Petrographic descriptions
of t h i n s e c t i o n s of d r i l l c u t t i n g s
from KCM No. 1 F o r e s t Federal well, Hidalgo
County, New Mexico
6 f
Antonius J. Budding and Ronald F. Broadhead
New Mexico I n s t i t u t e of Nining andTechnology
1977
Open F i l e Report of t h e
Neb7
Mexico Bureau of Mines and Mineral Resources
Socorro, Neb7 Mexico
~
'
Open-file
=Port
75
~
?s
Introduction.
This r e p o r t c o n t a i n s p e t r o g r a p h i c d e s c r i p d o n s
of t h i n s e c t i o n s
prepared from d r i l l c u t t i n g s
of the KCM No. 1 ForestFederalwell,
Hidalgo County, New Mexico.
The d e s c r i p t i o n s a r e i n t e n d e d
in conjunction with the thin sections
theirstudy.
and can serve as
to
be used
a guide to
Each d e s c r i p t i o n is accompanied by a photomicrograph
and sketches of p e r t i n e n t p a r t s o f t h e t h i n s e c t i o n .
The reader i s r e f e r r e d t o C i r c u l a r
of Mines andMineralResources,
Rocks, andThermal
152 of t h e New Mexico Bureau
e n t i t l e d "Geology, PetroleumSource
Metamorphism i n KCM No. 1 Forest Federal
Hidalgo County, New I.Iexico", compiled by SamThompson
tionalinformation.
.
Well,
111, for addi-
Thin sections prepared
Depth fi tn.
50
210
230
270a
270b
320
380
450
480
5 20
640
760
800
1080
1210
1230
1810
1920
2010
2280
2360
2460
2640
2660
2820a
2820b
2960
3130a
3130b
3380
3680a
3680b
3740a
37401,
3750
3780
4000
4010
4040
4350
4460
from d r i l l c u t t i n g s of KCM No. 1 FF-well.
Name
Rock
m
lim
i cSeriislttio
ycn e
Quartz Latite
Quartz Latite
Sandy dolomitic Limestone
Sandy dolomitic Limestone
Argillaceous Limestone
Limestone
B i o m i c r i t i c Limestone
B i o m i c r i t i c Limestone
M i c r i t i c Limestone
Limestone
Dolomitic Limes tone
Calcareous Mudstone
Calcareous Mudstone
Calcareous Mudstone
Sandy, Calcareous Mudstone
Argillaceous Limestone
M i c r i t i c Limestone
Tremolite-bearing Limestone
Diopside Marble
Diopside-wollastonite Marble
Wollastonite hornfels and Quartz
Wollastonite Marble
Cherty Limestone
Wollastonite' MazbTe
Wollastonite Marble
Quartz Monzonite
Quartz Monzonite
Quartz Monzonite
Diopside Marble
Diopside Marble
Wollastonite Marble
Marble .
Marble
Tremolite Marble
Diopside Hornfels
Diopside Hornfels
Quartz Monzonite
Diopside Hornfels
Quartz Nonzonite
Quartz Monzonite
Monzonite
Thin Section Number: KCMIFF-50
Rock Name: Silty
micritic limestone
Composition:
Calcite - Micrite: (cryptocrystalline brown calcite)
Golden brown color; homogeneous with abundant random "inclusions", of
silty quartz.
Quartz :
Silt-sized, as "inclusions" inmicrite
Hematite:
on the carbonate.
Separate grains and as a coating
Texture:
Grain sizes: Quartz
-
length .038 m, width .018 mm
or .025 x .025 m
m, equant.
I FF -
H
0 .r c m
IS.
(.
Thin
Section
Number:
Rock
Name:
KCMIFF-210
Quartz l a t i t e
Composition:
Matrix:
67%
A c r y p t o c r y s t a l l i n e brown mass which shows no extinction under crossed
is g r e a t e rt h a nt h a t
ofquartz.
It
n i c o l s . Its indexofrefraction
appears to be highly altered.
Matrix:
13%
Quartz occurs i n p a r t s of the matrix.
Potash
Feldspar:
6%
Occurs as phenocrysts.
Q u a r t z : 6%
Anlsedral,rounded c r y s t a l s which show undulatory extinction and are
phenocrysts i n t h e m a t r i x .
The q u a r t z c r y s t a l s sometimes have f i n e
fracturesatthegrainboundarieswiththematrix
i n places.These
1).
commonly have a s i n g l e , p r e f e r r e d o r i e n t a t i o n ( s e e s k e t c h
e
PlagioclaseFeldspar - Albite: 4%
These crystalsarepresentaselongate,subhedralphenocrysts.These
c r y s t a l s a r e sometimeszoned.
Hematite: 3%
Occurs a s s m a l l , b l a c k e u h e d r a l c r y s t a l s i n a u a r t z
and f e l d s u a r e r a i n s
and as l a r g e r t r a n s l u c e n t , blood-red splotches with needle-like internal
t e x t u r e . Theseblood-redsplotchesarecontainedwithinthematrix,
notwithinthefeldspar
and q u a r t z c r y s t a l s . '
The crystalsappearprimary.
The redtranslucentvarietyappearssecondary.
The a l t e r a t i o n (?) zones
(i..e. red translucent variety) contain
some hexagonal crystals.
I
B i o t i tter :a c e
The b i o t i t e c r y s t a l s appear as phenocrysts i n t h e matrix.
Z e o l i t e (?): t r a c e
Appears a s a few f i b r o u s c r y s t a l s i n s i d e t h e
matrix.
C a l c i t er a: c e
Occurs a s twinned phenocrysts i n t h e m a t r i x ( s e e s k e t c h
Pyroxene (?): t r a c e
Pyroxene occurs as phenocrysts
in the matrix.
Arsenopyrite ( ? ) : t r a c e
is s i l v e r - g r e y i n r e f l e c t e d l i g h t .
Blackopaquewhich
crystals inside the hematite (see sketch
3).
II)
2).
m
m
.
It occurs as
Texture:Averagegrainsize
of phenocrysts i s 0.15
The matrix i s cryptoc r y s t a l l i n e and individual crystals cannot be distinguished with the
microscope.
ThinSection
Remarks:
Number:
KCMIFF-210 (continued)
This may be a f e e d e rd i k e t o a v o l c a n i cs t r u c t u r e .
The p o t a s hf e l d s p a r
may b e r e s p o n s i b l e for a low b l i p on t h e r a d i o a c t i v i t y log.
k&
I
.
.
