1978LPSC....9.1053F Abstract-The considered Silicate and or complex information include metallic metamorphosed , population population parent silicate evolutionary fragments ites are differentiation clasts. magmatic majority of morphism understood. Oak Union Floran A *Present The modified the highly Ridge, comparison © (6 body, Carbide Lunar impact mesosiderites mesosiderites fractions et assemblage of and falls, described in of evolved annealed and address: petrography, a on Tennessee al., rock include mesosiderites Department (Powell, most differentiation, individual close and events classification the Much Corporation melts. metallic history consist mesosiderites 1978b) with types can 14 were mesosiderites distribution Planetary . genetic Environmental , by crystalline of be produced inferred finds) 37830. A Warner such additional mesosiderites. 1969, mixed of , of related of comprise petrographic and support contain relationship portions orthopyroxene, Review of Mineral under Proc. as differentiated Institute lack mesosiderites of Variable as that classification, cumulate their lunar 1971). et metaeucrites, the matrix and Lunar to brecciation, magmatic lithic, solids. al. New Printed contract Sciences variations both a this diverse Sciences, the petrochemical a (1977). analogs Planet. can significant relationships are and study R. • is York, relatively INTRODUCTION Ongoing and recrystallization subsequent in , diogenitic Although Provided complex uncertain. the J. Sci. , W-7405-eng-26 differentiates potentially Division, preserved proposed suite new metal Textural of United in New indicates recrystallized American FLORAN* 1053 planetary Conf metal-silicate the all and melt basaltic of States York petrologic similar 9th by small observations clasts. and and metamorphism 20 plagioclase/pyroxene Differences record Oak volcanic-plutonic by may observations (1978), component to the data that mesosiderites and of Powell Museum eucritic of a and 10024 eucrites America other origin Ridge NASA shed Mineral be clast but bodies. with breccias, silicate succession p. the olivine. of polymict is 1053-1081. meteoritic (1971) studies important in National events. required bulk types the clasts. Astrophysics of much and mixing, indicating suggest the of of matrices fragments Natural Within U.S. Lithic and reveals of dunites, the breccias is occur Ca/ rock the The modified the equivalents (Nehru However, ratio impact-melt of Laboratory group Department light that Al to clasts, and associations History occurred that group mesosiderites mesosiderites: in that occurrence events groups ratios as their dominate on as Data the understand mesosiderites indicate well on and well the the burial most matrices et which of System of of brecciated as (operated expanded the the silicate al., after of as breccias. involving is howardites secondary contain granulitic meteor- that found the Energy), the of poorly provide origin meta- can 1978; early of major lithic clast clast they the and and the by be as to A a 1978LPSC....9.1053F evolution of crystallized 1054 events dominant larger many mesosiderites meteorites. resulted planets processes by belt coherent ites groups. several mesosiderites then-known which mesosiderites,, ( extends among and Hewins the several (1969, especially existing 20 key (1977, 1921 placed body 1974). 1962) The This As which collisional-fragmentation mesosiderites, impact-melt to were is Hewins © ), (Floran noted Lunar unanswered shown -the unravelling provided were was on 1978) and first mesosiderites, 1971) mesosiderites. (Wetherill, of Most et Our paper and in in group of examined is role including the them, al. critical Impact Duke plutonic probably or the primordial nine and modern modifies a (1978) later knowledge by by (1977) on recently, and and detailed but clast-laden that including igneous-textured presents were group Planetary excellent origin the and Powell Rb/Sr, mesosiderites. and and Prinz, in complemented both the although impact 1976), first-order cratering on in present given impact and and the attempts determining insufficient the Silver presumed related Recent as history of offers textural, detail containing the Mittlefehldt melting studies of Institute the (1969), all and a distribution Nehru Simondium, 1978). and volcanic classification nature SILICATE-METAL but whole by processes mesosiderites cooling of size (1967) processes the melting, results some 40 except meteoritic perceptive studies is Prior, of the questions Ar- those to During were et mineralogical, now matrix. source • this and scope distribution of as textural to by accretional discuss R. Provided the 39 al. environments numerous tentative history the Ar well touched who cause have J. Mount group. of (1977) that of recognized and primarily Ni, igneous (1978) Hainholz, relative (Chapman, and FLORAN scheme systematics of the mesosiderites, bodies individual petrographic groups, Powell as a in remain, was relative played Ga, Powell and the by his of petrographic total that next a RELATIONS the The upon Padbury conclusions the has of on series significantly energy Emery; clast investigation differentiation origin importance Ge of proposed chemical, other of the concerned (1969, NASA the parent-source and and 50 nature or as within in determined had especially the differentiated abundances individual mesosiderites 1976). and of of years asteroids types petrology the even a Pinnaroo; lunar accompanying descriptions data petrology of Floran Astrophysics (McCall, papers Estherville. the fundamental examined 1971) of evolution Ir the by the reconnaissance regarding partial none and impact-melt within the advanced data of breccias. with are Powell remains the mesosiderite mesosiderites, et which (Prior, mesosiderites of various of REE studied clast cooling of and of bodies and not al. 1966). Emery; meteorites. on include those include other (Wasson role clast Data the melting a of the of Murthy (1978a,b) (1971) population relationships process is variably origin metal such patterns definitive the Emphasis seven 1910; 1918; 1910; by impressive, moon mesosider- System rock of ten controlled rate types for meteorite origin Lovering Kulpecz Powell's impact impact survey, of parent of et of of in these to types data, et each as that The as and the the al., the the re- for for al. all on 17 of m is is a a 1978LPSC....9.1053F settling solid favored metal assumed in interpreted that that below, clasts during depositional meteorite random be contain is (1963), from meteorites weight. 1972) mineral however, found also apatite)*, Patwar; typically secondary farringtonite and decreasing been possibly (Ramdohr, 1965); * the Mesosiderites a valid As © occur zircon were gradation or in metal suggested reported in solid observed Lunar is in Powell's deposition magnetite the liquid silicate and a magnetic for Considerable Crab compatible Estherville phases stanfieldite to in as Barea, solid-state present was intimately in augite, mineral consisting state. question in order be all to clasts all and their pointed 1965), in Silicate virtually in state by Vaca correct formed. Orchard, be metamorphosed in from origin inclusions by interpretation mesosiderites, Planetary Mincy PETROGRAPHY generally Dowty Dyarrl are For well-sorted of polarity impact in with some (Powell of schreibersite, Powell formed at petrography, (see and Muerta with as out origin abundance: in mixed trace the Crab the low-Ca of the for or variation all (1977), (Malissa, These to silicate Estherville mesosiderites, Institute by roughly Island Fig. due Vaca Bondoc purposes either mesosiderites metal. the whether time (Fig. melts. (but of and present (Powell, amounts by Orchard, Mason as (Marvin metal nature the bulk to 3, clasts of pyroxene, is classification, solids terrestrial of inclusions not Weiblen, mesosiderites, OF l; Muerta, and a Powell, term metamorphic in a • A ilmenite, However, troilite, a 1974); sphalerite one-half mixing Axon metallic (Wilson, Provided solid-state the of MATRIX of observed in major nodules the and directional (Fuchs, have 1971). are Emery merrillite (Fig. the the (Powell, and Mount metal all especially proportions (Floran and Jarosewich indicative 1971), mesosiderites. present plagioclase, Veramin, with tridymite, a 1967) weathering, to mesosiderites and factor Klein, by silicates liquid, and 1). The AND directional the in Nasir, 1972). metal-rich (Mason component in 1969) is the origin origin and Padbury, silicate Bondoc, Wilson reorganization. used 1971). the fabric but rutile; relatively et 3-dimensional and CLASSIFICATION NASA discussion contributing 1964). or the is of al., in of in Bondoc 1977; and is and for The (1973). and of chromite, not extreme copper the and a Pinnaroo preference is material, olivine-bearing, Astrophysics is highly (1972) as In 1978a) the lineation solid first the metal This assumption silicate one-half uncertain of Bondoc mesosiderites Pinnaroo, true include, Magnetite also Dalgaranga presence Powell, is addition, Jarosewich, large mesosiderites latter metallic mesosiderite; reported and lawrencite Minor state (Ramdohr, of plastic recrystallized observed has and to appear Metal interconnection to merrillite (Ramdohr, clasts although the for metal that whitlockite. (Wilson, Ni-Fe 1971) in two Data at the shown whether silicates of and Vaca reasons mesosiderites component graphite is the approximate deformation by was clasts to (Fig. steady (Ramdohr, System lawrencite, probably phases 1973) "nodules" stony-iron which for and accessory Nininger metal time be 1965) was may that Wilson, he (and/or Muerta formed 1972); 1965); this metal clasts given 1). exist, often there ones, later 1055 in this was and and not the has are by of in is is a a 1978LPSC....9.1053F

0 -V, O'I

@ r' = ""I § Q. "t:I § .....re .... 1;l.....

