RICE UNIVERSITY
STUDIES ON JADEITES AND ALBITITES FROM GUATEMALA
by
Zanaide Carvalho Gongalves da Silva
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF ARTS
Thesis Director's Signature*
Houston, Texas
May 1967 3 1272 00081 1008 ABSTRACT
In the central part of the San Agustln Acasaguastlan Quadrangle* north of the Metagua River Valley, Guatemala, jadeite-rich rocks occur as inclusions in serpentine. The associated minerals are albite and in minor amounts, muscovite, actinolite and zoisite. The country rock is generally highly sheared serpentine, although massive serpentine is also present in lesser amounts.
Most of the jadalte in the area is whit® or slightly greenish, having only small amounts of diopside, acmite and hedenberglte molecules.
The green variety has a higher content of these pyroxene molecules and the variation in optical properties of the different specimens of jade- it© analyzed is related to the impurities present.
Jadsite seems to have formed before serpentinization of the ultra- basic body and later reacted with silica-bearing aqueous solutions form¬ ing secondary albite.
Albitites are quite abundant in the area, occurring as large included bodies in the serpentine. From field relationship, chemical and mineral composition, they seem to have originated from a pegmatite which underwent desilication. TABLE OF CONTENTS
PAGE iNrnmjcnoM 1
General Statement 1 Adknowledgamenta 2
GENERAL GEOLOGY . . , , * 3
General Considerations . 3 Rock Units of Eastern Guatemala ...... 4 Serpentine-flstaraorphic Association of the Motague Valley .... 4
ROCK TYPES WITHIN SERPENTINE ...... 6 Serpentine .... 6
Albitites ...... 9 Jadeitas * ...... 12
Green Jadeite .... 14 Mineralogy, Chemistry and Optics of the Jadeltes ...... 15
CHEMICAL COMPOSITION OF ROCKS 17 SEPARATION AMD ANALYSIS OF SAMPLES ...... 18
19 REFERENCES ...... 21 TABLES FIGURES INTRODUCTION
General Statement
The area under investigation is located on the central part of the San Agustin Acasaguastlin Quadrangle, which is located on the Motagua River Valley of eastern Guatemala* Field work covered an area of about 12 Km"1" in the vicinity of Estancia do la Virgen, Manzaftal and Quebrada de Uyus, north of the Atlantic Highway. The San Agustin Acasaguastlln Quadrangle is now under study by Eric Bose, a graduate student at Rice University, from whom much infor¬ mation was obtained, especially concerning the structural and petrolog¬ ical relations between the serpentine and adjacent areas. Jadeite from Guatemala has been reported both by antropologists and geologists (Foshag 1955, 1957} and (McBimey, 1964), and some chem¬ ical and optical data are available from previous works, mostly repre¬ senting samples from Manranal. The present work is mainly concerned with the mode of occurrence of jadoite, its relation with the surrounding rocks, its associated minerals, and the petrological significance of its chemical and optical properties.
- 1 - 2
Acknowl odaaments
This study is one of a series of studies in the older rocks of
©astern Guatemala financed by the Motional Science Foundation (GP 2824) and carried out in cooperation with the Institute Gecgrafico Hacional d© Guatemala.
Dr* Thomas Donnelly was the thesis advisor to whom the writer wants to express gratitude for the suggestion and arrangements made for this work, and all orientation given during its development.
Thanks aro also given to Eric Bose for his cooperation in the field, helping with reconnaissance and information about the area, to
Ray Jacobson who assisted the field work and to Mrs. Nancy Howard, chemical analyst, for hor aid during the rock analysis in the laboratory.
The author appreciated very much some observations made by Dr. John
Rogers, who helped to clarify various problems.
Transportation and other facilities were provided in Guatemala by the Institute Geografico Hacional, through the courtesy of the Ing.
