HEI959-60jERUPTION

VOlCTlNO

'"'

PETROGRAPHY OF 

THE LAVAS

' GEOLOGICAL SURVEY 

^PROFESSIONAL PAPER 537- D
Petrography of the Lavas 

of the 1959-60 Eruption of 

Kilauea Volcano, Hawaii 

By D. H. RICHTER and K. ]. MURATA 

THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 537-D 

A detailed picture of changes in lava 

mineralogy with respect to time, 

temperature, and bulk composition 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1966 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 20 cents (paper cover) 
CONTENTS 

Page 

Abstract___________________________________________ D 1 Petrography ______________________________________ _ 

Introduction_______________________________________ 1 The summit lavas ______ .... _______________________ _ 

Acknowledgments___________________________________ 2 The flank lavas ________________________________ _ 

Previousstud~s------------------------------------ 2 Thermal data _____________________________________ _ 

Literature cited ____________________________________ _ 

ILLUSTRATIONS 

Page 

FIGURE 1. Graph showing the mode of 1959-60 lavas___________________________ D 5 

2-7. Photomicrographs of2. Skeletal olivine microphenocrysts_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 6 

3. Large resorbed olivine phenocrysts___________________________ 7 

4. Large euhedral olivine phenocrysts_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 7 

5. Flow sample F-1_------------------------------------------ 8 

6. Resorbed plagioclase phenocrysts_________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 9 

7. Flow sample F-20------------------------------------------ 10 

8. Temperature stability fields for phenocrystic minerals_________________ 11 

TABLE 

TABLE 1. Modal composition of the lavas of the 1959-60 Kilauea eruption________ D 4 

III 

Page 

3 

4 

7 

10 

12 
THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

PETROGRAPHY OF THE LAVAS OF THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

By D. H. RICHTER and K. J. MuRATA 

ABSTRACT 

Petrographic studies of a suite of lava samples, collected 

throughout the 1959-60 eruption of K'ilauea volcano, have yielded a detailed picture of .the changes in lava mineralogy with 

respect to time, temperature, and bulk chemi•stry. 'Tile re'sults 

are explained in terms of fractional crystallization of bas,altic 

magmas .and of the mixing of two magmas of different vintage. 

The ea·rliest and coolest lavas of the 1959 summit phase of 

the eruption were characterized by moderately abundant mic.rophenocrysts of olivine (Fau-1s), augite (En5oFS:toWo.o), and 

pl·agioclase ( Ano4). These lavas evidently represented the upper 

part of the magma body a:t ,the summit, and the minerals were 

·separating out of the melt under equilibrium conditions. 

·The later lavas of the summit eruption, representing the lower 

and ho.tter part of the magma body, contained no phenocrysts 

of augite or o·f plagiodase but only coarse, euhedral to rounded 

phenocrysts of a less fayalitic olivine ( Fa12-14). This olivine is 

tlhe first silicate mineral to separate from the primitive melt and 

settles in the melt to form picri.tic magmas. The further cooling 

of the oliv.ine-depleted restmagma leads to the stage of crystallization manifested in the earliest lavas of •the eruption, described 

above. 

Petrographically, the 1960 flank-phase lavas of the eruption 

can be divided into two distinct 1i1agma. ty.pes: (1) a cooler 

early-1960 type characterized :by phenocrysts of plagioclase 

( An1~-oo), augite ( En.7.oFsl~.:J,V04o.,), small euhedral olivines 

( Fa20-2•) , larger rounded oli vines ( Fau-1o), and mino.r hyper-

~thene (Fs2o-2s) ai1d (2) a hotter late-1960 type containing principally large euhedral to slightly rounded phenocrysts of olivine 

( Fa1~-1o) accompanied by minor amounts of rounded residual 

phenocrysts of augite and plagioclase. 

Lavas of the .intermediate .period of the flank eruption point to 

an intermixing o·f the cooler early-1960 type of magma and the 

hotter late-1960 ty.pe. All .phenocrystic minerals of the early11)60 magma type (except olivine ~~a12-1o) are ·to be seen in various stages of resorption, and a concomitant rapid increase in the 

amount of coarse phenocrysts of olivine Fa12-1o marks the transition to the late-1!)60 type of magma. 

By correla.ting the petrographic data on the lavas with temt»erature:s measured during their eruption, the following schemes 

of crystallization of .the 1959 summit and the 1960 fl'ank 

magmas have been derived. The observed range of temperature over which a mineral separated from the magma is given; 

where only one temperature is gin•n, it denotes the point of .the 

initial separation of the minel"lal. 

Mineral 

Summit magma: 

Approximate terrvperature 

of separat~on ( 0 0) 

Olivine, Fa12-H-------------------------------- 1180-1125 

Augite, En5oFS1o,V04o---------------------------. 1120 

Olivine, Fa11-1s-------------------------------- 1100 

Plagioclase, An84------------------------------ 1090 

Flank m3 gmas : 

Olivine, Fa12-1o-------------------------------- 1080-1055 

Augite, En4sFS12'\Vo4o--------------------------- 1080 

Plagioclase, An12-ao-----------------------.----- 1070 

Hypersthene, Fszo-25--------------------------- 1060 

Olivine, Fa2o-24-------------------------------- 1055 

The order of the first separation of the major phases from 

primitive Kilaue!a magma is olivine-augite-plagioclase. This 

same order was obtained in laboratory quenching experiments 

by other researchers on dry melts of Kilauea lavas of similar 

composition. However, the liquidus temperatt1res and the indicated temperatures of complete crystallization of the magmas, 

derived from the data of the 1959-60 eruption, are appreciably 

lower than those determined in the quenching experiments. 

INTRODUCTION 

Kilauea and Mauna Lao volcanoes on the Island of 

Hawaii have poured out vast quantities of tholeiitic 

lavas within historic ( post-1790) time. The study of 

these lavas by many investigators over the years has 

demonstrated the importance of fractional c;rystallization of olivine in the first stage of differentiation of the 

primitive magmas. But in general, the eruptive regimens of these volcanoes apparently do not allow the 

primitive magmas to pass much beyond this first stage 

of differentiation, so that the simple mineralogy of most 

of the historic flows is monotonously similar. 

The 1959-60 eruption of Kilauea, consisting of both 

a summit and a flank phase, yielded lavas whose composition and mineralogy varied to an unusual degree. 

The usual phenocrysts of olivine were ahmidant in the 

hottest lavas of the summit phase; but in the cooler lavas 

of both the summit and flank phases, notable amounts 

of clinopyroxene and plagioclase phenocrysts were 

D1 
D2 THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

present. These lavas thus afforded an opportunity to 

study somewhat more advanced stages of basaltic differentiation. Because of a timely augmentation in the 

staff and laboratory facilities of the Hawaiian Volcano 

Observatory in 1958, it was possible to measure many 

chemical and physical parameters of eruptive activity 

more or less simultaneously. As a result, the fractional 

crystallization of Kilauea magma was revealed in 

fascinating detail. 