.....re • "t:I 8 'Tl s:re s Q. > C" z '-<..... =-re z >00. > > "'q '§. '-< "'n... "' ael Fig. 1. Photograph of polished surface of Emery mesosiderite. Matrix consists of intimate mixture of fine-grained metal (white) 00. '-< and silicates (dark). Visible clasts include metal (right) and large fragment with thin metalliferous vein (left). Most ;;-"' silicate clasts do not exhibit sharp boundaries with matrix and some contain numerous minute inclusions of metal. Maximum = dimension: about 10 cm. 1978LPSC....9.1053F relationships, representing such included various these among pyroxene In vided Subgroups (3) except incorporates plagioclase continued disintegration continued either light mesosiderite petrographic Clarke, (1971) Crab Chinguetti Patwar Mount Dyarrl Barea Vaca Not tUnidentified *Powell's On In © general, grain recrystallized (1935, Lunar Subgroup as Table a classified: meteorites Orchard Muerta the pers. on slightly Island that subgroups. Pad new and subgroups the (1) relations, (1971) textural 1962 basis and bury cannot boundary comm., the mesosiderite 1, poikiloblastic Ramdohr nature lA subgroup (1) degree an mesosiderite, Silicate (1) 1 the descriptions Powell Dalgaranga Planetary Table 2, respectively) ( same 1) a subgroups of implied be and 1978). and main revised related and various of grounds and IA. petrography, of criteria divided contacts, more A. B. the or (1965). 3 3, Institute preservation Classification other Metamorphic due ( elements part recrystallized remain given sequence Veramin possibly of Subgroup Clover 6) which to moderately well classification clast (PLAG of either petrographic to many of extent clearly have into the after individual in weathered petrographic West classification, • Springs (4) population parentheses. is a (2) Provided mesosiderites Lowicz essentially 2 been the the fragment members of highly of of Point of POIK) scale delineates of the West Powell's increasing coronal pyroxene nature brecciated used or for collection, mesosiderites phases by criteria, Emery A. of B. recrystallized, Point and of further all mesosiderites. the features of recrystallized in intact of [Plag Lowicz Emery Mincy Budulan Bondoc Morristown t(West [Px Subgroup textural Morristown origin development into NASA 20 available this this differences collection highly scheme. because Poiks] the U.S. poikiloblastic recrystallization. Poiks] mesosiderites dealing texture, (3) (3) three study. elucidates of Point) meteorite as (silicate reader Astrophysics National are 3 the heterogeneity, both specimen. defined (3) was (found, Silicate mesosiderites illustrated metamorphic has Additional primarily Moderately portion).* of as (2) donated around is Museum; these been group. well Igneous, the 1887); referred silicate by (PX Simondium Pinnaroo within several and Estherville? Hainholz Data is textures meteorites Subgroup petrogenesis to Powell presented These further as Crab olivine impact in the this the System melts with For POIK) information Metaigneous Patwar (5) clasts similarities grain subgroups Figs. metamor- to USNM meteorite West (2) Orchard detailed criteria low-Ca (1) matrix ( 4 Powell of came clasts. subdi- 1971) size, 2-4. Point that 1057 and the (R. of to is

1978LPSC....9.1053F

1058 1058

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the the (a) (a) 1978LPSC....9.1053F olivine Note lower nicols; blastic (c) © Lunar Highly optical right). width clast, within texture, Silicate and recrystallized = outlined continuity Most coarser Planetary 3.0 Budulan. petrography, mm. of anhedral by the between (d) chromite Numerous Institute mesosiderite, field Highly classification, plagioclase; of pyroxene view (black) recrystallized • rounded Provided Lowicz, consists clasts is transmitted and present granules by of origin with and mesosiderite the a at single inclusion-rich pyroxene NASA of of light; upper the orthopyroxene pyroxene width mesosiderites with Astrophysics right; poikiloblastic plagioclase = overgrowths partially crystal. 2.3 are mm. Data enclosed texture. poikilo- Former crossed (left, System 1059 1978LPSC....9.1053F

1060

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1061 1978LPSC....9.1053F 1062 olivine Fig. reaction Fig. © Lunar 4a. 4b. grain corona Poikiloblastic Same and is left Planetary view, is outlined recrystallized and crossed center orthopyroxene by Institute distribution are nicols. to in several R. • optical pseudomorphous Olivine Provided J. mm. FLORAN of coarse pyroxene continuity; chromite; is by completely the after width transmitted NASA poikiloblasts. olivine replaced = Astrophysics 3.0 in mm. light; and Emery. Dark width fine-grained Data Original grains = System 3.0 at 1978LPSC....9.1053F

