 11 LumarSci. Conf.(editor A. A. Levinson), Vol. 2, pp. 1007-1027. Perg8mon. COWP~TON W., VERNONM. J., B-Y H., RTJDOWSKI R., GRAYC. Y., Waaa: N., CEAPPELL B. W. 8nd EAYX M. J. (1972) Age and petrogenesisof Apollo 14 bsaalts (8bStmCt). In LuwScaence 111 (editor C. Wetkins), pp. 161-163. Lunar %entx Contr. No. 88. DECAL C. (1963) Itwrganic ThermogmvimetticAnaiyai8, 2nd Ed. Elsevier, New York. MWTHY V. R., E~ENEENN. M., JAEN BosMrwo and COSOIOM. R. (1972) Rb-Sr ages, trace elements, and speculations on luner differentiation (abatmct). In tinor gcience 111 (editor C. Wetkins), pp. 571-672. Lunar Science Contr. No. 88. PAPANMTASBIOU D. A., WASSERBUBU G. J. and B-TT D. S., (1970) Rb-Sr ages of lunar rooks from the Se8 of Trenquillity. Earth Plant. Sci. Letter8 &l-19. PAP~AST~SSXOUD. A. and Wksslsa~oaa G. J. (1971) Rb-Sr ages of igneous rocks from the Apollo 14 mission and the 8ge of the Fra Mauro Formetion. E&h. Planet. Sci. Letter8 12, 36-48. SHIELDSW. R., G-R E. L., HEDGE C. E. and GOLDICHS. S. (1963) Survey of Rbes/Rbe7 ratios in minerele. J. &aphye. Rss. 68, 2331. TAT~~XOTOM., HEDQEC., DOE B. R. 8ndUwsus D. (1972) U-Th-Pb and Rb-Sr measurements on some Apollo 14 lunar samples. Pmt. Apollo 14 Lunar Sci. Conf. (editor A. A. Levinson), Vol. 2 (in press). &ochlmica et Comxxhimlca Acta.1973.vol.37,pp.702to 708. Pergamon Preaa.Printed inNorthern Ireland
Beryllium
in deeg-mhd
orustal rocks
G. P. SIQEINOLFI Istituto di Minemlogia e Petrologia, UniversitB di Modena, 41100 Modene, Itely
(Received 0 June 1972; acceptedin revisedform 12 September1972) &&&-In the gmnulites of the Brazilian shield, beryllium decreeees in the order: intermediate granulites, basic grsnulites, gmnitic gmnulites. Two hypotheses Bpeput forward for this peculiar distribution: (1) isochemicel beheviour during metamorphism of the original sediment, where Be w8e more 8bundant in p&tic th8n in 8ren8ceous rocks; (2) dehydration reactions 8nd/or partial melting, with removel of 8 Bebe8ring mobilizate, affecting the granitic more then t,heintermediate or b&o gmnulitee.
703
N0t.M
INTRODUCTION
of beryllium and the mechanisms which regulate its distribution in magmatic processes have been sufficiently discussed. Little is known, on the other hand, of the geochemistry of beryllium in metamorphic formations, particularly in high-grade metamorphic rocks. Recently, some authors (HURLEY, 1968 ; LAMBERT and HEIER, 1968) pointed out that high-grade metamorphic rocks are present in the lower Earth’s crust. The present work deals with the distribution of beryllium in a granulite terrain in the Precambrian Brazilian shield, contributing to some extent to the knowledge of this element in the lower crust. Detailed petrographic descriptions, general geochemical trends followed by main and trace elements and discussion on the role of metamorphism in the redistribution of elements are reported in previous works ( SICWINOLFI, 1970,197 1). They are granulitic rocks in which medium- to high-pressure types predominate; their most probable ages are 1900-2100 m.y. Beryllium was determined (in 62 samples) by flameless A.A. spectroscopy using the Perkin-Elmer heated graphite atomizer HGA 70 and Model 303 spectrophotometer. The detailed procedure is described by SIQHINOLFI (1972). Precision (about 10 per cent) and accuracy checks were carried out on USGS standard rocks. THE BEEAVIOUR
GENERALDISTRIBUTION OF BEBYLLZUBI IN THE Gm TERR&IN Table 1 reports the average Be content in the whole terrain and in some single rock types subdivided according to the SiO, content. Figure 1 shows the distribution of beryllium on a histogram as plotted by BEUS (1961). The average content of 2.1 Table 1. BeryIlium in various geologid environmente
Range
ppm Average
n
04-64 0.6-3-7 04F3.4
2.1 1.6 1.7
62 9 11
This work This work This work
1.2~0.4 0.6-4.5
2.6 13
25 17
This work This work
0.9 1.6 5.5 4.5
22 7
SANDELL(1962) SANDELL(1962) HORMANN(1967) BEUS (1961)
Beryllium in whole SmmIlita terrain a&d: SiOs > 70% sub-acid: SiO, 66-70% intermediate: SiO, 56-65x basic: SiO, < 56% Subsilicic rocks Dioritse Gra’Xlites biotite granites muscovite and twomicas granites A.lkalic rocks Pelagic clays Bedeposited clays Platform sands schists Gneisses Amphibolites Earth% crust n = number of samples. 22
I-30
l-50
10.0
11.4 6.0
50
2.6 2
5 26
4 3
20
2-3
2.8
6
BEUS (1961) SEAWE and BERNOLD(1964) HORBUNN(1967) MEILBILL et cr2.(1960) BEUS (1966) HIIWT (1962) BEUS (1966) BEUS (1966) SLEPNEV(1959) TAYLOR ( 1964)
704
Fig. 1. Distribution
of beryllium in gmnuiitic
rocks.
