Journal of Non-Crystalline Solids 323 (2003) 97–103

www.elsevier.com/locate/jnoncrysol

Volatiles in vitreous basaltic rims, HSDP 2, big island, Hawaii

Klaus Heide *, Christian M. Schmidt

Institut fuer Geowissenschaften, Friedrich-Schiller-Universitaet, Jena, Germany

Abstract

Temperature resolved analysis of volatiles from vitreous basaltic rims (HSDP 2 core, Hawaii) and from experimental

melts was carried out to investigate the total volatile content of basaltic melts and the influence of magma contami-

nation on the degassing behaviour of volcanic rocks. The degassing of H2O, CO2, and SO2 from vitreous specimens

shows characteristic differences associated with depth. Secondary minerals, generated by alteration of basaltic rocks,

can be characterized by gas release profiles due to their decomposition in the temperature range below 800 �C. Processesof degassing at temperatures higher than 800 �C are correlated to volatiles in the melt and to fluid inclusions of

phenocrysts as olivine. Obviously there are no correlations in the degassing characteristics between H2O, CO2 and SO2.

The different maxima of the degassing velocity, especially of CO2 and SO2, are indications of the different bonding

forces of the volatiles in the melt. First laboratory tests show that these differences may be caused by remelting of

sedimentary rocks in the basaltic magma.

� 2003 Elsevier B.V. All rights reserved.

1. Introduction

The Hawaii Scientific Drilling Program 2

(HSDP 2) on Big Island, Hawaii, offers a unique

possibility to investigate the nature and content of

volatiles in igneous melts depending on depth and

the age as well as on the type of eruption (subae-rial, submarine). It remains under discussion if the

enrichment of volatiles in ocean island basalts

(OIB) correlates to the �hot� and/or �wet� nature ofthe mantle plume [1].

Numerous authors (e.g. [2–5]) have shown that

significant anomalies in trace element content and

isotope ratios of rocks of the Hawaiian volcanic

centres cannot be explained by fractional crystal-

* Corresponding author. Tel.: +49-3641 948 715.

E-mail address: ckh@rz.uni-jena.de (K. Heide).

0022-3093/03/$ - see front matter � 2003 Elsevier B.V. All rights res

doi:10.1016/S0022-3093(03)00285-0

lization alone. For example, depletions in Th and

U content and enrichments in Sr content in Ha-

waiian volcanic rocks are interpreted by [4] as the

result of recycling of oceanic gabbro through the

Hawaiian mantle plume. Furthermore the two

active volcanic centres on Big Island are charac-

terized by specific signatures in 18O, with that ofMauna Kea rocks having been interpreted as the

result of recycling of pelagic sediments in the

mantle plume [6].

Actual data of H2O, CO2, and S concentrations

in basaltic glass from Loihi seamount, Hawaii,

allow to model of degassing, assimilation, and the

distribution of major volatiles within and around

the Hawaiian plume [1]. Experimental studies ofwater and carbon dioxide solubilities in mid-ocean

ridge basaltic liquids have yielded data for cali-

bration and solubility models [7].

erved.

Fig. 1. Equipment for high-vacuum extraction experiments

(DEGAS) 1: sample crucible; 2: furnace; 3: mass spectrometer;

4: turbomolecular pumps; 5: measuring gauge for total pres-

sure; 6 and 7: mechanical valves.

98 K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103

Different facts are considered in the investiga-tion of the origin of volatiles in the OIBs of Hawaii

[1]:

• assimilation of seawater by magma shallow deg-

assing effects,

• redox melting at the interface of relatively re-

duced ambient mantle with the more oxidized

subducted lithosphere,• progressive melting with depletion in mantle

volatiles, especially He, and equilibration of

volatiles in the magma chamber reservoir.