Jorge Gcdoy. The author is also grateful to the logs* Oscar Salazar and Marco Antonio Acoituno of Direcci&n General da Mineria y Hidrocar- buros, for furnishing material for patregraphical work there. mem GEOLOGY
.General Considerations
This area is located in the Central Cordillera Geologic province, as defined by McBirney (1$63) to the north of the Motagua Valley* The principal rock in the area are seta-sedimentary rocks which are intruded by elongate serpentine bodies*
/vs a result of tectonlsm in this area, amphibolites, schists, limestones, and some jadeite-rich rocks are found aa inclusions in the serpentine. In many places, in the vicinity of these inclusions occur boulders of pure silica and magnesite, evidently representing materials expelled from the peridot!to during serpentinization* The effect of those solutions on the jadeite rocks will bo discussed later.
The conditions which gave rise to the formation of jadeite in this area arc not well understood. Its presence hero is related to the serpentine, and its apparent association with albitlte may indicate reactions subsequent to serpentinization. Rocks containing jadeite are mostly found as bouldors, ccnmoaly together with albita, associated or not with the albitlte bodies in the serpentine* In some places jadeite is found adjacent to areas of whit®, arenaceous soil, whore the under¬ lying rock is possibly albite or jadeite rich. However, jadeite has never boon found in outcrop.
It is worthwhile to mention the presence of holes (3 motors deep) in the central part of the area, between San Cristobal and fcfenzanal, presumably made by the Mayans or early Spanish people in thoir search 4 for jadeite in the area. Although San Agustin Acasaguastlan is a noted archeological area, there is, however,' no positive evidence that this area was the source of the famous green jadeite of the Mayan world.
Unite ai .IMfeiaala.
The rock association here consists of a variety of sedimentary, plutonic, volcanic and metamorphic rocks* Forming the basement complex there are serpentine and peridotitss, a raetamorphic series which is a sequence of mica schists, gneisses, amphibolites and marbles and bodies of granite composition.
The raatamorphic series is named the Chuacus Series, and its rocks are the oldest of the area* Amphibolites* probably derived from a series of basic lavas or tuffs are abundant in the section. Mica schists and gneisses are the other rocks of the series, and in some places are more abundant than amphibolites.
The plutonic bodies are of granitic composition and lie in the northern part of the Chuacus Sorias.
Serpentine-Motaroorohlc Association
sJL U& M&3H& .Ml>ax
The three principal belts of ultxabasie rocks recognised in the
Central Cordillera are more or less serpent ini zed pe-ridotiia bodies, showing a complete succession frost almost unaltered poridoiite through serpentine-rich to massive antigorits rocks. In the i.totagua River
Valley rocks are highly sheared and almost totally cerpentinized* s Associated to serpentine are rocks of the Chuscds Series. Schists and araphiholitea are coRmon inclusions, but there is no evidence to indicate the Intrusion of serpentine in these younger rock®. ROCK TYPES WXTHIM SERPEMTIME
Serpentine
The serpentine body which covers most of this area is sheared, especially in the east, where the affects of faulting are more conspic¬ uous* Massive serpentina is more concentrated In th® west,, where a slightly altered perldotita is still present* Albitit© bodies occur throughout the area* Although they crop out in several places, their relationship with the serpentine is some¬ what obscure. The serpentine at the contact of one wall-exposed body is highly sheared, with the foliation parallel to the contact. The question whether the albltite is a tectonic inclusion within the ser¬ pentine, or whether it represents a cross-cutting intrusive mass is uncertain because of relatively young movements v/ithin the serpentine. The tendency for serpentines to undergo shear so readily as to appear concordant and, hence, younger than any other rock with which they occur is, of course, well known as a persistent source of difficulty In deciphering field relationships of serpentine bodies and their associated rocks. Locally, magnesite -and quarts blocks are found in association with serpentine, as the result of the process of serpentiniration, involving alteration of the peridotite. They are also present around faulted limestone blocks, southwest of Quebrada do Uyus, evidently forming as product of solutions which percolated during faulting.
- 6 - 7 Petrographic analysis of some serpentine samples show that antigorite is the most abundant mineral, making up to 909$?» of the
rock* Orientation of the antigorite is conspicuous in the sheared serpentine. Magnetite is the principal accessory mineral, occurring
as irregularly shaped grains surrounding antigorite grains*
Schists and amphibolites which are members of the Gbuacus Series, mapped by McBirnoy (1963) are found in the area as tectonic inclusions
in serpentina* The amphibol ites are character!red by an association of
actinolite, muscovite, quarts, plagloclase, and a pink garnet (Almandino?).