Thin Section Number:
DCMIFF-230
Rock
Name:
Quartz l a t i t e
Composition:
Quartz :
p r e s e n t a s a f i n e mosaic of a n h e d r a l c r y s t a l s . O f t e n , l a r g e r c r y s t a l s
are p r o p h y r i t i c i n a much smaller s i z e groundmass (see s k e t c h 1) of
quartz and feldspar.Quartzoften
shows undulatoryextinction.
Potash Feldspar:
This i s less abundantthanquartz.
It shows gridirontwinning.
Pfuscovite:
Occurs as small, c l e a r , c o l o r l e s s , e l o n g a t e c r y s t a l s
(see s k e t c h 2).
Fluorite:
Occurs a s a n h e d r a l , c o l o r l e s s c r y s t a l s .
Hematite:
some fragments
Red t o o r a n g et r a n s l u c e n ts t a i n si nt h er o c k .S t a i n s
(cuttings)completely.
Does n o t s t a i n some otherfragments a t a l l .
0
Calcite:
Calcite occurs as extremely small crystals scattered throughout the
quartz.
Texture:
The a v e r a g e g r a i n s i z e
i s 0.1
mm.
Thin Section Number: KCMIPF-270a
Rock Name: Sandy dolomitic limestone
Composi-:
Cryptocrystalline brown calcite: 73%
This isa brownish colored matrix
brownish colored.
material
in
the
limestoneis which
Microspar: 15%
Average grainsize is0.05 m. This is microspar or neomorphic spar
which occursin the micritic matrix.
Detrital Quartz, Chert: 11%
Average grain size 0.05
is mm. Occurs as small, anhedral,
subamlar
to subrounded clasts. Sometimes there a
ispreferred orientationof
elongate'quartz clasts in the micrite.(see sketch
1).
Cryptocrystalline clear calcite: 1%
e
Sparry calcite: trace
Occurs as straight "veins"
of clear, colorless calcite.Dark material
frequently foundin the bordering micrite. This dark material (organic
material?)issometimesarrangedasiflayered(seesketch
2 and 3 ) .
The calcite "veins" often cross-cut this layering at nearly right angl
Quartz clasts are not present in the calcite veins.
'
Pyrite:trace
Appears as amorphous masses (see sketch
1).
Plagioclase Feldspar: trace
detrital clasts
-
Potash Feldspar: trace
detrital clasts
-
Thin Section Number:
KCMIFF-270b
Rock
Name:
Sandy dolomiticlimestone
Composition:
C r y p t o c r y s t a l l i n e brown c a l c i t e : 66%
. Acts as a matrix f o r d e t r i t a l q u a r t z .
It i s ' b r o m and contains manv
some e o i i t e s ( ? ) o r p e l l o i d s (?).
blackspots.Contains
Detritaq
l u a r t z c, h e r t :
20%
Average g r a i n s i z e i s 0.02 mm f o r i n d i v i d u a l c r y s t a l s .
Shows undulat o r ye x t i n c t i o n s .
Minor small c a l c i t e c r y s t a l s o c c u r i n t h e c h e r t
aggregates. Could t h i s b e reworked Paleozoicchert?
Microspar: 8%
Average g r a i n s i z e is 0.02
mm.
D e t r i t aql u a r t z :
3%
Average g r a i n size i s 0.05
Occurs as s m a l l c l a s t s i n t h e
of c r y p t o c r y s t a l l i n e brown c a l c i t e . These areangular.
mm.
matrix
S p a r r yc a l c i t e :
1%
Average c r y s t a l s i z e i s 0.6
Rhombohedral, brownish c a l c i t e which
occursinlargeaggregates
of e u h e d r a l t o s u b h e d r a l c r y s t a l s ( s e e
.
.
sketch 1).
mm.
'
Hematite: 1%
This occurs as fracture filling
chert aggregates.
. P l a g i o c l a sF
e e l d s p a rt:r a c e
Has a l b i t e twinning.Occurs
clays:
and between q u a r t z g r a i n s i n t h e
i nt h ec h e r ta g g r e g a t e s .
trace
Limonite: t r a c e
Occurs as a s t a i n and a coating throughout the rock.
Remarks:
Is t h e m i c r i t e b e i n g s i l i c i f i e d
or is t h e c h e r t reworked Paleozoic chert?
e--
Thin Section Number: KCMIFF-320
Rock Name: Argillaceous limestone
Composition:
Microspar: 67%
Average crystal size 0.01
is mm. Occurs as small elongate crystals which
are separated by black and brown material (clays). These elongate
crystals havea preferred orientation.
-:
21%
Black opaque
material.
Cryptocrystalline brown calcite: 6%
Sparry calcite: 2%
Crystals with rhombohedral cleavage.
Chert: 2%
Average grain size 0.01
is mm for individual crystals. The chert
comes in small aggregates which sometimes come in line contacts
sparry calcite. It contains anhedral calcite crystals.
e.
Detrital quartz: 2%
Average grain size 0.01
is
(clasts) in the clay.
mm.
Occurs as small, angular includions
Pyrite:trace
Occurs in the clay.
Hematite:trace
Texture: The clays and elongated microspar give the impression of layering.
Some small veins of calcite cut across this "layering" (see
1). sketch
with
I
.
..
.. .
H
-.
..
.-
a
Thin Section Number:
KCMIFF-380
Rock
Name:
Limestone
Composition:
Microspar: 65%
Average g r a i n s i z e i s 0.01
Occurs a s s o c i a t e d w i t h c r v u t o c r v s t a l l i n e
brown c a l c i t e . The s p a r r y c r y s t a l s a r e i r r e g u l a r
which tendstosuggest
t h a t i t i s neomorphic spar. The microspar i s oftenlight-brown o r t a n
colored.Microsparhas
a blockytexture.
mm.
"
Sparry
calcite:
18%
Average g r a i n s i z e i s 0.2
hedral cleavage.
mu.
-.
Clear,colorlesscrystalswith
rhombo-
C r y p t o c r y s t a l l i n e brown c a l c i t e : 14%
Associated with microspar as noted above.
Chert: 2%
Fragmentswhich contain fine-grained, subhedral to anhedral quartz
c r y s t a l s and some s m a l l , a n h e d r a l c a l c i t e c r y s t a l s .
e
D e t r i t aql u a r t z :
1%
Angular to subangular chert-sized fragments
P l a g i o c l a sfee l d s p a rt:r a c e
- detrital, altering to
a brown c l a y
imbedded i n t h e microspar.
'.
Hematite:
trace
Small, b l a c k opaque to translucent red pseudocubic crystals.