This paper presents new data of H2O, CO2,

SO2, He, H2, HF, HCl, CO, N2, O2, and hydro-

carbon (HC) degassing profiles of samples from

the Hawaiian Drilling Project (HSDP 2). It aims toestimate the magnitude and nature of source

magma volatiles and contaminations (crustal ma-

terial, seawater, atmospheric gases). Melting ex-

periments with pure basaltic Hawaiian rocks from

the recent Pu�u O�o lava flow as well as with ad-

dition of selected distinct minerals and sediments

should give a basis for the interpretation of de-

gassing profiles of volcanic rocks.Quantitative and qualitative determination of

the degassing rate of volatiles from natural speci-

mens is possible by a combination of thermo-

gravimetry and mass spectrometric analysis. From

degassing profiles follow indications of the origin

of natural crystalline and vitreous rocks [8].

As demonstrated by laboratory experiments,

gas release curves point to two characteristic pro-cesses [9]:

• a continuous change of degassing rate with a

characteristic maximum temperature (e.g. dur-

ing decomposition of alteration products such

as Fe-hydrates, hydroxides, carbonates etc.),

• a spiky change in the partial pressure due to

bursting of bubbles, formed in a melt or dueto decrepitation of fluid inclusions in pheno-

crysts.

Gas release curves reflect differences in melting

temperature and in �raw materials�. Degassing

profiles of parental magma should differ from

degassing profiles of melts with recycled sedimen-

tary or volcanic material of the crust as well asfrom degassing profiles of reservoir equilibrated

magma. By laboratory experiments it is possible to

proof the influence of remelting of selected min-

erals and rocks on the gas release profiles.

2. Analytical technique

Degassing experiments with volcanic rocks

from the HSDP 2-drill core were carried out using

a special high-vacuum-hot-extraction method

DEGAS combined with a quadrupol mass spec-

trometer (QMS, Fig. 1) [10]. The nature of volatile

species can be determined in high vacuum degas-

sing experiments with a controlled heating rate

between room temperature and 1500 �C. Thegaseous species were analyzed in a multiple ion

detection (MID) mode and correlated with the

total pressure change in the sample chamber dur-

ing heating. For a more detailed description of the

analytical techniques see [11] and [12]. In contrast

to degassing experiments using a Knudsen cell

arrangement (mass pyrograms by [13]) the

DEGAS-experiments occur under highly non-equilibrium conditions. Reverse reactions among

0.1

0.15

0.2

0.25

0.3

0.35

Wat

er [m

g]

y = 8749.2x

K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103 99

volatiles and between volatiles and the melt canbe avoided. Quantitative determination of volatiles

is possible by calibration of the degassing curves

with crystalline materials e.g. for H2O hydroxides

(Mg(OH)2 brucite) or hydrates (MgSO4xH2O,

kieserite or CaSO4x2H2O, gypsum), for CO2 car-

bonates (CaCO3, calcite, or MgCO3 magnesite) or

for SO2 sulfates (CaSO4, anhydrite or gypsum)

[14].In Fig. 2 is shown the gas release profile of the

decomposition of brucite. With different sample

weights calibration plots were generated as shown

in Fig. 3 for the determination of H2O.

Vitreous volcanic specimens were selected by an

optical microscopic pick up in quantities of about

20 mg.

As shown in Fig. 4 the brownish glass of therims is fresh and contains euhedrial crystals of

olivine and magnetite.

0

0.05

0.00E+00 1.00E-05 2.00E-05 3.00E-05 4.00E-05Peak area [a. u.]

R = 0.988

Fig. 3. Calibration of the MS-peak area with the dehydration

3. Results

Fig. 5 shows gas release profiles of glassy sam-

ples from the HSDP 2 borehole in a temperaturerange between 200 and 1400 �C. Gas release from

0 200 400 600 800 10000.0

2.0x10-6

4.0x10-6

6.0x10-6

8.0x10-6

1.0x10-5

Temperature [°C]

Ion

curre

nt [A

]

H2O (m/z 18)

Fig. 2. Gas release during the decomposition of brucite.

of brucite.