1Ogruithmic scale aa a function of frequency (log Z:
Be concentrations
iu s
arithmetio mean).
standard deviation C % = 45.5) is slightly lower than the crustctleetimate of TAYLOR(1964). The Be distribution in the various types of granulites differs markedly (see Table 1) from that in magmatic rocks: there beryllium tend8 to increz18eregularly from basic to acid rocks, showing a maximum accumulation in the latest differentiate8 such as granitic pegmatites or in alkalic rocks. SHAWX and BERNOLD (1964, 1966) found a close relationship in magmatic rock8 between beryllium and silica. In the granulite terrain beryllium in general does not appear to be signiflcantly correlated either with the silica content (see Fig. 2) or with the alkalic character of the rocks. On the contrary, the maximum Be content is found in the more diffuse ‘intermediate’ type, while rocks of granitic composition appear to have very low Be contents, both in comparison with magmatic rocks showing the 8ame acidity, and in comparison with basic granulites. Furthermore, detailed ob8ervations of the result8 show that the Be distribution can be regulated by several Merent factors, such 88 spatial localization within the terrain or the peculiar chemical or mineralogical character of the rock. For example, some anomalous high Be content8 are found sporadically in samples showing alkalic tendency or in hornblende- or in biotite-rich rocks. ppm (rehkive
Be DISTRIBUTION AND HIGH-GRADEMETAMORPHISM: POSSIBLEINTERPRETATIONS Conclusion8 of preceding works (SIGEINOLFI,1970, 1971) on the same granulite terrain based on geochemical data such as K/Rb values, Li content, etc., lead the author to consider granulites as unmelted residuals of partial melting proce88es. These residuals would be deprived of some granitophile elements through depletion8 in a migrating melt phltse and/or through dehydration reactions. Owing to it8 high mobility in fluid compounds, particularly fluorine-rich fluids, beryllium would al80 be moved, at least partially, from granulitic residuals. The results of this work make it difficult to assert that noticeable Be depletions from the granulitic rocks have
705
NOtee
Fig. 2. Variations of beryllium iu gwsulitee
88
8
function of the 8ilio& camkant.
