Geochemical Processes at Mineral Surfaces - American Chemical

c a l c i t e even though S r C 0 3 , strontianite, forms an orthorhombic lat tice. ... between 0.05 and 0.07, but rose to values between 0.1 and 0.2 ...
0 downloads 0 Views 1MB Size
27 Modes of Coprecipitation of Ba and Sr with Calcite 2+

2+

Nicholas E. Pingitore, Jr. Department of Geological Sciences, University of Texas at El Paso, El Paso, TX 79968-0555 Non-lattice incorporation can play a significant role in the aqueous coprecipitation of large cations with calcite. Coprecipitation experimental results yield a partition coefficient of Ba into calcite of 0.04; the partition coefficient is affected by rate of precipitation, presence of other ions, and type of seed used to nucleate growth. Such sensitivity to experimental conditions characterizes non-lattice incorporation, a conclusion suggested by earlier EPR studies of calcites doped simultaneously with Ba and Mn . Previous coprecipitation experiments have shown that the incorporation of Sr into calcite involves both lattice and non-lattice substitution, a finding also consistent with published EPR data. A model of increasing importance of non-lattice incorporation with increasing deviation of the ionic radii of host and trace cations emerges. 2+

2+

2+

2+

The

incorporation

of

trace

areas

of

environmental

range

of

chemical,

the

mineral

marine the

human

compositions mation element of

These

and t e r r e s t r i a l

caliche, cision,

biological,

calcite.

continental of

and

calculi, these

speleology,

of

impacts

deep

encode,

limestone, crusts. with

the solutions

The a n a l y s i s limestone

paleo-oceanography,

composed

of

element of

pre-

for their of such

understanding

of

many

deposits,

degrees

of

and d i a g e n e s i s , and

of

The trace

varying

of

wide

sediments

and i n t e r p r e t a t i o n

genesis

the

cave

responsible

has l e d to a better

to

and tests

the calcareous

ocean,

a number

due

materials

the shells

and hard-water

the compositions compositions

calcite

and g e o l o g i c a l include

materials

or alteration.

into

and geochemistry

invertebrates,

shelf

biomineralization,

tion,

elements

chemistry

fortrace

processes lithifica-

environmental

chemistry

(1-10)* Experimental certain (e.g.,

doubly Mn2 + ,

incorporated

and

charged Zn2+,

into

empirical cations

Fe +, 2

calcite

of

Cd2+,

studies ionic

have radius

and

C o 2+)

precipitated

from

0097-6156/ 86/ 0323-0574506.00/0 © 1986 American Chemical Society

demonstrated less can

be

aqueous

than

that

calcium

extensively solution

at

27.

PINGITORE

earth

Coprecipitation

surface

conditions

diffraction, these in

and

trace

cations

calcite

carbonate

salt

true,

2

,

+

and The

2

may

enter

which may

are

participate (21).

to

crystal

a

tice

S r

calcite

even

tice. ity

2

Note of

the

that

The little most

calcite and

appropriate

that

or bonding

both

of

of

this

even

a

the

Sr

2

+

2

cation

modes

the

adsorption/trapping calcite.

tation

at

surface

and a p p l i c a t i o n

cipitation

of

experiments.

terminology,

and

be

i n Driessens

The

Incorporation

At

least

value

of

a dozen

papers The

to

+

+

,

or

Pb

2

+

,

and

Therefore in

i t

conditions) these

calcite,

an

but

substitu­

ion

"adapts" the

lat­

structure.

Very

For

lattice

of lat­

groups

limited

with

2 +

calcite

and

in

miscibil­

a

the

into

limited

integrates

then,

of

these

of

investi-

This large

processes

paper

solid

and

cations

which

to the

can

interpre-

and any o t h e r on

to

their

formation

of

crucial

is

discuss

and p r a c t i c a l

of

is

which

incorporation

copre-

characteristics,

solution

formation

volume). Calcite;

the past

coefficient different

and

information

aspects

the

experiments the

solution

range

(the

not the

geochemistry.

a mineral

Ç3,7_,

is

Our p u r p o s e ,

solid

decades

presented

paper

coprecipitation

with

(31)

in into

2 +

two

that

present

dominates

and

Sr

incorporation

incorporation,

the

of

appeared

locus

partitioning

2 +

attracted

elements

characterize

The

calcite.

