Crystal chemistry and petrology of coexisting galaxite and

Crystal chemistry and petrology of coexisting galaxite and

American Mineralogist, Volume 68, pages 449455, 1983
Crystal chemistry and petrology of coexistinggalaxite and jacobsite
and other spinel solutionsand solvi'
E. J. ESSBNEAND D. R. PBecon
Department of Geological Sciences
The University of Michigan
Ann Arbor, Michigan 48109
Abstract
Galaxite (Gx:MnAlzO+) and jacobsite ("ID:MnFezO+)-richspinels occur together in the
metamorphosedmanganesedeposit near Bald Knob, North Carolina. They show limited
mutual solubility with lz-lgVa Jb in Gx and 19-22% Gx in Jb. The implied solvus is
consistentwith synthesesoflshida et al. (1977)alongthe Gx-"IDpseudobinary.Refinement
of the structure of one galaxite (Gxg5JbrcSpaGhr)
reveals that Mn is located on tetrahedral
sites and Al on octahedralsites and that galaxite is therefore a normal spinel. All available
data suggestthat jacobsite is also a normal spinel at low temperatures,and the solvus
between galaxite and jacobsite does not seemto be causedby differencesin normality/inverseness.Chemicaland experimentaldata availablefor (Mg,Zn,Mg,Fe2*XFe3*,Al)zOa
spinels suggestthat the ferrites (acobsite, franklinite, magnesioferriteand magnetite)show
extensivesolid solution and are separatedfrom aluminatesolid solutions(galaxite,gahnite,
spinel (s.s.) and hercynite)by wide solvi at metamorphictemperatures.
Introduction
The manganesedeposit near Bald Knob, North Carolina contains a wide range of unusual manganeseminerals
which have equilibrated under amphibolite facies metamorphicconditions(Winter et al.,l98l). The depositwas
originally described by Ross and Kerr (1932). We have
subsequentlycarried out extensive mineralogical-petrological studies of the several mineral groups occurring
there (Peacoret al., 1974;Winter et al., 1981, in prep.;
Simmonset al.,l98l). The spinelgroupminerals(galaxite
andjacobsite) found at Bald Knob are relatively simple in
composition and therefore serve as a source of insights
into the crystal-chemical and phase relations of spinels.
This paper is a description of the mineralogy and petrology of those manganesespinels.
Only a limited amount of experimental data are available regardingthe nature of solvi among spinels at low to
moderate temperatures.Turnock and Eugster (1962)experimentally determined the magnetite-hercynite solvus
showing complete solid solution above 870"Cand a wide
miscibility gap below 600"C.Thesetwo spinelsare largely
inverse and normal, respectively.The area of complete
solution probably representsa continuum ofcation distributions,but the occurrenceofthe solvusmust be related
in part to ordering into the inverse versus the normal
cation distribution. Experiments on the binaries
I Contribution No. 375 from the Mineralogical Laboratory,
Departmentof GeologicalSciences,the University of Michigan.
0003-004x/83/0304-0449$02.00
449
(Vincent et al., 1957;Price, 1981;LindsFe3Oa-Fe2TiO+
ley, 1981) and FqOa-ZnFezO+ (Valentino and Sclar,
1982)suggestthat the solvus observed in natural materials must form below 500-600'C. Experiments in the
systems MnFe2Oa-MnAlzO+(Ishida et al., 1977) and
ZnFe2O4-ZnAlzOr(Carvalho, 1978)reveal extensivemiscibility gaps at metamorphic temperaturesof 500-7fi)'C
with the crest of the solvi located at 900-1100'C. Experiments of Muan et al. (1972\ on the ternaries FeAl2Oashow
Fe2TiOa-FeCr2Oa
and MgAl2Oa-Mg2TiOa-MgCr2Oa
solvi extending to more than 1300"Cbetween the aluminate and titanate speciesbut with complete solution at ?
> 1000"Cengenderedwith addition of 30-40Vo of the
chromites. There are no experiments on the join
MgAl2Oa-Fe3Oeand one must turn to natural occurrences to estimate the form of this solvus.