Clay m i n e r a l st:r a c e
Loose on s l i d e a n d ' a s a t t a c h e d t o m i c r i t i c
Chlorite (?):
Texture:
and s p a r i t e fragments.
t r a c e , a s i n g l ec r y s t a l
In t h e c h e r t , t h e r e may be a replacement involved with the calcite,
b u t i t i s n o t c l e a r what t h e r e l a t i o n s h i p is. S i l i c a i s probably
being replaced by c a l c i t e .
e
ThinSection
Rock
Name:
Number:
KC$fIFF-450
Biomicriticlimestone
Composition:
Calcite:
Occurs mainly a s c r y p t o c r y s t a l l i n e brown c a l c i t e which i n p l a c e s i s
r e c r y s t a l l i z e d t o microspar o r even s p a r r y c a l c i t e .
Average g r a i n
s i z e of microspar and spar i s 0.025
nun.
Clays ( ? ) o r Organicmaterial ( ? ) :
T h i s occurs as dark streaks in the micrite (see sketch
1).
Detrital quartz:
. T h i s o c c u r s as randomly
Average g r a i n s i z e i s 0.075 mm x 0.038
oriented silt-sized clasts in the micritic material.
mm.
Fossils:(seesketches
2 and 3) Abundant f u s u l i n i d s are presentalong w i t h
an echinoid spine
and a c r i n o i d columna1 and perhaps a molluscan
fragment
.
Texture:
"
Many c a l c i t e
veinlets
r uthrough
n
the
microspar.
-
e
Thin Section Number:' KCMIFF-480
Rock Name: Biomicritic limestone
Composition: .
Cryptocrystalline brown calcite:
It is light
brown to almost black and actsa matrix
as
and microspar.
for
fossils
Calcite-Microspar Veinlets:
Branching veinlets of microspar. Could these represent plant remains?
(see sketch1)
Microspar
and
Spar:
Average grain size
of microspar is0.'038
Average grain size of
spar is 0.15 m. These are present as recrystallization products of
cryptocrystalline brown calcite.
Chert: minor amounts
Average grain
.e
'
Magnetite:
Amorphous.forms
mm.
size 0.050
is
mm.
associated
with
the
microspar
Fossils: Abundant fusulinids with wall structure similar to those in thin
section KCMIFF-450. Recrystallized crinoid ossicle (?). Coralline
algae (?).The fossils occur mostly in unaltered cryptocrystalline
brown calcite (see sketch
2).
k
H
0.T-Z.m
*
Thin Section Number: KCMIFF-520
Rock Name: Micritic limestone
Composition:
Cryptocrystalline brown calcite: micrite
Microspar and Spar:
Average grain size
of microspar is 0.050 mm. Average grain size of
spar is0 . 3 2 mm. These are alteration products of micrite. Some
crystals are very small and hexagonal in cross section.
Dolomite:
Average grain size is
0.013
a few dolomite rocks.
mm.
Some fragmentsof micrite contain
. Quartz:minor
Chert and Chalcedony: minor
a
Organic material:
concentric
Spherical material which shows aboth
and has no X-ray diffraction pattern.
Fossils:
"
and
radial
structure
Fusulinids and forams (wall structure as in KCMIFF-450).
spine (?) (see sketch 1). Also, recrystallized brachiopod (?) o r
molluscan (?) fragments.
Echinoid
Thin Section Number: KCMIFF-640
Rock Name: Limestone
Composition: (percentages are visual estimates)
Cryptocrystalline brown calcite: 60%
Microspar: 25%
Probably results from recrystallization of cryptocrystalline brown
calcite (i.e., it is neomorphic). Average grain size 0.01
is
mm.
~~
’
Sparry calcite: 10%
Clear crystals with rhombohedral cleavage. Sometimes
it appears
to
..
be recrystallized to microspar. Average grain size0 . 3is
m
m
.
Chert: 5%
A few
aggregates of fine-grained quartz are present. The average
grain size of the individual crystals
0.01is
e
mm.
Hematite:trace
This occurs both as cubic (pseudocubic (?))‘black opaque crystals and
as red-translucent staining on microspar and crystocrystalline brown
calcite.
Zeolite (?): trace
A single fibrous
crystal
Texture: The aggregates of microspar and micrite are reminiscent of ”Structure
Grumeleuse.”
Thin Section Number: KCMIFF-760
Rock Name: Dolomitic limestone
Composition.:
Cryptocrystalline brown calcite:
Acts as a matrix for fossils.
Micro=:
Average grain size 0.05
is
crystallization product of
_
I
mm.
This is probably
a neomorphic re+
micrite.
Sparry calcite:
Average grain size is
0.3
A few crystals are present.It is
probably-a recrystallization product; sizes grade into microspar.
Twinned calcite also occurs as cross-cutting veins.
mm.
clays:
Black
material
which
is separated by microspar.
Chalcedony:
Minor amounts of radiating, fibrous silica
Chert:
Average
mm.
grain size of individual quartz crystals
0.04 is
Occurs in the micrite.It may locally replace the micrite.
Dolomite:
A few dolomite rhombs exist in some cuttings which are
wholly microspar with
no cryptocrystalline brown calcite.
largely
Pyrite and Magnetite: trace
These occur near fossils.
Fossils: Fusilinids, crinoid columnal, molluscan fragments, brachiopod fragments, coralline algae, forams. Also,
a bryozoan fragment (?) (see
sketch 1).
Texture: Possibly a recrystallized ooid is present (see
sketch :
)
2
or
a
-
ThinSection
Number:
KCMIFF-800
Rock Name:
Calcareousmedstone
Composition:
52%
Brown t o b l a c k opaque m a t e r i a l i n transmitted plane light. Acts
matrix.
C
a
ly
s
:
as a
Microspar: 37%
Average g r a i n s i z e i s 0.05
The microspar crystals occur in the
c l a y matrix and a r e e l o n g a t e d and have a p r e f e r r e d o r i e n t a t i o n .
It
a l s o o c c u r s i n v e i n s whichrandomly cut across the rock.
These v e i n s
cross-cut a l l o t h e r f e a t u r e s .
mm.
C r y p t o c r y s t a l l i n e brown c a l c i t e :
7%
Detrital quartz: 1%
Average g r a i n s i z e i s 0.075
Occurs as angular,subspherical clasts
of s i l t - s i z e d q u a r t z i n t h e c l a y m a t r i x , w i t h
random d i s t r i b u t i o n . The
presence of d e t r i t a l q u a r t z i s generally exclusive of the presence of
l a r g e amounts of c a l c i t e i n a s i n g l e c u t t i n g .
m
m
.
0
Sparry
Calcite:
1%
Average g r a i n s i z e i s 0.35
rence as f o r microspar.
mm.