The chemical compositions of the lavas, of the 

phenocrystic minerals, and of basaltic glasses separated 

from some of the lavas are given by Murata and Richter 

(1966). These data have been freely drawn upon in the 

present study; conversely, the results of the petrographic investigation have been used as a guide in interpreting the tr~nds of chemical variation; This correlation of chemical and mineralogic information, in conjunction with the known temperatures of the lavas, has 

yielded a consistent scheme of differentiation of the 

primitiv~ Kilauea magma. 

ACKNOWLEDGMENTS 

Throughout the eruption, assistance in collection of 

lava and pumice samples was received from staff members of Hawaii National Park and from the writers' colleagues of the Hawaiian Volcano Observatory. R. T. 

Okamura isolated concentrates of phenocr:ystic minerals 

from the lavas. F. H. Hildebrand determined the composition of .many olivine crystals by means of their Xray spacing. H. A. Powers was very helpful with various aspects of the study. 

PREVIOUS STUDIES 

The main petrographic features of Kilauea lavas are 

conveniently summarized by ~Iacdonald (1949a, b). 

Lavas containing variable amounts of phenocrystic 

olivine are the most abundant, those with phenocrystic 

augite and plagioclase are less common, and those with 

phenocrystic hypersthene are rare. Depending on the 

rate of cooling of the extruded lava, the groundmass 

ranges from basaltic glass typically charged with microlites of opaque minerals to intergranular intergrowths 

of clinopyroxene, plagioclase, and opaque minerals. 

Kilauea lavas, along with those of Mauna Loa, represent the general tholeiitic type of basaltic magma that 

characterizes the major shield-building stage of Hawaiian volcanoes (Stearns and Macdonald, 1946; Tilley, 

1950; Powers, 19·55). Lavas of the alkalic-basalt 

magma type typically constitute the late outpourings of 

the senescent or ex·tinct volcanoes (Hualalai, Mauna 

Kea, and Kohala) on the Island of Hawaii. The principal mineralogical differences between the two basalt 

types are in the groundmass minerals. The groundmass 

of the tholeiites contains plagioclase and augite and 

(or) subcalcic augite, whereas that of the alkalic basalts 

contains plagioclase and augite (generally alkalic) 

together with olivine. Moreover, hypersthene is absent 

from the alkalic basalts. Tholeiitic basalts with less 

than about 10 percent modal phenocrystic olivine are 

oversaturated, whereas the alkalic basalts, regardless 

of their phenocrystic content, are undersaturated. 

No lavas with alkalic affinities have yet been found in 

samples from l\{auna Loa or Kilauea Although the 

residual melt eollected from directly below the crust in 

the 1959 l{ilauea Iki lava lake 7 months after the eruption had a chemical composi·tion approaching that of 

hawaiite of the alcalic-basalt series (Macdonald and 

Katsura, 1961), subsequent investigations indicate that 

this relatively alkali-rich melt is transient and upon 

crystallization reverts to a normal tholeiitic basalt 

(Richter and Moore, 1966). 

Slight but persistent differences exist between the 

composition of tholeiitic lavas of Kilauea and Mauna 

Loa (·Macdonald, 1949a; Powers, 19·55). Mauna Loa 

lavas tend to be slightly more sil,iceous and. somewhat 

poorer in ealcium oxide :as well as in alka.Jies, and these 

differences are reflected by the more common occurrence 

of hypersthene phenocrysts in Mauna Loa lavas (Tilley 

and Scoon, 1961). In addition to these differences hetween the lavas of the two volcanoes, Powers (1955) 

noted that the primitive tholeiitic. ·magma of each volcano has fluctuated in composition within the period 

represented by its accessible lavas. He eoncluded that 

all Kilauea lavas erupted in historic time were derived 

from a single large batch ·'Yf magma, which was generated in the mantle more than a century ago and has been 

erupted -in small amounts ever since. Prehistoric (pre1790) lavas have compositions that suggest derivation 

from one or more earlier batches of pri·mitive magma. 

As shown by Murata and Richter (1966), the composition of the 1959 summit lavas indieates a clear affinity 

to the historic primitive magma. 

The 1840 and the 1954-55 eruptions of Kilaue.:'l, like 

that of 1959-60, involved an initial aetivity in the summit region which was .followed by a major outbreak on 

the flank along the east rift zone. The 1840 summit lava 

was olivine-poor basalt, 'whereas the flank lava was picrite. The summit and flank lavas were interpreted as 

representing the upper, olivine-depleted part and the 

lower, olivine-enriched part, respectively, of the magma 

column. A separation of minor amounts of augite and 

plagioclase was also indicated by the differences in lava 

composition (Macdonald, 1944, 1949b; Muir and Tilley, 

1957). 

The 1954 summit and the 19·55 flank lavas were uniformly poor in olivine, and the latter lavas contained 
PETROGRAPHY OF THE LAVAS D3 

phenocrysts of augite and plagioclase in unusual 

abundance (Macdonald, 1955; Maedona;ld and Eaton, 

1957; Tilley, 1960). The genetic relationship among the 

1954-55 lavas has become clarified through the present 

study of similar lavas produced in the 1959""""'60 eruption. 

The coarse green phenocrysts of olivine, so common in 

J{ilauea lavas, have 2V close to 90° and hence a fayalite 

content of about 13 mole percent.. Only four analyses 

of J{ilauea olivines have been published, and they average 13.0+2.0 mole percent fayalite. The total range of 

fayalite content reported for unaltered Kilauea olivines 

by previous workers, on the hasis of optical or X-ray 

measurements, is Fa11_ 26. However, as well shown by 

Muir and Tilley ( 1963), physical methods of determining the composition do not always yield concordant 

results when applied to Kilauea olivines. Depending 

on the property measured ( 2V, indices of refraction, 

or X-ray spacings), the indicated compositions may 

differ by as much as 10 mole ·percent fayalite. The difficulty arises in part from the fact that the available determinative curves are based mostly on olivines from 

plutonic and hypabyssal rocks, and they do not seem to 

hold accurately for olivines of v'Olcanic rocks (Chudoba 

and Frechen, 1943). Further work on determinative 

methods for volcanic olivines is muc4 needed. 

It commonly is accepted that the low-iron olivine of 

tholeiitic magmas has a discontinuous reaction relationship with the cooling melt, but convincing petrographic 

evidence for this relationship has not been found among 

J{i]auea lavas. Fine-grained coronas of enstatitemagnetite that rim olivine phenocrysts are observed in 

some lavas of J{ilauea, but Muir and Tilley (1957) have 

shown that these are products of partial oxidation of the 

olivines rather than a reaction of the olivines with the 

melt. Rounding and embayment of olivine phenocrysts 

are commonly manifested, but these features may be 

. due to a continuous reaction of the phenocrysts with 

melts of varying temperature and composition. 