Surprisingly few examples exist of observations on
naturally occurring two-phasespinelsdespitethe fact that
such observations may have the advantage of demonstrating equilibrium cation distributions at relatively low
temperatures. Studies of minerals in lunar basalts have
revealed high-temperature solvi in the system (Mg,
Fe2*)Alzoo-(Mg,Fe2*)Crzo+-(Mg,Fe2*)2Tio4(Haggerty, 1971, l972a,b,c; El Goresy et al., 1972, 1976;
Nehru et al., 1974).Muir and Naldrett (1973)and Berg
(1976) analyzed coexisting spinels and magnetitesfrom
igneousrocks, finding a wide miscibility gap in the system
Fe3Oa-MgAl2Oawhich contracts with increasing Cr in
solid solution.Plaksenko(1980)describesincipient exsolution in chrome spinels from ultramafic rocks. Kuno
450
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
(1960) and Bowman (1978) report analytical data on
metamorphicspinel-magnetitepairs which equilibrated at
ca. 700oC and show even less mutual solution. The
systemMgAl2Oa-Fe3Oaappearsto have a wide, symmetrical miscibility gap from temperatures of less than
I100"C. Manganeseand zinc spinelshave both ferrite and
aluminate representativesin nature but the solubilities
involving Mn ys. Zn, arrd Al ys. Fe3+ are still poorly
understood. Franklinite (ZnFezOi has extensive miscibility at high temperatureswith jacobsite (MnFezO+)and
magnetite (Deer et al., 1963).Frondel and Klein (1965)
and Carvalho (197E)have described exsolution blebs of
gahnite in franklinite consistent with the existence of a
low-temperature solvus in this system. We have examined many franklinite samplesand found one with similar
blebs with compositions of a complex aluminate (Mg,
Zn,Mn,Fe2+)(Al,Fe3+)2O4
in a matrix of franklinite
(Zn,Mn)Fe2Oa;the phasesare thus multi-component and
do not contribute to general conclusionsregarding solvi.
Galaxite (MnAlzO+)is known from only a few localities
and only limited data are available on its miscibility with
other spinels. Hirowatari (1969)and Chopin (1980)have
reported the existence of two-phase jacobsite-galaxite
mixtures. At Bald Knob galaxite is restricted to carbonate-rich rocks undersaturatedin silica which also contain
tephroite or the Mn-humites-manganhumite, alleghanyite or sonolite(Rossand Kerr, 1932;Winter et al.,1983).
The color ofgalaxite is variable in thin-section and ranges
from golden-yellowto deepred to red-black apparentlyas
a function of iron content. When deep red it is easily
confusedwith associatedpyrophanite but that mineral is
anisotropic and has higher reflectivity. While routinely
examining polished sections, we noticed a secondten to
twenty micron-sizedopaque phasewith higher relief and
higher reflectivity coexisting with galaxite. Qualitative
microprobe analysis suggestedthat it was jacobsite with
some Al in solution. The mineral assemblagesnoted in
each sample are:
635: manganhumite-sonolite- spessartine-kutnahoritegalaxite-kellyite-jacobsite
BK6: alleghanyite-kutnahorite-galaxite-jacobsite-pyrophanite- alabandite-cattierite-kellyite- stilpnomelanefluorapatite
BK I I : alleghanyite-kutnahorite-galaxite-jacobsite-pyrophanite-alabandite-cattierite-caryopilite-kellyite
Table l. Electron microprobe analysesofjacobsite and galaxite from near Bald Knob, N. C.
Sanple
Mineral
Oxide l{tl
Ti02
At2ca
vro"
'Fer03
^Fe0
ttln0
7n0
Co0
Mgo
sum
635
Gx
<0.05
5 6 .3
0.14
46.0
0.0
3 9 .I
0.43
0.25
0.83
101.7
BK6-1
Gx
Jb
K6-2
Gx
Jb
Kll
Gx
Jb
K14
Gx
B//.22
Gx
Jb
49.4
0 .1 4
14.5
1.4
33.5
0 .9 7
0 .7 0
1.47
102.1
0.37
10.4
0.66
57.6
3.3
29.8
<0.05
0.2L
0.02
102.4
0.67
49.3
0.87
12.5
5.8
32.1
<0.05
0.62
1.30
103.2
9.4
6.?
0.58
44.2
5.9
33.5
0.62
0.7L
0.19
101.3
0.13
44.5
n.d.
18.7
0.7
36.3
n.d.
n.d.
1.44
101.8
0.38
8 .1 4
n.d.
5 9 .5
0.5
32.L
n .d .
n .d .
0.03
100.6
<0 . 0 5
50.5
0.20
9.0
5.9
30.4
0.61
I .07
0.92
98.6
<0.05
4 5 .1
0.25
16.6
L.4
35.7
0.10
0.84
0.53
100.5
0.34
9.7
0.39
57.6
3.1
29.2
0.13
0.62
<0.05
101.1
0.00
1.77
0.00
0.23
0.03
0.86
0.02
0.02
0.07
0.01
0.43
0.01
1.55
0.10
0.90
0.00
0.00
0.00
0.01
1.70
0.02
0.27
0.14
0.79
0.00
0.01
0.06
0.26
0.27
0.01
1.20
0.18
1.03
0.02
0.02
0.01
0.00
L.57
n.d.
0.42
0.02
0.92
n.d.
n.d.
0.07
0.01
0 .3 5
n .d .
1.62
0.02
0 .9 9
n.d.
n .d .