The s p a r r y c a l c i t e h a s t h e
Chert:
trace
Average s i z e of
i n d i v i d u a lq u a r t zc r y s t a l s
i s generally associated with microspar.
same occur-
i s less than 0.01
Chalcopyrite:
trace
This occurs as minute grains inside small patches
sketch 1).
m
m
.
This
of microspar (see
Fossils:
2% Fossilsincludebrachiopodfragments
(see sketch 2).
Texture:
The rock i s l a m i n a t e d ; t h e l a y e r s a r e
made up of micrite. This
laminadue t o b i o t u r b a t i o n ?
t i o n i s very locally disrupted, could this be
and bryozoan (?) fragments
Rock Name:
Calcareous mudstone
Composition:
Microspar: 45%
Average g r a i n s i z e is 0.1 mm. The microsparoccurs as p a t c h e s ' i n t h e
I n some places,microspar may b e t h e r e s u l t
of degrading
clay matrix.
neomorphism of c r i n o i d o s s i c l e s ; i n o t h e r p l a c e s ,
it appears to be the
r e s u l t of aggrading neomorphism of c r y p t o c r y s t a l l i n e brown c a l c i t e .
The microspar often appears as elongate "rods" in the clay
matrix (see
sketch 1). The microsparalsooccurs
i n v e i n s which cross-cutthe
layering.
clays: 40%
I n some c u t t i n g s , t h e c l a y
i s interlayered with the microspar;
i t a c t s as a matrix for patches of microspar (see sketch
1).
S p a r r yc a l c i t e :
10%
Average g r a i n s i z e is 1.3
This i s t h e same occurrenceas
microspar,exceptthat
i t i s less abundant.
mm.
e
i n others,
for
C r y p t o c r y s t a l l i n e brown c a l c i t e : 3%
This appears to be altering to microspar.
Quartz: 1%
Average g r a i n s i z e i s 0.04
clastswithintheclaymatrix
chaloedony-filled veinlets.
m
m
. Detrital
quartz,appearsasangular
and inthemicrospar.
Also, i n some
Chert:
trace
Average g r a i n s i z e i s 0.03 mm f o r i n d i v i d u a l q u a r t z c r y s t a l s .
The c h e r t
a p p e a r s i n some c u t t i n g s as being intermixed with calcite (microspar)
Chalcopyrite:
trace
Hematite:
trace
Dolomite: t r a c e (?); presencequestionable
There may be a few dolomite rhombs i n a microspar matrix.
Fossils:
Foram (?); (seesketch 2 ) .
neomorphism to microspar.
Texture:
The microspar and t h ec l a y s seem t o b e i n t e r l a y e r e d i n
some c u t t i n g .
One cutting looks bioturbated; there
i s no o r d e r t o t h e d i f f e r e n t i n swirls i n a matrix of amoruhous
gredients a t a l l ; t h e c l a y s a p p e a r i n
c a l c i t e . I n some p l a c e s ,t h em i c r o s p a ra p p e a r st or e c r y s t a l l i z ei n t o
spar.
e.
I
Crinoidossicle,undergoingdegrading
'
c
I
I
I'
a
ThinSection
Rock Name:
Number:
KCMIFF-1230
Sandy,Calcareous
mudstone
Composition:
Microspar: 30%
Average g r a i n s i z e i s 0.1
mm.
C r y p t o c r y s t a l l i n e brown c a l c i t e :
Dominant c o n s t i t u e n t .
26%
clays: 25%
..
Quartz: 18%
Average g r a i n s i z e i s 0.075 m. D e t r i t a l q u a r t z - corroded,angular,
s i l t - s i z e d g r a i n s which are set i n a microspar matrix, there
is a
11
wacke" t e x t u r e . Where quartz grains come i n t o c o n t a c t w i t h one
another,point and concavo-convex c o n t a c t sa r ep r e s e n t .
Some q u a r t z
i s c h e r t y and a s s o c i a t e d w i t h r e d i r o n s t a i n s .
Sparrc
y a l c i t et:r a c e
P y r i t er a: c e
euhedral crystals
Hematite:
trace
is dominant c o n s t i t u e n t , some p l a c e s are c r y p t o c r y s t a l l i n e
Texture:Microspar
brown c a l c i t e i n d i c a t i n g t h a t t h e l a t t e r h a s p r o b a b l y
undergond aggrading
neomorphism.
i
’
ThinSection
Rock
Name:
number:
KCMIFF-1810
Argillaceouslimestone
Composition:
Microspar: 57%
Average g r a i n s i z e i s 0.08
and p a r a l l e l t h e l a y e r i n g . V e i n s
layering.
mm.
Largepatches of microspar are elongate
of spar and microsparcutacross
clay: 18%
Present as "layers" (patches) alternating with the microspar.
Spar:
12%
Average g r a i n s i z e is 0.4
microspar?
nun.
A r e s u l t of r e c r y s t a l l i z a t i o n of
Chert: 11%
Average s i z e of i n d i v i d u a l q u a r t z c r y s t a l s : t h e c r y s t a l s i z e
is
g r a d a t i o n a l from 0.1 mm t o <0.001
I n p l a c e s ,c h e r tr e p l a c e s
s p a r r y c a l c i t e , m i c r o s p a r and c r y p t o c r y s t a l l i n e brown c a l c i t e .
Occurs i n v e i n s , s m a l l p o c k e t s
and i r r e g u l a r p a t t e r n s .
nun.
,
1%
Average g r a i n s i z e i s 0.05 mm.
Quartz:
S m a l l q u a r t zc r y s t a l sa s s o c i a t e d
with
c h e r t ,p o s s i b l y a r e s u l t of s i l i c a r e c r y s t a l l i z a t Z o n ?
Also, direct
replacement of c a l c i t e by quartzwith no chertevident (?). D e t r i t a l
quartz: a few p i e c e s of quartz are a n g u l a r , s i l t - s i z e d c l a s t s i n a n
argillaceous carbonate (usually micritic)
matrix.
C r y p t o c r y s t a l l i n e brown c a l c i t e : 1%
Some c u t t i n g s a r e a l m o s t e n t i r e l y c r y p t o c r y s t a l l i n e
c e p t f o r v e i n s and pockets of microspar.
brown c a l c i t e ex-
P y r i tter a
: ce
Dolomite: t r a c e
A f e w zoned dolomite rhombs e x i s t i n t h e c u t t i n g which are dominantly
microspar.
*:
The c l a y s a r e g e n e r a l l y more abundant a t t h e edges of t h e s p a r t h a n t h e
microspar, t h e r e f o r e ,t h e
c l a y s may w e l l have been i n s o l u b l e r e s i d u e
which was separated f i r s t as a r e s u l t of t h e aggradation of micrite t o
microspar and l a t e r of microspartospar.Planarboundaries
between two
d i f f e r e n tl i t h o l o g i cp a r t s
of a c u t t i n g are common. Burrow ( ? I : p o s s i b l e
J-shaped s i l i c i f i e d ( c h e r t ) burrow inmicrite.Probablybioturbated.