The rarer phenocrysts of augite, plagioclase, and 

hypersthene in J{ilauea lavas have been studied by Macdonald (1949a) and by Muir and Tilley (1957, 1963). 

The latter authors gave the analyses of two phenocrystic 

augites, one :from an 1840 flow and another from a flow 

of the 1921 eruption. The two augites have very similar 

compositions, averaging En4 8. 7 Fs1o.1 Wo.w.H· Muir and 

Tilley (1963) noted also that the optics of augite phenocrysts from Hawaiian tholeiites tended to indicate too 

femic a composition and ascribed this to the possible influence of chromium oxide, which commonly is present 

in excess of 0.5 percent in such phenocrysts. 

Plagioclase phenocrysts in Kilauea lavas range in 

composition from An7 :! to An50, and hypersthene phenocrysts, noted hitherto :from only two lavas, have not been 

closely characterized ·(Muir and Tilley, 1963). 

Hypersthene in the gabbroic rock of the U wekahuna 

laccolith of J{ilauea has a composition of En7 a.4Fs21.a 

Wo5.3 (Muir and Tilley, 1957). The groundmass 

minerals of Kilauea lavas have been studied by several 

investigators, but these minerals will not be reviewed 

here because they play no role in the pre-eruptional differentiation of magmas. 

Existing information on phenocrystic minerals, thus, 

suggests that the only phases that participate in the 

differentiation of Kilauea magmas are olivine, augite, 

plagioclase, and minor hypersthene, in various proportions. The compositions of some of the lavas also suggest the occasional involvement of opaque minerals, but 

phenocrysts of opaque minerals, other than the early 

spinel :found embedded in olivine, are rare. 

PETROGRAPHY 

The lavas erupted during the 1!;)59-60 eruption range 

from ~holeiitic olivine basalt, with a minimum Si02 

content of 46.7 percent, to tholeiitic basalt, with a maximum Si02 content of 50.8 percent. All the 'lavas are 

porphyritic and exhibit a relatively wide variety in the 

type and amount of phenocrystic minerals present. 

Magnesian olivine is the principal and usually the only 

phenocryst present in those lavas containing less than 

49.4 percent Si02 • Above 49.4 percent Si02, phenocrysts and clots of clinopyroxene and plagioclase become increasingly more abundant; and at about 50.2 percent Si02, hypersthene appears. The texture and 

mineralogy of the groundmass depends almost entirely 

on the cooling history of the lava. Where rapidly 

cooled, such as in the flow tops and pyroclastic debris 

from the fire :fountains, the groundmass is completely 

glassy. With slower cooling, as in the center of the 

thick flows, the texture becomes hyalo-ophitic to intersertal. Small laths of plagioclase, stubby prisms and 

anhedral grains of clinopyroxene, and microlitic 

growths of opaque minerals constitute the groundmass 

minerals where present. 

Owing to the pumiceous nature of most of the samples 

collected during the eruption, not all the lavas chemically analyzed were useful for study in thin section. 

However, there were sufficient relatively dense rocks 

collected from time to time to supplement the analyzed 

samples and to trace adequately the changes in 

mineralogy with respect to time, temperature, and bulk 

chemical composition. 

Modes of the rocks, expressed in volume percent, were 

determined with a point counter, utilizing at least 500 

points per analysis. Olivine X-ray studies were made 

by Fred A. Hildebrand, U.S. Geological Survey, using 

the method of Yoder and Sahama ( 1957). Indices of 
D4 THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

refraction were used to determine the compositions of 

the plagioclase, pyroxene, and some olivine. 

The model analyses of 8 summit and 8 flank lavas are 

listed in table 1. These same modal data are also presented graphically, as a function of time, in a somewhat 

modified form in figure 1, together with the measured 

lava temperatures and bulk silica content. 

THE SUMMIT LAVAS 

With the exception of the relatively small volume of 

lava extruded during the 'first 2 da.ys of eruption and 

the negligible quantity extruded in the last .(17th) phase 

of the summit activity, there was no marked change 

in the gross mineralogy of the lavas. The great bulk 

of the summit lavas contain between approximately 4 

and 30 ·mode -percent of phenocrystic olivine set in a 

glassy or extremely fine grained intersertal groundmass. 

There were, however, changes in the amount and character of the olivine phenocrysts which appear to correlate with changes in temperature ( a.nd hence are 

directly related to the degree of crystallization) and 

with other physical para·meters of the eruption. Phenocrysts and microphenocrysts of clinopyroxene and 

plagioclase were observed only in the early and extremely late lavas; no hypersthene was detected in any 

of the summit lavas.1 

Samples S-1 and S-3, erupted on November 14 and 

16, 1959, respectively, are assumed to be typical of the 

early lavas, and they represent approximately 5 percent 

of the 30 miUion cubic meters poured into Kilauea Iki 

during the first phase of summit activity. Both samples contain relatively abundant microphenocrysts, as 

much as 0.3 mm long, of euhedral a.nd skeletal olivine 

(Fa1s, determined by X-.rays), euhedral to slightly 

rounded clinopyroxene (a pprox. En50Fs10 W 0 40, deter1 Trace amounts of clinopyroxene and plagioclase phenocrysts were 

also found by Howard A. Powers (written commun., 1963) in concentrates of crystals from samples S-10, S-12, and S-14. In view of the 

relatively low observed temperatures of these samples, these additional 

data lead to a more consistent pattern of phenocryst distribution. 

mined from optical properties), and plagioclase ( An64, 

determined hy index of refract.ion) in a dark-brown 

glassy matrix sprinkled with a few microlites of pyroxene, feldspar, and opaque minerals. Sample S-1 also 

contains a fe·w larger phenocrysts ( 0.6-1.2 .mm) of more 

magnesian olivine (Fa13, determined 'by X-rays) that 

exhibit rounded crystal outlines. The smaller, more 

fayalitic olivines display a variety of remarka;ble skeletal forms, many with a characteristic "arrowhead" termination at one or more of the principal apexes (fig. 2). 

These skeletal olivines also contain irregular to rodshaped inclusions of brown glass that generally a.re 

lighter in color and more transpa..rent than the groundmass glass. The plagioolase microphenocrysts are unzoned and occur as individual laths in the groundmass 

or are intimately intergrown with stubby clinopyroxene 

prisms to form glomeroporphyritic clots. Both the 

clinopyroxene ·and plagioclase microphenocrysts appear 

to have sharper and better formed crystal outlines in 

sample ~S-1 than in sample S-3. This is especially true 

of the plagioclase crystals, many of which in sample 

S-3 have very ragged terminations and scalloped edges, 

apparently indicative of resorption. 