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1063 1978LPSC....9.1053F of and of the with mesosiderites has phosed Powell's tallization 1064 shown is that the mineral Spectacular subgroup (Floran coronas Padbury), Vaca Coronal appears development Lowicz), remnants are dissolution. the has reaction impact generally Hainholz), matrix rocks. (Fig. melts. possibility acoording meteorites 1975). Although not At An textural these distribution been completely PLAG mesosiderites, possibility © these an ragged, 4a,b). least Muerta). a Lunar Coronal alternate to In meteorites, These reactions impact-melt consistent et melts abundances; to development mesosiderites, is criteria rims highly added be this of acknowledged 3, to mantles to processes. that al., one reorganization be although POIK and variable Powell Outlines and largely development olivine recrystallized, but their variable is irregular as related scheme, "metamorphosed 1978b). and of (Simonds that In members development, absent Planetary replaced of variable to that classification well absent in are Powell's mesosiderites subgroup metamorphic indicator chromite. accommodate Clover are there (1971) successful remain. similar Apollo some origin. it Another of thus within observed to (Patwar), of as potentially is clearly metaigneous in Simondium, former outlines Institute from concentration to highly of individual (Morristown) by are recrystallized of et the and Springs observed criteria, drew of clast-laden represent A 14 subgroup 3, of coronas Some these one al., each As especially problems the impact-melt problem detailed extensive his developed in appear crystalline is progressive olivine in variable respectively. attention characteristics; to breccias" • noted or categorizing suggestive clast-laden, presented 1977), influenced mantles subgroup subgroup subgroup Provided R. olivine and clearly the group relationships clasts more mesosiderites Hainholz around J. subsolidus 1 to clasts, mineralogic impact extent gradients is FLORAN elsewhere Veramin, or may in coronas impact-melt with in be in failure though grains, to matrix not mm-sized developed and occurs by with subgroup recrystallization. Estherville. have mesosiderites subgroup textural 1 in be the 2. 1 A of the however, olivine by this of igneous ranged observed similarities melts. and mesosiderites new shown In Table within the petrographic NASA are close reequilibration. an been reaction of at pre-metamorphic along represent breccias in may (Floran the such actuality, classification. and the Pinnaroo, inferred the major present Emery unstable precursors orthopyroxene (Chinguetti, 1, in clasts from resemblance between 1, Astrophysics reinterpreted to and olivine-matrix lB only are In classification individual is with petrologic (Mincy). as olivine-matrix terrestrial extensively be (Simondium, coronas these meteorites very and et subgroup, (Cameron which perfectly Hainholz metaigneous slight an where partly recrystallized but Powell melt is surrounding al., the may features is differences phase intermediate similar disregarded. variable of given 1978b), development This First, Data history anticipates (Barea, around Crab often report the reflect mesosiderites. eventually metamorphic textures (1971) developed preserved poikiloblasts as are subgroup to and undergoing reaction System variability PX to boundary. consistent elsewhere Pinnaroo, clast-rich allow Orchard, many only textured (Emery, grouped of of coronal olivine- matrix, olivine, recrys- among Mount impact Fisher, olivine POIK noted three these these level tiny and The the for be by of of in 4, is 1978LPSC....9.1053F rather originally interesting the mesosiderites within rare, not noted, boundary evidence are angular cores Estherville tory, moderately roxene (2) ( Crab In several 1) Crab Chinquetti Patwar Dyarrl Barea Vaca within and Mount In Members addition, impact recrystallized as highly a extremely © Subgroup Crab the with and Orchard Orchard or Muerta slightly Lunar Patwar than pyroxene. Island pronounced obvious Padbury clasts grains {l) and clasts clasts. alternate for Orchard contacts (6) suggested Table a to tentatively melts irregular to recrystallized and (1) do of their some subgroup (1) 1 Silicate is that reaction note (Fig. (1) subgroup have as subgroup fine-grained Planetary not 1B. not These while former in of classification, may tend that Alternate evident petrography, elastic 2a). partially by resemble in the the A. B. is 3 coronas others Metamorphic represent observations to Powell recrystallized some shape Institute Veramin Subgroup The Hainholz Clover 1 moderately designation included subgroup pyroxene existence 1 be nature (cf., and texture, are classification comminuted sutured, fine-grained recrystallized olivines appear Springs classification, but (1971). the Powell, around characterized many (2) • (2) Estherville 2 incipient of with Provided being optically clasts 1 fine-grained are as Hainholz (Table to mesosiderites, (4) clasts lack of the olivine 1971, compatible, observed have the A. B. a textural have matrices and by development silicates impact coronas concentration to recrystallized mesosiderites [Plag Emery Estherville is Lowicz Bondoc Budulan Morristown tWest Mincy [Px Subgroup are continuous lB). the origin Table been plagioclase, by tentatively highly are narrow, would Poiks] subrounded NASA Poiks] mantles very Point heterogeneity, (3) In (3) in of melts highly of completely and 4) are though (5) 3 the the ( some the 1) Astrophysics (3) place fine-grained for (silicate inclusion-filled of mesosiderites have pigeonite with not (Table preferred of assigned variable, slightly of the opaque-filled the mesosiderites not tiny rather it present, ragged subgroup portion). the PX following replaced, in entirely IA). while chromite Subgroup Data Simondium Pinnaroo subgroup POIK inclusion-poor appears to Igneous than recrystallized classification, impact as matrices melts subgroup edges System previously present, (3) rims orthopy- angular, satisfac- the reasons: 1. texture. such 4 grains grain to as It only 2 1065 that and be as as in is is 3 1978LPSC....9.1053F 1066 Springs slightly tive removed with poikiloblasts poorly forms associated anhedral discrete should the recrystallized poikiloblasts poikiloblasts observed described lunar In rounded plagioclase be polarized se Fig. (see Hainholz, typical the no two Simondium. siderite anhedral clasts PLAG recognizable Floran pyroxene ~ inclusions, plagioclase 100-200 Subgroup Pyroxene The impact recrystallization, the highly poikiloblasts, textures © mesosiderites the breccias a Lunar or developed. silicate et of PLAG POIK coarser not is with masses, connecting granules and plagioclase, in 4, and light al. by part and melts terrestrial display inclusion-poor new with variable and microns clasts. (Fig. Powell, and POIK of Bondoc. be 2 is, (Fig. In Bence but reclassified 1978a,b). a igneous lathy matrix fractions have mesosiderites. has but Veramin and subhedral of POIK orthopyroxene pyroxene grained to unique Planetary contrast, and confused allowing 2d). is while often igneous 2c), some the classified two is mesosiderites response Hainholz, plagioclase. et network been rare long. 1971). hence extensive and tridymite, This well grains. Plagioclase texture, al. mesosiderites both matrix. The texture of members poikilitically in PX extent, (Fig. Institute as or convincingly "necklaces" lunar Estherville pyroxene (1972). cores subgroup Other displayed textures mineral are with Lowicz texture The a POIK high as absent of between as subgroup Many The 2b) although recrystallization, that more coarse similar clasts impact-melt controlled chromite, that Much However, metaigneous, silicate • of the clast grains are as and Despite R. poikiloblasts Provided poikiloblasts and similar and is has inclusions poikiloblasts in 4 accurately rounded of in J. it does orthopyroxene enveloped is Apollo characterized to not pyroxenes anhedral overgrowths mesosiderites, are Clover demonstrated contents clast FLORAN of did reflected inverted PLAG to 4 the a Morristown also portions thermal consist metaigneous highly always troilite occasionally the not an it by by the to in larger cores. is rocks moderately the those inferred Springs metal 16 clasts, Powell's only resemble coarser POIK not including intergranular termed of up within from partial contain of NASA light. which recrystallized to effects of and obvious pyroxene Hainholz (Floran clear pyroxene to Variations of microophitic achieve Hainholz abundance; the by most and occurs by textures pigeonite rare and 5 terrestrial (Fig. Astrophysics metamorphic mesosiderite. observed polysynthetically poikilitic-matrix plagioclase classification, tends mm-sized checkerboard mm Simonds of PX whether either numerous to recrystallized, tiny metal in metal; the et as a 3c) cm-sized and as optically POIK poikiloblastic in grains lesser transmitted, basaltic to al., partially of in melt smaller plagioclase clast-laden the are is length numerous, in limit near basalts occurs Simondium these intergrowths subgroup et exsolved the Data common 1978c). orthopyroxene Emery, similar extent PX mesosiderites contains inclusions al. contain (i.e., origin, The dimensions but size the continuous melting) the System texture have grains (1972) POIK irregular retains has breccias. in (Fig. twinned distinc- little rims Clover size that Of augite of plane- to in a metal meso- 3 small laths, rocks these been been both tiny few and · but the the the the are 3a; of of or to or of of of of is a 1978LPSC....9.1053F

include hypervelocity tentatively

ene,

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Crab

fragments

track

2)

metal.

in

and

unmelted

examination were

to

may

clast

undulatory

Anders,

under

to

of

include

recrystallized

was

Institute

whose

kamacite

are

Jain

lunar

PETROGRAPHY

small

certainly

that

terrestrial

a

are

Orchard,

that

400

et

extinction;

ages

planar

plagioclase

found

of be

number

Identification types mosaic

examination,

classification,

al.

due

aggregates

broadly

considered

not

and

have

kilobars,

static

thermally

Reheating

Chinguetti

or

with

igneous size

study (140 to

low-Ca

(1968),

1976).

