Microstructures associated with deep crustal subduction

Microstructures associated with deep crustal subduction deformation in theCycladic Blueschist belt, Syros, Greece

Gabriel J. Nelson

Senior Integrative ExerciseMarch 10, 2004

Submitted in partial fulfillment of the requirements for a Bachelor of Arts degree fromCarleton College, Northfield, Minnesota

Table of Contents

Abstract -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 1Introduction -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 2Tectonic Setting -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 4Geology of Syros -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 5Microstructures and Mineralogy of Blueschists -- -- -- -- -- -- -- 8

Bimodal size distribution of glaucophane -- -- -- -- -- - 11Mineral inclusions in garnet -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -11Garnet pressure shadows -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --15

Discussion and Conclusions -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 18Acknowledgements -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -22References Cites -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - 23Appendix 1 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - 25Appendix 2 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- - 29

Microstructures associated with deep crustal subduction deformation inthe Cycladic Blueschist belt, Syros, Greece

Gabriel J. Nelson

Senior Integrative Exercise

March 2004

Cameron Davidson, advisor

AbstractPressure shadows and inclusion trails in garnet from Blueschist facies rocks on

the Island of Syros, Greece reflect deformation events at blueschist facies conditionsduring Eurasia-Africa collision and subduction. Approximately 25% of all pressure

shadows are asymmetric, and 44% of all thin sections contain garnet inclusions at high

and low angles to foliation. To produce these microfabrics the deformation had aprogressively changing (non-coaxial) maximum direction of compression during

metamorphism.

Keywords: Syros, blueschist, deformation, garnet, pressure shadows, inclusions

2

Introduction

The island of Syros is in the Cycladic Blueschist belt of the Eastern

Mediterranean (Figure 1). It is likely that the rocks of the Cycladic Blueschist have been

the object of geologic study since early Phoenician influence in the region (Schumacher

and Helffrich, 2001). These metamorphic rocks formed during subduction at deep crustal

depths of 50 to 60 km and temperatures of 450-500° Celsius (Gealey, 1988; Lister et al.,

1984; Rosenbaum et al., 2002), and the exhumation of these rocks has been attributed to

syn-orogenic and post-orogenic collapse processes (Jolivet and Faccenna, 2000; Lister

and Raouzaios, 1996). Exhumation models typically employ low angle detachment faults

producing non-coaxial shearing (Avigad et al., 1997; Lister and Raouzaios, 1996). These

models typically use observations gathered from fabrics formed during deformation at

shallow crustal levels (Rosenbaum et al., 2002). Deformation at deep crustal levels has on

the other hand been interpreted as coaxial (Rosenbaum et al., 2002). Studies of deep

crustal deformation have been done in part by the observation of high-pressure and low-

temperature fabrics preserved in blueschist facies rocks. These rocks typically have the

assemblage garnet + omphacite + glaucophane + quartz (Rosenbaum et al., 2002).

Rosenbuam et al. (2001) concluded that the blueschist facies rocks of Syros record

multiple deformation events based on mineral inclusion trails in garnet and the geometry

of pressure shadows.

Over the past four years the Keck consortium has sent three teams of

undergraduates to addresses geologic problems on the island of Syros. This paper is the

result of the 2003 Keck project to Syros lead by Jack Cheney and Tekla Harms (Amherst

College), John Brady (Smith College), and John Schumacher (Bristol University). This

20°

20°

25°

25°

34° 34°

36° 36°

38° 38°

40° 40°

42° 42°

H H H H H H H H H H H H H

H H

H

OMC - M.Weinelt H H H H H H H

Greece

AlbaniaItaly

Bulgaria

Turkey

Syros

Hellenic Trench Pliny/S

trabo

Trench0 100km

inferred extension:

GMT Jan 11 16:32OMC - M.Weinelt

24°

24°

25°

25°

26°

26°

27°

27°

36° 36°

37° 37°

38° 38°

39° 39°

0 50 100km

Syros

SifnosSerifos Paros Naxos

Kea

Kithnos

Milos IosAmorgos

Ikaria

Mykonos

Tinos

AndrosEuboia

Cycladic blueschist belt Blueschist-facies carbonatesGranitic rocksUltramafic rocks

C yc lades

AfricanPlate

Motion

after Blake et al. (1984)

Figure 1. Geographic and Geologic of the Cyclades and Syros, from J.C. Schumacher (1999)

3

4

study is one project from the 2003 geology project to Syros with the support of the

KECK consortium. This paper takes a fresh look at the fabrics recorded by the blueschist

facies rocks of Syros. Microfabrics of glaucophane crystals suggest deformation occurred

in isolated bands on the scale of a thin section. Garnet inclusion trails and pressure

shadows around garnets suggest that deep crustal deformation was non-coaxial. The

finding of non-coaxial deformation agrees with conclusions of shallow crustal

deformation during the same exhumation event (Jolivet and Faccenna, 2000; Lister and

Raouzaios, 1996), but contradict the conclusions of Rosenbaum et al. (2002) about deep

crustal deformation in these rocks.