The two chemically and physica1ly different oliv.ines 

in the early summit lavas appa·rently represent two distinct stages of olivine crystallization. The few large 

resor.bed magnesium-rich phenocrysts of olivine (F~ ) 

were undoubtedly not in equilibrium with. the liquid 

(glass) in which they are now found, but evidently 

formed deeper in the eruption conduit under conditions 

of higher temperature and in a melt of lower silica content with a higher ratio of magnesia to iron. The assemblage clinopyroxene-plagioclase-olivine (Fa18 ), on 

the other hand, does appear to be in equilibrium with 

the glass, which is in accord with the lower temperatures and relatively high.bulk silica content .of the lavas 

during the early part of the first summit phase. 

By November 1'8, 1959, all 'traces of phenocrystic 

clinopyroxene, plagioclase, and the relatively highTABLE I.-Modal composition of lavas of the 1959-60 Kilauea erupt?:on, in volume percent 

[Tr., trace} 

Summit lavas Flank lavas 

8-1 S-3 S-5 S-9 S-14 S-16 S-20 S-25 F-1 F-4 F-6 F-8 F-10 F-14 F-16 F-20 

-------------------------------

Phenocrysts: Olivine __________________ 3 5 30 I4 4 24 2I 6 2 I I 5 9 I3 I4 8 Clinopyroxene ____________ 9 4 0 0 Tr.t 0 0 2 6 6 7 5 3 3 2 2 

Plagioclase _______________ I 2 0 0 Tr.t 0 0 I 9 9 IO 4 2 <I <I I 

Hypersthene _____________ 0 0 0 0 0 0 0 0 <I <I <I <I 0 0 0 0 

Glass or fine-grained ground- . mass ______________________ 87 89 70 86 96 76 79 9I 83 84 82 86 86 84 84 89 

1 Determined by Howard A. Powers from concentrates of bulk sample. 
) •, 

-,.l 

co 

~ Nl 

,_. 

~ 

~ 

r 

~ 

LLJ 

a:: 

:::::> <(I-

><( 

<(C:: 

_JLIJ 

0 

(i) 

UJ 

Cl 

0 

~ 

a.. 

~ 

UJ 

1-

(.) 

(/) 

IJJ 

IJJ 

a: 

(.!) 

IJJ 

0 

~ 

1-

z 

IJJ 

(.) 

a: 

IJJ 

Q.. 

II 

(.!) 

w 

~ 

(/) 

I-(/) 

zc:c 

IJJ~ 

uO a::Z 

LLJ::::l 

a..o a:: 

(.!) 

(/) 

1-

(/) 

u..>-

oa:: (.) 

t-0 

zz 

LLJIJJ 

<.>I 

a: a.. 

~~ 1-

0 

1-

'f' 

1200 fl I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I II I I I II I I I I II II II II II II II II II II II I II I I I II II I II II II II I I 11)1 

A._ . J '1. , ...... 1100 / -

1000 

49 

100 

90 

80 

70 

60 

20 

S~S-13 9\S-14 

S-10 oS-18 S-20 

~'S-11 J,S-17 S-~9 S-22 

), 0 o OS-24 

S-15 S-16 OS-21 

oS-25 

SUMMIT ERUPTION 12 14 

2 

[.! 3 4 5 67 8 9 11113/ 17 PHASES CJ D El 9~ 0 B ll 111(1 113 

S-3 10 15 16 

S-1 S-5 S-9 .S-14 S-16 S-20 S-25 

--r-~ .-.-.-- -- --- ------

15 

1 

I 0 X 

: ~ X 

20 25 30 

NOVEMBER 

X 

5 

1959 

)( 

I 

I 

l 

10 15 20 

DECEMBER 

25 5 

F;:1 

~ 

~ F-7 F-6 ~ .. , 

FLANK ERUPTION 

t:::::::O:·:O:"·:o:-:-:·:::::<:>:::::·: ·.·.·.·.·.·.· .·.·:0.·.-.·t .·::.·.·.·.<·.·':.·.<-:·:-: .:' .'.·.·:·.·7 ····· ············.·.·.·.·.·.·.·.·.·.·.·.;.;.;.;.;.·.·· ·<·::1 

F-1 F-4 F-6 F-8 F-10 F-14 

C\...F"-s£. 

~\...~---, I 

I 

I 

cu~o~'<R ~£.~£. \ ~----, 

10 15 20 25 30 

JANUARY 1960 

5 

F-16 F-20 

10 15 20 

FEBRUARY 

FIGURE I.-Temperature, bulk silica content, eruptive interval, and mode of 1959-60 lavas as a function of time. In the mode, the amount of groundmass is 

expressed as volume percent of vesicle-free lava. The relative amounts of the several phenocrystic minerals are expressed as volume percent of total 

phenocrysts. 

'"d 

trJ 

8 

~ 

0 

~ 

~ 0 

l:l:j 

~ t"l 

~ > Ul 

tj 

Cl1 
D6 THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

2mm 

FIGURE 2.-Photomicrographs of skeletal olivine microphenocrysts (ol) in sample 8-3, erupted November 16, 1959. Microphenocrysts of plagioclase (pi) and clinopyroxene (cp) are also scattered throughout the dense black groundmass glass. Large 

light-gray areas are vesicles. Note the "arrowhead" projections at the apexes of the olivine crystals and the irregular 

inclusions of brown (black) glass within the crystals. The large olivine crystal (left photomicrograph) and the small 

V-shaped one below it are in optical continuity. 

fayalite olivine had disappeared. Sample S-5, a pumice 

erupted on November 18, contains approximately 30 

percent large olivine phenocrysts, as much as 4 mm in 

diameter, in the mode. The olivine phenocrysts are 

mostly euhedral; a few exhibit incipient rounding of 

the crystal form. Partial chemical analyses of large 

olivine phenocrysts separated from pumice erupted No-

' vember 17 (sample S-4) and November 19 (sample 

S-6) indicate an Fa content of 12.5 mole percent in the 

olivines of ·both samples, suggesting that olivine of sample S-5 has that composition. 

Sample S-9, of spatter and pumice thrown out by the 

lava fountain at 8 :00p.m. on November 21, represents 

the last lava extruded during the '"eek-1ong first phase 

of summit activity. Mineralogically, the material is 

very similar to most of the summit lavas. Olivine is the 

only phenocryst present; it occurs as large crystals, as 

much as 4 mm in diameter, set in a glassy groundmass 

rendered opaque by abundant microlites. The olivine 

phenocrysts in this sample, however, all show marked 

rounding and some show strong embayment, due to 

magmatic resorption (fig. 3). 

Sample S-14 is a flow lava collected less than 200 feet 

from the vent during the fourth phase of activity on 

December 4. Again, the lava consists of olivine phenocrysts in a very dark glassy to microcrystalline groundmass. The olivine phenocrysts are sparse, smaller in 

size (as much as 2 mm in diameter) than observed in 

most of the summit lavas, and are rounded and deeply 

embayed by resorption. 