•

Strong

to

lamellae

terrestrial abundant

to

Provided

completely

although

of

data

Lipshutz

is

extinction

that

plagioclase

and

in been

of

reheating

individual

gabbroic

orthopyroxenite

±

non-representative

one

mosaicism

conditions,

defined

of

mineral

which

but

nature

40

textures,

Of

and

sources.

and

OF

resemblance

pyroxene,

concluded

(Fig.

definitive

Dalgaranga

shock

or

recrystallized

identified

additional

when

m.y.)

by

of

by

in that

CLASTS

are

uncertain

origin

in

more

analogs,

Axon

they

(1973)

the

orthopyroxene;

lithic

mosaic

that

melted

a

textures;

the of

below

as 3b).

and

mesosiderites.

within

not

was

effects

NASA

available,

and

and

late

of

It

while

polished

most

may

thus

medium

and

is

mesosiderites

evidence

plagioclase,

the

that

lithic

should

in

clasts

typical

"Anorthositic"

estimated

cosmic

present

recrystallization

samples

examined

such

pyroxene

450°C

to

silicate

impact

significance

Astrophysics

and

mesosiderites

had

each

a

Nasir

recognizable,

well

maskelynite.

are implying

mesosiderites.

similarly,

these

-rich

of

cumulate

clasts.

as

is

and

thin

be

the

basalt

experienced

of

to

mesosiderite

ray

invariably

of

be

in

following

based

the

and

(1977)

inclusions

For

probably

is

is

noted

true

main

literature

on coarse

is origin

sections

olivine

olivine,

measured

present

exposures

These

but

equivalence

supported

likely

Data rare

accompanied

a

example,

metaeucrites

eucrite

is

the

respectively.

on

clasts

anorthosite

have

concluded

mass; non-shock

that

A

have

the

in

cumulate

System

during

checker-

clasts

features

basis

grained,

a

McCall textural

of

abseµt,

formed

similar

various

to

pyrox-

in

within

shock

shock

based refer-

wide-

these

been clast

each

ages been

have

only

1067

as

add

this

the

by

of

of

of

a

a 1978LPSC....9.1053F 1068 eucrites. likely grained may but examination origin However, classified thosite" hand 01 melt (1966), Subgroup Chingetti Crab Dyarrl Barea Patwar Vaca Subgroup Subgroup Mt. Veramin Clover Emery Lowicz Subgroup Budulan Morristown Bondoc Mincy UnKnown, Simondium Hainholz Pinnaroo ?Dalgaranga ?Estherville Based = may breccia; © Padburgy specimens well olivine, Orchard Muerta to (2) Lunar for 3 Springs (2) Island (5) Wasson (plagioclase-rich (2) on (2) (3) as (2) recrystallized (3) be be For (3) (1 (3) 2 1 3 4 be studies coarse-grained a fragment-laden Wt ) (2) (2) RB (4) Di high considered the (2) and (3) (1) present (2) (4) these Table of Pt with (3) (1974), = = grade source Planetary (1) of diogenite; their recrystallized supportive 2. 52 reasons 4 in Clast mesosiderite. Px polished McCall Iithic X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X matrices non-representative, rocks and Mineral some E Institute Pl plagioclase types clasts clasts); = they data, impact-melt breccia. (1965), thin eucrite; of mesosiderites. 01 ?X X in X X X X X X X X X X X X X X most where are in sections mesosiderites • is Du Di ?X R. Provided 5 X X X For X reflected X EC suggested Prior best = J. derived olivine noted, "dunite" the = ?X FLORAN (number E X X X X X (1918). described cumulate breccia 5 purposes cumulate by from EC Dunite (mineral X X X X clasts. X X light by the by (olivine-rich Px for the the NASA eucrite; ME the clasts ?X of = each X X as Lithic (Figs. literature; The clasts Ca-poor this fragmentation eucrite presence plagioclase-rich A lithic X X X X X X X X X X X mesosiderite Astrophysics ME table, is distinction lithic 4c,d). are ?X Du often pyroxene; X X xi > X X X = X 1 fragments. Dalgaranga Lacroix metal). metaeucrite; rather clasts); of ?X3 RB X X X X X An indicated in tiny Data of parentheses) Pl= between (1924); IMB impact-melt rare IMB ?X lithic anorthosite plagioclase System is (Fig. A plagioclase; tentatively = but = 2 Metal by McCall clasts impact "anor- X xi X X X X X X X X X x4 X X X X X X fine- 3c). are and an 1978LPSC....9.1053F laths commonly a defined metamorphosed texture. the mineral more (Fig. rocks sensitive A The (I) (2) (3) ( present 4) general in numerous 1). prior © following The type a pyroxene, in PLAG rich fragments amounts common cumulate of The grained, Budulan, and least igneous-textured Padbury three mesosiderites. mesosiderites, to above important Island, their matrix be (Wasson, Lithic Metal nodules Breccia clasts Lunar sampling most indicator clasts served diogenites. be to most grain subgroup although Patwar. mineral matrices. 2 relationship Silicate metamorphic and meteorites brecciation silicate are clasts clasts mesosiderites, metal. Budulan, POIK than clasts mesosiderites basaltic-textured that as observations of breccias. (McCall, and lithic common Planetary 1974, as plagioclase, source far of eucrites size problem, clasts earlier-formed of petrography, nuclei are orthopyroxene recognizable are have Mincy clast more the Rare, pigeonite without 1 clasts textures elastic Plagioclase-rich As In relative clast Fig. mesosiderites. best and is (target) matrices physically most but and noted that Institute Patwar, lithic for been 1966). Metal with difficult abundant population XIV-3), subgroups may olivine-rich preserved it that Simondium. types vs. Emery are these but mixing. and obvious classification, the appears thoroughly is to (Table occurs by clast melt identified high rock. be eucrites apparent worth metal • were Recrystallized the the growth mesosiderites. clasts olivine. suggestive Phinney slightly were are in to Provided separated significant. contain (Hewins type than origin. igneous-textured apparent assess coarse in Plagioclase Clover The and modal probably is 1). to lithic but selectively clasts. noting not substantial fragments are are and is This of described dominated be Orthopyroxene lithic in from Other therefore apparent et by recrystallized diogenite. are metal-silicate In matrix positively but origin a true grained clasts al. every of et angular the Springs plagioclase from This indicates that major these Although lack clasts most an derived al., However, may impact (I breccia NASA and of of 977), replaced examination relationship, of these phases, finer mesosiderite are lack the amounts most 1977) clasts (dunite) of every clast be by Most prevalent which which identified. olivine to matrices Astrophysics and mesosiderites one from that also due feldspar melting clasts of their three grained three abundant segregations is breccia subrounded, contents. these type individual and may mesosiderite metal coarse producing Emery, or or the are in to solid in the abundant, clasts occur absence both are turn in Mount sampling. meteorites invaded phases: are several of in are those dominant in occur morphology fragmentation except (Fig. nodules of Dyarrl matrix Data metal single clasts part, Table found classified subgroup in are more while are in the These in fragments in a subgroup that System Padbury could in Bondoc, 4d). eucrite- sharply quench present low-Ca usually reflects several was by crystal is Mount as Dyarrl source Island 2: retain metal in likely in trace clast have finer may that 1069 are hot are the At all be an as is 1 1978LPSC....9.1053F 1070 near-surface brecciated formation complex necessary in grade ites howardites. phosed POIK LL 4 the may their recrystallization have recrystallization. erites fact, of (Dodd absence The The Petrographic the possibly Mincy (5) 7 as PLAG © . be led their near-perfect (Table H, Lunar mesosiderite variety impact textures. et clasts coarse a destruction lization monomineral material monomineralic, mesosiderites eucrite and of There 1 mesosiderites inferred present of to history mesosiderites. L, recognizable al., clast (the of inferred to recognizable appearance development equivalent POIK However, LL PLAG and lunar 1) except environments 1975; are of pyroxene account melts and only tends types As 3 Planetary is observations and which outlined sequence textures The of Portions -- distinct not preservation breccias texture with cumulate equivalence POIK PLAG of clast can Berkley for matrix (Floran is 6 clasts to is not matrix well the clast to slight, at somewhat This is premetamorphic of for polycrystalline obliterate diogenites. poikiloblasts the plagioclase of DISCUSSION Institute be found and by + recognition high the differences established, the of mesosiderites; of the are POIK and as matrix derived the chondrites, is by Powell population et eucrite suggest et clast texture despite Emery increasing well perfectly consistent PX melted mesosiderites of not al., grade in in