0.01
0.00
1.80
0.00
0.20
0.15
0.77
0.01
0.03
0.04
0.00
1.62
0.00
0.38
0.04
0.92
0.00
0.02
0.02
0.01
0.38
0.01
1.46
0.09
0.83
0.00
0.02
0.00
<0.05
Cations/3 Cations
Ti
AI
v
1F.3*
1F.2*
14n
7n
Co
Irlg
0.00
1.90
0.00
0.10
0.00
0.95
0.01
0.00
0.04
LFez+fte3+
calculated to yield o=4
n.d. = not determined
451
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
MgFe20a
BK 14: manganhumite-sonolite-kutnahorite-galaxite-(acobsite) - alabandite - stilpnomelane - caryopilite kellyite-fluorapatite
BK22: alleghanyite-kutnahorite-galaxite-jacobsite-alabandite-cattierite-cobaltite-kellyite-fl uorapatite.
te-'
A consideration of the solubility limits of galaxite and
jacobsite as represented by those Bald Knob samples,
their cation distribution and the nature of the solvus
between them comprises the subject matter of this note.
At + Fe3+
Chemical analysis
Electron microprobe analyses were obtained under
operatingconditions ofan acceleratingpotential of 15kV,
an emissioncurrent of 150nA, a samplecurrent of 0.01
pA and using digitized beam current. Standards used
were synthetic TiO2, Al2O3, V2O5, Mn2O3, MgAl2Oa,
Fe2O3,CorS+, ZnS and NiS. Spectrometerdata were
corrected for atomic number, fluorescence, absorption
and drift efects using the program EMPADR VII written
by Rucklidge and Gasparrini (1969). Analyses of the
spinels are given in Table l. The totals deviate by 2-3%
from l00Vowhen Fe2* is estimatedby the equation Fe2*
: Vs(Al+ V + lFe) + 4/3(Ti)- %(Mn+ Mg + Zn + Co\
generatingfour oxygens for spinels normalized to three
cations. While imperfect, these estimates and totals are
judged adequatefor the purposesof this paper.
The jacobsite and galaxite show a relatively symmetrical miscibility gap with about l2-20Vomutual solution of
each component. Only minor amounts of additional components are generally present in solid solution. We have
plotted our analyses along with those reported by
Hirowatari (1969) and Chopin (1980) in the system
(Fig. 1). They
MnAl2Oa-MnFe2O4-MgAl2Oa-MgFe2Oa
define a reasonablemiscibility gap when the analysesare
combined with the binary experiments of Kwestroo
(1959)and of Ishida et al., (1977\.Rossand Ken's (1932)
analysis of Bald Knob galaxite falls slightly within the
inferred solvus. Few other analysesare available which
are reasonably representedby the composition space of
Figure 1. Most jacobsiteshaveeither Fe3Oa,ZnFe2Oa,or
Mn3Oain solid solution. Spinelanalysesare also plotted in
the composition space MnAl2Oa-MnFe2Oa-ZnAl2OaZnFe2Oa(Fig. 2). A relatively symmetrical solvus separating Mn, Zn aluminates from Mn, Zn ferrites can be
inferred by combining our data with the binary experiments and observationsof Ishida et al. (1977)and of
Carvalho (1978).Ignoring the substantialFe2*, the titanian jacobsite of BK-6 is plotted in the composition space
MnAl2Oa-MnFe2Oa-Mn2TiOafor comparison with data
of Fukuoka and Hirowatari (1980)and of Fukuoka (1981)
(Fig. 3). It can be seen that there is substantial solution
between MnFe2Oa and Mn2TiO4 at metamorphic temperatures. It is anticipated that a new spinel mineral
specieswith dominant Mn2TiO4will eventually be found
in a metamorphosedtitaniferous manganesedeposit.
o
MgAlzoa
MnAl2oa
Mn2+
M g* M n 2 *
Fig. l. The composition spaceMnAl2Oa-MnFe2Oa-MgAl2OaMgFe2Oawith spinel analysesplotted. Closed circles: data on
Bald Knob spinels; open circles: data from other occurrences.
References:Ross and Kerr (1932)Stillwell and Edwards (1951),
Lee (1968), Kuno (1960), Deer et al., (1962), Berg (1976),
Bowman (1978),Carvalho(1978),Chopin (1978),Fukuoka and
Hirowatari(1980),Fukuoka(1981).Spinetswith >0.05 Zn,Fe2* ,
Mn3* or Ti per four oxygens are excluded.
Cation ordering
A yellow-colored galaxite from Bald Knob, sampleno.
635 (collection of D. R. Peacor),was analyzedand found
to contain approximately 92 moIVocomponent MnAI2Oa
(Table l), making it the purest naturally occurring galaxite which we have been able to obtain. Because we
wished to determine its cation distribution in detail,
crystals were separatedfor single-crystal X-ray diffraction. Film data confirmed the existence of extinctions as
consistent with the usual spacegroup for spinels, Fd3nt-.