Samples S-16 and S-20, erupted December 6 and 13, 

respectively, are representative of two of the shorter 

intermediate phases (fifth and ninth) of the summit 

eruption. Although sample S-16 is a pumice and sample S-20 is a pond lava collected about 750 meters from 

the vent, they are mineralogically and chemically similar. Both contain abundant large phenocrysts of 

olivine, as much as 3 mm in diameter, set in a dark 

glassy to microcrystalline groundmass. The . olivine 

phenocrysts are strikingly euhedral (fig. 4) and in sample S-20 contain 12.5 mole percent Fa (partial chemical 

analysis). 

As mentioned previously, the very small volume of 

lava erupted during the last (17th) phase of the summit 

activity also contained minor amounts of phenocrystic 

clinopyroxene and plagioclase. Sample S-25, of the 

short flow extruded during this phase, contains large 

phenocrysts of euhedral to partly rounded olivine and 

microphenocrysts of olivine, clinopyroxene, and plagioclase in a dark glassy groundmass. No attempt was 
PETROGRAPHY OF THE LAVAS D7 

FIGURE 3.-Photomicrograph of large resorbed olivine ·phenocrysts in sample S-9, erupted November 21, 1959. Matrix 

groundmass (black) contains almndant equidimensional 

vesicles (light g·ray). 

made to separate the minerals for determinative purposes. 

The general correlation between the fayalite content 

of olivine phenocrysts and <t·he temperature of their separation from the melt is in accord with the well-kno·wn 

melting relationships in the system forsterite-fayalite 

(Bowen and Schairer, 1935). In addition, the crystal 

habit of unreSOl'bed olivine crystals seems to be temperature dependent. Phenocrysts that separated from many 

of the hotter melts were large and euhedral (fig. 4), 

whereas those that separated from the cooler melts were 

small and skeletal (fig. 2). These differences in crystal 

habit are probably due in part to a decrease in the kinetics of crystallization of the slowly cooling melt and 

in part to a shorter period of growth for olivines of the 

cooler melts. Very similar differences in the habit of 

olivine phenocrysts were observed experimentally by 

Kopecky and V old an ( 1959) in their study of the crystallization of basaltic glasses at different temperatures. 

THE FLANK LAVAS 

Unlike the lavas erupted at the summit, the flank 

lavas underwent an extreme and abrupt change in composition during the course of the 5-week flank eruption 

between January 13 and February 19, 1960. Moreover, 

the early flank lavas, which contained relatively 

abundant phenocrysts of plagioclase and clinopyroxene, 

and minor olivine and hypersthene, were markedly different from any of the summit lavas; only during the 

last 2 weeks of eruption did the composition of the flank 

lavas approach that of the summit lavas (fig. 1, samples 

F-10 to F-20). The early flank lavas did, on the other 

hand, bear a remarkable mineralogical and chemical 

similarity to the late lavas of the 1955 eruption that 

occurred in the same general area of the east rift zone. 

The abrupt change in composition of the flank lavas 

occurred with dramatic suddenness on the evening of 

January 27. At 21 h45m on that date, the vents in the 

main eruptive area ceased fountaining, and for 5 minutes all was quiet. Then eruption resumed, both from 

the old vents and from a line of new vents extending 

more than 300 meters to the northeast on strike with the 

old vents. 

Almost immediately after the resumption of activity, 

a decided decrease in viscosity of the lavas was observed. 

Temperatures in the core of the fountains increased 

from 1040°C, just prior to the change in eruptive pattern, to 1060°C on the morning of January 28, a few 

hours after the change. By the morning of January 29, 

temperatures had increased still further to 1080°C, and 

large phenocrysts of olivine were abundant in the lavas. 

Both the temperature and olivine content continued to 

increase through the next week, the temperatures reaching a maximum 1125°C on February 6-the last date of 

temperature observations; a parallel drop was observed 

in silica content, from 49.87 percent on January 29 to 

48.4 percent on February 7. 

l<'rouuE 4.-Photomicrogrruph of large euhedral olivine 

phenocrysts in sample S-20, erupted December 13, 1959. 
DS THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

Flow samples F-1, -4, and -6 collected on January 

13, 18, and 21, respectively, apparently are typical of the 

early flank lavas erupted before the marked change in 

magma composition on January 27. The three samples 

are remarkably similar, both chemically and mineralogically, and do not hint at any trend by which the change 

on January 27 might have been anticipated (fig. 1). 

The rocks, which are highly vesicular, contain phenocrysts of plagioclase, clinopyroxene, olivine, and 

hypersthene, in order of decreasing abundance, set in a 

dark glassy groundmass constituting approximately 83 

percent, by volume, of the solid rock (fig. 5). 

Plagioclase, which composes more than half (52-57 

percent) of the total phenocrysts, ranges in size from 

large equant euhedral and subhedral crystals 2 mm in 

diameter to small needlelike crystals less than 0.1 mm 

long. The bulk of the plagioclase appears to fall in the 

composition range An72_66 (determined by indices of 

refraction) ; minor zoning to An64-56 was observed only 

in some of the larger crystals. Clots of plagioclase and 

clinopyroxene crystals are very common, and a few of 

the large plagioclase crystals contain small clinopyroxene inclusions in rows parallel to one or more of the 

principal plagioclase faces (fig. 5). 

Clinopyroxene occurs as euhedral to subhedral stubby 

prisms ranging in size from 1.5 to 0.1 mm in diameter. 

Simple twins are common, and a few crystals exhibit 

exsolution lamellae of orthopyroxene. The composition of the early clinopyroxene, based on the analysis of 

l<'IGURE 5.-Photomicrograph of flow ~ample F-1, erupted January 13, 1960, showing plagioclase (pi), cinopyroxene (cp), 

and olivine (ol) in dense black vesicular groundmass. Note 

the row of clinopyroxene inclusions along the bottom margin 

of the largest plagioclase phenocryst. 

a pure concentrate separated from sample F -1, is En47 _6, 

Fs123, "\iV 0 40.1. (The analysis is given by Murata and 

Richter, 1966.) 

The few olivine phenocrysts scattered through the 

early flank lavas appear to be of two distinct physical 

and chemical types, similar in some respects to those 

observed in the early summit lavas. One type occurs as 

large resorbed crystals as much as 1.2 mm in diameter, 

and the other-and possibly more common typeoccurs as small euhedral crystals less than 0.5 mm in 

length. Although it was virtually impossible to separate the two types completely, X-ray studies of handpicked larger olivine crystals from sample F-1 indicate 

a composition of Fa17, whereas the smaller, apparently 

more euhedral olivines from the same sample have a 

composition of Fa24 • A partial chemical analysis of a 

pure olivine concentrate from sample F-1, which included both large and small crystals, gave an average 

composition of Fa21 . X-ray studies of olivines from the 

other early lavas also strongly suggest that the change 

in physical type is indicative of a change in composition : large olivine phenocrysts in sample F -2 (January 

14) and sample F-6 contained Fa14 and Fa12, respectively, and small euhedral olivines in sample F-4 contained Fa2o· 

Hypersthene, the least abundant of the phenocrysts 

in the early flank lavas, was not recognized in any of the 

thin sections studied, but it was present in heavymineral fractions from all th:r:ee samples. It occurs as 

equidimensional grains as much as 1 mm in diameter, 

and probably constitutes no more than 1 percent of the 

total phenocrysts. On the basis of index of refraction 

(Ny=l.695+.005) and measured specific gravity (3.3), 

the composition of the hypersthene is approximately 

Fs2o-2s· 

Sample F-8, a pumice fragment erupted on January 

29 approximately 30 hours after the change in eruptive 

activity, gives some idea of the abruptness and magnitude of the accompanying mineralogical changes and 

decrease in silica content. Plagioclase is no longer the 

predominant phenocryst; instead three mineralsolivine, clinopyroxene, and plagioclase-are present in 

roughly equal amounts, olivine being somewhat more 

abundant than the rest. 