Very often they are found in the vicinity of jadeitic rocks, suggesting that they have been carried by the same tectonic movements.
The schistose rocks are .mostly albitic, with muscovite, chlorite, and quartz, and are locally found In faulted contact with serpentine.
They are not as abundant as the amphibolites and crop out in the areas
to the southeast of Esiancia d© la Virgin and northeast of Manzanal (specimen 43, chemically analyzed* ceases from Esiancia do la Virgen). Less common, but also found in the area axe actinolitic serpentines
(specimens 16 and EV) and actinolii©~auscovit© schists. The formation of these actinolitic rocks seems to be related to
a met a somatic process which involved the ultrabasic rock and pegmatite bodies in the area. Dlsgrammatically, the process would bet This hypothesis is consistently verified in the present case since the actual composition of samples 16 and EV falls in an inter¬ mediary position of that of the original material# Analysis of a common peridotite given by Georg© (1943) and of a Lithium-bearing pegmatite reported by Johns (1953) are presented below as well as the analysis of samples 16 and EV to illustrate the chemistry of the process.
Peridotita Pegmatite 16 EV
$102 38.00 74.5 56.40 46.70
Ti02 imim 0.05 1.55 A12°3 8.00 i"4#9 7.31 12,80
F — 3.86 Q.24 «2°3 12.50 FG 0 2.21 0.83 t%9 29.50 12,50 6.25 GaG 6.70 0.2 8,75 9.94 0.075 3.3 2.66 0,18 0.087 5.4 1.50 1.66 *9° U..0 — 0.7 '#*‘*0* —
wm# H20 — 0.6 awiiw* F 0.9
This mode of formation of actinolitic rocks is well known and has been reported from other places (Macdonald, 1941). 9
Albitltes
Next to serpentine, which is the country rock, the most abundant rock typo is albitlto in which albite, associated with muscovite, quartz, actinolite, and less commonly soisite, is the main component*
The association albite-jadeito and its origin will bo discussed on the jadoite section* Of a different generation are the albitltes which occur within the serpentine. Their texture is very distinct from that in the jadeltic rocks* Mbits is normally the most abundant mineral, forming xencblastic grains, sometimes twinned, in a granoblastic texture
{Figs. 3, 4). Muscovite Is commonly found in albitltes, often as inclu¬ sions in the albite grains.
The relative age between these albitltes and the aiblto rocks originated from jadeites is not clear. However, If the albitltes formed by a desilication process, as will bo discussed later in this chapter, they must have formed later than the albitltes which originated by re¬ placement of jadeitos during serpentinization in a low silica environ¬ ment.
Actinolite is another common mineral associated with aiblto in these rocks, forming elongate green crystals within the aiblto ground- mass and sometimes giving a light green color to the rock. Under the microscope, the mineral varies from colorless to light green?- it is non-pleochroic, having parallel or low angle ( 10°) extinction in longitudinal sections* Locally, at contacts between albite and serpen¬ tine, actinolite forms compact aggregates. 10 A common mineral in both albitites and jadaitie rocks is zoisite. The origin isay bo the saaa in both rocks, but this statement can not be made presently* Apatite, ophene, and zircon are found occasionally in albitites as accessory minerals. It is very likely that these albitites represent a granite peg¬ matite instead of pure albite veins. From their chemical composition the conclusion can not be drawn, however, for no on© of the analyzed samples seams to have a composition of a normal pegmatite. Analysis of a lithium-bearing pegmatite reported by Jahns (1953) was taken for com¬ parison with the albite rich rocks of the area (table V). Its chemical composition Is shorn below* together with the albite composition of this pegmatite and the analysis of on© sample (K) from the area under discussion which represents a pure albitite* Pegmatite Albite from Pegmatite Albltite (K) SiCb, 74.5 60,3 63,05
TIO2 mm* ***** 0,01
Ai2U3 14.13 19.7 19,03
Fe203 — :#*** 0.27
FeO mm mm***. — HgQ — — 0.28 o&o 0.2 0,3 0.49 Na„0 3,3 11.4 10*81 Kp 5*4 0.3 0.07 I.i,~p 0.7 — —
HgO 0.6 ■m-m* «*•**
F 0.9 mm 11 In the present case, the original material is likely to have been a pegmatite* and a process of desilication may have been responsible
for the concentration of albita in the area* Si0o, then, must have been removed along with Kp and both of these are now dispersed through the rocks of the area, as reflected in the local variations in composition of the albititos.