Fig. 4. Olivine phenocrysts (Ol) and magnetite (M) in a vitre-

ous matrix (V).

alteration products (e.g. iron hydroxides, amor-

phous silica, and clay minerals) and mineral

02x10-9

4x10-9

6x10-9

8x10-9m/z 2

0.02.0x10-10

4.0x10-10

6.0x10-10

8.0x10-10m/z 15

02x10-9

4x10-9

6x10-9

8x10-9m/z 32

01x10-11

2x10-11

3x10-11

4x10-11m/z 4

0.0

5.0x10-9

1.0x10-8

1.5x10-8m/z 16

0.02.0x10-12

4.0x10-12

6.0x10-12

8.0x10-12m/z 36

0.0

5.0x10-10

1.0x10-9

1.5x10-9m/z 12

0.0

1.0x10-7

2.0x10-7

3.0x10-7

m/z 18

0.02.0x10-12

4.0x10-12

6.0x10-12

8.0x10-12m/z 37

0.02.0x10-11

4.0x10-11

6.0x10-11

8.0x10-11m/z 13

0.0

1.0x10-10

2.0x10-10

3.0x10-10

m/z 20

0.0

5.0x10-10

1.0x10-9

1.5x10-9m/z 44

0 200 400 600 800 1000 1200 14000.0

2.0x10-9

4.0x10-9

6.0x10-9

8.0x10-9m/z 14

0 200 400 600 800 1000 1200 14000

2x10-9

4x10-9

6x10-9

8x10-9m/z 28

0 200 400 600 800 1000 1200 14000

2x10-11

4x10-11

6x10-11

8x10-11

Ion

curre

nt (A

)

Temperature (°C)

m/z 48/64

<1>

<2>

Fig. 5. Degassing profiles subaerian sample SR 118-8.8 (238 m bsl) h1i CO2-release by decomposition; h2i CO2-release by bubbling.

100 K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103

admixtures (e.g. limestone) can be observed in a

temperature range between RT and 800 �C (Fig.

5h1i). The gas release above 800 �C results fromvolatiles bonded in the vitreous matrix or from

decrepitation of fluid inclusions of high tempera-

0 200 400 600 800 1000 1200 14000.0

5.0x10-10

1.0x10-9

Temperature [°C]

Ion

curre

nt [A

]

m/z 64

200 400 600 800 1000 1200 14000.0

4.0x10-9

8.0x10-9

Temperature [°C]

Ion

curre

nt [A

]

m/z 44

200 400 600 800 1000 1200 14000.0

5.0x10-8

1.0x10-7

Temperature [°C]

Ion

curre

nt [A

]

m/z 18

Fig. 6. Water-, CO2-, and SO2-release sample SR 863 (2625 m

bsl).

ture crystallization. CO2 escaped in a more or less

significant two step process by diffusion and bub-

bles (Fig. 5h1i and h2i). No or smooth correlationexists between H2O- and CO2-evolution (Fig. 6).

A He-release (m/z 4) is detectable only in traces

in the samples SR 785 and SR 863 in the temper-

ature range of maximum temperature of SO2 re-

lease (1090–1105 �C) (Fig. 7h3i). A decrease in

oxygen partial pressure (m/z 32) was detected

during high vacuum heating in the temperature

range of 1200–1350 �C (Fig. 7h4i). Obviously thebasaltic melt is significantly oxygen-deficient.

Furthermore results from the degassing profiles

that chlorine (H35Cl: m/z 36) is not detectable from

the subaerial and submarine melts. A degassing of

nitrogen may be excluded in the detection limit

of DEGAS, but evolution of HF (m/z¼ 20) is

observed in samples deeper than 2000 m.