Many of the olivine phenocrysts have a fresh, "new" 

appearance. They occur as skeletal crystals as much as 

1.5 mm in diameter and as large euhedral crystals, which 

show slight evidence of resorption, as much as 2.5 mm 

in diameter. The composition of the olivine ranges from 

Fa12 to Fa16 (determined by index of refraction). Small 

rounded grains of olivine, as much as 0.2 mm in diameter, are also present and may represent remnants of 
PETROGRAPHY OF THE LAVAS D9 

the more fayalitic olivine of the early lavas, which had 

not been completely resorbed by the hotter melt. 

The :plagioclase phenocrysts (An12, some zoned to 

An64 ), besides being relatively abundant, also show the 

effects of the higher temperatures. The lathlike crystals 

exhibit rounded and ragged ends; some of the zoned 

crystals show selective resorption of the more calcic interiors (fig. 6). 

Clinopyro:xene in sample F -8 is the least affected of 

the phenocrystic minerals. Its mode, relative to the 

total phenocrysts, is virtually unchanged and most of 

the crystals are still euhedral; however, some exhibit 

slight rounding of the crystal faces, and a few are embayed by the groundmass glass. 

A few grains of hypersthene are present in heavymineral separates of the sample, but in amounts noticeably less than in the early lavas. 

By the next day (January 30), the effects of the compositional change and increase in temperatiure of the 

erupting lava were even more pronounced. Sample 

F-10, of a lava flow on that date, contains very abundant large slightly rounded olivine phenocrysts as much 

as 4 mm in diameter, as well as minor phenocrysts of 

plagioclase and clinopyroxene that show evidence of 

strong attack by the melt; in fact, the few plagioclase 

crystals still remaining are elongate small (less than 

1 mm long) rounded grains tha.t exhibit none of the 

selective resorption observed in the lavas of a day 

earlier (fig. 6B). One rounded crystal of olivine, 

rimmed by an overgrowth of fine-grained clinopyroxene 

(augite?) crystals, is the only evidence Olf reaction noted 

in all the flank or summit lava samples. No hypersthene 

was observed in either the thin sections or in the heavymineral separates. 

Samples collected on February 4 (F-12) and February 12 (F -16) contain 78 and 89 percent olivine, respectively, in the phenocrystic mode, and only 1 percent plagioclase. The olivine crystals continue to be 

large (as much as 3 mm in diameter) and euhedral to 

slightly rounded, whereas the minor clinopyroxene and 

rare plagioclase show more and more evidence of resorption. Composition of the rounder grains of plagioclase in sample F -14 is An1o· 

The last flow (sample F-20) extruded during the 

flank eruption on February 18 shows a slight increase in 

the phenocrystic clinopyroxene and plagioclase contents. The olivine phenocrysts (Fa12, determined by 

X-rays), although still large (as much as 4 mm in 

diameter), also show more pronounced rounding of their 

crystal form. The clinopyroxene phenocrysts are all 

rounded and have a maximum size of 0.7 mm. Some of 

the plagioclase phenocrysts (An70 , determined by index 

of refraction), on the other hand, tend to be slightly 

more euhedral, but most show the pronounced resorption characteristic of the plagioclase observed in the 

lavas of a few days earlier. A photomicrograph of a 

thin section from this February 18 flow is shown in 

figure 7. 

FIGURE 6.-Photomicrographs of resorbed plagioclase phenocrysts erupted after January 27, 1960. Compare 

with figure i'i. A (left) , Sample F-8, erupted Jan nary 29, 1960, showing selective resorption of more 

calcic interior of t be plagioclase crystal ; crossed nicols. B (right), Sample F-10, erupted January 30, 

1960, showing complete rounding of feldspar crystal; crossed nicols. 
DlO THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

FIGURE 7.- Photomicrograph of flow sample F-20, erupted 

February 18, 1960, showing olivine (ol), clinopyroxene 

(cp), and plagioclase (pi) in a dense black vesicular 

groundmass. Compare with early flank lava in figure 5. 

The mixing of magmas of different vintage, observed 

so clearly in the series of lavas of the 1960 flank eruption, emphasizes a process for which there was very 

little evidence in Hawaiian lavas studied heretofore. 

Mixed magmas have been recognized in many other 

,·olcanic provinces, such as the Medicine Lake highland 

of California (Anderson, 1941) and the San Juan region of Colorado (Larsen and others, 1938), largely by 

the presence of xenocrystic minerals in the lavas. The 

sequential changes observed petrographically in the 

1960 flank lavas, correlated with concurrent data on 

volcanic activity, lava temperature, and lava composition, provide a most vivid picture of the mixing process. 

The disso~ution of phenocrysts, especially those of 

plagioclase, in the hotter melt also raises the interesting 

possibility of Kilauea magmas becoming more salic by 

melting the more fusihle minerals of the wallrock. The 

importance of this process is difficult to assess because of 

its dependence on a complex interplay of thermal and 

chemical factors (Bowen, 1928). It probably is of only 

minor importance in tholeiitic magmas of Kilauea, as 

they genera1ly have a short residence time within the 

volcanic edifice, but it may be highly significant in the 

generation of alkalic magmas in older, less vrgorous 

Hawaiian volcanoes (Daly, 1944). 

THERMAL D.AT.A 

Besides the obvious relationship between bulk composition and the phenocrystic mineral assemblage of the 

1959-60 lavas, there is also a concomitant relationship 

between lava temperature and phenocrystic minerals. 

The 1959-60 eruption provided an excellent opportunity 

to measure lava temperatures with modern precision instruments. Temperatures were measured with incandescent filament-type optical pyrometers throughout 

each night of the eruption when and where conditions 

permitted. The methods utilized and precautions observed are outlined in the paper by Ault, Eaton, and 

Richter (1961) on lava temperatures in the 1959 summit 

phase of the eruption. Most of the temperatures were 

measured in the core of the erupting lava fountains 

whereas some of the samples studied were collected from 

flows at some distance from the fountains ; therefore, 

some of the observed temperatures were possibly higher 

than the prevailing temperatures in the sampled flows. 