Pegmatites occur in other parts of the area mapped by Bose,so these albitites in question may all represent parts of the same peg¬ matite. The lack of analysis representative of a pegmatite may be, than, a sampling problem. Jadgitea
The jedoitic inclusions are restricted in their occurrence to the sheared variety of serpentine and are raore concentrated in the eastern part of the area* south of Quebrada d© tlyus and north of Manranal, from where a few samples have been analysed previously (Foshag, 1955, 1957), (McSirney, 1964)# The mineral association here consists of jadeite, alblte, with subordinated nuscovito, zoisitc and more rarely, actinolite# Jadeite form ©qjuidlmensional grains (1 to 20 mo), irregular in shape, but forming compact aggregates (Figs, 5, 6), soraetiaes having fibrous terminations. In the more jadeite rich rocks the mineral is relatively free of inclusions, unlike the more albitic rocks, In which inclusions of muscovite are occasionally found# Alblte in the jadeitic rocks is a later mineral, formed through the reaction of silica and jada.it®» The replacement is less conspicuous in the more jadeito-rich rocks whore* albit© is subordinate and interstitial, but in rocks with more abundant albito, jadeite boundaries have typical reaction rims of untwinned albits. Field relationships are not very clear due to the absence of outcrops, but the peculiar way in which jadeite is found—-as boulders among albititos and within tbs serpentines—*is a good clue for the petrological significance of the association# This mode of occurrence of jadeite in association with albitito in serpentine bodies is common in Burma and Japan (Yoder, 1960) and in dear Creek, California (Coleman, 13 Th© conditions under which jadeit© formed in Guatemala are beyond the scope of the present investigation* Its time of formation* however, seems very likely to have been before serpentinination of the ultrabaaic body. Low silica environment favors the formation of jadeite and the situation during the serpentinisation was the opposite of this, i*e., SiQg was probably released by the ultx-ahasic. At this time, then, it started forming albite* Based on experimental work and determinations of some thermo¬ dynamic properties, the systems Ab + Ho ~ 2 Jd has been studied {Voder and Weir, 1951) and stability fields for that reaction wore calculated by Adams (1953). From experimental work, it has been found that pressure plays an important role in the formation of jadeite. Also in support of this idea is the fact that jadeit© molecule is present in Omphacite, the pyroxene found as the main component of eclogltes which axe rocks con¬ sidered to form at great depth and very high pressures* Other possible reactions for the formation of jadeite in the absence of water ares Ab = Ota + Jd (1) He + Qtz ~ Jd (2) In the presence of water, Anal cite may form at 400-500°C, if proper pressures are applied (Adams, 1953)? Jd + SKgQ = Anal cite In the present case, equation (1) is of special interest* It does not explain the formation of jadeite, but supports the hypothesis 14 of the formation of albite at the time of serpentinization of the ultra- basic* Birch (1960) studying the reactions Ah = Qfcz -r Jd and
Jd + Qta » Ab t at pressures between 15 and 25 Kilobars and temperatures between 600 and 10G0°C, set limits for pressure required in both reac¬ tions, and found that for the formation of albite this limit is lower, although not far from that required for albite to break down Into jade- its and quartz* This moans that the pressure involved in shearing which affected the serpentine body was not high enough to prevent albite from forming, once silica was available, released during serpentinization of th© ultrabasic.
Green Jadeite
Special attention is called to th© green jadeite specimen (sample
20) studied from the area under investigation. Th© rock itself is very compact, composed mostly of green jadeite with subordinate sodic plagio- clase, dark green hornblend©, scarce muscovite and garnet, and having a cataclastic texture (Fig* 7)* Hornblende occurs as euhedxal crystals with jadeite inclusions and appears to b© replacing the jadeite (Fig* 8).