Tectonic Setting

The tectonic story of the lithologic package of the Cycladic Blueschist belt begins

in the Triassic and Jurassic. The tensional forces responsible for the fragmenting Pangaea

created rifting between what are today the African and Eurasian plates (Gealey, 1988).

The rifting formed the Hellenides Platform and the Pindos-Cyclades ocean basin between

the two plates (Papanikolaou, 1987). The sedimentary protoliths of the marbles, pelitic

schists, and metabasites that compose the Cycladic Blueschist belt formed in the Pindos-

Cycladic ocean basins. The extensional forces became compressional in the Late

Cretaceous when the relative motions of the Africa and Eurasia plates changed (Jolivet

and Faccenna, 2000). The ocean basin closed, ophiolites obducted, and subduction began

northward along the Pindos Zone (Gealey, 1988). The collision and subduction date of

this tectonic model fit with zircon ages of 78Ma, interpreted as the time of subduction

metamorphism (Brocker and Enders, 2001). The magnitude of the plate collision slowed

5

the absolute motion of the African plate (Jolivet and Faccenna, 2000). The slowing of the

African plate caused trench-rollback to the Hellenic Trench, changing plate boundaries

between the African and Cycladic microplate (Gealey, 1988).

The rollback lead to the back arch extension in the Aegean around 25-11Ma

(Lister et al., 1984). Normal and some listeric faults were active in the region since at

least the late Miocene (Papanikolaou, 1987) due to the positioning in the back arc of two

trench systems (Avigad et al., 1997) (Figure 1). The extensional processes allowed for the

exposure of the high-pressure metamorphic rocks formed during subduction before trench

rollback. This sequence of events formed, subducted, and later exposed the Cycladic

Blueschist belt rocks (Gealey, 1988; Jolivet and Faccenna, 2000).

Geology of Syros

The name “Syros” is derived from two Phoenician words meaning “happy” and

“rock” (Schumacher and Helffrich, 2001). After Phoenician naming practices the island

of Syros does not appear in significant geologic context until the late nineteenth century.

In 1845 Hausmann first described glaucophane from the island of Syros. After Hausmann

there was another break in the geologic consideration of this Aegean isle. Extensive

studies of the geology of Syros did not appear in English language geologic papers until

John Ridely’s work in the late 1960.

Syros is composed of alternating packages of shallow northeasterly dipping pelitic

schists, marbles, and metabasites (Figure 2). Deformational features notable on a map

scale include tectonic duplication represented by the alternating packages of rock types

(Dixon, 1987), isoclinal folding on the kilometer scale (Papanikolaou, 1987), and several

Marbles

Schists

Metabasites

Serpentinite

Vari Gneiss

0 3km

N

Figure 2. Syros and its basic lithology, modified from Dixon and Ridley (1987).

0 3km

N

Figure 3. Names, locations, and thin sectionsfrom field sites on Syros.

San MichaelKastri

Paradice

Windmill Hill

North Ermopoli

Kini Airport

Charrasonis

Perdiki

Katerghaki

Sample Locations with location names

Total Samples

0-4

5-10

14

6

7

fault zones cutting across the island (Figure 2). Faults are identified by zones of

serpetintization and brecciation.

The metamorphic rocks of Syros contain greenschist, eclogite, and blueschist. The

eclogites, and blueschist facies rocks developed during high-pressure subduction

metamorphism at 40 – 80 Ma (Brocker and Enders, 2001; Lister and Raouzaios, 1996;

Ridley and Dixon, 1984). The temperatures and pressures were approximately 14kbar

and 450°-500°C (Dixon, 1976). During this metamorphism the blueschist developed

foliation and lineation (Rosenbaum et al., 2002). These structures are represented by the

preferential orientation of micas into the near horizontal foliation and preferred alignment

of glaucophane into the lineation. The greenschist is a retrograding overprint of

eclogite/blueschist and is more pervasive in the south of the island. It is identifiable by

the chlorite overgrowth of garnet and glaucophane crystals. Greenschist metamorphism

occurred at similar temperatures to the blueschist/eclogite metamorphism but at much

shallower depths (Schiestedt and Matthews, 1987). The overprinting happened 20-25 Ma

(Lister et al., 1984; Schiestedt and Matthews, 1987). The preservation of some blueschist

during exhumation required maintaining high subduction type pressures while lifting the

blueschists to surface conditions without passing the low pressure phase of greenschist

overprinting (Wijbrans et al., 1993). Wijbrans et al. (1993) proposed thrust faulting as a

result of repeated delamination of lighter supercrustal rocks of the subducting plate. The

story of metamorphism and subsequent exhumation is not a complete one. Continued

work in this area is identifying further constraints on pressures, temperatures, timing,

deformation, and chemical processes in the framework of subduction and exhumation

processes.