..
ThinSection
Number:
KCMIFF-1920
Rock
Name:
M i c r i t i cl i m e s t o n e
Composition:
Calcite:
Mostly m i c r i t e ( c r y p t o c r y s t a l l i n e brown c a l c i t e )
Calcite:
microspar
Average g r a i n size i s 0.04
Occur as l e n s e s i n t h e
micrite.
few microspar veins which c u t a c r o s s l a y e r i n g a r e a l s o p r e s e n t .
mm.
A
C a l c i t es: p a r r y
calcite
Thisspar i s g e n e r a l l y f u l l o f i n s o l s .
Average g r a i n s i z e is 0.4
This spar comes from r e c r y s t a l l i z a t i o n of 'microspar.
"
mm.
Chert :
Average s i z e of i n d i v i d u a l c r y s t a l s i s 0.04 mm.'
m i c r i t e have been replaced by c h e r t .
Some microsparand
Hematite: t r a c e
Both red-translucent and black opaque v a r i e t i e s .
e
P y r i tter a
: ce
F l u o r i tter :a c e
Fossils:
Foram ( f u s u l i n i d ( ? j )
- w a l l sr e c r y s t a l l i z e d .
Bryozoan? ( s e es k e t c h
1).
Texture:
Some s t y l o l i t e s e x i s t i n t h e r o c k , w i t h b l a c k i n s o l s . c o n c e n t r a t e d a l o n g
show a
them. when microspar entirely makes up o n e c u t t i n g , c r y s t a l s
p r e f e r r e d o r i e n t a t i o n i n one d i r e c t i o n .
*
Thin
Section
Rock
Name:
Number:
KCMIFF-2010
Tremolite-bearinglimestone
Composition:
Microspar: '54%
Average g r a i n s i z e is 0.05
clay)material.Microsparoccurs
mm.' Associated with black (organic or
C r y p t o c r y s t a l l i n e brown c a l c i t e :
i n elongatelenses(seesketch
1).
33%
Sparry calcite: 6%
Average g r a i n s i z e is 0.2
R e c r y s t a l l i z e d frommicrosuar and
c r y p t o c r y s t a l l i n e brown calcite. Black material (organic- or clay)
n o t a s s o c i a t e d with this l i t h o l o g y .
mm.
~~
Chert: 5%
Average s i z e of i n d i v i d u a l q u a r t z c r y s t a l s
i s 0.01
Smallfragments
of c h e r t which are stainedblack.Chertreplacingmicriticfragments.
mm.
C r y p t o c r y s t a l l i n ec l e a rc a l c i t e :
2%
P y r i t e and c h a l c o p y r i t e :t r a c e
Associated with black (organic or clay)
Muscovite:
material.
trace
Tremolite:
trace
F o s s i l s :C o r a l l i n ea l g a e
-
associatedwithblackmaterial.
Texture:Coarser-grained"clear"calcite
(organicallyrich?)(seesketch
i s sometimes i n t e r l a y e r e dw i t h micrite
2).
l-"i
0.5-Gm
*
ThinSection
Rock Name:
Number:
KCMIFF-2280
DiopsideMarble
Composition:
Chert:
Average s i z e of i n d i v i d u a l q u a r t z c r y s t a l s
i s 0.01
Smallquartz
crystals surround anhedral sparry calcite
which shows cleavage (see
sketch 1). Only a few c h e r tf r a g m e n t sa r ep r e s e n t .
Replacement of
c a l c i t e by c h e r t i s suggested.
m
u
.
Calcite:
Average g r a i n s i z e of spar i s 0.2
S p a r r y ,a n h e d r a lc r y s t a l so c c u r
in large aggregates. These
are c l e a r and show no o r g a n i c m a t e r i a l .
Other c a l c i t e i n t h e s l i d e i s much f i n e r and more irregularly shaped.
It i s characterized by brown s t a i n i n g .
mm.
Diopside:
Average g r a i ns i z e i s 0 . 3 mm.
crystals are also present.
e
*
Chalcopyrite:
Small c r u s t i n g- forms.Occurs
s t a i n e d brown.
Two i d i o b l a s t i cc r y s t a l s .
inthoserocks
Other smaller
which are o r g a n i c a l l y (?)
e
Thin
Section
Number:
Rock Name:
KCMIFF-2360
Diopside-WollastoniteMarble
Composition:
Spar:
43x
Average g r a i n s i z e i s 1.0
less spar.
Microspar:
mm.
Occurs i n l a r g e b l o c k s
of c l e a r , c o l o r -
32%
Chert: 12%
Average s i z e of i n d i v i d u a l q u a r t z c r y s t a l s
is 0.02
Chertaggregates
c o n t a i n small a n h e d r a l c r y s t a l s of c a l c i t e , s m a l l p l a t e s of muscovite,
and anhedral diopside crystals.
m
m
.
Wollastonite: 6%
Average l e n g t h of f i b e r s i s 2.0
Average width of f i b e r s is 0.2 mm,
Occurs i n fi'orous aggregates. . 2Vx = 36".
mm.
Diopside: 4%
Average g r a i n s i z e is 0.2
C r y p t o c r y s t a l l i n ec l e a rc a l c i t e :
m
m
.
I
Associated with wollastonite
and c h e r t .
1%
C r y p t o c r y s t a l l i n e brown c a l c i t e :t r a c e
Muscovite: t r a c e
Average l e n g t h of c r y s t a l s i s 0.30
0.15
Hematite:
mm.
trace
P y r i tter a
: ce
Potash
Feldspar:
trace
P l a g i o c l a sF
e e l d s p a rt:r a c e
mm.
I
.
Average width of c r y s t a l s . i s
*
Thin
Section
Number:
KCMIFF-2460
RockName:
Wollastonitehornfe'ls
+ Quartzmonzonite
Composition:
Q u a r t z monzonite and c h e r t : 63%
Groundmass i s fine-grained.Enclosesporphyritic,anhedralquartz
c r y s t a l s and small,anhedralcalcitecrystals.Encloseslarge
c r y s t a l s of potash feldspar.
10%
Plagioclase
Feldspar:
Albite,alteringtosericite.
Wollastonite: 10%
F i b r o u s ,r a d i a t i n g .
Q u a r t z - i n d i v i d u a lc r y s t a l s :
6%
Microspar: 3%
Occurs i nc h e r ta g g r e g a t e s .
Spar:
Dolomite (?)