4. Discussion

In general the degassing behaviour of industrial

produced glass forming melts can be characterized

by three processes [15]:

01x10-9

2x10-9

3x10-9

4x10-9m/z 2

0.02.0x10-10

4.0x10-10

6.0x10-10

8.0x10-10m/z 15

02x10-9

4x10-9

6x10-9

8x10-9m/z 32

01x10-11

2x10-11

3x10-11

4x10-11m/z 4

0.01.0x10-8

2.0x10-8

3.0x10-8

4.0x10-8m/z 16

0.02.0x10-12

4.0x10-12

6.0x10-12

8.0x10-12m/z 36

0.01.0x10-9

2.0x10-9

3.0x10-9

4.0x10-9m/z 12

0.02.0x10-8

4.0x10-8

6.0x10-8

8.0x10-8m/z 18

0.02.0x10-12

4.0x10-12

6.0x10-12

8.0x10-12m/z 37

0.02.0x10-11

4.0x10-11

6.0x10-11

8.0x10-11m/z 13

0.0

5.0x10-11

1.0x10-10

1.5x10-10m/z 20

0.01.0x10-9

2.0x10-9

3.0x10-9

4.0x10-9 m/z 44

0 200 400 600 800 1000 1200 14000.0

2.0x10-9

4.0x10-9

6.0x10-9

8.0x10-9m/z 14

0 200 400 600 800 1000 1200 14000

2x10-9

4x10-9

6x10-9

8x10-9m/z 28

0 200 400 600 800 1000 1200 14000

2x10-10

4x10-10

6x10-10

8x10-10

Ion

curre

nt (A

)

Temperature (°C)

m/z 48/64

<6>

<3>

<4>

<5>

Fig. 7. Gas release profiles vitreous rim sample SR863 20.7 (2731 m bsl) h3i He-release; h4i oxygen release and consumption; h5i HF-release h6i hydrogen release.

K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103 101

• between 800 and 1050 �C, CO2 and H2O from

the �raw material� are liberated by diffusion

and bubbling,

• physically dissolved gases (e.g. oxygen or nitro-

gen, noble gases etc.) escape in a temperature

range between 1050 and 1200 �C,• redox reactions of �fining additives� (polyvalent

cations) produce volatiles above 1200 �C e.g.O2, and SO2.

In contrast the gas release of natural glass oc-

curs in a higher temperature range, but as shown

in the Figs. 5–7, there are several maxima of deg-

assing rate at different distinct temperatures too.

From laboratory experiments we know that gas

release temperatures are correlated to the temper-ature of the melting process. Degassing data of

natural glasses suggest a melting process higher in

temperature and pressure(?) as in an industrial

glass melter.

The formation of mixed CO2–H2O bubbles as a

result of a �degassing process� of �raw materials� (innature this �raw material� can be recycled from the

lithosphere) has not been observed in the gas re-lease profiles between 800 and 1200 �C. This

means the degassing does not cause a polymer-

ization of the melt [16] according to

4½SiO3OH�3� þ 2½CO3�2�

) 4½SiO4�4� þ 2ðH2O=CO2Þ:

A significant high-temperature (>900 �C) CO2-

release was observed both in the subaerial lava

eruption (SR 118-8.8) and in the submarine sam-

ples. The source of CO2 could be a recycling ofcarbonate sediments (Fig. 5h2i). In comparison to

industrial produced glass, the temperature of the

maximum degassing rate above 1100 �C is an in-

dication for a completely different bonding state of

carbonate ions in the natural silicate network.

The degassing of industrial melt occurs during

the �fining�-process, which is released by fining

additives such as Na2SO4. Here, mixed CO2- andSO2-bubbles generated O� in the melt:

½CO3�2� þ ½SO4�2� ) 3O2� þ ðCO2=SO2Þ:

3200

3000

2800

2600

2400

2200

2000

1800

1600

1400

12000,00 0,02

H2O [%]

dept

h [m

]0,00 0,01

CO2[%]

0,0 0,5

SO2[a.u.]

0,0 0,5

Cl [a.u.]

0,00 0,05

Cl [%] *

0,0 0,1

S [%] *

Fig. 8. Degassing of vitreous rims in dependence on core depth compared to Cl- and S-content (�data: Sobolev, Mainz, personal

communication).