The unit translationwas determinedto be a : 8.181(2)A
Mn Fe2Oa
oo
ZnFe2Oa
o
9
I---oo-
a
c-
ferrilecc
a
-----
Fe3*
Al + Fe3r
a
a
o€
Et-MnAl2O4
------
oluminote..
Zn
Mnz++ zn
ZnAl2Oa
Fig. 2. The composition spaceMnAl2Oa-MnFe2Oa-ZnAl2OaZnFerOowith spinelanalysesplotted. Symbolsand referencesthe
same as for Fig. l, with additional references: Palache (1935),
Kayupovaet al. (1970),Vogel et al., (1976).Spinelswith >0.05
Mg,Fe2*,Mn3* or Ti per four oxygens are exluded.
452
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
Mn2TiOa
that each form factor represents minor amounts of elements other than Al and Mn. The total Al (plus Me)
required by theseoccupanciesis slightly greater than that
indicated by the analysis (1.94 Al + MC, per 8 O).
However, there is some variation in composition of
diferent crystals within the specimenserving as a source
for the crystal used for the diffraction data. The results of
the refinement of the occupancy values can therefore be
interpreted as consistent with a complete, or nearly
complete normal cation distribution, with Al and Mn
occupying only the octahedral and tetrahedral sites, reMnAl20a
Mn Fe204
spectively.
Fig. 3. The compositionspaceMnAl2Oa-MnFe2Oa-Mn2TiOa The cation ordering is also connrmed by the cationplotted.Symbolsandreferences
with spinelanalyses
thesameas oxygen distanceswhich are 1.991(l) and 1.927(l)A for
for Figurel. Spinels
with >0.30Fe2*,or 0.10Mg,Zn,Mn3l are the tetrahedral and octahedral sites respectively. This
excluded.
result differs somewhat from the study of Greenwald er
al. (1954)who found that synthetic MnAl2Oa is approxiusing data from an internally standardized powder difmately 70Vonormal. This exemplifies the importance of
fractometer pattern.
using natural materials to determine low-temperature
Three-dimensionalintensity data were measuredusing ordering parameterswhere possible as synthetic materi'
a Supper-Paceautomated system, employing measure- als may have metastable states of order due in part to
ment of backgroundon both sides of a peak and graphite relatively rapid rates of formation.
monochromatedMoKa radiation. The crystal used was
Prediction of cation ordering in jacobsite is somewhat
an octahedron with an average edge length of approxi- uncertain. While some writers (Verwey and Heilman,
mately 0.ll mm which was obtained from the same area 1947; Gorter, 1950, 1954; McClure, 1957; Dunn et al.,
of the samespecimenas the analyzedmaterial. Data were
1965; Burns, 1970; Strunz, 1970) regard jacobsite as
:
(/,
probably inverse, measurementsof synthetic materials
corrected for Lorentz-polarization and absorption
66.5 cm-t) effects.Up to six symmetry-relatedintensities show that it is approximately 80-90Vonormal (Hastings
were measuredto a sin0limit of 0.60. Following averag- and Corliss, 1956; Harrison et al., 1957; Butler and
ing of symmetry related values, the final data set consist- Biissem, 1962;Lotgeing, 1964; Sawatzky et al., 1967,
ed of 82 structure amplitudes. Of these, one (044) was
1969; Lotgering and Van Diepen, 1973; Brabers and
subsequentlyfound to be seriously affectedby extinction
Klerk. 1974).Jacobsitehas extensive solution with frankand excludedfrom the refinement, and sevenwere below
minimum observablevalues. Refinementwas carried out
Table 3. Atomic parametersfor galaxite
using the program nrrNn (Finger and Prince, 1975)using
neutral form factors of Doyle and Turner (1968). Form
factors for Al and Mn were used both for the octahedral
Tetrohedrolly coordinoted site
and tetrahedral sites, the small amount of Mg being
(rccuPonc),
0.89(3)Mn + 0.l l Al
representedby the Al form factor and the iron and traces
temperolure foctor
B t| =0 . 0 0 7 r 7 r ( r s )
of Co, Ti, V, and Zn by the Mn form factor. Refinement
Beq = 0.46 A
was carried out by varying the single oxygen coordinate,
M - 0= t . e e t 0E)
anisotropic temperature factors and the occupancies of
Octohedrolly coordinoted site
the tetrahedraland octahedralsites. The final conventional unweighted R-value, excluding unobserved data, is
1.03(2)Al - 0.03 Mn
occuPorrcy
Z.EVo.Structure factors are listed in Table 22 and final
temperqture focfors
BtI =0.00t0506)
atomic parametersin Table 3.