terrestrial al., the • metal-deficient (Van relict the he analogous metamorphic R. Provided the POIK types, In as represented 1976) pyroxene clasts ( 1978a,b) from fragments same AND J. 1971) studied) but extensive that are primary of of result in contrast, PLAG breccia despite or FLORAN fragments. Schmus uncertainty clast-matrix dominated preserved. clast-laden, the Crab particularly texture, with the recrystallization textures CONCLUSIONS informative the classified in impactites. ultrametamorphosed a two by kinds for in lower to the clast the indicate original of adds POIK as PLAG the clasts the textures distinct these replacement Orchard the and the the and among grade NASA subgroup PLAG a analogs but of view classification populations subgroup within succession grade In yet formation PX by are exists by Wood, mesosiderites. igneous textures. are meteorites. lithic processes the distinction A POIKS Astrophysics that some in to another of large Dodd that paths POIKS remarkably known POIK similar completely suggests the low this lithic mesosiderite as of within 1 highly clasts, they 1967), increasing (Fig. instances, to textured mesosiderites 3 PX single grade et of mesosiderites-the of regard of lack mesosiderites, mesosiderite. of contain whether mesosiderites. by clasts, dimension mode that al. Shaw recrystallization accumulated petrologic between PX POIK Data 3d). and the that the with Powell recrystallized (1975) precursors recognizable free crystals replaced and led because of mesosider- System PX the In leading metamor- recrystal- meteorite subgroup solely however, a extensive mesosid- a of origin Emery, variety overall (1971) PLAG elastic to higher POIK to could lithic as types and The the the the by an by to In of of in is 1978LPSC....9.1053F fundamental lack essentially The low PX rich role or in impact-melted PLAG the same siderites subdivisions (Schnetzler and altered does these recrystallization. experienced troilite-metal the ry; bears beyond partial crystallized mesosiderites radiating by subgroup (1) are and they mesosiderites most metal and In In An any silicates. are only lunar impact-melt REE supported lack POIK in troilite lithic possibly probably not of REE are contrast addition sulfide meteorites mesosiderite on © intriguing or of the fragmental mesosiderites, preservation the POIK Lunar lithic a to resemble bordered of silicates. the the abundances highlands. away 3 very clasts. evolution mesosiderite identical pattern scope more may and "troilite Curved igneous-textured from more of masses difference Silicate mesosiderites origin Estherville. these and to troilite relationships. to by the clasts mesosiderites. minor the textures, from Philpotts, the may be mesosiderites, question This evolved the of Several Planetary the intense a In that partially entire mesosiderites of breccias relations fragmental petrography, of are this of metal-troilite metallic PLAG of of is to other divergent Veramin, does metal never amount present subgroup and is fine-grained the Clover generally of the with completely clast-laden study the especially Emery meteorites a metallic lines recrystallization, is Hainholz any positive Institute not silicate 1969). indicates mesosiderite than have third by POIK into whether plagioclase-rich A that are other This melt investigation matrices is but other classification, appear Springs Ni-Fe of most in paths troilite detailed 1, contain present as not the but contained associated diogenites, contained borders The origin. represent sequence the evidence sequence • Eu fraction component true mesosiderites, mesosiderites. surrounded impact-melt (Floran igneous Provided with observed, is metamorphosed that silicate troilite its the of anomaly metal" textural to apparent is an accompanied of (as moderately parent both recrystallization examination Powell be plagioclase physically silicate metaigneous and and Clover obvious small and as a were suggest extends recrystallized et by well with textures preferentially exists occurs variable fraction and significant cumulate origin (Powell, cumulate noted the implying occurrence and the al., by obtained suggest body clasts rarity (1971) disseminated matrices mixed Clover Spring silicates as NASA anastomosing silicates, the of the 1978b). linking link at from separated that recrystallized above the did that mesosiderite. as suggested by in amounts of the unique textures with 1971). of meteorites that that Astrophysics eucrite, it noted mesosiderites eucrite silicate between by as mesosiderites not Springs preservation and the troilite igneous-textured meso- true leading of clast-rich did rather metal-silicate of of associated for although solids Wanke metamorphosed In quench the most the play silicate is the These Crab in that from anorthositic texture Hainholz, grains the such of supported by that melt and metallic nature silicate Serra the and and than least as the to if at silicate themselves. in subgroup Data et recrystallized impact metal textures, not Orchard) prominent observations as occasionally the evolution plagioclase- both component: the matrices surrounded the with al. two metal within metal suggest that thermally de of Hainholz System all matrices bounda- prior PX fraction and (1972). time related matrix troilite phases and major Mage either clasts metal melts have 1071 and and was ... the the (2) (3) In of of to of in is a a 1 1978LPSC....9.1053F Relationships ized their variations 1072 breccias breccia size Of and after cation al. rock breccia been granoblastic- which and granulitic matrix Although basis summarized uie, near-surface dunite), diverse 2c,d ments ANT population and The that the roxene probably ell, appear 1000°C By Bickel Similarities A © these (1977). granulites, and possible impact Lunar 1971). as with have types PLAG major revised approximate plagioclase formation of analogy suite of purposes structure appear crystalline in clast to types formation. grain morphology is (Warner criteria, formation. the and the Fig. been in the have and were impactites given dominated difference Although The melts material; (Phinney, clast POIK duration in population closest are latter Planetary Warner with boundary to and mesosiderites. 1 emphasized and defined. Table to defined recrystallized is and, of in (Warner lunar self-evident slow grain differences content, present mesosiderite matrix these et be lunar Simonds Warner Evidence poikiloblastic-textured mesosiderites feature differences textural of in al., of and 4. between (eucrite, the Institute analogous the 1978, by (1978) breccias cooling remain matrix addition, Another that relationships boundaries Both metamorphism. criteria impactites breccias. in et 1977) plutonic classification (2) subgroup by mesosiderites is et et al. some al., pers. analogs includes in As of or not at are refractory the al., subdivided • feldspar the largely various analogs. feldspar rate between Provided listed localized lower difference include a 1977). whereas h~ve present metamorphosed and termfeldspathic primarily comm.), R. (1977), 1977). mesosiderites two result, Table rock the J. tend 3 of for and plutonic intact. in genetic the FLORAN temperatures, groups mesosiderites breccias) (4) the Crystal Some presented mesosiderites by morphology types. The nature (Simonds Table in appear the the 3 the textural plagioclase the mobilization Warner to poikiloblastic-textured the glass the impactites between various lists mesosiderites, to lunar For NASA granulites feldspathic of mesosiderites significance. approach is silicate (e.g., petrographic The 3. of shapes subgroup various content, (Fig. the the and the to A the polymict in et development granulitic rocks et subgroups Astrophysics the granulites diogenite, dominance criteria detailed contain fragmental are possibly are the al. unknown grain clast can al., 1). portions with are and two lunar (1977), and very were 120° and latter similar granulite be matrix 1977): anhedral 3 population, breccias size. features groups migration that recognizable below (5) discussion broadly suite, a mesosiderites, 600-700°C useful and breccia annealed mesosiderites cumulate are Data triple (metal) of of somewhat paper is matrix and The matrix distinguish textures (compare (1) granulites textural plagioclase not mesosiderites derived and is System suite 500°C and with upon for Phinney granulites, character- the correlated types junctions. has identical. (3) of orthopy- breccias at environ- of texture. classifi- eucrite, equant, on a nature which of metal (Pow- about clast- grain these since types more from clast may and Fig. the are the are the are et in 1978LPSC....9.1053F