(this

have

Eastman

at

lattice)

of

has

these

the past

non-lattice

cation

Ba

of

the p a r t i t i o n i n g

the results

over

,

2 +

the carbonate

for experimental

of

Sr(II)

the p a r t i t i o n

16,18,19,23-29).

and

thermodynamic

of

2

also

Additional

can

found

2

6-fold

an orthorhombic

over

interplay

Familiarity

the growth

S r

chemistry

affects

Ba

surface

that

partitioning

cation

environmental how

in

investigated

into

of

,

2+

when

forms

substitution

and i m p l i c a t i o n s

occur

Zn

carbonate,

i n the rhombohedral

2 +

and R a

a new s e t o f

larger

ion

calcite.

recognition

with

,

substitution.

calcite

into

+

occurs

Pingitore

gations

illustrates

2 +

isomorphous"

different.

foreign

non-lattice

these in

(Mn

i t s own b y o c c u p y i n g

In contrast

Ba

of

with

that

document

these

calcite,

calcite.

"forced

of

+

isodimorphy

in

2 +

findings

indicates

of

2

Sr

t h e low c o n c e n t r a t i o n s

Recently

trapping

Ca

such

of P b

intensively

evidence for

on

calcite,

may e n t e r

substitution

major

quite

(22).

studies

16,18,19,23-30).

those

is

due t o

has been

substitution

Thus

orthorhombic

earth

with

from

for Ca

i t

e.g.,

strontianite,

3

characterizes

several

site

SrC0 ,

waters

that

(at

substitution

different

coprecipitation

natural

expected

with

miscibility

the

,

+

or

the coordination

attention

2

isomorphous

structures

normally

of

site

rhombohedral

calcite.

carbonate,

form Ca

isodimorphous

though

these

to

than

may s u b s t i t u t e

+

a l l

lattice

a

solutions

size

isomorphous

of

structure

of

example,

each

course,

in

a

carbonates

Isodimorphous

site

such

larger

incapable

tion

of

the rhombohedral

orthorhombic

are not, of

cations

x-ray

or

is

forms

with

solid

or limited

coordination

Cations form

is

produce

9-fold

only

2 +

ion

to

aragonite. Ra

)

2 +

behavior

cations

isostructural (Cd

many

).

+

calcium

coordination

these

experiments,

that

i n the calcium

2 +

isomorphous,

by complete

Co

Ca

substitution

of

is

or

indicated

for

575

Calcite

Partitioning

have

Such

each

which

form

characterized Fe

(20).

3

with

2+

(11-19).

studies

grounds;

and Sr

2+

substitute

(CaC0 )

structural cations

Ε PR

of Ba

of

A

Review

two d e c a d e s S r

2

+

into

experimental

have

discussed

calcite, systems

the

r

03>Z>

and

their

k

c

S

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

576

conditions cently

have

cipitation those

previous runs

a a

that

tribution

to

the

amounts

in k

of

Ba

S

or

2 +

encountered

high

in

interpreted S r

at 2

of

cient

rapid

due In

to

lattice

and

of

each

of

k

c

S

run.

Experimental

Methods

the

to 7

Ba

2

10~

selected cite

runs.

seed

evolve

4 χ

red

(magnetic

temperature

three

days to

one

40

approximately

85%

lated

partition

yield

in

hastened

hours per

this

cc).

of

Chemicals

and

g

c

S

(0.05

to

sites

This these

greater

to

an

the

low range

which

increase to

the

0.07).

in

have

An

the small

with

to

r

effect

attributed

in

tendency k

c

S

with

r

increase

in

partition

2

a

NaCl the

rate

and

the

bubbling of

6

the

the

coeffi­

g

not

solutions

Baker

in χ

Analyzed

from

g

of

were

suspended

were SrC03,

from

ranging

(precipitation The

calcu­ time

or

decarboxylation

nitrogen g

to

stir­

lasted

cc).

which 5

in cal­

allowed

precipitation

10"

ml

ranging

precipitate per

200

added

seed

runs

procedures

Reagents

in

0.005

the

the

introduced

dissolved

with 4

of

to

calcu­ of

were

3

solutions

hour

runs

experimental

(30,31).

BaC0

were

keep

related

approximately

dissolved

Normal

per

the

CaC03,

to

of the

Calcite

solution

The

recoveries

Speed

these

the

originally

was

with

of

also

18°C.

calcite

overall

conditions

dissolution

and

model

calcite,

compositions

sufficient at

the

were

opening.

runs.

rate

Eastman

Puratronic

of

to

amounts

SrC03

flask

calcite

of

and

a

into

+

Ba(II)

calcite

yielded

10~

of

solution

.

+

presented Sr*

specific

Varying

2

in

3 x

(31) of

the

of

C0 ·

coefficient

Details

runs

sites.

of

experiments k

non-

for

Addition

of

cation

on

maintained

(precipitation

Pingitore

in

+

value

At sites

of

account

of con­

lattice number

may

coprecipitation

constricted

at

series by

Na

Eastman

completion

week

rate

was

a

was

from

of the

be

and

0.11

placed

bar)

to

substantial

studies.