Bl2 = -0.000r8(8)
Occupancy values for the tetrahedral site are 0.11(3)
Beq = 0.28 Aand 0.89for the Al and Mn form factors, respectively, and
M-0= | .e27(
t) f
1.03 and -0.03 for the octahedral site. The latter values
Oxygen
are consistent with complete ordering of Al on the
octahedral site, and those for the tetrahedral site also
x = 0.2655Q1
imply the presenceof some Al, taking into consideration
2 To obtain a copy of Table 2, order Document AM-83-216
from the Business Office, Mineralogical Society of America,
2fi[ Florida Ave. N.W., Washington,D.C., 20009.Pleaseremit
$1.fi) in advancefor microfiche.
lemperoture foctors
BtI = 0.0023009)
l(ls)
qz = -0.0001
Beq = 0.62A-
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
linite (ZnFe2Oa)and studies show that these solutions are
normal or close to normal (Knoavitch et al.,1963; Kiinig
1966;Kdnig and Chol, 1968;Morrish and Clark, 1975;
Korneev et al., 1975;Vogel er al., 1976).Jacobsitealso
has extensive solution with magnetite at high temperatures (Mason, 1947)but the cation ordering in these
solutions is unknown. Natural jacobsites are most likely
to be normal spinels; the solvus between jacobsite and
galaxite(like that for franklinite and gahnite)involves two
normal spinels and is not driven by differencesin cation
distributions.
Status ofjacobsite
The status of jacobsite as a distinct mineral has been
questionedby Mason (1943,1947)and by Van Hook and
Keith (1958),who describedjacobsiteas an intermediate
member of the magnetite-highhausmanniteseries based
Because
on experimentsalong the join Fe3Oa-Mn3O4.
jacobsiteis a normal spinel,(Mn2*)lv (Fe3*)yroa, it is not
a disordered solid solution (Mn3r1 Fe.'01)tu
@n'zriFe?j3/uOanor a compoundobtainedby combination of % MnlOa and 2/t FerOa, (Mn3iFel6+7)rv
(Mn33lFe'?fiMnl3lFe:6i)vto4.
It is a unique end-member
with distinctive cationic valency and distribution. Mason's (1943)definitionsof spinelson the MnrOa-Fe:Or
join should be discardedandjacobsite acceptedas a valid
mineral.
Petrology
Galaxite should only be stable in undersaturatedrocks
for it should react to form spessartineand an aluminosilicate in the presenceof quartz:
3MnAl2Oa+ 5 SiO2: MnrAlzSi:Or2+ 2Al2SiOs(1)
The instability of galaxite with quartz is an important
factor in explainingits scarcity. Reactionsof galaxitewith
other manganesesilicatesmay be considered:
+ Mg2SiO4(2)
MnAI2Oa+ 4MnSiO3= Mn3Al2Si3Or2
453
than the reduction of magnetiteto wiistite (Ulich et al-,
1966;Shchepetkinand Chufarov, 1972).Jacobsitewill
also oxidize to hematite". and a more Mn-rich spinel:
02 + MnFe2Oo= (Fe,Mn)zO: * (Mn,Fe)rOr
(4)
The upper limit of oxygen fugacity permitted for jacobsite
is about two orders of magnitude higher than that for
(Ono et al.,l97l; Peltonet al.,1979).
magnetite-hematite
Thusjacobsite has the samewide oxidation and reduction
stability as magnetite but shifted to somewhat more
oxidizingconditions.This is in qualitativeagreementwith
the oxygen fugacities estimated at Bald Knob by Winter
et al. (1981).More complicatedreactionsinvolving manganesesilicatescan be inferred forjacobsite:
MnFezOa+ (Mn,Fe)SiOr : (Mn,Fe)zSiO4+ 02
(5)
MnFezOa+ (Mn,Fe)SiO, + CO2
: (lt4n,Fe)2Sio4
+ (Mn,Fe)CO3+ 02
(6)
but presentthermodynamicdata are inadequatefor calculation of thesereactions.Winter et al. (1981)have shown
that the Bald Knob rocks with jacobsite and galaxite have
formed at relatively low oxygen fugacity (near quartzfayalite-magnetite)and high sulfur fugacity (near pyrrhotite-pyrite) and with Xco, = 0.5 for T = 575"Cand P : 5
kbar. These conditions should be consistentwith the lefthand side ofreactions (4) and (5) sincejacobsiteis found
with pyroxmangite at Bald Knob. Other more complicated oxidation-reduction-carbonation-hydration reactions
may be balancedfor various humites,pyroxenoids,carbonates and jacobsite. Such reactions probably buffered
the ratios of various fluid speciesduring metamorphism
of the jacobsite-bearingrocks.
Note added in press:
The wt.Vo FezOr of Gx635 in Table I should read 4.6
wt.Vo.