2%
A few l a r g e blocky c r y s t a l s a r e p r e s e n t .
C r y p t o c r y s t a l l i n e brown c a l c i t e :
Pyrite:
1%
1%
Diopside: 1%
Crystals are associated with wollastonite.
Muscovite:
trace
Hematite:
trace
Potash
Feldspar:
trace
With small vein running through
Texture:
.
it.
Average g r a i n s i z e of phenocrysts i s 0.8
mm.
.
H
0.5-Linl
a
Thin Section Number: KCMIPF-2640
Rock Name: Wollastoni.te Marble
Composition:
Spar: 44%
Average grain size is.0.8
mm. Pieces of large, blocky, twinned, anhedral crystals.
Cryptocrystalline brown calcite: 31%
Brown, large masses, recrystallized into sparite.
Microspar: 12%
. - Chert:
4%
Average grain size
of individual quartz crystals
is 0.01mm. Chert
fragments contain diopside, fibrous wollastonite, varying ofamounts
calcite which has
a poikiloptic texture. One chert fragment contains
about 20% anhedral calcite with
no other impurities. In chert fragments,
the non-chert minerals are usually concentrated.
Cryptocrystalline clear calcite: 3%
a
Wollastonite: 3%
Average lengthof crystals is0.3
Average widthof crystals is
0.01 m. Occurs as crystals in radiating, fibrous aggregates.
mm.
'
Fibrous calcite:
1%
Diopside: 1%
Average grain size 0.3
is mm. Associated with wollastonite and cryptocrystalline brown calcite.
Pyrite:trace
Present in calcite, especially
in cryptocrystalline
has not been greatly recrystallized.
Fluorite:trace
Apatite:trace
brown
calcite
which
1
a
Thin Section Number: KCEIIFF-2660
Rock Name: Cherty Limestone
Composition:
Cryptocrystalline brown calcite: 45%
Microspar:29%
Average grain size is
0.05
mm. Neomorphic
spar.
Chert: 16%
Chert replaces calcite.
Cryptocrystalline clear calcite:
6%
Hematite:2%
Trace of hematite asa red, translucent staining. Also appears as
black opaque crystals in chert.
Spar:
e
1%
Pyrite: 1%
Some cubic
crystals
disseminated
in
dark
black
Fossils: Foraminif era and bryozoa.
Textures:
In some places, the calcite looks as if a it
dirty
is micritein an
organic structure which is being replaced by sparry calcite
neomorphic spar.
Remarks: There areno signs of metamorphism in this slide.
*
. .
material.,
. .
and
Thin Section Number:
KCMIFF-2820a
Rock
Name:Wollastonite Marble
"
Composition:
Calcite:
Microspar, c r y s t a l s have a p r e f e r r e d o r i e n t a t i o n i n
t h i s is probablyneomorphic s p a r .
Diopside:
in aggregates
Wollastonite:
small r a d i a t i n g f i b e r s a s s o c i a t e d w i t h d i o p s i d e
P y r i tter :a c e
F l u o r i t er a: c e
Texture:Averagegrain
s i z e i s 0.02
rmn.
some fragments;'
H
0 . 5 Crn
ThinSection
Rock
Name:
Number:
KCMIFF-2820b
Wollastonite Marble
Composition:
.-Chert:
Occurs in masses.Corroded,anhedralmicrosparoccurs
in patches
i n t h e s e masses of chert, along with corroded crystals of diopside
and tremolite.Chertappears
l&inated
due t o ' s i z e d i f f e r e n t i a t i o n .
Calcite:
Occurs a s a g g r e g a t e s o f r e c r y s t a l l i z e d c a l c i t e
which is microspar
andprobably was o r i g i n a l l y c r y p t o c r y s t a l l i n e brown c a l c i t e . Calcite
a l s o o c c u r s a s c r y p t o c r y s t a l l i n e brown c a l c i t e which i s p a r t i a l l y
r e c r y s t a l l i z e d t o neomorphic s p a r . L a r g e b l o c k s o f c a l c i t e s p a r a l s o .
occur. These a d j o i n t h e c r y p t o c r y s t a l l i n e brown calcite ( s e e s k e t c h I).
Wollastonite:
Occurs i n c h e r t a g g r e g a t e s .
Diopside:
Occurs i n c h e r t a g g r e g a t e s .
Pyrite:
trace
Hematite:
trace
.Muscovite and S e r i c i t e :t r a c e
Prehnite (?): trace
Shows second order interference colors.
Texture: The a v e r a g e g r a i n s i z e
is 0.02 m.
Thin Section Number:
KCMIFF-2960
Rock
Name:
Q u a r t z monzonite
Composition:
Quartz-Chert:
i s 0.06
CherthasangularincluAverage s i z e o f q u a r t z c r y s t a i s
sionsofpotashfeldspar
and plagioclase. It a l s o h a s i n c l u s i o n s o f
i s intergrown i n a micrographic(runic)
texrounded quartz.Quartz
ture with potash feldspar
and some plagioclase.Larger-grained
quartz and p o t a s h f e l d s p a r o f t e n comes i n t o s h a r p c o n t a c t w i t h ' m a s s e s
of micrographic intergrowths of quartz
and f e l d s p a r ( s e e s k e t c h 1).
mm.
Potash Feldspar:
Kspar more abundantthanplagioclase.
Alters toclayminerals(possib l ys e r i c i t e ) .S a n i d i n e
(7) i s present.
Plagioclase Feldspar:
Composition is An
4'
(possibly sericite)
a
.
Shows a l b i t e twinning.
Sericite:
Alterationproductofdecayingfeldspars.
tracesofthefeldspars.
Alters t oc l a ym i n e r a l s
It i s alignedalongcleavage
P y r i t er a: c e
F l u o r i tter :a c e
Zircon:
trace
Calcite:large-grainedsparcrystals
Texture:
The a v e r a g e g r a i n s i z e
0.35
m
m
.
which are probablycavings.
of t h e major c o n s t i t u e n t s o t h e r t h a n c h e r t
is
ThinSection
RockName:
Number:
KCMIFF-3130a
Quartzmonzonite
Composition:'
Quartz:
Potash Feldspar :
2Vx = 50"
Perthitic Feldspar:
Plagioclase Feldspar:
Na-rich ( a l b i t e (?)). A l t e r s t o s e r i c i t e
+ c h l o r i t e + hematite
I
Pyrite:.
Biotite:
Alters t o c h l o r i t e
*
+ hematite.
Sericite:
Alteration product of feldspars.
Chlorite:
Pleochroic yellow-green.
Zircon:
Hornblende:
Pleochroic, associated with pyrite.