Coprecipitation

Ba

5

through

and

earlier

(defect)

starting

10" M Upon

were

CO2

concentrations a

limited

concentrations,

of

with

typical

to

8

for

bubbling

produce χ

in

depending

experiments

+

by

the effect

incorporation

mode

r

experimental

water

of

to

number

crystallization.

lated

of

limited

of

may

Pingitore

contribution

For

artifact. results

coefficient.

non-lattice

non-lattice

value

low

3

transforma­

of a

10"

almost

occupancy

non-lattice

summary,

Into

for

the

partition

concentration

likewise

in

experimental

makes

fall

0.2

increasing

amounts

+

to

and

reported

sets

from

explain

found 0.1

(25)

At

sites

and

may

ratio

both

defects.

competitive

the

an

copre­

calculated

respective

rate

contribution

2

al.

favorably

decreased

a

was

r

Re­

of

aragonite-calcite

were

occupancy

+

S r

occupy

precipitation

2

as

their

to

+

Sr

S

molar

et

concentration

large

of

cations,

the

encountered

concentrations

the

c

which

between

interpreted

overall

r

k

a

Katz

non-lattice

This c

(below

data

probably

saturated

of

results. range

technique

model

values

partitions

+

the

sites.

variation

than

2

sites,

the

lattice

was

(31)

Sr

of

value

using the

wide

experimental

to

ratio

+

98°C

concentrations

dominates

2

a

partitioning

calcite).

at

some

occupancy

higher

/Ca

+

Eastman

non-lattice ,

2

conflicting

explored

single

rose

concluded

and

apparently (31)

The

but

resultant

they

indicate +

Sr

findings

but

Pingitore

2

0.07,

low

the

identical

S r

with

constructed and

a

in

tion,

some

Eastman

inconsistencies. 0.05

with

range

and

conditions

results

between

of

yielded

Pingitore

gas

lasted

calcite are

per

available

Johnson Fisher

12 hour in

Matthey Certified

27.

PINGITORE

ACS

NaCl

pure of

Coprecipitation

and

BaC0 , The

3

the

solid VI

Precision for

the

for

in

the

only

Details

of

the

an

the

evolving

In

light of

broader

of

B a

of

(30).

varying

initial

and a

the

Ba a

the

the

An

Beckman

10%

Spectra-

the

as

Ba

high

as

which

Calcite calcite

under

one

produced

available

in

except

5%.

runs

of

(DCP).

2%

2 +

speed

hour

vaterite.

Pingitore

and

radii

are

and

Attempts of

limited

c

B

varies

a

the

A value this

refine therefore

and

(31);

suggest

A;

Sr

2

results in

the

0.04

a

partition set

of

extreme

lower

value

ratios.

,

1.21

A;

that

l i t t l e

0.01

thus char-

the

Figure reflect

k

c

c

S r

of and

B a

appropri,

1.44

A

none

of

the

2

+

the

defects, grows.

Ba

and

2 +

is

Hahn

differentiated

1,

with

the

more

as

(34)

between

along

preferred

trace

experimental

element

experimental

from any

would

be

is, the

procedure

warranted;

value

random

of

to

to

in

the

B

a

of the

one

of

(21,34).

achieve more

applicable

c

more

of

fact,

latter

resultant

k

behavior

Sensitivity

conditions

former

the

compared

substitution.

coefficient

Ba or

(the

k

crystal).

in

the

for

Instead,

calcite

of

misfit

The

and

various

further

the

conditions.

0.05

and

value

the

is

+

on

may

not

•+/-

absolute

calcite.

as

and

lattice

are

and

results

adsorption/trapping

the

0.03

covered

trapping

distinguishing

of

precipita-

solutions

concentrated

by

of

These

and

0.05,

widely

addition

which

+

surface,

points

a

and

system,

2

in

of

concentration

throughout

a

concentration ratio.

would 1.08

with

the

between

in

formation

to

the

B a

,

Pingitore

rates

element

coefficient to

differing

(31),

covering

solutions

without

crystal

of

consistency

in

and

trace

to

appropriate

seed. k

the

sites

behavior

for

of

process

of

of

crystal

Eastman

in

mixed

coprecipitation

tests

with

with

and

(the

0.03

used

model a

undertaken,

anomalous

scatter

the

was

of

proved

considered

concentrations

+

these

physical this

has

was

conducted

of

low

2 +

interior

Pingitore

those

that

at

calcite

by

by

partitioning

lattice

the

reproducible

than

in

of

during

(32)

Doerner-Hoskins the

solution

(y-axis).