Because of unassessable factors such as these, plus possible inaccuracies in the temperature measurements, it 

should be stressed that the finite temperature stability 

limits proposed for the various minerals or mineral 

assemblages be used with prudence. 

Moreover, unlike laboratory experiments in phase 

equilibria where temperature and other parameters can 

be varied or fixed as demanded, the data presented here 

are based almost entirely on the petrographic character 

of the lavas (preceding section), whose temperatures, in 

general, increased erratically from beginning to end of 

eruption. Equilibrium, therefore, was only approached 

from one direction (increasing temperatures) ; and 

where ambiguous criteria existed for establishing the 

stability or nonstability of a mineral phase in the melt, 

the final interpretation may be somewhat subjective. 

The probable temperature stability fields for the 

phenocrystic minerals in both the summit and flank 

lavas of the 1959-60 eruption are shown in figure 8. The 

summit lavas containing roughly between 47 and 49 percent Si02 have a liquidus temperature of about 1180°C, 

with magnesian olivine (Fa14_12 ) the first mineral to 

crystallize. At lower temperatures and a slightly 

greater silica content of the melt, lesser quantities of 

more fayalitic olivine (Fa1 8 _17 ) crystallize, and at about 

1120°C clinopyroxene begins to form. At 1090°C 

plagioclase (An64 ) begins to crystallize, and the 3 

minerals crystallize together. The break in the olivine 

field between noooc and 1125°C, as shown in figure 8, 

is not meant to imply a discontinuity in olivine crystallization but merely denotes a lack of mineralogical data 

for this temperature interval. Olivine, progressively 

more fayalitic, evidently forms throughout the entire 

crystallization range of the lavas. 
PETROGRAPHY OF THE LAVAS Dll 

OLIVINE __j --Summit (Fa 18_d__,_j ~ Summit(Fa14_12 ) 

--Flank (Fa 24_20) -~ Flank (Fa16) --j I I 

CLINOPYROXENE ----Summit (En 50 Fs 10 Wo40) 

-Flank (En 48 Fs12 Wo4o)~ 

PLAGIOCLASE 

--Summit (An6J 

--Flank (An72 zoned to An )~ 

HYPERSTHENE 

--Flank (Fs25_20)1 

I I I I I=:)::Jl:::::l:::::l:::::l:::::f:::::l::::::l:::::l:::::J:::::I::::::I:::::J:::!:I:!:!:f:!:!l!:!:!~:!:!:I:!:!:J!:!::I:::::~:::::~:::::i:::::l:::::t:::::l::::::i::::=l::::::l:::::l~:!:!:!:!:!:l!:!:!l!:l I 

1000 1025 1050 11075 1100 1125 1150 1175 1200 

TEMPERATURE, IN DEGREES C 

Fll~ Eruption 

Summit Eruption-------____,~ 

·I 

FIGURE B.-Temperature stability fields for the phenocrystic minerals in the summit and flank lavas of the 

1959-60 eruption. 

The liquidus temperature of the early flank lavas 

(bulk silica content, 50.4 to 50.8 percent), on the other 

hand, is apparently about 1080°0, .with olivine (Fa16) 

and clinopyroxene appearing simultaneously. Plagioclase ( An66-72 zoned to An56-64) apparently begins 

crystallization at slightly lower temperatures (1070°C) 

and hypersthene (Fs25_ 20 ) still lower at about 1060° C. 

Although abundant olivine phenocrysts with a fayalite 

content as low as Fa12 occur in the later and more mafic 

flank lavas, none appear to be in equilibrium with the 

melt. The late high-magnesian olivines are interpreted 

to be phenocrysts from a hotter, more primitive magma, 

such as that which fed the summit eruption and which 

evidently began to erupt and mix with the highly differentiated early flank lavas on January 27. Moreover, 

the minor amounts of large partially resorbed olivine 

phenocrysts (Fa1 z_17 ) in the early flank lavas are not 

considered in this attempt to deduce stability fields for 

the phenocrystic minerals. They undoubtedly are not 

in equilibrium with the enclosing melt, but may represent additions from local hot spots within the flankmngma reservoir. 

Except for olivine FRt6 from the flank forming at 

lower temperatures than olivine Fa18_ 17 from the summit and for the difference in the upper limit of stability 

in the two clinopyroxenes of virtually the same composition, the stability ranges proposed for the phenocrystic 

minerals from both eruptive phases are in general correspondence. These discrepancies may be due to errors 

in determinations of composition and temperature or to 

actual differences in the bulk composition of the two 

lavas. 

The sequence of fractional c-rystallization manifested 

by summit and flank magmas is summarized in the following table. The temperature interval through which 

a mineral separated from the magma is given; where 

only one temperature is given, it denotes the point of 

the initial separation of the mineral. 

Mineral Approximate temperature 

Summit magma: of separation ( oo.) 

Olivine, Fa12-u-------------------------------- 118().-,.1125 

Augite, Enoo;FStoW040--------------------------- 1120 

Olivine, Fa11-1s-------------------------------- 1100 

Plagioclase, An64- ___ ------_ ------------------- 1090 

Flank magmas : 

Olivine, Fa12-1s-------------------------------- 1080-1055 

Augite, En48FS:t2Wo.o ___________ .:_______________ 1080 

Plagioclase, An12-s6---------------------------- 1070 

Hypersthene, Fs2o-26--------------------------- 1060 

Olivine, Fa2o-2•-- _ ------_______ - --------------- 1055 

Qualitatively, these ther.mal data compare favorably 

with the results obtained by Yoder and Tilley (1957, 

1962) in their melting experiments on Kilauea lavas. 

Both sets of data show that in tholeiitic lavas with a 

bulk silica content below about 50.2 percent, the order 

of crystallization with decreasing tempera:tiure is: ( 1) 

oliv.ine, (2) clinopyroxene, and (3) plagioclase. However, quantitatively, the two sets of ther·mal data are 

not in good agreement; the temperatures obtained in the 

laboratory experiments are all consistently higher than 

the temperatures deduced for corresponding points in 

this study. 

Yoder and Tilley (1962) found the liquidus of the 

1921 Kilauea lava ( 49.16 percent Si02 ) to be approximately 1235° C, whereas the present study indicates 

liquidus temperatures on the order of 1180° C for lavas 

with even less Si02 • Moreover, the temperature range 

of complete crystallization, as determined in the laboratory, is relatively small: 1060° to 1235° C for the 
DI2 THE 1959-60 ERUPTION OF KILAUEA VOLCANO, HAWAII 

1921 Kilauea lava and 1065° to 119,5° .C for a prehistoric 

Kilauea lava. Yet in the 19·59-60 lavas a glassy groundmass, constituting between 80 and 90 percent of the total 

rock, is present at temperatures as low as 1030° C. Also, 

optical pyrometer measurements of temperatures within 

the centers of thick flows indicate that at temperatures 

of 950° C the lava has a sufficently low viscosity to be 

mobile. 