Calcite:
P r e s e n t ' i n minor amounts associated with micrographic intergrowths
q u a r t z and potash feldspar.
Texture:
of
m
m
.
Average g r a i n s i z e of crystals in micrographic intergrowths
is 0.12
Average g r a i n s s i z e o f o t h e r major minerals (quartz, Ksparand plagioMicrographicintergrowths
of quartz and potash
c l a s e ) is 0.45
f e l d s p a r forms a m a t r i x i n which large crystals of quartz, potash
f e l d s p a r ,p e r t h i t e ,
and p l a g i o c l a s e a r e set. The micrographicintergrowths commonlycame i n t o s h a r p c o n t a c t w i t h l a r g e c r y s t a l s o f
q u a r t z and f e l d s p a r ( s e e s k e t c h
1).
m
m
.
. .
e
ThinSection
Rock Name:
Number:
KCMIFF-3130b
Quartzmonzonite
Composition:
Potash Feldspar:
Quartz:
Potash feldspar and quartz a r e p r e s e n t b o t h as l a r g e c r y s t a l s and i n
micrographic intergrowths.
L a r g e c r y s t a l s of quartz are rounded.
Potash feldspar i s angular, anhedral t o subhedral.
Plagioclase Feldspar:
i s presentbothaslarge
Severelyalteredtosericite.Plagioclase
s i n g l e c r y s t a l s and inthemicrographicintergrowths.Na-rich
( a l b i t e (?)).
Perthitic Feldspar:
Present as l a r g e c r y s t a l s
Biotite:
Alters t o c h l o r i t e i p y r i t e .
e
. .
Chlorite:
Generally platy as a n a l t e r a ition pr oduct of bicItite. I:t i s:' a l s10 f i b r ous
and r a d i a t i n g when a s s o c i a t e d w i t h l a r g e , s p a r r y c a l c i t e .
Brown
chlorite intergrowths with quartz.
Pyrite:
Calcite:
Minor amounts are associated with the micrographic intergrowths of
quartz and potashfeldspar.
One largesparryfragment
i s alsopresent.
Zircon:
As inclusions in the biotite
Hematite:
Fluorite:
Penninit e ( 1 ) :
Pleochroic red-brown-colorless, associated with pyrite.
Texture:
e
Average g r a i n s i z e of crystalsinmicrographicintergrowths
Average g r a i n s i z e of o t h e r major minerals i s 1.0
mm.
i s 0.09
m
m
.
.
..
I
0
ThinSection
Rock Name:
Number:
KCMIFF-3380
DiopsideMarble
Compositiork
Calcite:
Mostly spar
Chert:
Fine-grained
Diopside:
Alters t o c h l o r i t e
Associations:
Calcite
Diopside
Diopside
+ quartz
+ quartz
+ calcite
i
I
Thin S e c t i o nN u m k :
Rock
Name:
KCMIFF-3680a
Diopsidemarble
Composition:
Microspar: 43%
Twinned, sparry,anhedralcrystals.
laminated,micritic(caving
(?)).
Spar:
One p i e c e ofIimestone
i s brown,
20%
Same occurrence as microspar.
20%
DiopsideandOlivine:
Diopside > Olivine (Forsterite). Diopside.
and brownish birefringence.
is mineral with high relief
- i n d i v i d u a lc r y s t a l s : 4%
This has t w o forms: (1) Larger,separate,anhedral
c r y s t a l s , (2)
Anhedral c r y s t a l s which are smaller than spar-and are mixed w i t h c a l c i t e .
Quartz
e
Potash
Feldspar:
2%
A large subhedral crystal occurs
has inclusions of c a l c i t e .
which is associated with calcite.,
It
2%
In aggregates
Chert:
I
I
C h l o r i t e : 2%
An a l t e r a t i o n p r o d u c t of diopsode; occurs
the
diopside.
Pennite.
Plagioclase
Feldspar:
1%
Amphibole: 1%
C r y p t o c r y s t a l l i n ec l e a rc a l c i t e :
P y r r h o t i t e and P y r i t e :
Zircon:
trace
Hematite:
,
trace
A p a t i t er a: c e
Tourmaline:
bluscovite:
trace
trace
1%
1%
. .
as small v e i n s c r o s s - c u t t i n g
Thin Section Number: KCMIFF-3680a (continued)
m
m
.
Texture:
Average grain size of small crystals is 0.03
Average grain size
of large crystals is0.8
Large crystals include quartz, feldspar,
and calcite.
RemArks:
This thin section iscontaminated by limestone cavings.
m
m
.
e
Thin Section Mumber: KCMIFF-3680b
Rock Name: Wollastonite Marble
Composition:
Spar: 56%
Large,
blocky spar crystals with rhombohedral cleavage.
Microspar: 22%
Some cuttings
microspar.
which
are
dominantly
micrite
contain
patches
of
spar
Wollastonite: 5%
Forsterite: 5%
Occurs in calcite
Cryptocrystalline brown calcite: 4%
Some cuttings are predominantly
are laminated.
cryptocrystalline
brown
calcite
and
Chert: 4%
a
In aggregates combined
potash feldspar.
with
plagioclase
and
much
largerof crystals
Cryptocrystalline clear calcite: 2%
Plagioclase Feldspar: 1%
Potash Feldspar: trace
Quartz- individual grains: trace
Muscovite:trace
Gypsum:trace
Pyrrhotite:trace
Texture: Average size of larger crystals 1.3
is mm. Average size of smaller
crystals is0.05 nun. Larger crystals are sparry calcite, quartz, and
feldspar.
e
Thin
Section
Number:
Rock
Name:'
KCEIIFF-3740a
Marble
Composition:
Microspar: 51%
Neomorphic a l t e r a t i o n of c r y p t o c r y s t a l l i n e brown c a l c i t e .
Spar:
29%
Large aggregates
of blocky, anhedral spar.
C r y p t o c r y s t a l l i n e brown c a l c i t e :
16%
C r y p t o c r y s t a l l i n e clear c a l c i t e :
1%
.
Chert: 1%
Aggregates of chert contain corroded sparry calcite.
Muscovite:
trace
P y r i t er a: c e
.a
Zircon:
trace
"
Pyroxene:
Texture:
trace
Average s i z e of l a r g e r c r y s t a l s
c r y s t a l s i s 0.13
mm.
i s 1.5
m
m
. Average s i z e of
smaller
I
.
e
Thin Section Number: KCMIFF-37405
Rock Name: Marble
Composition:
Microspar: 78%
Average grain size 0.04
is m. Associated with cryptocrystalline brown
calcite. It is probably strongly recrystallized. In some places it
is large and blocky.