8

Microstructures and Mineralogy of Blueschists

Blueschist facies rocks on Syros have the mineral assemblage garnet +

glaucophane + omphacite + epidote + white mica + quartz + sphene (Rosenbaum et al.,

2002). Samples of blueschist were collected from around the island (Figure 3).

Approximately eighty geochemical spot analyses were done on four thin sections of

blueschist with a Scanning Electron Microscope (SEM) that has an Energy Dispersive X-

ray Spectrometry (EDS) (Appendix 1). Results shows that garnet composition is 60%-

65% almandine and 16%-18% grossular with lesser components of pyrope and

spessertine (Figure 4). Transects across garnet crystals show a reduction in magnesium

corresponding to an increase in manganese from rim to core (Figure 5). These results are

consistent with findings of Ridley and Dixon (1984). All glaucophane crystals have the

chemical composition of true glaucophanes (Figure 6), and show a reduction in ferrous

iron from rim to core (Figure 7). Variation in iron content from rim to core of

glaucophane crystals has been noted by Ridley and Dixon (1984) and Schiestedt et al.

(1987).

The blueschists of Syros have a near horizontal foliation defined by the preferred

orientation of mica crystals and a lineation within the plane of this foliation defined

predominately by glaucophane crystals (Dixon, 1987). Garnet crystals have trails of

mineral inclusions composed of white mica, quartz, and glaucophane. Pressure shadows

around garnet crystals are composed of quartz, white mica, glaucophane, and chlorite.

100% Almandine (FeO)

50% Pyrope (MgO)

50% Grossular + Spessartine (CaO+MnO)

Figure 4. Garnet chemical composition plot. Note that the Grossular + Spessartine and the Pyrope verticies are at 50% composition.

Figure 5. Transects from rim to core of three garnets. Garnets show reduction in Mg and an increase in Mn toward the core. Average transect is 0.9 mm.

0

0.04

0.08

0.12

0.16

0.20

XMg XMnRim Core

9

0

0.5

1

0 0.5 1

Fe2/Fe2+Mg

Ferro-Glaucophane Riebeckite

Magnesio-RiebeckiteGlaucophane

Figure 6. Sodic amphibole composition plot. All glaucophane crystals analyzed plot as true glaucophane.

Fe+3/(Fe+3+AL)

Fe+

2 /(F

e+2 +

Mg)

0.7

0.9

1.1

1.3

1.5

Rim Core

Ferrous Iron

Figure 7. Transects from rim to core of seven gaucophane crystals. Glaucophane shows a reduction in ferrous iron toward the core.

Fer

rous

Iron

10

11

Bimodal Size Distribution of Glaucophane

The size of glaucophane crystals in thin section remains within approximately

30% of an average glaucophane crystal size. There is the exception of a small population

of thin sections (13 of 48) that show glaucophanes where crystal size is not uniform, but

instead has a bimodal size distribution. In thin sections with bimodal size distribution,

larger glaucophane crystals form bands parallel with foliation corresponding to areas of

the highest concentration of garnet (Figure 8). Ten thin sections with bimodal size

distribution of glaucophane are from one field location (Figure 9). Geochemical analyses

from larger and smaller glaucophanes in thin sections with bimodal size distribution show

no conclusive chemical difference between sizes of crystals (Figure 10).

Mineral Inclusions in Garnet

Roughly 97% of garnets observed in the thin sections contain mineral inclusions.

The inclusions mainly consist of quartz, white mica, and glaucophane crystals. During

garnet growth minerals are enveloped, which preserves crystal orientation (Davis and

Reynolds, 1996). Consequently, textures present in the rock before or during garnet

growth can be overgrown and preserved in the garnet.

In the thin sections, garnet inclusions trails are straight (Figure 11) or curved

(Figure 12, 13). Additionally, the trails are at high or low angles to the shallowly dipping

foliation. Within individual thin sections, garnet inclusion trails exist that fit the four

combinations of curved/straight and high/low angle types of trails. Trails that are at an

angle of greater than 45° to foliation are considered at a high-angle to foliation (Figure

11), trails less than 45° to foliation are at a low-angle to foliation. Geographically, nine

10

12

0

4

8

12

NorthErmopoli

Airport Charrasonis

Figure 8. Pictomicrograph photo of bimodal size distribution of glaucophane in association with garnets. Sample number 26121.

Figure 9. Total thin-sections with bimodal size distribution of glaucophanes from locations across Syros. Locations are arranged from north to south on the island. Locations with no observed bimodal distribution were omitted.

area

of l

arge

r gl

auco

phan

esar

ea o

f sm

alle

r gl

auco

phan

esGarnet

Garnet

Garnet

Garnet

Garnet

1 mm

12

0

0.5

0 0.1 0.2 0.3 0.4 0.5Fe+3 / (Fe+3 + Al)

Small GlaucophanesLarge Glaucophanes

Figure 10. Composition plot of large and small glaucophane crystals on the glaucophane quadrant of a sodic amphibole plot. Variation in crystal size shows no correlation with respect to chemical composition.