occurred. Acid graxmlites behave abnormally showing Be levels markedly lower in oomparison with other rooks of granitic oomposition. On the basis of theee observatioae two hypotheses c&cerning possible relationships between Be distribution and metamorphism can be considered: (a) high-grade metamorphism hae not notably affected the Be distribution: in this case the at&al levels of beryllium in the vtious rock typea merely represent features of the origimxl material. AB a sedimentary sequence, as shown by many obeervations, is the most probable original material of this terrain, the aotual distribution of beryllium reflects the fact that, in aedimtmte,pelitic rooks normally oontain higher Be levels than more silicic arenaceous rocks (eee Table 1). (b) A *bution of beryllium within the same gram&e terrain ocaurred, analogous with other mobile elements, following fluid phases, so that local concentrations or depletions of beryllium were caused by local chemico-physical conditions. The low Be levels in ‘granitic’ granulite~ in this IXM would be the results of dehydration reaotiona and/or partial melting proce~~a which obviously &eot granitic material more than intermediate or b&c rocks. REFERENCES BEUS A. A. (1961) Distribution of beryllium in granites. Uwchemtiq (USSR) (English Transl.) 6, 432-437. BEVB A. A. (lfM3) Uc&w&q/ of &uy&utn. Freeman. HURSTD. %f. (1862) The geo&m&q of modern wdimente from the Uulf of Park-II. The location end diataibution of trace elements. &o&k. Ckwwc&m. A&x $6, 1147-1187. H&XANN P. K. (1989) Handbook of @iochemistry. II-l. BwyUiwa. Springer. HURLEY P. M. (1968) Aboolute abundance and distribution of Rb, K and Sr in the Ikth. G’wchk Uoanwch&n. Acta 88,273-283. LAMB- I. B. and HEIEB K. 8. (1908) Gteochemicsl iuveatigatione of deep-seated rocks in the u&r&an Shield. Lithoa 1, 30-&i3. MkUULL J. R., LYDENE. F. X., HONDAM. and ARNOLDJ. R. (1960) Sedimentery geochemistry of the beryllium isotopes. &whim. Cosmochim. Acta 18, 108-129.
706
xotes
SANDELLE. B. (1962) The beryllium content of igneous rocks. Qeochim. Cosmochim. acta 2, 211-216. SHALE D. R. and BERNOLD S. (1964) Distribution of beryllium in igneous rocks. U.S. Beol. Surv., Prof. Paper 501-B, 100-104. SEAWE D. R. and BERNOLD S. (1966) Beryllium content of volcanic rocks. U.S. Geol. Sure. Bull. 1214-C, 11. SIQKCNOLFI G. P. (19’70) Investigations into the deep levels of the continental crust: petrology and chemistry of the granulite facies terrains of Southern Bahia (Brazil). Atti Sot. Tosc. SC. Nat. &fern. A17, 327-341. SIOHMOLPI G. P. (1971) Investigations into deep crustal levels: fractionating effecta and geochemical trends related to high-grade metamorphism. f_Jwchim. Coemochim. Acta 35, 10061021. SIOEINOLIFI G. P. (1972) Determination of beryllium in standard rock samples by flameless A. A. spectroscopy. Atomic Absorption Newektter II, 96-98. SLEPNEYY. S. (1969) The characteristics of distribution of some rare elements in metamorphio rocks, granites, and rare metal pegmatites of the Sayan Mountains. Ueochemietry (USSR) (English Transl.) 4, 312-314. TAYLOR S. R. (1964) Abundance of chemical elements in the continental crust: a new table. Qeochim. Coemochim. Acta aS, 1273-1285. Oeochlmica et Coamochlmica Aeta,1973.Vol. 97, pp. 706to 708. Pergamon Pm.
Trace elements
in finesfrom
the
Apoh
PrIntedin Northern Ireland
15 deep dpill
PHILIP A. HELMKE, KAREN M. TELANDEB, CHARLES K. WEISS and L-Y A. BASEIN Department of Chemistry, University of Wisconsin-Madison, (Received 22 August 1972: accepted in rev&&form
53706, U.S.9.
10 October 1972)
Al&&--No systematic variations in concentrations with depth were found for lOtrace elements in samplea from the Apollo 15 deep drill. Presence of a sign&ant amount of KREEP is indiceted.
SAMPLESof fines ( < 1 mm) from the bottom of the Apollo 16 deep drill core and from each junction between the six 42.5 cm long segments of the drill stem were analyzed for Ag, Co, Cr, Cs, Cu, Ga, Hf, Rb, SC and Zn by neutron activation. Prooedures used were adapted from our earlier work (-KIN et al., 1970 ; ALLEN eb al., 1970). The samples weighed approximately 50 mg each ctnd were splits of approximately 2 g, sieved samples used for biomedical testing. The results of the analyses are shown in Fig. 1. The indicated analytical uncertainties are based mainly on counting statistics. The samples were subjected to a minimum of kndling in our laboratory prior to neutron irradiation. Each plastic vial was removed from its inner T&on@ bag and opened inside a cleaned stainless steel and luoite cabinet in an air atmosphere. The contents were transferred immediately into weighed, cleaned quartz tubes. The tubes were weighed with$he samples in them and sealed off. Exposure time between opening the plastic vials and sealing the quartz tubes ranged from 5 to 16 minutes. The samples were irradiated for 7 hours at a neutron flux of approximately lOls n/cmz/ sec.