Cryptocrystalline brown calcite: 7%
Cryptocrystalline clear calcite:
7%
Diopside:3%
Averane grain size if
0.04 mm. Second-order interference colors.
Appears ina matrix of recrystallized calcite.
"
Spar:
2%
Chalcopyrite: :.l%
Associated with
cryptocrystalline
brown
calcite.
Potash Feldspar: 1%
'In ore fragment, Kspar and chert are intergrown; in this fragment,
anhedral calcite crystals are present.
'
Chert:trace
Some chert is
crystallized.
Fluorite:trace
present
in
cuttings
in
which
the
calcite
is
highly
.
I Thin Section Number: KCEIIFF-3750
Rock .Name: Tremolite Marble
Composition:
Calcite:
Most fragments are microspar. Some fragments are anhedral
spar
crystals. Occasional patches of cryptocrystalline
brown calcite
occur in fragments which are dominantly microspar.
Tremolite:
S m a l l anhedral
crystalsin calcite
Pyrrhotite:trace
Muscovite:trace
Texture: Average size of sparry calcite
is 0.5
crystals is0.05
mm.
m
m
.
Average sizeof all smaller
Thin Section Number: KCMIFF-3780
Rock Name: Diopside Hornfels (Metamorphic chert horizon)
Composition:
.
. . .
.
.
Chert:
Average sizeof individual crystals is
0.01 mm. Fine-grained quartz
associated with small pyroxenes.
Quartz:
Average sizeof crystals is0.2 mm. Large, anhedral quartz crystals
which occur in
a chert matriz; these crystals appear corroded.
Calcite:
S m a l l anhedral
crystals
Diopside:
Small anhedral
Zircon:
0
*
Muscovite:
Corroded
to subhedral crystals
"
H
I .o m m
-7
42
-
ThinSection
Rock Name:
Compositioni
Number:
KCMIFF-4000
DiopsideHornfels
The rock i s e s s e n t i a ' l l y 100%diopside
Diopside:
Average g r a i n s i z e i s 0.02
mm.
Occurs i n l a r g e masses.
,
... .
Chert:
'
"_
Small chert veinlets cut through the diopside.
'
'
.~
(
I
I, 0 m m
e . .
Thm
Sectlon
Number:
Rock Name:
”
Quartz
KCMIFF-4010
monzonite
Composition:
Potash
Feldspar:
40% .
Found as micrographic intergrowths with quartz
and as l o n g e r , s o l i t a r y
c r y s t a l s . The potashfeldspar sometimes containssmallinclusions
of
carbonate(seesketch
1). A l s o , thepotashfeldspar
i s occasionally
perthitic.
Plagioclase
Feldspar:
35%
Has combined Carlsbad-albitetwinning.
Na-rich.
A l t e r i n gt os e r i c i t e .
B i o t i t e : 1%
Hematite: 1%
. A small intergrowth with quartz
and f l e d s p a r i s present.
P y r i tter a
: ce
A few e u h e d r a l c r y s t a l s i n s i d e q u a r t z ‘ c r y s t a l s
e
Carbonate:
Extremely small euhedral to anhedral crystals are
’
i nq u a r t z ,p o t a s hf e l d s p a r ,
and plagioclase.
Sericite-:
trace
An a l t e r a t i o n p r o d u c t of plagioclase.
Texture:
The averagegrain
s i z e i s about 0.5
nun.
found as inclusions
*
Thin'
Section
Rock
Name:
Number:
KCMIFF-4040
DiopsideHornfels
Composition:
Diopside: 51%
Small e u h e d r a l t o s u b h e d r a l c r y s t a l s w i t h
a slightly greenish cast.
y '. Z = 40". Associated with chert .in
masses (see sketch 1).
Quartz-Chert:
40%
Small anhedral(occasionallysubhedral)crystals.Associatedwith
diopside.
C a l c i t e : 9%
Small c r y s t a l s p r e s e n t as borders t o massesof diopside and q u a r t z .
This shows rhombic cleavage;(see sketch 1 for occurrence).
Texture:
The average grain size
of t h e q u a r t z
and t h e d i o p s i d e is 0.01
m
m
.
v
L-4
1.0 nrm
*
ThinSection
Rock
Name:
Number:
KCNIFF-4350
Quartzmonzonite
Composition:
Quartz: 32%
Intergrown with p l a g i o c l a s e and potash feldspar.. The q u a r t z c r y s t a l s
are smaller and more rounded than those of potash f e l d s p a r .
Potash
Feldspar:
31%
Associated with quartz
and plagioclase.
Plagioclase.Feldspar:
24%
Composition i s An5. Intergrownwithquartz
and potash feldspar.
P e r t h i t i cF e l d s p a r :
12%
Dominantly potash feldspar.
e
B i o t i t e : 1%
Elongate brown, c l e a r c r y s t a l s which a l t e r t o greenpseudomorphic
c h l o r i t e . Leucoxene ( ? )i~
n cleavage plans of c r y s t a i s whichhave
altered to chlorite. - .
Hematite: t r a c e
A s a primary intergrowth with quartz
"
and f e l d s p a r .
C a l c i t er a: c e
Minor amounts a s i n c l u s i o n s i n q u a r t z
Fluorite:
trace
Chlorlte:
A s a n a l t e r a t i o n p r o d u c t of b i o t i t e , u s u a l l y
b i o t i t e b u t sometimes a s r a d i a t i n g c r y s t a l s .
Texture:
Average g r a i n s i z e is 0.5
nun.
pseudomorphic a f t e r
L
a
!
j
I
I
I
I . 0
rrrm
+
H
0.rc-m
ThinSection
Rock
Name:
Number:
KCMIFF-4460
Quartzmonzonite
Composition:,
30%
Plagioclase
Feldspar:
Na-rich ( a l b i t e ) . Has combined .Carisbad*albitetwinning.
Potash
Feldspar:
Quartz:
28%
27%
P e r t h i t i cF e l d s p a r :
10%
B i o t i t e : 2%
Presentaseuhedralcrystals
a l t e r i n g t o green chlorite.
and a few s t r a n d s .
Hematite: 1%
Present as b o t h t h e t r a n s l u c e n t r e d
a s i t i s intergrown with quartz.
and b l a c k v a r i e t i e s .
C a l c i t e : 1%
Present on ( i n ?) quartz and f l e d s p a rc r y s t a l s .
l a r g e , twinned c r y s t a l .
A p a t i t er a: c e
Zircon:
trace
Garnet ( ? ) : t r a c e
Zoned, green
Texture:
The a v e r a g eg r a i ns i z e
is 0.5
nun.
It i s a l t e r e d o r
It is primary
Alsopresentas
a