@ Table 3. Generalized classification of lunar breccias (in part modified from Simonds et al., 1977; Phinney et al., 1977; t""' Bickel and Warner, 1978) and mesosiderite equivalents. = e; Lunar Breccia Type ~Mesosiderite Equiv. (see Table lB) ;:;· I>) Q. .... = G ::si Very High A. Fragmental Matrix Beccias; no recrystallization; variable Clast/Matrix Ratio amounts of glass present; anhedral matrix minerals; seriate '8.... none; but subgroups 1-3 (excluding Hainholz ., [ grain size 0 and Estherville) may be metamorphosed (IQ., 1. light matrix I>) 'O ..... fragmental breccias ::r 2. dark matrix ::: .... 3. devitrified-glass matrix (") ii5'" ;'" "' B. Crystalline Matrix Breccias [Igneous]; lathy or subhedral "' • Si matrix feldspar; little or no recrystallization g.... 1. clast-rich impact melts (Fra Mauro breccias, Apollo 16 none o· 0 ? < poikilitic matrix breccias) ....Q. I>) 2. clast-bearing impact melts (Apollo 16 basaltic matrix subgroup 4 S~mondium ::s Q. Pmnaroo 0.. l 0 C" Very Low breccias) ., '-< (iQ" ; Clast/Matrix Ratio 3. clast-free impact melts (14310) none 5· ...,0 z C. Crystalline Matrix Breccias [Annealed]; equant or anhedral .... > ::r rn G > matrix feldspar; poikiloblastic; granulitic texture l. Granulitic (fine grained) ?subgroup 1 (slightly recrystallized) 8 >Cll 2. l (medium grained) ?subgroup 2 (moderately recrystallized) 0 0 3. lmpactites (coarse grained), poikiloblastic, subgroup 3 (highly recrystallized) "' "C Gs.: ::i . '-<=- granulitic) .... Cll G ....t") "' Cll Note: while some Igneous Crystalline Matrix Breccias (i.e., clast-rich impact melts) may show evidence of recrystallization, no reheating episode 0 a is implied; in contrast, Annealed Crystalline Matrix Breccias may have undergone extensive reheating over a long but unknown period of time. rn '-< Cll ;'" ...... 0 -.I s w 1978LPSC....9.1053F /~ episode that represent have exceedingly impossible lites. 1074 prolonged, ites surface may noted which unlike characteristics repeated populations exceeds and of extensive -eucrite-diogenite Bickel Arguments a © should resided heterogeneous be the experienced Lunar important should single-stage in A. metamorphosed B. that is and impacts. a apparent transportation a Differences Similarities for dominant 4. conditions annealing 2. mineral 3. protolith 1. blanketed rapid, high and have of in new, long of abundant annealed impactites polymict Warner also advanced the for early mesosiderites, most Planetary temperature slowly differences decelerating the period silicates the a Table Lack be planet. genetic ejecta impactites similar breccias lunar (metamorphic) clasts mesosiderite characteristics applicable by (1978) 4. Institute fragmental of previously cooling of and a Characteristics of in silicate breccias blankets an T plagioclase fragmental extended impact breccias?) with suite. multi-impact time plutonic history relationships mesosiderites ~ between the interpret annealing cooling mixing atmosphere l000°C relatively Granulites • associated environment portions to textures melts Provided required large R. The parent time suggest origin implying the on breccias on J. (70--80%) matrix of from for of of (and FLORAN lunar the variety span the fine-grained mesosiderite of number a detrital feldspathic history body impact by mesosiderites. formation, different between and lunar to for that elevated granulites with the (Table very and (Powell, have of is reduced cooling NASA the surface. of hypothesized impactites. supported terrestrial rock efficient debris. matrices granulites terrestrial experienced different parent slow fragmental orthopyroxene unknown, 3). 500° breccias (0.1 the temperatures recrystallized parent Astrophysics or to 1971). types °C/10 If below gravitational cooling and Mesosiderites mesosiderites The be regolith, The true, mixing and by body. 350°C body. but very 6 Engelhardt clast occurring craters, yr) impact matrix mesosiderites the between 500°C, validity for the these extremely (55-70%) Data old on or However, polymict types For mesosiderites lunar produced same a the formations System mesosider- field impactites the reheating makes example, as and of surface present kind ( granu- 1971) clasts allow lunar these_ clast may the the by of it 1978LPSC....9.1053F Relationships number petrographic powerful butions subgroup of endmember mafic nent been be (4) howardites mesosiderites. unrecognized. be in matrix that pers. (METAEUCRITE) The Future the any present. consolidated EUCRITE dunite, © consisting rare ites. Fig. done comm.). and Lunar silicate of of lithic of of These tool 5. clasts the Emery clast work ultramafic 1 representative with (Powell, (5) Silica The components and Silicate studies clast mesosiderites. mesosiderites. with endmember The to include The of For recrystallized 6 types, Planetary exist RECRYSTALLIZED into howardites the major may contains a enrichment present which group DIOGENITE types relative petrography, BRECCIA example, 1971), together howardites, both with an meteorite and clast show Institute (Fig. igneous igneous to of within samples unusually components investigation high components hence suggesting abundances heterogeneous determine However, (Dreibus To of breccias, that with 5): classification, mesosiderites could mafic-ultramafic modal (primary) types, • the eucrites individual (1) a or Provided modal may additional first high that primary be ratios eucrite, perhaps microprobe et abundances and and endmember and did due be and comprise IMPACT-MELT of amounts and al., and and BRECCIA approximation by DUNITE breccias. of few such able (6) a not sedimentary mesosiderites to the affinity. tend (2) origin sedimentary component various diogenites 1977). bulk components that a impact-melt reveal contain NASA the to cumulate clasts siliceous of studies of to silicate of chemical mixing quantify a No the tridymite This Astrophysics silica-rich mixing tridymite; the contain (secondary) in mesosiderites CUMULATE most mesosiderite EUCRITE portions comprised presence other of there eucrite, clast or (Table components. is are breccias. the analyses Emery of components secondary especially more (M. them. of type, component contributions mesosiderites in present } relative Data are mesosider- (3) 2) of addition, "SECONDARY" "PRIMARY" Prinz, IGNEOUS have contains of Si0 such System These 6 previously of provide diogenite, OR distinct, Further compo- true a silicate contri- 2 in as shown clasts 1978, large than may 1075 can has the the all of is a 1978LPSC....9.1053F unknown, such speculative from phosphate silicate silicates formed cantly chemical differences differing irregular Pinnaroo. metal reactions. with minerals fraction, boundaries the relation repeated be and eucritic amount found Jarosewich Jarosewich 1076 mesosiderites mesosiderite, metallic pointed and and cumulate been plagioclase/pyroxene presented probably (1973). 1973) Although The dissolved the Ahrens, therefore © observed the discussed as oxidation within Lunar rather higher Ca/ noted material, Several by debris. between Kapoeta out of are closest fragmentation, are silica fractions Pinnaroo, thus metallic reflects analysis eucrite Under but in Several within subsolidus Al and at (1973) tridymite which (1973), and similar to rare Table 1971). disseminated the than in 17%, but its that a this TiO yielding ratios distribution contents, within the Planetary additional affinities by search of silicate elemental like kamacite debris. appropriate relatively howardite. the in large similar 2 workers would area make point, who concentrated prior and 2. McCarthy phosphate silicon This author clast for content Dyarrl the of phosphate, observed will A oxidation kamacite. ratio "higher" should noted in mesosiderites metal a Clover Institute mixing, matrix tridymite metallic low to the a high but result types to to Ca/ observations have as Morristown Si (Fuchs, low close the (Keil, in by of Island the (Powell, According or, their Ca/ silicate might the reducing randomly in Al ratio masses be abundance and solid Ed tridymite minerals metal-poor occur plagioclase/pyroxene Springs may in been may average of the and • silica Fuchs alternatively, Al close in genetic fractions ratio made Provided R. inclusion 1968). aggregation has Stolper and P 1969; as Ahrens explain discrete metal ratio ultimately subsolidus J. portions solution have dissolved in and also 1971, and well chemical conditions, contents. FLORAN (1.12) contains are the (1969) for to has oriented, plagioclase mesosiderites howardite occur relationship Powell, can and their originated by of and the Magnetic at contributed howardites of worth as them. and lowest a the (1971) Table of the patches. eucrite very metal-silicate of Ti mesosiderites. significantly be within bulk surrounding proposed plagioclase this in have a reaction comparison tendency NASA similarity as also preferentially this At mesosiderites enrichment considered rodlike noting Excess 1971; large up the low weight 9). or mesosiderites. analysis and component least to had fragments by mineral recognized ratio. separation to Astrophysics metal. Admittedly, eucrite metal. is uncertain. and Ca/ Perhaps by subsolidus be several Mason that between in Dyarrl Mason amount the regions silica in some between Al percent the howardites, higher the silicates in associated boundaries. with given some indicative Nevertheless, same relative most A Such ratio association. (1.09) light fragmentation contain might at Morristown the in weight with of and Island. similar and throughout procedures the by Data howardites has howardites In of mesosiderites, in than origin, Ca Dyarrl metal-silicate metal-silicate An Dyarrl the metal (0.61), which disseminated mesosiderite may of a Jarosewich, Mason silicate (McCarthy addition Mason the to Jarosewich plagioclase System also phosphate clast source tridymite of there unknown % with a This all Kapoeta reaction A explain silicate signifi- i.e., of Si a Island Island These result other large some data high and was and and and any can the are Ca for by of to is 1978LPSC....9.1053F of is with near older Ca/ but clasts. in ratio ently eucrites, in is mesosiderites Vesta degrees overall mesosiderites the mesosiderites the nite (Nehru which but indicate Emery sequence. studied (McCord (Consolmagno thermal may metamorphism below elastic content impacts time however, parent consistent consistent The Despite Serra The this Bondoc same, may Al presence are © identity and this near but published have occurred, Lunar The might as mesosiderite. impact-melt 500°C, debris body extensive occurrence similarity ratios by not et of of de that of be histories and are coarse-grained et equivalent the always albeit or al., and Powell these partial much some Mage considerable been due limited and al., with with (Floran these Silicate of of be at and not have in rather (Powell, various source 1978). Budulan and for the analyses Planetary obliterating its variably the to 1970), expected heterogeneous meteorites chemical mesosiderites higher its in buried very (0.96) obvious related produce (1969) howardites melting. biased meteorites, REE of above an to, sampled petrography, Drake, surface mesosiderites mineral silicate observed than et clast On of metal unusually types poor differentiated phase 1971). al., Ca/ (0.63) Institute reported pattern magnitude recrystallized (B. the the at appear meteorite sampling on to impact homogenization differences, 500°C, The a types indicates 1977) of development 1978b). Al primary a chemistry the shallow Mason, textures the nodules other of equilibria much basaltic is high unlike classification, very the In may are planetary ratio absence a breccias • with to mesosiderite presence long by in must strong Provided melts highly is parent hand, abundance compatible of have resulting diverse (see were Such greater McCarthy be of incompatible liquids howardites that the 1978, mineral and depths. Serra pyroxene-rich period indicate breccia between the the (Stolper, have accentuated of undergone (Simonds howardites, argument Prinz the of body. metamorphosed body. as metal probably and impact various of by indigenous between related pers. spectrum de the common and quantity tentative the formed of major recognizable origin compositions in parent They of with Mage. clasts, et and that Supporting plagioclase time. eucrite, NASA must comm.). cumulates 1977) and cumulate the events al., lithic with of mesosiderite, et favoring based common the Ahrens clasts a elastic areas, indicate must by at the they body. al., of have Although Astrophysics The and occurrence the high observed identification of glass 1977). same and the metal-rich mesosiderites cumulate overestimation rock clasts on Very consolidated, 1976). and on have slightly the mesosiderites relatively plagioclase-rich experienced a been eucrite plagioclase/pyroxene poikiloblastic produced surface this trace in (1971) components the in a common on slow types spectrophotometry that Alternatively, common slow many matrix the indicate low undergone earth contention all the abundant Veramin recrystallization The element Data cooling eucrite, of clasts mesosiderites, is surface recrystallized mesosiderites hypervelocity Ca/Al but cooling that of mesosiderite high lithic unexpected by high System experience diogenites, and has asteroid origin these of polymict different that variable include, in such and texture studies history Ca/ (0.88), appar- at dioge- moon, burial ratios clasts Al metal is areas lithic rates both 1077 low one the the the too Al on as in 4 1978LPSC....9.1053F