+

Ca

explanation

from

partition

2

changed

equation

Discussion

were

lattice

distributed

The ranging

2

of

concentration effect

Sr

occlusion

randomly

Ba

the

solution

experiments

types

dependence

described

surfaces)

and

solution,

of

calcite

on

internal

more

for

The

the

ratios,

+

calcites

with

incorporated

value

the

2

magnitude

occupies

adsorbs

the

a

diffractometer;

the

presented

runs

/Ca

+

characterize

ionic

has

Ultra-

5 and

x-ray

study)

in

of

partitioning of

odds

in

+

2

range

orders

(33). Ba~2

Alfa

coprecipitation.

demonstrates

pronounced

ate

rose

equilibration

different

1

wide

at

2 +

to

resultant

which

it in

on

Doerner-Hoskins

conditions Ba

with

acterizes seem

and

coefficients.

model

These

NaCl

Figure

the

partitioning

+

Eastman

three

was

between

spectrophotometer

3%

are

ratio

+

Results

the

2

range

or

2

aqueous

Experiments:

set

/Ca

composition

Ba(II) the

2 +

without

low-temperature

in

which

procedures

partition

to

under

was

this

seed

analyzed

emission

except in

the

comprised

run.

a Philips

recorded

Ba

to

tion,

a

were

in

on

experiment,

calculate

3

samples

noted,

of

analyses

included

coprecipitation

SrCO

end

plasma

2 +

analytic

Because

new

as

577

Calcite

(30,31).

course to

the

determined

(not

of

Eastman

Ca

phase

duration

at

with

2+

typically

precipitates

dilute

was

seed

current

the

most

mineralogy was

and

direct

and Sr

2+

except

calcite

recovered

Solutions Span

and,

3

CaC0 .

of Ba

greater precise

only

to

a

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

578

10.0

1.0

0.1

0.01

-L

0.001 0.01

0.02

0.03

0.04

JL

±

0.05

0.06

0.07

0.08

calcite Figure Ba

2 +

0.03

/Ca to

calcite

1. 2 +

The solid

0.05 and

partitioning solution

independently also,

by

of

Ba

ratios. of

the

implication,

2

+

into

Note

calcite

that

k

concentration in

the

parent

c

B

a

of

at

various

varies Ba

2

+

solution.

from in

the

27.

PINGITORE To

explore

lattice were k

c

B

sites

added .

a

0.1

wise,

surface

adsorption of

Ba

non-lattice

0.1

at

low

with the

habit

fewer

being

2

and

S r

3).

foreign

of

favorable by

Ba

large

2

but

not

for a

,

+

a

direct

inappropriate.

is

B

c

not

can

NaCl

per

fell

to

the

surprising

that

such

an

;

displace

Ba

displaced

lower

the

lattice

coefficient

internal

to

from

2 +

S r

2

value

of

k

experimental

adsorption

and

the

c

of

a

vacancy crys­

conditions of

the

solution to

on

signi­ range

quantity

surface

(31).

in

res­

0.03

sites,

sites.

but

did

not

Sensitivity

conditions mixed

of

probability

overwhelming

S r

anomalous

calcite surfaces

growing

0.02

defect

for

occupancy

low

yielding

adsorption

from

+

2.)

liter

is

calcite

the

growth

a

by

values

a

in

comparison

of

k

;

+

In

it

into

2 +

experimental

of

mois

2

radius,

other

rendering

0.48

Ba

with

larger

(approximately

change

Sr

but

its

coefficient

yielding

for

ionic

or

equiva­

effective

versa,

calcite

encroachment

seed

vice

the

Like­

an

The more

partition

,

+

.

+

with

1.) 2

2

dehydration.

into

Ba

displace

partial

that

of

ranged

consistent +

+

Sr

2 +

on

on

of

coefficients

NaCl

partition

2

to

Sr

effect

calcites by

the

of

efficiently

(31).

the

Sr

partial

the

2

include:

sites its

in

Sr

exceeds

sites

to

is ease

that of

presence

studies

+

ions

contrast,

istic

2

It

significantly a

note

after

depressed

(Figure In

due

addition

ficantly of

the

site

partition

The

to

shown

occupy

apparent

dislodged

sites

2 +

not

amounts

resultant

not

displaces

+

no

adsorbs

been Sr

explanations

differences

pective

to

does

+

with

2 +

is

greater

incorporation

trapped

+

2

non-lattice

unfavorable Ba

Ba

2

varying

the

Ba

and

have

2 +

relative

to

in

2 +

non-lattice

non-lattice

or the

Ba

that

due

of

3.)

of

2),

that

concentrations)

favorable

tal;

Ba

defects

from

+

Possible

growth

on

therefore,

the

to

+

appears

Ba

calcites,

(Figure

consequent

fact

surprising,

2

that

579

Calcite

2

these

runs

Sr

2 +

and

the

(0.04).