Fe2+

/(F

e2+ +

Mg)

Figure 11. Pictomicrograph photo of straight garnet inclusions at high angle to foliation. Inclusion trend is marked with white arrow. Foliation is horizontal, sample number 16123

0.4

0.1

0.3

0.2

13

15

out of ten field locations have inclusion trails at high and low angles to foliation, and all

field locations have curved and straight inclusion trails. Forty-four percent of thin

sections contain garnet inclusions at both high and low angles to foliation. High angle

garnet inclusion trails are present in 6% more thin sections than low angle inclusion

trails. (Figure 14).

Garnet Pressure Shadows

Sampling on Syros was restricted to blueschist with garnets likely to exhibit

pressure shadows. Samples came from outcrops with deformation textures such as

elongate boudens or garnet pressure shadows observable by hand-lens. Each set of garnet

pressure shadows from oriented thin section was recorded (Appendix 2) as a sigma, delta,

symmetric, or undetermined (Davis and Reynolds, 1996). The symmetry determination is

made by imagining a line parallel to foliation through the center of the porphyroblast,

which in this study is the center of garnet, and evaluating the position of the pressure

shadows in relationship to the line (Figure 15) (Passchier and Simpson, 1986). Symmetric

pressure shadows are centered on a line through the center of the porphyroblastic system

(Figure 16). Sigma and delta porphyroblasts are both asymmetric (Figure 15, 16). Garnet

pressure shadows with undetermined pressure shadows are of two types. One type lacks

noticeable pressure shadows and the other has highly distorted pressure shadows. Highly

distorted pressure shadows generally occur in close proximity to other garnets. Pressure

shadows bend and distort around the large crystals, so that the tips do not represent

deformation around one porphyroblast, but instead indicate significantly more

complicated deformation associated with interaction of several porphyroblasts.

0

5

10

15

20

25

30

SanMichael

KastriParadiceWindmill

HillNorth

Ermopoli

Kini

Airport

Charrasonis

Perdiki

Inclusions at low angle to Foliation

Inclusions at High Angle to Foliation

Figure 14. Total thin-sections, by location, with garnets containing inclusion trails at a high or low angle to the foliation. Locations are arranged from north to south on the island.

San

M

icha

el

Kas

tri

Par

adic

e

Win

dmill

Hill

Nor

th

Erm

opol

i

Kin

i

Airp

ort

Cha

rras

onis

Per

diki

Kat

ergh

aki

16

18

Of the approximately 1200 garnet pressure shadows observed, 25% are

asymmetrical and 40% are symmetrical (Figure 17). The asymmetric pressure shadows

are less abundant than symmetric ones but constitute a significant proportion of total

garnet pressure shadows. Asymmetric pressure shadows are also a substantial population

of the pressure shadows observed from each field location (Figure 18).

Discussion and Conclusions

Lister and Raouzaios (1996) suggest that metamorphic mineral growth in the

Cycladic Blueschist belt precedes tectonically driven deformational events. It would be

possible, but unlikely, that bimodal size distribution is the result of one size of

glaucophane crystals growing during an early metamorphic growth and the other size

crystals forming in a later metamorphic growth. Preliminary tests show that the crystals

of larger and smaller glaucophanes do not have a distinct chemistry (Figure 10). Ridley

and Dixon (1984) concluded that chemical equilibrium changed progressively during the

formation of high-pressure minerals. Additionally, The chemical zoning noted in

transects across of crystals (Figure 5 and 7) within these blueschist facies rocks has been

interpreted as prograde metamorphic mineral growth (Schiestedt et al., 1987), and a

record of fluid-enhanced chemical exchange (Dixon, 1987). The progressive change in

chemical equlibrium, and chemical zoning as a result of different crystal growth events

would indicate that crystals forming at different times would have different chemistries

reflecting the progressive change in chemical equilibrium of the rock. This is seemingly

not true for the different sizes of glaucophanes in thin sections with bimodal size

290

470417

0

100

200

300

400

500

Asymmetrical Symmetrical Undetermined

0 3km

N

San Michael

North Ermopoli

Airport

Katerghaki

Charrasonis

Kini

AsymmetricalSymmetrical UndeterminedSample Locations

Figure 18. Syros with thin section analysis by sample location. Each graph shows relative proportions of garnet porphyroblastic systems. Only locations with more than one hundred porphyroblastic systems recorded are shown.

Figure 17. Total of each type of porphyroblastic system observed in thin section

19

20

distribution, so the size variation is likely due to something other than glaucophanes from

two blueschist metamorphic growth events.