Acknowledgments
us
Jr. whofirstintroduced
We wishto thankW. B. Simmons
to theBaldKnobdeposit,andG. A. WinterandJ. W. Geissman
+ 3MnSio3
MnAl2oa
ltnojrotrroorz + Mnco:
(3) whoaidedin someof theanalyses.WealsothankW. C. Bigelow
andhis staffof the Universityof MichiganMicrobeamLaboraGalaxite-rhodonite/pyroxmangiteand tephroite-spessar- tory for providingfacilitiesfor analysis.
tine assemblagesare both known at Bald Knob, and three
References
samples(BK4, BK8, BKl8) have all four phasesapparmaficandultramaficrocksin
ently coexisting. Reaction (2) is apparentlybridged by as- Berg,J. H. (1976)Metamorphosed
the contactaureolesof the Nain complex,Labrador,andthe
semblagesat Bald Knob presumablydue to variable solid
in naturalCr-Almiscibilitygapbetweenspinelandmagnetite
solution and could be of great use in metamorphosed
Abstractswith
of
America
Society
spinels.
Geological
Fe3*-Ti
(3)
will
manganesedeposits once determined. Reaction
8, 773.
Programs,
limit spessartine-rhodochrositeto lower temperatures
Bowman,J. R. (1978)Originof C-O-H skarnfluidsin theBlack
and/or CO2-richfluids, but the reaction cannot be located
Butte aureole.Ph.D. thesis,Universityof Michigan,Ann
until adequatethermodynamic or experimental data are
Arbor.
available for these phases.
Brabers,V. A. M. andKlerk, J. (1974)The infraredabsorption
Reactionsinvolvingjacobsite are complicatedby possiferrite.Solid
spectrumandtheinversiondegreeofmanganese
ble variations in the oxidation state of iron and perhaps
14,613-615.
StateCommunications,
manganese.Jacobsitewill be reducedto a manganwtistite Burns,R. G. (1970)Mineralogicalapplicationsof crystalfield
England.
UniversityPress,Cambridge,
theory.Cambridge
at oxygen fugacities about one order of magnitudehigher
454
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
Butler, S. R. and Biissem,W. R. (1963)Magnetizationof Mn
ferrite. Journal of Applied Physics, 34, 1754(1957).
Carvalho, A. V. III (1978)Gahnite-franklinite intergrowths at
the Sterling Hill zinc-deposit,SussexCounty, New Jersey; an
analytical and experimental study. M.S. thesis, Lehigh University, Bethlehem,Penn.
Chopin, C. (1978) Les paragenesesreduites on oxydees de
concentrationsmanganesifiersdes schisteslustrds de HauteMauriene (Alpes frangaises). Bulletin de Minerdlogie, l0l,
514-53l.
Deer, W. A., Howie, R. A. and Zussman, J. (1962)Rockforming Minerals. Vol. 5. Nonsilicates. Longmars, Green and
Co. Ltd., London.
Doyle, P. A. and Turner, P. S. (1968)Relativistic Hartree-Fock
X-ray and electron scatteringfactors. Acta Crystallographica,
A24,390-397.
Dunn, T. M., McClure, D. C. and Pearson,R. G. (1965)Some
asp€ctsof crystal field theory. Harper and Row, New York.
El Goresy,A., and Ramdohr,P., and Taylor, L. A. (1972)Fra
Mauro crystalline rocks: mineralogy, geochemistry and
subsolidus reactions of opaque minerals. Proceedingsof the
Third Lunar Science, Conference,333-350.
Finger, L. W. and Prince, E. (1975)A system of Fortran IV
computor programsfor crystal structure calculations.National
Bureauof Standards,U.S. TechnicalNote, 854.
Frondel, C. and Klein, C. (1965) Exsolution in franklinite.
American Mineralogist, 50, 1670-1680.
Fukuoka, M. (1981)Mineralogicaland geneticalstudy on alabandite from the manganesedeposits of Japan. Memoirs of the
Faculty of Science, Kyushu University, Series D, Geology,
24,207-25r.
Fukuoka, M. and Hirowatari, F. (1980)Chemical compositions
ofjacobsites from the bedded manganeseore deposits. Science Reports, Department of Geology, Kyushu University,
t3,239-249.
Gorter, E. W. (1950)Magnetization in ferrites. Saruration magnetization of ferrites with spinel structure. Nature 165, 7098800.
Gorter, E. W. (1954)Saturationmagnetizationand crystal chemistry of ferrimagnetic oxides. Phillips Research Reports, 9,
403-443.
Greenwald, S., Pickart, S. and Grannis, F. (1954)Cation distribution and factors of certain spinelscontaining Ni, Mn, Co, Al
Ga, and Fe. Journal of Chemical Physics, 22, 1597-160f.
Haggerty,S. E. (1971)Compositionalvariationsin lunar spinels.
Nature: PhysicalSciences,233, 156-160.
Haggerty, S. E. (1972a)Apollo 14: subsolidus reduction and
compositional variations of spinels. Proceedings of Third
Lunar ScienceConference, 305-332.