2

and Sr + with

2+

in

+

It

Sr

of

radius

view

of

and

of

2

of

amounts

amount

ionic

set

100.

minor

lent

a

of Ba

Interpretation

Ca

ratio

to

calcite

the

for

to

The

from

Coprecipitation

is

a

of

character­

crystal

formation

(21,34,35). Speed

runs,

in

in

rapid

coprecipitation.

in

the

Figure

number

and/or

more

The be

noted.

Since

witherite

equilibrium ratios χ

10~

3

these

1:3. from to

to

3.6

2.3

χ in

χ

with

200 ml

the

C0

solution

boxylation

to

to

4

To the

2

would in 3

2

at

"

3.9

can

the

to

exceed

calcite

appear

presence start

atmospheric

of

times

ratio speed

final

calcite

levels

a

run of

C0

is 2

9.1 and

increase

to

enhanced

as a

of

soluble

Ba

2

to

+

had

Ba

2

+

seed. χ

10~ M. 7

g

+

the Such

decarboxyla­

Viewed 0.11

2

2.6

from

required.

of

+

during

ranging

by

at 2

/Ca

from

witherite

been

as

Ca

supersaturates

achieve

the must

solution

of runs

in

also

compositions

have to

concentration

of

due

supersaturations

would

an

crystallization,

from

solubility

difficult

hours,

precipitated

decarboxylation

minimum

12

characterize

diffraction)

molar

and

3

in

a

growth.

three

the

B

c

ions

2 +

phase

3

x-ray

for

the

rapid

saturation the

BaC0

the

10"

k

include

precipitate

i f χ

calcite,

respect

Ba

rapid

by

compositions

ΙΟ" . to

with

approximately

only

which

especially

fashion,

10"

relative

130

is

of

disorderly

adsorbed

separate

latter

calcite

supersaturations tion,

the

Starting

runs,

solution 14

with

of

to

undetectable

calcite

(BaC03),

a

completed

values

interpretations due

entrapment

that

levels

was

higher

sites

capture

physical

(at

that

Possible

defect

possibility

runs

exceeds

of

of

precipitation

document

efficient

probability speed

4

which

shown

in

another

calcite After

precipitation

of

per

decar­ calcite

580

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

100

10

I

0.1

0.01

JL

L 0.02

0.03

_L

X

0.04

0.05

0.06

0.07

0.08

, Ba calcite Figure

2.

calcite. Ba

2 +

into

vertical

The The the axis.

effect

of

S r

incorporation calcite

does

2

on

+

of

up

not

the to

partitioning 100

alter

times k

c

B

a

«

as

of

Ba

much

Note

into

2 +

Sr

2 +

as

change

in

PINGITORE

Coprecipitation

of Ba

and

2+

5r

2+

with

Calcite

581

10.

0.48

M

NaCl

1.0

0.1



0.01

x

o.ooi I 0.01

1

I

0.02

0.03

I

I

0.04

I

0.05

0.06

I

I

0.07

0.08

calcite Figure

3.

calcite. trations

The e f f e c t The

presence

significantly

of of

NaCl

on

NaCl

lowers

at

the

partitioning

approximately

the value

of

k

c

B

a

·

of

Ba

marine

2 +

into

concen-

582

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

10.

1.0

0.1

0.01

0.001 0.14

0.09

0.15

calcite Figure of

4.

The

partitioning

precipitation.

days Figure

to

hours 1.

Note

Reduction

yields change

larger of

of

Ba

of

precipitation

2

+

values

horizontal

into of

calcite k

c

scale.

B

a

,

at

times as

high from

rates several

compared

with

27.

PINGITORE

the

C0

duct

2

3

~

Coprecipitation

concentration

of witherite

maximum

Ba

minimum

C03 ~

χ

A

of

set

seed

used

to i n i t i a t e

k

reported

of

value

encountered

cern.

The

studies B

a

and

batch

Alfa

of

laboratory

reproduce surface

the

area

or

more

are

since

layers

many

coefficient Increases

run

did

2

also

not

to affect

+

imately

nonetheless template sites

not

k

B

c

a

.