Chemical composition of the rock is presented in table IV together with other jadeit©-bearing rocks. It has a very distinct composition as a result of its mineral content. Iron and calcium oxides reach high values mainly due to the composition of th© green jadeite which makes almost totally th© whole rock.
Up to now, the way in which jadoite formed in the area is obscure.
Nevertheless, the occurrence of the green jadeite, associated with 15 amphibols and garnet in a eataclastic texture is a good clue to suppose that shearing involving pressure are related to its formation. Further- more, this variety of jadeite has only about 73.2 percent of jadeite molecule, having Diopside (7.9,$, Acinite (15.2,$ * and Hedenbergite (3.7?$ in the composition. This type of pyroxene seems to be comparable with the sodium-rich type of pyroxenes of the oaphacite group which occurs in eclcgltes.
QlSE&SSaX iM 8R&&9. M MM-Mi
Both white and green jadeites in this area exhibit two distinct habits* White jadeite forms columnar aggregates of anhedral grains. They are uncolored under the microscope, with moderate birrefringence. The green variety (sample 20) is also colorless under the microscope, but has higher birrefringence and dispersion. It forms more irregular grains with a eataclastic texture having a compact arrangement. Five samples were chosen from different localities on the area to be chemically and optically analyzed. Of these samples, four are considered here white jadeites, although a faint green color, gradually increasing from th© most pure jadeite (sample 28) to the on© with higher percent of the other components (sample 37-A) is observed. Th© fifth specimen (sample 20) is the green jadeite, the only one found in the area. Mineral separation was made by using a heavy liquid—'tetrabromo- cthane (d = 2.95) and the magnetic separator. Optical determinations made for that specimens do not differ 16 substantially among the whit® varieties, but the green jadeite has a higher refractive index n » and lower optic angle 2 V . Values are y ^ shown in table III. Chemical analyses are presented in table II in comparison with sample analyses from other localities. The variation in Iron, Calcium, and Magnesium Oxides contents of the specimens is a reflection of the presence of other pyroxene molecules. From the chemical composition, after calculating to 1003>, Diopside, Acmite, and Hedenbargite percents were determined (table III), according to the method described by Hess
(1949). White jadeitos are almost pure jadaitei Jd (Na^C . Alo0^ . 4Si0p), contrasted with the green variety in which appreciable amounts of Diopside? Di (GaO . MgO * 2Si02), Acmite* Ac (Sfe2G . Fe^ . 4Si02), and Bedanbergite* Ha (CaO « FeO , 2Si0o) molecules are present. CHEMICAL COMPOSITION OF ROCKS
Twenty-one rock specimens, representative of the typical mineral associations in the area were chemically analyzed*
Determinations for the major elements oxides (except <4n) are presented in table IV and V. Sine© the main purpose of these analyses was to detect any trend, if it existed, for the variation of metal oxides in relation to the SiO^ content of the rocks, determinations for H^O were not made, even for the serpentine samples, where it can foe as high as
14 percent*
Among the jadeito-bearing rocks, the range of variation for the oxides is not large. The two dominant minerals are alfoite and jadeite, with small and variable amounts of muscovite, actinolite, and zoisite.
The range of variation within albitic rocks is large, reflecting the variable contents of muscovite, actinolite, and zoisite in these rocks* Furthermore, within these rocks there is a variation in composi¬ tion in the direction of the jadeitos.
Three samples of serpentine were analyzed, two of the sheared variety and one of a serpentine breccia (39). The chalcedony deposited between fragments of the serpentine is responsible for the high value of SiO^ in that sample. Other mafic rocks analyzed (16 and EV) are actinolitic serpentines and have higher values for SiO^, Alo0^, and
K^Q than common serpentines. These rocks occur in different locations, adjacent or not to albitites, and are possibly tectonic blocks whose chemical compositions resulted from metasomatism.