These differences in thermal data between laboratory 

experiments on natural rocks and those .deduced from 

field observations appear to be real. The reasons are 

probably manifold : a greater volatile content of the 

lavas in their natural environment compared to those 

remelted in the laboratory may he a deteTITiining factor, 

and the air oxidation of the samples during the melting 

experiments may be another. The fact that the com·positions of the .minerals obtained in the melting experiments are as yet unknown also precludes a close comparison between field and laboratory observations. 

'Vhatever the cause of the discrepancies, the field evidence indicates that stability temperatures of the 

crystalline phases in the naturally forming lavas are 

appreciably lower and cover a much larger range than 

those determined in laboratory phase-equilibria studies 

or in melting experiments on natural rocks. 

LITERATURE CITED 

Anderson, C. A., 1941, Volcanoes of the Medicine Lake highland, 

California: California Univ., Dept. Geol. Sci. Bull., v. 25, 

no. 7, p. 347-422. 

Ault, 'V. U., Eaton, .J.P., and Richter, D. H., 1961, Lava temperattnes in the 1959 Kilauea eruption and cooling la~e: Geol. 

Soc. America Bull., v. 72, no. 5, p. 791-794. 

Bowen, N. L., 1928, The evolution of the igneous rocks: Princeton, N.J., Princeton Univ. Press, 334 p. 

Bowen, N. L., and Schairer, J. F., 1935, The system Mg0-Fe0-

Si02: Am. Jour. Sci., ser. 5, v. 29, no. 170, p. 151-217. 

Chudoba, K. F., and Frechen, Josef, 1943, Der Einfluss der 

Temperatur auf die Beziehung ~wischen Optik und Chemismus der Olivine: Neues .Jahrb. Mineralogie Monatsh., Abt. 

A, H. 6, 'P· 91-106. 

Daly, R. A., 1944, Volcanism and petrogenesis as illustrated in 

the Hawaiian Islands: Geol. Soc. America Bull., v. 55, no. 

12, p. 1363-1399. 

Kopecky, Lubomfr, and Vold{tn, Jan, 1959, Crystallization of 

melted rocks: Geotechnica (Czechoslovakia, Ustl'ed. Dstav 

Geol.) v. 25, 218 p. (Czech., English summary). 

Larsen, E. S., Irving, John, Gonyer, F. A., and Larsen, E. S., 

3d, 1938, Petrologic results of a study of the minerals from 

the Tertiary volcanic rocks of the San Juan region, 

Colorado: Am. Mineralogist, v. 23, no. 4, p. 227....:.257. 

Macdonald, G. A., 1944, The 1840 eruption and crystal differentiation in the Kilauean magma column [Hawaii] : Am. Jour. 

Sci., v. 242, no. 4, p.177-189. 

---1949a, Petrography of the Island of Hawaii: U.S. Geol. 

Survey Prof. Paper 214-D, p. 51-96. 

---1949b, Hawaiian petrographic province : Geol. Soc. 

America Bull., v. 60, no. 10, p. 1541-1595. 

---1955, Hawaiian Islands, Pt. 3 of Catalogue of the active 

volcanoes of the world including solfatara fields: Naples, 

Italy, Internat. Volcanol. Assoc., 37 p. 

Macdonald, G. A., and Eaton, J. P., 1957, Hawaiian volcanoes 

during 1954: .. U.S. Geol. Survey Bull. 1061-B, p. 17-72. 

Macdonald, G. A., and Katsura, Takashi, 1961, Variations in the 

lava of the 1959 eruption in Kilauea Iki: Pacific Sci., v. 15, 

no. 3, p. 358-369. 

Muir, I. D., and Tilley, C. E., 1957, The picrite-basalts of Kilauea, 

[Pt.] 1 of Contributions to the petrology of Hawaiian 

basalts: Am. Jour. Sci., v. 255, no. 4, p. 241-253. 

--1963, The tholeiitic basalts of Mauna Loa and Kilauea 

[Pt.] 2 of Contributions to the petrology of Hawaiian basalts: Am. Jour. Sci., v. 261, no. 2, p. 111-128. 

Murata, K. J., and Richter, D. H., 1966, Chemistry of the lavas 

of the 1959--60 eruption of Kilauea volcano, Hawaii: U.S. 

Geol. Survey Prof. Paper 537-A. (In press.) 

Powers, H. A., 1955, Composition and origin of basaltic magma 

of the Hawai-ian Islands: Geochim. et Cosmochim. Acta, v. 

7,nos.1-2,p.77-107. 

Richter, D. H., and Moore, J. G., 1966, Petrology of the Kilauea 

Iki lava lake, Hawaii: U.S. Geol. Survey Prof. Paper 537-

B, p. (In press.) 

Stearns, H. T., and Macdonald, G. A., 1946, Geology and groundwater resources of the Island of HawaH: Hawaii Div. 

Hydrography Bull. 9, 363 p. 

Tilley, C. E., 1950, Some aspects of magmatic evolution [presidential address] : Geol. Soc. London Quart. Jour., v. 106, pt. 

1, no. 421, p. 37-61. 

---1960, Differentiation of Hawaiian basalts-some variants 

in lava suites of dated Kilauean eruptions: Jour. Petrology, 

v.1,no. 1,p.47-55. 

Tilley, C. E., and Scoon, J. H., 1961, Differentiation of Hawaiian 

basalts-trends of Mauna Loa and Kilauea historic magma: 

Am. Jour. Sci., v. 259, no. 1, p. 6Q-68. 

Yoder, H. S., Jr., and Sahama, T. G., 1957, Olivine x-ray determinative curve: Am. Mineralogist, v. 42, nos. 7-8, p. 475-491. 

Yoder, H. S., Jr., and Tilley, C. E., 1957, Basalt magmas: 

Oarnegie Inst. Washington, Geophys. Lab. Ann. Rept. 1956--

1957, p.156-161. 

--1962, Origin of basalt magmas : an experimental study 

of natural and synthetic rock systems: Jour. Petrology, v. 3, 

no. 3, p. 342-532. 

U.S. GOVERNMENT PRINTING OFFICE: 1966 0- 792-271 
./ 

CHRONOLOGICAL NARRATIVE 

The 1959-60 Eruption 

of Kilauea Volcano 

Hawaii 
Lava fountain, 900 feet high, and full lava lake during the eighth phase of the summit eruption in Kilauea lki Crater. The 

tops of rising lava jets appear as bright-orange patches through a shroud of cooler, darker falling clots of pumice, and 

a brown cloud of still cooler pumice fragments and dust drifts downwind left of the fountain. Sulfurous bluish fume rises 

from a floating island of cinder and pumice detached from the cone during the third phase. View west from Byron Ledge 

overlook. The slope of Mauna Loa rises gradually to the right in the background.