.

a

between

in

seed

used

in

experimental

runs

by

the with in

Figure

Eastman

(30).

the

seed

the

during

a

EPR

Studies

2

The

growth

and

experimental

is

demonstrate

unaffected

k

suggest sites

and i s

Ba

over

B

c

l i t t l e

but

by growth

tion

of

S r

gest

that

and

the

(37,38).

by

spectra

for

different indicated ions

the

which

2 +

is

with

the

most

the Mn

a change Angus

2 +

i n the l o c a l

et

a l .

with

broad

of

Sr

2

.

+

the B a

2

+

is

adsorbs

the c r y s t a l .

a

amount with

of both

calcites

Sr

to

2 +

2

+

.

lattice

of

additional

et

a l .

(20)

are

previously sites

in

amounts

and M n

2 +

2 +

been

calcite of

were

previously.

the paramagnetic

strain

not

ppm M n

The r e s u l t a n t

produced

environment

related

had

sug­

substi­

an

hundred

varying

Mn

study

interest

few

that

coprecipita­

non-lattice

lattice

with

indicate

the

Angus

It

into

calcites

doped

of

(31)

of

EPR s p e c t r a .

-doped

the

precipitation

(EPR) o f f e r s

cations

calcites

small

partition­

2 +

the present

lattice.

incorporated

the c a l c i t e s

from

that

produced

of

chiefly

resonance

the c a l c i t e

resultant

next

along

2

involves

precipitating

the Mn They

Ba +,

in

limitation

measuring

and the r e s u l t s

paramagnetic

conditions

established or

calcite

coprecipitation

+

Electron

paramagnetic

a

which

i n Calcite

characterize

overcame

is

favorable

instead

of

and Eastman

into

It

provides

amounts

o r none

i n Pingitore

with

2+

and r a p i d

a

in calcite,

trapped

and Ba(II)

that

substitution

tution.

approx­

masses

Ba

by moderate

decrease

results

of

results

probe

seed

provide

and n o n - l a t t i c e 2

in a

sufficient

one ppm.

polycrystalline

a

preci­

contained

crystallized

B

c

par­

used

contained seed

k

the

seed

lattice

+

r u n and

was b e l o w

the

of

calcite

concentration

lattice

+

of Sr(II)

2

in

value

of

crystal

which Greater

of

seed

fresh

5,

t h e amount seed

gas,

A

produced

larger

the commercial

o f NaCl

and defects

Ba

nitrogen study.

i n t h e amount

of

con­

showed

Neither

consists

for

two

in

the rapidly

the

i t

These

in C a

surfaces

B

experiments

on

quantities

incorporated on

these

and that

Substantial

c

0 . 0 6 , and

cause

difference

results

of

10 f o l d )

(30),

the

substantial

and

formed

of

between

the

i n

explain

are

subsequent

depend

tested

increases

or

5

incorporation.

+

summary,

does

range

defects 2

the

independent

that

χ

The d i s p a r i t y

solutions

and the l a b o r a t o r y

+

during

for B a In

ing

2

possible

for

propagate

calcite

k

5.5

i n the present

defects to

the experiment;

3 ppm B a

the

Pingitore

surface

affect

the

difference

the

yielded

(up to

10~ M,

0.04, i s

produced

bubbling

of

was

pitated.

2.9

pro­

and the

precipitation,

and Eastman

procedures

was

insufficient of

(36)

the importance

growth. work,

explain

on

seed

was

demonstrates

CaC03 was u s e d

findings

laboratory tition

by

runs

temperature

(30)

Ultrapure

the s o l u b i l i t y

strengths

witherite

i n Pingitore

check

decarboxylation

whereas

for

calcite

to

Eastman

speed

the present

(7°C)

complete

Pingitore

Ba

in

insufficient

A

rapid

B

slight

is

.

a

c

Since

low i o n i c

the

experiments

value

.

5

583

Calcite

exceeded.

final

of

10"

at

needed

was n o t

the

c

in

9

with

2+

1.25 χ 1 0 "

concentration

the

k

is

1.6 χ

apparently

5

and Sr

2+

concentration

+

2

10~ M,

type

2

is

of Ba

associated

Sr

2

+

EPR quite This Mn

2 +

with

584

G E O C H E M I C A L P R O C E S S E S AT M I N E R A L S U R F A C E S

0.1

0.01

APPROXIMATE LIMITS OF k [ ?

a

FROM

l c i t e

PINGITORE & EASTMAN (1984)

J

L

0.02

0.03

0.001 0.01

J 0.04

ing

5.

of

The

Ba

nuclei

the S r

2

produced

reagent)

reported

effects

240

to

effect was

1270 on

not

cation with the

ppm

the

the

the Ba

Mn

would

Sr

2

EPR

+

.