Haggerty, S. E. (1972b)Luna 16: an opaque mineral study and
systematicexamination of compositional variations of spinels
from Mare Fecunditatis. Earth and Planetary ScienceLetters,
13,328-152.
Haggerty, S. E. (1972c)Solid solutions. subsolidusreduction and
compositional characteristics of spinels in some Apollo 15
basalts. Meteoritics, 7, 353-370.
Harrison,F. W., Osmond,W. P. and Teale,R. W. (1957)Cation
distribution and magneticmoment of manganeseferrite. Physical Review, 106, 865-866.
Hastings, J. M. and Corless, L. M. (1956)Neutron diffracrion
study of manganese
ferrite. PhysicalReview, IM,328-331.
Hirowatari, F. (1969) Jacobsite with inclusions of exsolved
galaxite from Kiruagi mine, Japan. Science Reports, Faculty
of Science,Kyushu University, Geology,9, 159-166.
Ishida, K., Momoi, H. and Hirowahn, F . (1977)Hydrothermal
synthesisof the jacobsite-galaxitejoin. Kyushu Daigaku Rigakubu Kenkyu Hokoku, Chishitsugaku, 12, 289-297.
Kayupova, M. M., Marzuvanov, V. L. and Polyakova,T. P.
(1970)Zinc-containingjacobsite from Atasui deposits in central Kazakhstan. Doklady akademii Nauk USSR Earth ScienceSection.192.ll0-113.
Konakovitch, Ya. and Saksonov,Y. G. (1963)A neutron difraction study of a manganese-zincferrite. Soviet Physics. Crystallography, 8, 18-22.
Ktinig, U. (1966)Kationenverteilungund MagnetischeMomente
der lonen der Tetraeder-undOktaederplatzedes Mangan-zinkferrites Mn 55Zn31Fe2ssOa.
Zeitschrift fiir Angewandte Physik.22. 103-106.
Konig, U. and Chol, G. (1968)X-ray and neutron diffraction in
ferrites of Mn*Zn;*Fe2Oatype. Journal of Applied Crystallography, l, 124-126.
Korneev,E. V., and Belov, A. F., Khimich, T. A., Belov, V. F.
and Kolesnikov, I. M. (1975)Crystallochemicaland magnetic
properties of manganese-zinc ferrites. Russian Journal of
Physical Chemistry, 49, 1547-1550.
Kuno, H. (1960)Notes on rock-forming minerals. (16) Titaniferous pyroxene, spinel and magnetite in hornfels from Sisakazima Islands, Japan. Journal of the Geological Society of
Japan66, 626.
Kwestroo, W. (1959) Spinel phase in the system MgO-Fe2O3Al2O3.Journal of Inorganic and Nuclear Chemistry, 9,65-70.
Lindsley, D. H. (1981) Some experiments pertaining to the
magnetite-ulvcispinelmiscibility gap. American Mineralogist,
66,759J62.
Lotgering, F. K. (l%4) Semiconductionand cation valenciesin
manganeseferrites. Journal of Physics and Chemistry of
Solids,25, 95-103.
Lotgering, F. K. and Van Diepen, A. M. (1973)Valencesof
manganeseand iron ions in cubic ferrites as observed in
paramagnetic M<issbauer spectra. Journal of Physics and
Chemistry of Solids, 34, 1369-1377.
Mason, B. (1943)Alpha-vredenburgite:GeologiskaF<ireningens
i Stockholm, Forhandlingar, 65, 263-270.
Mason, B. (1947)Mineralogical aspects of the system Fe3OaMn3Oa-ZnFe2Oo.American Mineralogist, 32, 426-511.
McClure, D. S. (1957)The distribution of transition metal cations
in spinels.JournalofPhysics and ChemistryofSolids, 3, 3ll317.
Morrish, A. H. and Clark, P. E. (1975) High-field M6ssbauer
study ofMn-Zn ferrites. Physical Review B 11,278-286.
Muan, A., Hauck, J. and Lofall, T. (1972\ Equilibrium studies
with a bearingon lunar rocks. Proceedingsof the Third Lunar
ScienceConference(Supplement3, Geochimicaet Cosmochi
mica Acta), I, 185-196.
Muir, J. E. and Naldrett, A. J. (1973)A natural occurrence of
two-phasechromium-bearing spinels. CanadianMineralogist,
11,930-939.
Ono, K., Ueda, T., Ozaki,'1., Ueda, Y., Yamaguchi,A. and
Moriyama, J. (1971)Thermodynamicstudy of the iron-mangan€se--oxygensystem. Joumal of the JapanInstitute of Metals,
35,757J6f .
Palache, C. (1935)The minerals of Franklin and Sterling Hill,
SussexCo., N. J. U. S. GeologicalSurvey ProfessionalPaper,
180,135pp.