are

evolution Lunar

tiated

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fragments required According because tiated latter the

consistent planetesimals the

Murthy

diogenite-mesosiderite

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Acknowledgments-I

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Laboratory, (USNM where (USNM

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Research performed

Axon

nodule

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1978)

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1976)

Prinz,

#1468,

Clarke

REFERENCES

since

that

Environmental

Institute,

Provided

R.

rates

Lunar

of

the

mesosiderites

on

Hebe

#3203),

relatively

proven

EPILOG

(1977)

probability

J.

He

(USNM

from

formation

scientist

criticisms

than

between

the

Principal

Mineral.

of

isotope

FLORAN

differentiated

v6

and

(1977)

Dyarrl including

Jr.

Clover

(and

two

the

and

may

concludes

the

mesosiderites)

detailed

and for

the

and

by

secular

same which

Marty

of

Pinnaroo the

wrong,

sections), Planetary

Vesta

original

which

earth

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West

the

more

the

the

by

appointment

and

old

Island

be

Springs

Mag.

by

Investigator).

raises

Sciences

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mesosiderite

8

lunar

with

that

NASA

in

is

implication

mass-fractionation

American

Smithsonian Prinz

J.

Point

important

microprobe

can

glimpse

Flora,

Flora

ages

include

operated

manuscript.

resonance

shallow

detailed,

and

(USNM

but

41,

that

have

the

Wood,

Mincy

Bondoc

(USNM Contribution

they

(Clayton

the

for

(USNM

breccias

near

Astrophysics

collection

121-122.

National be

Division,

current

(Begemann

the

stimulating

may

the

merit

at

might

possibility Museum

"mesosiderite"

(USNM

M.

produce

fully

of

A

the

#2312),

by

(USNM

near-surface

the

Institution

the

examination

#5725),

quantitative

basaltic

parent-body.

long basaltic

sources

portion

This

Prinz,

how

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the

(Wetherill,

Aeronautics

(USNM

12 and

et

Lunar

Oak No.

special be

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of

#207),

Universities

periods

Data

large

discussions; other

al.,

Veramin

earth-crossing

#2578),

and

residual

335.

originated

of

mesosiderites

Natural

Emery

Ridge

line.

et

that

for

Crab

of

and

achondrites

-

was

this

during

#5770);

System

of

especially

1976)

al.,

Morristown

for

attention

the

asteroids

differen-

differen-

environ-

and

a

some

supported

Planetary

studies.

work

of

or

National

(USNM

(USNM

Orchard Budulan

In

1976).

metallic

History

loan

1976;

lunar

earth

Roger

Space Space

time

any

"px

Tom

the

are

the

was

on

of

E.