The variation in crystal size may instead be the result of the restrictive presence of

fluids. If fluids favorable to the growth of glaucophane were concentrated in zones

defined by garnet populations, the result would be larger glaucophanes in these zones.

Fluids could also be concentrated as a result of movement to shielded areas and away

from deformational shear bands. The pressure shadows around garnet porphyroblasts are

a result of mineral recrystalization of reaction-softened material from the matrix in areas

shielded from deformation, (for example quartz and white mica) (Passchier and Simpson,

1986). These shielded locations may also concentrate fluids favorable to glaucophane

growth. The shield locations could also simply preserve larger glaucophane crystals.

Ridley and Dixon (1984) found that larger glaucophanes from one growth event in one

field location are broken into smaller polygonal crystals in other field locations. This

breaking of glaucophane into smaller crystals may also be evident in bimodal

glaucophane bands on the scale of a single thin section.

Rosenbaum et al. (2002) concluded that there are three deformational events at

blueschist facies conditions that are preserved in blueschist fabrics. The fabric from the

earliest deformational event is preserved as inclusion trails in garnet porphyroblasts

(Rosenbaum et al., 2002). The next deformation event is evidenced by the shallowly

dipping foliation and symmetric features such as pressure shadows (Rosenbaum et al.,

2002). Rosenbaum et al. (2002) found that garnet inclusions from the earlier

deformational event are typically orthogonal to the near horizontal foliation that resulted

in the later deformational event. They concluded that the porphyroblast inclusions are a

21

result of coaxial compression that was perpendicular to the later coaxial compression

producing foliation and symmetric pressure shadows. Therefore the first deformation was

during the African Eurasian continental collision resulting in deep crustal thickening. The

later deformation was separate from the earlier one and signifies that deep crustal

thinning in the horizontal direction was occurring during orogenic collapse (Rosenbaum

et al., 2002). The third fabric and deformational event produced isolated non-coaxial

shear bands (Rosenbaum et al., 2002).

Shear bands, as noted by Rosenbaum et al. (2002), were not observed in this

study. Sampling methods could have excluded blueschist with deformational fabrics

obscuring clear pressure shadows from an earlier deformation, and thus representative

shear bands of late blueschist deformation. It is also possible that the isolated shear bands

noted by Rosenbaum et al. (2002) produced the bands of larger and smaller glaucophanes

crystals (Figure 14).

Microstructures described by Rosenbaum et al. (2002) as indicators of the two

earliest blueschist metamorphic events were observed for this study, but the results and

interpretations of this study differ from those of Rosenbaum et al. (2002). The inclusion

trails in garnets were seen at high angle (greater than 45°) (Figure 11) to foliation,

including trails orthogonal to foliation. Inclusion trails were also often seen at low angles

(less than 45°) to foliation (Figure 12). The variation in inclusion angle is likely to be the

cause of garnet rotation after overgrowth of the earlier blueschist fabric. In addition, the

inclusion trails preserved in garnets are curved, (Figure 13) probably due to rotation of

the garnet crystal during growth. Asymmetric pressure shadows are 10%-40% of the

pressure shadows from each field location around the island (Figure 18). The asymmetric

22

pressure shadows (Figure 16) are likely the result of a non-coaxial deformation (Passchier

and Simpson, 1986). The microfabrics of garnet inclusion trails and porphyroblastic

systems indicated that blueschist deformational events were non-coaxial, similar to other

studies on the Aegean island of Sifnos (Lister and Raouzaios, 1996). The implication is

that maximum compressional directions change progressively during high-pressure

subduction deformation, and that orogenic collapse was occurring during continental

collision.

Acknowledgments

Thanks to all of the other undergraduate students on the 2003 Keck research trip to Syros

. There are no others with whom I would rather toss back a Mythos and discuss beautiful

blue rocks. I would like to thank John Brady, John Schumacher, Tekla Harms, and Jack

Cheney for dedicating themselves to provide me and other students the amazing

experience of Syros’ geology. Additional thanks to Jack Cheney for his never ending

passion for discussion about rocks, to Tekla Harms for provide direction to my field

work, and John Brady for the assistance and use of the Smith College SEM with EDS as

well as feeding and housing me for my stay at Smith College. I would be remised to not

thank Cameron Davidson for his help in the field, at the microscope, with drafts, papers,

and ideas. This project would not have been possible without these people or the funding

of the Keck consortium, the Charles W. Potts Endowment fund, and Thomas P. Cook

Educational Trust. Without these sources of financial support I would not have been able

to go to Greece, go to Amherst and Smith Colleges, ship rock samples home, have thin

sections made, or complete any part of this project.

23

References CitedAvigad, D., Garfunkel, Z., Jolivet, L., and Azañón, J. M., 1997, Back arc extension and

denudation of Mediterranean Eclogites: Tectonics, v. 16, no. 6, p. 924-941.