Table 1

Data of H2O- and CO2- release from vitreous basaltic rims, HSDP2 (>900 �C)

Sample Depth [m] Sample weight [mg] Peak area m/z 18 H2O [wt%] Peak area m/z 44 CO2 [wt%]

SR 514-10.7 1302 18.4 2.46E)07 0.0117± 0.0006 8.97E)09 0.0010± 0.00005

SR 515-3.6 1304 17.8 3.36E)07 0.0165± 0.0008 1.01E)08 0.0012± 0.00006

SR 759-4.0 2112 20.4 5.11E)07 0.0219± 0.0011 1.27E)08 0.0013± 0.00007

SR 785-0.6 2255 15.4 6.54E)07 0.0372± 0.0019 1.44E)08 0.0020± 0.00010

SR 816-7.7 2362 20.4 5.72E)07 0.0245± 0.0012 1.83E)08 0.0019± 0.00010

SR 863-20.7 2625 19.7 1.13E)06 0.0503± 0.0025 8.41E)08 0.0091± 0.00045

SR 889-13.6 2717 20.2 6.77E)07 0.0293± 0.0015 2.57E)08 0.0027± 0.00014

SR 930-9.1 2917 20.2 6.79E)07 0.0294± 0.0015 1.76E)08 0.0019± 0.00009

SR 935-21.4 2940 20.3 4.19E)07 0.0180± 0.0009 1.12E)08 0.0012± 0.00006

SR 942-5.7 2973 20.9 3.12E)07 0.0131± 0.0007 1.32E)08 0.0013± 0.00007

SR 954-10.7 3007 20.0 3.13E)07 0.0137± 0.0007 1.12E)08 0.0012± 0.00006

SR 961-14.0 3040 20.8 3.53E)07 0.0149± 0.0007 1.79E)08 0.0018± 0.00009

SR 962-18.1 3046 20.2 5.76E)07 0.0249± 0.0012 2.61E)08 0.0027± 0.00014

102 K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103

The rate of CO2- and SO2-formation in the melt

of natural glass is similar (Fig. 6). From the

differences of the maximum degassing rate it is

clear that the formation of bubbles must be

controlled by two individual processes different

to the fining process in an industrial glass melter.

Carbonate and sulfate complexes can be intro-

duced in the melt by igneous gases or by

recycling of carbonate or sulfate sedimentary

rocks. First laboratory experiments show the

modification of gas release profiles due to the

remelting of pelitic sediments (paleozoic silicified

black shale/radiolarite) in a batch of black sand

glass.

K. Heide, C.M. Schmidt / Journal of Non-Crystalline Solids 323 (2003) 97–103 103

Quantities of evolved gases depending on depthare summarized in Fig. 8 and Table 1. The sig-

nificant increase of H2O, CO2 and SO2 release in

the depth between 2100 m and 2700 m indicates

differences between degassed and undegassed pil-

low lavas. These results are in agreement with

chemical characterization by XRF.

5. Conclusions

By DEGAS experiments we detected the fol-

lowing volatiles in the melt: H2O (0.01–0.02 wt%),CO2 (0.001–0.01%), SO2 (0.0001–0.0005 wt%), as

well as traces of H2, HF, and He.

The absence of HCl, N2, and O2 indicates a

negligible interaction of the melt with air or sea-

water.

In the depth >2000 m the content of volatiles

increases significantly.

H2O, CO2, and SO2 release have differentsources, the �fining� of the melt occurs by differenttemperatures.

Laboratory experiments prove the oxygen in-

corporation of the melt under atmospheric condi-

tions.

Degassing profiles may reflect the recycling of

sedimentary materials in the basaltic melt. First

indications are that these differences are causedby different magma contamination.

The selective, temperature-dependent degassing

analysis represents an effective method for the

specification of magma composition.

Acknowledgements

We thank M. Schoder, J. Koerting and S. Lenk

for technical assistance. This study was supported

by the Deutsche Forschungsgemeinschaft (HE

1884/14).

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