of 1978LPSC....9.1053F Carter Cameron Bence Bickel Berkley Begemann Carver Consolmagno Clayton Chapman Dodd Dowty Duke Dreibus Engelhardt Floran Floran Floran Gaffey Jain Floran Hewins Keil Fuchs Kulpecz samples stony-iron lunar thermal Apollo igneous isotopes. Geophys. 40, Houston. Earth rare Cosmochim. eucrite Cosmochim. Cosmochim. Simondium, Simondium, chemistry. earth-moon Houston. p. (abstract). and Millman, Dence metal-silicate Res. mesosiderite 326-328. A. K. 467-477. R. M. A. cosmological C. earth E. N. E. L. 73, R. R. R. M. © R. highlands. J. V. R. G., Planet. (1968) R. A. A. A. T., 14 E., parent E. B. ( M. A. K. origin Lunar C. L., histories. (abstract). J., H. . Fodor L., 1977) J., J., Earth 6945--6976. and J. F., N., J. W. Res. ed.), H., Kruse breccias. meteorites: Gover elements. and and and Papike J. (1976) L. Grieve In Raleigh G. and Caulfield Caulfield system. R. and Lunar (1969) Jr. Hainholz, Hainholz, Acta Acta Acta Geochim. Weber v. Onuma Lipshutz Geophys. relations Mineralogical Sci. Kulpecz Silicate body. (abstract). and 73, J. Phosphate Anders Warner Silver Lunar p. and Planet. {1971) and (1978c) McCord Proc. H., J.E. Prinz and 683--695. Geochim. implications. J. 40, 39, 31, 5439-5461. Lett. Asteroids R. R. and Fisher In Earth Planetary Hewins C. Proc. The Geochim. Spettel Proc. J., H. N. L. Drake Cosmogenic J. J. V., 701-719. A. 1637-1665. 1585-1594. and Lunar and Lunar petrography, E. M. and Detrital B. Cosmochim. Sci. in and J. Res. A. Planetary Sueno M. 35, and T. B. B. W., Manicouagan phosphate (1976) F., in T. Taylor L. the and Lunar Planet. E. Lunar G. Brown A., Pinnaroo Planetary D. (1967) Lett. D., D., Pinnaroo Cosmochim. (1978) 347-351. R.H. Angra B. 83, M. and B. (1978) Phinney as Mayeda Sci. and {1973) Vilcsek Emery Institute W. DeCarli S. Cosmochim. Reidel, Proc. and Prinz impact Harlow Harlow (1977) meteorite J. 2737-2759. Fission Sci. and 30, G. Sci. chemical Planetary Conf Sci. Institute, G. (1978) (1975) elemental (1977) dos Petrology . Wanke Silicate classification, Acta. Textural-mineralogical J. mineralogy Shock mesosiderites Lunar 10-18. mesosiderite. E. Conf mesosiderites: Delano T. 11, W. M. Conf E. Science Lett. Dordrecht. Reis: P. and formations. Asteroid 4th, G. impact (1975) G. track • K. Acta Cooling and 249-250. C., S. and Olivine-matrix parent-bodies: Composition In Provided relationships H. E. E. Acta 9th. Keil Houston. history Sci. (1976) 25, 8th, Science Structure petrography (1968) p. production press. J. of Warner ages 40, Hintenberger and and Floran (1977) IX, 597--611. Pyroxenes 197-207. W. eucrites, This melt, Conf K. p. surface of 41, rate and 353-368. (abstract). Meteoritics of J. of A 211-227. Prinz Prinz (1972) p. (1976) Deformation Implications meterorites. IX, by 1271-1282. four volume. Geophys. classification J. mesosiderites. origin based The and R. 8th, 392-331. Quebec, of the rates, p. L., among materials: The howardites M. M. and reactions J. meteorites. the in composition Pyroxene 82-84. bulk p. The NASA relationships Simonds on of H. the (1977) (1978b) (1978a) In astronomical 113-143. eucrite exposure classification 12, schreibersite the Res. Shaw composition enstatite Lunar 1. Shaw (1976) Lunar for of In Lunar 254-257. Astrophysics of mesosiderites Mineralogic Stratigraphy, in olivine Nature 76, poikiloblastic Meteorite and impact Preliminary C.H., parent Geochim. meteorites Impact-melt Impact-melt meteorite: thermally (L-7) of and ages, and 5566-5574. Rare in and mesosiderites. the chondrites. in perspective. Planetary a growth 242, processes of Blanchard body: of chondrite. diffusion Ca3(PO Planetary stony Planetary population gases the Cosmochim. Research the characterizations Data based Evidence 26-28. metamorphosed observations petrology, rocks Evidence moon origin origin meteorites. for mesosiderites 4 and J. )i Science beyond System losses, on the D. Geochim. Geochim. Geochim. Institute, minerals. Institute, Geophys. from of and 36 oxygen (P. for for P. Emery for Cl ANT from Acta 1079 and and and the the IX, the the the M. an on J. in 1978LPSC....9.1053F Lacroix Lovering Malissa 1080 McCall Mason Marvin McCarthy Mittlefehldt McCord McCall Nehru Powell Phinney Murthy Murthy Nininger Prior Prior Prinz Powell Powell Simonds Schnetzler Prior Ramdohr achondritic, Mauritanie. mesosiderites. (C. crater, enclaves. the compositional in for bodies. of implications Lunar Estherville Planetary petrology nickel-iron. Ann. and composition the rare-earth D. Lunar 312-314. Muerta, Uberlegungen. mesosiderites. the Reidel, © the G. mesosiderites. M., B. Serra G. G. metal-silicate B. B. B. C. Mtg. B. U. G. Lunar V. G. V. H. Moore, Moon T. A. and Sci. C.H., T. Western W. Estherville H. Meteoritics T. N. and J. N. T. Nehru P. T. E., N. B. Hainholz, J. R., Mineral. C. (1921) R., H. of de (1924) Institute, B., D. (1974) H. and and F. (1971) Dordrecht. (1918) Planetary (1965) (1910) mesosiderite C., S. H. Conj and Geochim. Jarosewich Compt. and Hewins for of (1969) the C. Coscio and and Mage W. J. Warner.J. Alexander Adams (1963) and implications. Tshermaks (1962) ed.), (1965) C. Monatsber. Weiblen the barium Warner Australia. impact Klein and (1966) Emery iron Earth On (1977) Planetary Planets, 4th, Sur E., Mineral. Petrology Ahrens relationships. Electron mesosiderite. Mag. Uber On On meteorites Simondium, cumulate 12, p. Houston. M. Rend. Petrology the R. Philpotts Berkley meteorites Institute, Meteorite J. New Cosmochim. C. p. 179-197. The un the concentrations. 311-312. E. Planet. a induced R. mesosiderites P. The L. (abstract). H., REE South J. 35, B. 613-632. Mineralbestand E. (1964) meteoritic nouveau Mineral. L. (1973) p. W. Mineral. and 179, and Deutsch mesosiderite-grahamite Mag. material Science L. evolution and C. microprobe Institute and Garcia 1029-1060. 91-126. H. petrology eucrite. J. and Adare (1967) J. and and African Sabelin Sci. Houston. Phinney Jr. 309-313. L., fractionation. with and Wiley, Proc. Geochim. (1971) in chemistry Johnson Meteoritic 39, The A. igneous Acta and a type Keil Petrogr. In Lett. chemistry 168, Simonds Akad. Mag. D. Powder from, unique and stone typical (1969) 204-215. On Meteoritics NASA (abstract). Barea, Lunar of • Lunar In T. meteorites N.Y. The of Saito J., W. K., Provided de R. 33, analysis 1445-1447. the 11, von Ensisheim. meteorites-evidence T. 35, Meteorite ( differentiation Cosmochim. and of the Wiss. Harlow 1977) from C. J. Jarosewich fer zircon. composition Mitt. 789-810. features. Mill parent petrology Sci. Genesis V. 35-36. Dyarrl SP mesosiderites-11. and C. Pallasiten 476-487. K. In FLORAN (1972) of a Mount meteorique (1970) Soviet-American reconsideration 370. In 7, H. ( Simondium, Conj. Rb-Sr Creek. mesosiderites-1. 12, of Planetary 21, Mount by I Science 978) 923-938. group G. 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(1978) Science With 16 and 39 and achondrites desert Ar (I 7811-783. and (X). 151-172. poikilitic 977) and on and Mineral. mesosiderite the Data systematics rock analyses ed.), einige and and The Cosmochemistry Mineralogy IX, initial de and reflectivity Met. components composition its Petrogenesis of on Meteorites on meteorite System compositions the types: Ca/ l'Adrare p. p. rocks. achondritic a chondritic, Lunar in genetische Soc., Mag. review 799-801. 87 206-216. chemical of Al light Sr parent of Their Proc. / Vaca ratio 30th 86 and and and and the 15, en Sr of in of of of 1978LPSC....9.1053F Simonds Stolper Simonds Van Wasson Wasson Warner Wetherill Wanke Wilson Wetherill emphasis J. impactites meteorites. samples 587-611. Quijano-Rico 2066. their 1869-1893. the Cosmochim. Sci. Master's M. Schmus © earth Conj metallic Lunar W. E. (1977) J. J. H., J. C.H., C. G. G. and T. T., (1977) E. thesis, on L., and H., W. 7th, Baddenhausen W. and W. Geochim. 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NASA Proc. metal-rich after Sci. pp. (1972) swarm Geeslin Spettel C. of and of Mesosiderites-1. Conf. H. the all. Lunar Astrophysics Geochim. the regimes classification petrology Multielement subsequent (1977) mesosiderites Proc. J., B., earth 3rd, meteorite Brown Sci. Dreibus Lunar in p. and Feldspathic Cosmochim. cratered of Conj 1251-1268. R. to Data moon. the for groups. Sci. analyses the Compositions W. G., metal 8th, the System Conf. formation terrain and Proc. Palme chondritic granulitic Geochim. p. Acta nodules. of Rhodes 8th, 2051- Lunar lunar 1081 with 41, H., of p. of