2

less

spectrum

pretation

In Ca

into

tion

due

with

the

than

in

to

These

EPR

of

from

+

Ca

20,000 was,

provide of

S r

2

lattice

+

to

Cd

2 +

Cd

calcite

(rather

Ca

than

with

a

the

lattice

2 +

the

of

incorporation

of

produced

2

+

,

no of

than

that an

the

et

independent calcite

the

al.

a

Ba

a

2

+

large

associated

ionic

radius

distortion

calcite.

minimal

that

such

with

in

radii,

significant

concluded

significant that

ppm

sites.

range

no

with

Davis

partition-

with

19,400

al.

strain

atomic

in

the

substitution

course,

of

Into

et

of

occurs in

on

consistent

a

90

showed

of

sites

B

c

calcites

ppm

0.08

(30).

Angus

sites;

,

+

k

contrast,

lattice 2

evidence

studies

clusion

2

of

seed

ion

investigation

similarity

incorporation Ba

more

0.07

experiment

the

In

lattice

case

experimental

of

2 +

2 +

that

partial

Sr

Mn - d o p e d

lattice

the

large

even

an

Eastman

spectrum.

in

below

this 2 +

and

0.06

precipitation

values

throughout

EPR

similar

calcite

rapid

calcites.

+

2 +

yield A

C d

+

of

in

by

Pingitore

incorporated

slightly

2

in

of

Seeding

yields

persisted

produced

+

type

previously

incorporation

These

of

calcite.

+

commercial 0.06

effect

into

2

0.05

Ba calcite

k

Figure

L

The

incorporation strain

or

finding

of

interof

distor-

consistent

(39).

evidence lattice

for sites

at

least

and

the

the ex-

sites.

Implications The

range

of

experimental into

calcite.

tion

emerges

coprecipitation and

practical

Distinguishing as

a

primary

behavior

studies

of

lattice

concern.

discussed

herein

partitioning from

of

non-lattice

Experiments

which

impacts

trace

both

elements

coprecipita-

explore

a

wide

27.

PINGITORE

range

of

Coprecipitation

parameters:

precipitation

rate,

coprecipitation. vide esis

Ca

are

2

which

+

these the

are present

calcites

sible

by

contamination of

i t s relative

waters, bility the

S r

2

limited

of

of calcites

gests

that

i n many

of

S r

Ba

2

conditions.

growth

may p r o v e

+

carbonate

occurs,

inappropriate

impos-

the p o s s i -

component

i n general, of

large

of

under

the Ba

2 +

variation

composition,

rate).

as a diagenetic

to

Because

and n a t u r a l

despite

(solution

precipitation

(or

the rock.

The i n t e r p r e t a t i o n

of precipitation

of

waters and

materials tool

some

and subject

by the p o t e n t i a l l y

surface,

2

The n o n - l a t t i c e

calcite

i s hampered

of

of

radius

e . g . , Cd +

difficult

microprobe)

diagenetic

into

2+

i n ionic

i n natural

fraction

exclu-

the compositions

Unfortunately

analysis

incorporation.

the conditions

carbonate

making

diagen-

substitution

substitution,

tracers.

electron

an important

and p r e d i c t a b l e

kçBawith

type

as

abundance

coprecipitation

of

a l . (20), can pro-

but s i m i l a r

lattice

the non-carbonate

remains

+

therefrom,

of non-lattice

contents of

from

smaller

low concentrations

techniques

composition,

to the nature

of carbonate

lattice

for reconstructing

diagenetic

i n very

et

for the study

exclusively

derived

such

as Angus

exhibiting

Cations

the best

clues

regard.

reliable

exhibit

solution

e t c . provide such

585

Calcite

concentration,

cations

solutions.

i n theory

2

standpoint,

that

a r e t h e most

diagenetic to

aid i n this

i t i s clear

sively

cation

temperature,

a practical

and Sr + with

2+

EPR s t u d i e s ,

an obvious From

of Ba

This

sug-

tracer.

Acknowledgments Discussions gy,

Goodell ously and

with

my c o l l e a g u e s

especially

M.P. Eastman,

flavored

provided

t h e outcome equipment

0.1. Cilatan

Aguirre

typed

reviewers improved

provided

a t UT E l P a s o C A . of

Chang,

this

and supplies assistance

the camera-ready

and t h e suggestions

copy.

i n chemistry

and g e o l o -

J . D . Hoover,

and P . C .

project. and C . i n

M . P . Eastman Podpora,

the laboratory.

T h e comments

of editors

B.

J.A.

of

Davis

gener-

Deshler, Julieta

two a n o n y m o u s and K . F . Hayes

the manuscript.

Literature Cited 1.