- 17 - SEPARATION AND ANALYSIS OF SAMPLES
After pulverising samples for analysis* separation of Individual minerals was made by using tetrabromoathan© as heavy liquid and the magnetic separator*
For chemical analysis, samples were opened by NaOH fusion for the determinations of SiO^, Al^, TiC<2# FeO, and Fe203, in which
colorimetric methods were used, as described by Shapiro and Brannock
(1962)* The analyses for IfegO, K^O, CaO, and MgO were made by using the absorption flame photometer method and HF-HND^ solutions were used
for the opening of samples.
- 18 - CONCLUSIONS
Jadoito occurs In Guatemala as inclusions In serpentine bodies,
and the mineral association there Is also common in jadeitos from Japan
and China,
Jadeite is always in association with albite in Guatemala, where
a complete gradation from almost monomineralic jadeitic rock to almost
monomlneralic albitic rock Is observed. Direct evidence to elucidate
the way in which jadeite formed in the area is absent. The white typo
of jadeite is the most abundant in the area, and among the associated
minerals, albite is the most common, followed by muscovite, actinolite,
and zoisite. The green variety of jadeite has a different mineral
association and shows a different relation to them. The caiaclastie
texture, the composition of this graen jadeite and the associated
minerals are good clues to suppose that shearing involving pressure
are related to its formation, which is evidently different from that
of the white type.
The occurrence of jadeites in association with the albltites, their common mineral association and the tendency to form almost mono- mineral ic rocks suggest, at first, that both rocks had a common origin.
However, from observations made and petrographic relationships, it
seems that jadeite® have a distinct origin. The time of formation of the jadeitos is probably prior to serpentinication of the ultrabasic which carried the already formed mineral during toctonlsn.
Albito-rlch rocks are abundant in the area. Some of these rocks
have an origin related to the process of serpentinization of the
19 - 20 ultrabasic, when the release of SiD^ gave place to the formation of albite, then replacing jadoite. This relation albito-jadoite is very clear from petrographic observations. Other albltic rocks, the albitites, which occur also in the area, soom to have an origin different from that of the albitites just described# Chemically they have local high con¬ tent of Ko0, and apatite, zircon, and sphene are among the associated minerals. They suggest to be a result of raetasomatic process acting in a previous more silicic and potassic rode, probably a granitic peg¬ matite. The formation of aetinclitic serpentine, may then bo related to this process, involving both pegmatite and ultrabasic rocks.
The variation in chemical composition of th© jadoites is du© to the presence of Diopside, Acrnite, and Hedenbergite molecules and the optical properties vary according to the presence of these pyroxene molecules. The effect of the individual molecules of ©ach pyroxene, and, moreover, the extent in which they affect those properties of the jadeites, cannot be determined presently* REFERENCES
Adams, t# H., 1933. A Not© on the Stability of Jadeite. Am. Jour. Sci., vol• 231, p* 299.
Birch, F. and LoQomte, P., 19®. Temperature-Pressure Plans for Albita Composition. Am, Jour. Sci., vol. 233, pp. 209-217.
Coleman, R. G., 1959, Genesis of Jadaito from San Benito County, California. Bull* Gaol. See. Am., vol. 70, p. 1583 (Abstract).
» 1961. Jadeite Deposits of the Clear Creek Area, New Ydria District, San Benito County, California* Jour. Petrol., vol* 2, pp. 209-247.
Foshag, W, F«, 1955. Chalchihuitl—A Study on Jadeite. Am. Min., vol. 40, p. 1062.
. 1957. Minerologlcal Studies in Guatemala Jade. Qaithsonian Wise. Collection, vol. 135, n. 5, pp. 1-60.
George, R. D., 1943. Minerals and Rocks*
Hess, H. 11*, 1949, Chemical Composition and Optical Properties of Common Clynepyroxenes, Part I, Am, Min., vol, 34, pp, 621-666,
Jahns, R. H,, 1953, The Genesis of Pegmatites. Am. Min., vol. 38, pp. 1073-1112.
Macdonald, A. G,, 1941. Progressive Metassoraatissn of Serpentine in the Sierra Nevada of California. Am* Min., vol. 26, pp. 276-237.