Brocker, M., and Enders, M., 2001, Unusual bulk-rock composition in eclogite-faciesrocks from Syros and Tinos (Cyclades, Greece): implications for U-Pb zircongeochronology: Chemical Geology, v. 175, p. 581-603.

Davis, G. H., and Reynolds, S. J., 1996, Structural Geology: New York, John Wiley &Sons, Inc.

Dixon, J. E., 1976, Glaucophane schists of Syros, Greece (abstract): Geologic SocietyBulletin of France, v. 7, p. 280.

Dixon, J. E. a. R., J., 1987, Syros (field trip excursion), in Helgeson, H. C., ed., Chemicaltransport in metasomatic processes: Nato Advanced Study Institutes: Dordrecht,D. Reidel Publishing Company, p. pp. 489-500.

Gealey, W. K., 1988, Plate tectonic evolution of the Mediterranean-Middle East region:Tectonophysics, v. 155, p. 285-306.

Jolivet, L., and Faccenna, C., 2000, Mediterranean extension and the Africa-EurasiaCollision: Tectonics, v. 19, no. 6, p. 1095-1106.

Lister, G. S., Banga, G., and Feenstra, A., 1984, Metamorphic core complexes ofCordilleran type in the Cyclades, Aegean Sea, Greece: Geology, v. 12, p. 221-225.

Lister, G. S., and Raouzaios, A., 1996, The tectonic significance of a porphyroblasticblueschist facies overprint during Alpine orogenesis: Sifnos, Aegean Sea, Greece:Journal of Structural Geology, v. 18, no. 12, p. 1417-1435.

Papanikolaou, D. J., 1987, Tectonic Evolution of the Cycladic Blueschist Belt (AegeanSea, Greece), in Helgeson, H. C., ed., Chemical Transport in MetasomaticProcesses, D. Reidel Publishing Company, p. 429-450.

Passchier, C. W., and Simpson, C., 1986, Porphyroclast systems as kinematic indicators:Journal of Structural Geology, v. 8, no. 8, p. 831-843.

Ridley, J., and Dixon, J. E., 1984, Reaction pathways during the progressive deformationof a blueschist metabasite: the role of chemical disequilibrium and restrictedrange equilibrium: Journal of Metamorphic Geology, v. 2, p. 115-128.

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Rosenbaum, G., Avigad, D., and Mario, S.-G., 2002, Coaxial flattening at deep levels oforogenic belts: evidence from blueschist and eclogites on Syros and Sifnos(Cyclades, Greece): Journal of Structural Geology, v. 24, no. 9, p. 1451-1462.

Schiestedt, M., Altherr, R., and Matthews, A., 1987, Evolution of the CycladicCrystalline Complex: Petrology, Isotope Geochemistry and Geochronolgy, inHelgeson, H. C., ed., Chemical Transport in Metasomatic Processes, D. ReidelPublishing Company, p. 389-428.

Schiestedt, M., and Matthews, A., 1987, Transformation of blueschist to greenschistfacies rocks as a consequence of fluid infiltration, Sifnos (Cycladed), Greece:Contributions to Mineralogy and Petrology, v. 97, p. 237-250.

Schumacher, J. C., and Helffrich, G., 2001, Bristol Mapping Course: Syros and theCyclades.

Wijbrans, J. R., Wees, J., Stephenson, R., and Cloetingh, S. A. P. L., 1993, Pressure-temperature-time evolution of the high-pressure metamorphic complex of Sifnos,Greece: Geology, v. 21, p. 443-446.

Appendix 1. Table 1 SEM analyses of garnet crystals

Garnet DataSample # 16103 16103 16103 16103 16103 16103 16103 26125 26125 26125 26125 26125 26125analysis # 5 6 7 8a 8b 8c 8d 1a 1b 1c 1d 2a 2b

RIM CORE RIM CORE RIMWt% oxideMgO 2.578 2.156 2.041 2.206 1.166 0.966 0.758 4.326 4.115 3.807 3.763 4.405 4.401Al2O3 21.566 21.641 21.337 21.685 21.261 20.833 21.351 21.467 21.239 21.190 21.314 21.127 21.774SiO2 37.063 37.336 36.990 36.857 36.441 36.900 36.655 37.479 37.314 37.116 37.498 37.848 37.320CaO 9.220 8.741 8.925 8.303 8.233 8.189 8.225 6.250 6.005 6.140 6.258 6.366 5.727MnO 0.259 0.235 0.387 0.184 0.934 1.156 2.210 1.972 2.329 2.403 2.410 1.876 2.186FeO 28.291 29.236 29.010 29.831 30.820 30.100 29.792 27.833 27.172 27.536 27.378 27.155 27.255total 98.979 99.345 98.690 99.066 98.855 98.143 98.992 99.327 98.174 98.193 98.622 98.777 98.663