ESSENE AND PEACOR: COEXISTING GALAXITE AND JACOBSITE
Peacor,D. R., Essene,E. J., Simmons,W. B. Ir., and Bigelow,
W. C. (1974)Kellyite, a new Mn-Al memberof the serpentine
group from Bald Knob, N. C. and new data on grovesite.
American Mineralogist, 59, ll53-l 156.
Pelton, A. D., Schmalzried,H. and Sticher, J. (1979)Thermodynamics of Mn3Oa{o3Oa, FerOa-MnsOr, and Fe3O4-Co3O4
spinels by phase diagram analysis. Berichte Bunsengesellschaft ftir PhysikalischeChemie 83,241-252.
Plaksenko,A. N. (1980)On the nature of the non-homogeneityin
accessorychromespinelidsfrom ultrabasitesof Lowmanonsky
differentiatedintrusion. Zapiski Vsesoiuznoemineralogieheskoe obshchehestvol14, 91-98.
Price, G. D. (lg8l) Subsolidusphase relations in the titanomagnetite solid solution series. American Mineralogist, 66,751758.
Ross, C. S. and Kerr, P. F. (1932)The manganeseminerals of
Bald Knob, N. C. AmericanMineralogist,17, l-18.
Rucklidge, J. C. and Gasparrini, E. L. (1969)Specificationsof a
complete program for processing electron microprobe data:
EMIADRvrr. Dept. of Geology, University of Toronto, unpublished circular.
Sawatzky,G. A., van der Wonde, F., and Morrish, A. H. (1967)
Note on cation distribution of MnFe2Oa.Physics Letters, A,
25,ln-14E.
Sawatsky,G. A., van der Wonde, F., Morrish, A. H. (1969)
Mcissbauerstudy of several ferrimagnetic spinels. Physical
Review, Series2, 187,747-:757.
Shcheptekin,A. A. and Chufarov, G.l. (1972)The dissociation
of solid solutions of oxides in M-Fe-O systemsunder equilibrium conditions. RussianJoumal of Inorganic Chemistry, 17,
792J94.
Simmons,W. 8., Jr., Peacor,D. R., Essene,E. J. and Winter,
G. A. (1981) Manganeseminerals of Bald Knob, N. C.
Mineralogical Record, 167-17l.
Stilwell, F. L. and Edwards, A. B. (1951) Jacobsite from the
Tamworth District of New South Wales. Mineralogical Magazine, 2l2, 538-541.
Strunz, H. (1970)MineralogischeTabellen. Akademische Ver-
45s
lagsgesellschaft,Geest und Portig K.-G. Leipdg.
Takeda, H., Miyamoto, M. and Reid, A. M' (1974) Crystalchemical control of element partitioning for coexisting chromite-ulvospinel and pigeonite-augite in lunar rocks. Proceedings ofthe Fifth Lunar ScienceConference, 1,727-:741.
Tumock, A. C. and Eugster, H. P., (l%2) Fe-Al oxides: phase
relationshipsbelow 1000"C.Journal ofPetrology, 3, 533-565.
Ulrich, K. H., Bohnenkamp, K. and Engell, H. J. (1966)
Equilibrium of magnetite-hausmannitemixed crystals and
wiistite-manganese(ll) oxide mixed crystals and oxygen and
the reduction of magnetite-hausmannite mixed oxides.
Zeitschrift fiir Physikalisch Chemie, Neue Folge. Frankfort
5r,3549.
Vincent, E. A., Wright, J. B., Chevallier,R. and Mathieu, S.
(1957)Heating experimentson some natural titaniferous magnetites. Mineralogical Magazine, tl, 624-655.
Valentino, A. J. and Sclar, C. B. (19E2)Experimental study of
the magnetite (FeFezOaFfranklinite(ZnFe2Oa)solid-solution
series.EOS, 63,470.
Van Hook, H. J. and Keith, M. L. (195E)The system FerOrMn3Oa.American Mineralogist, 43, 68-83.
Verwey, E. J. W. and Heilman, E. L. (1947)Physical properties
and cation arrangement of oxides with spinel structure l.
Cation arrangementin spinels. Journal of Chemical Physics'
15. 174-180.
Vogel, R. H., Evans, B. J. and Swartzendruber,L. J. (1976)
Intra-site cation ordering and clustering in natural Mn-Zn
ferrites. AIP ConferenceProceedings,34, 125-127.
Winter, G. A., Essene,E. J. and Peacor,D. R. (l9El) Carbonates and pyroxenoids from the manganesedeposit near Bald
Knob, N. C. American Mineralogist, 6,27E-2E9.
Winter, G. A., Essene,E. J. and Peacor, D. R' (19E3)Mnhumites from Bald Knob, North Carolina: mineralogy and
phase equilibria. American Mineralogist, in press.
Manuscript received, November 9, 1981;
acceptedfor puhlication, November 4, 1982.