Amiel, A.J.; Friedman, G.M.; Miller, D.A. Sedimentology 1973, 20, 47-64. 2. Chave, K.E. J. Geol. 1954, 62, 266-83. 3. Kinsman, D.J.J. J. Sed. Petrology 1969, 39, 486-508. 4. Pingitore, N.E. J. Sed. Petrology 1976, 985-1006. 5. Morrow, D.W.; Mayers, I.R. Can. J. Earth Sci. 1978, 15, 376-96. 6. Veizer, J. In "Stable Isotopes in Sedimentary Geology"; Soc. Econ. Paleont. Mineral.: Tulsa, 1983; Sec. 3, pp. 1-100. 7. Holland, H.D.; Kirsipu, T.V.; Huebner, J.S.; Oxburgh, U. M. J. Geol. 1964, 72, 36-67. " 8. Lowenstam, H. J. Geol. 1961, 69, 241-60. 9. Graham, D.W.; Bender, M.L.; Williams, D.F.; Keigwin, L.D., Jr. Geochim. Cosmochim. Acta 1982, 46, 1281-92. 10. Dodd, J.R. J. Geol. 1963, 71, 1-11. 11. Bodine, M.W.; Holland, H.D.; Borcsik, M. In "Problems of Postmagmatic Ore Deposition—Proc. Symp.": Prague, 1965; pp. 401-406.

586

G E O C H E M I C A L PROCESSES AT M I N E R A L SURFACES

12. Tsusue, Α.; Holland, H.D. Geochim. Cosmochim. Acta 1966, 30, 439-54. 13. Crocket, J.H.; Winchester, J.W. Geochim. Cosmochim. Acta 1966, 30, 1093-1109. 14. Dardenne, M. Bull. Bur. Rech. Geol. Min. 1967, 5, 75-110. 15. Michard, G. Comptes Rendus Acad. Sci. Paris, Ser. D 1968, 267, 1685-8. 16. Ichikuni, M. Chem. Geol. 1973, 11, 315-9. 17. Richter, D.K.; Fuchtbauer, H. Sedimentology 1978, 25, 843-860. 18. Lorens, R.B. Ph.D. Thesis, University Rhode Island, Kingston, 1978. 19. Lorens, R.B. Geochim. Cosmochim. Acta 1981, 45, 533-61. 20. Angus, J.G.; Raynor, J.B.; Robson, M. Chem. Geol. 1979, 27, 181-205. 21. Benes, P.; Majer, V. "Trace Chemistry of Aqueous Solutions"; Elsevier: Amsterdam, 1980; p. 136. 22. Langmuir, D.; Riese, A.C. Geochim. Cosmochim. Acta 1985, 49, 1593-1601. 23. Holland, H.D. Final Report, AEC Contract AT(30-l)-2266, 1966, p. 1-53. 24. Kitano, Y.; Kanamori, N.; Oomori, T. Geochem. J . 1971, 4, 183-206. 25. Katz, Α.; Sass, Ε., Starinsky, Α.; Holland, H.D. Geochim. Cosmochim. Acta 1972, 36, 481-508. 26. Usdowski, E. Contr. Mineral. Petrology 1973, 38, 177-95. 27. Jacobson, R.L.; Usdowski, E. Contr. Mineral. Petrology 1976, 59, 171-85. 28. Baker, P.Α.; Gieskes, J.M.; Elderfield, H.; J. Sediment. Petrology 1982, 52, 71-82. 29. Mucci, Α.; Morse, J.W. Geochim. Cosmochim. Acta 1983, 47, 217-33. 30. Pingitore, N.E.; Eastman, M.P. Chem. Geol. 1984, 45, 113-20. 31. Pingitore, N.E.; Eastman, M.P. Geochim. Cosmochim. Acta (in revision)· 32. Doerner, H.A.; Hoskins, W.M. J. Am. Chem. Soc. 1925, 47, 662-715. 33. Whittaker, E.J.W.; Muntus, R. Geochim. Cosmochim. Acta 1970, 34, 945-56. 34. Hahn, O. "Applied Radiochemistry"; Cornell Univ. Press: Ithaca, 1936; pp. 98-131. 35. Walton, A.G. "The Formation and Properties of Precipitates"; Interscience: New York, 1967; pp. 102-107. 36. Krauskopf, K.B. "Introduction to Geochemistry"; McGraw-Hill: New York, 1967; p. 82. 37. Fujiwara, S. Anal. Chem. 1964, 36, 2259-61. 38. Wildeman, T.R. Chem. Geol. 1970, 5, 167-77. 39. Davis, J.A.; Fuller, C.C.; Cook, A.D. Geochim. Cosmochim. Acta (submitted)· RECEIVED

June 25, 1986