McBirney, A, B.» 1963. Geology of a Part of the Central Guatemalan Cordillera. Univ. Calif. Publ. in Gaol. Sorias, vol* 33, n. 4, pp, 177-242.
and Bass, M, M. and Aoki, K. I,, 1964. Jadeita do Manranal, Guatemala. Antropologia © Historic de Guatemala, vol. XVI, n. 2, pp, 13-16.
Shapiro and Brarmock, 1962. Rapid Analysis of Silicate, Carbonate and Phosphate Rocks. USGS Bull. 1144-A,
Voder, H. S*, Jr., 1350. The Jadeite Problem. Am. Jour, Sci,, vol. 23, pp. 225-247, 312-334,
21 Table 1 mineral iiDosi uion )f the O 0 * Suitss (*) Table I (cont.)
Q) 03 -P +•> 0 •H P rH 0 U to •H to O P O •P P -P P a *H bD •H 0 •H to •H -P N-« Q
n P ciS -P •H «P O to r~» i—! 2 O4 O cd Sphene Garnet j Samples Zircon j
• Chlorite i Hornblende j —■*
N) !
jjadeite j 'Muscovite i P3
37-A D B G F
TD-1 C 3
v-* 20 D J3> G 3 H |
13 3 F 3 D
U0 3 D F F !
r» ta 3 ill D
U3 B G D
25 3 G 3 G G F —
2V G G 3T*> F G
n 16 U G 3 C G —
39 3 3
15 P F — ■
12 3 3
2-A ■c -n ,„2_ (*) Location, of samples shown in Fig. 2 A > 90 $ ill• n 5-106 B 50-90?; F 2-56 C 20-506 G 1-26 D 10-20,6 H 1 6 Table II
Chemical Analysis of Jabeite CO
VO n r CO H CM LA IA ON O i—1 (—! 'H CO EH CM rH Q CVJ G> M CM O r
(*) Calculated to 100y& Table IV Chemical Composition ox the Jadeite-Bearing Rocks
~Zr7 TD-1 20 28 29 30 3 (-11 4
Si02 61.80 57.08 61.52 61.80 61.8/4. 60.52 65.40
Ti02 ' 0.02 0.25 0.02 0,02 0.C8 0.64 0.02
A12°3 22.39 1940 22.55 21.80 23.00 21. 30 21.00 Fe^O^ 0,15 6, Co 0.61 O.71 .... i 1 0.39 0.65 0.27
ReO 0.30 0,53 - - - ~ KgO 1.68 1.66 0.57 1.10 0.71 1.35 0.75 CaO 0.60 3.08 0.32 1.21 O.56 1.50 0.17
Na20 1243 11.75 13.63 12.73 11.12 12.63 12,33
K2O 0.26 0.21 O.Oij. 0.32 1,72 0.09 0.01
Total 99.63 99.90 99. C/J. 99.62 99.74 98.08 99.85 CHEMICAL COMPOSITION OF THE ALBITITES AND MAFIC ROCKS ~7T
\ X-SL ; VO CO •-Gl t-3 7 OJ lf\ \—l rn i— H 1—1 H ON m rn rH i—! O'- rn «—i ai t i ! 1 1 i ! V. i 1 t y< 1 Vn VO —>~j ~r: co vo VO vo —J _rt —j —j CO vo vo CD CO —-j 7 7 o O ITv O in 7 o cvj KV m o tn 7 t\! o m 7 un 7 o 7 in H O Ln rH m tn o o o o o Li'N ON o o o '.'vj * • • • * » • • • • 9 9 9 • 9 ~7\T vo _rt LOt’ o o O o rH CD i-i o rH LTV -V o o OJ o 7 o O' O 7 o O o o o o o o o o o rH 1—1 rH m •H rH ON ■ 9 OJ I I a • 4 • • • • • • • • *. » ... _rH_ W 1 1 v0 CO CO r* j CO CO 00 00 CO —-J ‘•0 rn o o 7 rH H r j OJ 7 OJ o rH i— O H in o H o 7 H 0- o 0J rH ON ON H 7 o CVJ tc\ o o N 7 (VJ rH H ON ‘ON rH O —4. OJ rn • » • • • • • « • • * 9 9 « • *
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