Stoichiometry [Cations based on 12 O]Mg 0.308 0.257 0.245 0.264 0.141 0.118 0.092 0.512 0.493 0.457 0.449 0.523 0.523Al 2.035 2.038 2.027 2.054 2.037 2.004 2.043 2.011 2.010 2.011 2.011 1.982 2.046Si 2.968 2.984 2.981 2.962 2.963 3.012 2.976 2.978 2.996 2.989 3.001 3.013 2.976Ca 0.791 0.748 0.771 0.715 0.717 0.716 0.716 0.532 0.517 0.530 0.537 0.543 0.489Mn 0.018 0.016 0.026 0.013 0.064 0.080 0.152 0.133 0.158 0.164 0.163 0.127 0.148Fe 1.895 1.954 1.955 2.005 2.096 2.055 2.023 1.850 1.825 1.854 1.833 1.808 1.818

Pyrope 0.102 0.086 0.082 0.088 0.047 0.040 0.031 0.169 0.165 0.152 0.151 0.174 0.176Almandine 0.629 0.657 0.652 0.669 0.694 0.692 0.678 0.611 0.610 0.617 0.615 0.603 0.610Spessartine 0.006 0.005 0.009 0.004 0.021 0.027 0.051 0.044 0.053 0.055 0.055 0.042 0.050Grossular 0.263 0.252 0.257 0.239 0.238 0.241 0.240 0.176 0.173 0.176 0.180 0.181 0.164Mg/Fe 0.162 0.131 0.125 0.132 0.067 0.057 0.045 0.277 0.270 0.246 0.245 0.289 0.288

Garnet DataSample # 26125 26125 26125 26125 56141 56141 56141 56141 56141 56141 56141 56141 56141analysis # 2c 2d 2e 2f 5 13 14a 14b 14c 14d 15 16a 16b

COREWt% oxideMgO 3.781 3.704 3.623 3.213 3.507 2.817 3.306 3.168 3.162 3.078 3.348 3.926 2.883Al2O3 21.664 21.316 21.192 21.274 21.612 21.986 22.056 22.267 22.009 22.244 22.171 21.912 22.023SiO2 37.708 37.608 37.547 37.439 37.825 38.310 37.900 38.089 37.837 38.450 38.562 38.555 38.211CaO 6.065 6.564 5.636 6.078 8.642 8.969 8.883 8.995 8.125 9.129 9.165 8.287 9.070MnO 2.583 2.907 3.617 4.483 0.621 1.753 0.728 0.752 0.755 0.887 0.702 1.043 0.829FeO 27.018 26.592 26.841 25.598 27.849 26.061 27.615 27.894 27.970 27.009 27.420 27.553 26.935total 98.818 98.692 98.455 98.084 100.056 99.896 100.489 101.166 99.857 100.797 101.367 101.275 99.951

Stoichiometry [Cations based on 12 O]Mg 0.449 0.441 0.433 0.386 0.412 0.330 0.387 0.368 0.372 0.358 0.387 0.454 0.337Al 2.034 2.008 2.005 2.019 2.009 2.038 2.039 2.047 2.047 2.044 2.027 2.006 2.037Si 3.004 3.006 3.014 3.015 2.983 3.013 2.974 2.971 2.987 2.997 2.992 2.994 2.998Ca 0.518 0.562 0.485 0.525 0.730 0.756 0.747 0.752 0.687 0.762 0.762 0.690 0.762Mn 0.174 0.197 0.246 0.306 0.041 0.117 0.048 0.050 0.050 0.059 0.046 0.069 0.055Fe 1.800 1.777 1.802 1.724 1.837 1.714 1.812 1.819 1.846 1.761 1.779 1.790 1.767

Pyrope 0.153 0.148 0.146 0.131 0.136 0.113 0.129 0.123 0.126 0.122 0.130 0.151 0.115Almandine 0.612 0.597 0.608 0.586 0.608 0.588 0.605 0.609 0.625 0.599 0.598 0.596 0.605Spessartine 0.059 0.066 0.083 0.104 0.014 0.040 0.016 0.017 0.017 0.020 0.016 0.023 0.019Grossular 0.176 0.189 0.163 0.178 0.242 0.259 0.249 0.251 0.232 0.259 0.256 0.230 0.261Mg/Fe 0.249 0.248 0.241 0.224 0.224 0.193 0.213 0.202 0.201 0.203 0.218 0.254 0.191

Note: Arrows from rim to core indicates mineral analyses along indivigual crystals transects 25

Appendix 1. Table 2 SEM analyses of glaucophane crystals Glaucophane DataSample #analysis #

Wt% oxideSiO2Al2O3FeOMgOCaONa2OTotal

Stoichiometry [Cations Bases on 23 Oxygens]All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric

Si 8.011 7.797 7.955 7.797 7.956 7.776 8.008 7.800 8.061 7.857 7.921 7.754 7.998 7.823 7.979 7.803Al 1.780 1.733 1.841 1.804 1.836 1.794 1.814 1.767 1.730 1.686 1.821 1.782 1.846 1.806 1.837 1.797Fe+3 0.000 1.226 0.000 0.913 0.000 1.040 0.000 1.191 0.000 1.164 0.000 0.969 0.000 1.006 0.000 1.017Fe+2 1.260 0.000 0.932 0.000 1.064 0.000 1.222 0.000 1.194 0.000 0.989 0.000 1.028 0.000 1.040 0.000Mg 2.005 1.952 2.324 2.278 2.190 2.140 2.025 1.972 2.073 2.021 2.326 2.277 2.134 2.087 2.158 2.111Ca 0.036 0.035 0.089 0.087 0.058 0.057 0.032 0.031 0.040 0.039 0.085 0.083 0.052 0.051 0.039 0.038Na 2.013 1.960 1.967 1.928 2.042 1.996 1.969 1.918 1.951 1.902 2.054 2.011 2.041 1.996 2.097 2.050

Stoichiometry [Cations based Si + Al + Fe(total) + Mg = 13]SiAlFe+3Fe+2MgCaNa

Fe3/Fe3+AlFe2/Fe2+Mg

Glaucophane DataSample #analysis #



Si 8.012 7.782 7.977 7.713 7.979 7.725 7.902 7.648 7.989 7.735 7.992 7.706 7.957 7.669 7.916 7.699Al 1.812 1.760 1.760 1.702 1.789 1.732 1.917 1.856 1.828 1.769 1.683 1.623 1.729 1.666 1.922 1.869Fe+3 0.000 1.320 0.000 1.524 0.000 1.466 0.000 1.478 0.000 1.466 0.000 1.644 0.000 1.670 0.000 1.260Fe+2 1.359 0.000 1.577 0.000 1.515 0.000 1.527 0.000 1.515 0.000 1.704 0.000 1.733 0.000 1.296 0.000Mg 1.834 1.782 1.731 1.673 1.765 1.708 1.677 1.623 1.672 1.618 1.672 1.612 1.651 1.591 1.886 1.834Ca 0.040 0.038 0.037 0.036 0.042 0.041 0.091 0.088 0.065 0.063 0.042 0.040 0.061 0.059 0.093 0.090Na 2.051 1.992 2.121 2.050 2.074 2.008 2.052 1.986 2.058 1.992 2.147 2.070 2.095 2.019 2.021 1.966


Fe3/Fe3+AlFe2/Fe2+Mg 0.474 0.477 0.474 0.3940.414 0.450 0.433 0.463

0.006 0.097 0.124 0.0350.033 0.083 0.085 0.041

2.057 2.138 2.084 2.0182.048 2.113 2.066 2.0480.065 0.042 0.061 0.0930.039 0.037 0.042 0.0911.671 1.665 1.642 1.8831.832 1.725 1.758 1.6741.504 1.517 1.479 1.2241.296 1.413 1.343 1.4430.010 0.181 0.244 0.0700.061 0.159 0.166 0.0811.827 1.677 1.719 1.9191.810 1.754 1.782 1.9147.987 7.960 7.915 7.9048.001 7.950 7.950 7.888

95.244 96.294 94.670 94.87095.632 96.542 95.819 95.7477.436 7.768 7.446 7.3307.493 7.738 7.536 7.4380.426 0.273 0.393 0.6090.261 0.245 0.278 0.5967.857 7.868 7.630 8.8998.719 8.214 8.341 7.90812.689 14.298 14.274 10.89611.510 13.339 12.758 12.83610.864 10.021 10.105 11.46710.893 10.566 10.692 11.43355.973 56.065 54.823 55.669

3c 3d 3e 41 2 3a 3b16103 16103 16103 1610316103 16103 16103 16103

0.322 0.253 0.320 0.3140.346 0.243 0.291 0.3680.107 0.100 0.012 0.0280.101 0.091 0.082 0.023

56.757 56.439 56.214 55.536

RIM

1.942 2.045 2.040 2.0942.005 1.959 2.035 1.9680.040 0.084 0.052 0.0390.036 0.089 0.058 0.0322.064 2.316 2.133 2.1561.997 2.315 2.182 2.0230.982 0.783 1.005 0.9861.056 0.744 0.898 1.1780.206 0.202 0.023 0.0530.198 0.184 0.163 0.0431.722 1.813 1.845 1.8351.772 1.834 1.829 1.8138.025 7.886 7.994 7.9707.977 7.923 7.928 8.000

99.000 95.948 95.749 97.62197.206 97.558 96.886 95.4587.439 7.615 7.562 7.9107.508 7.447 7.637 7.2290.274 0.569 0.348 0.2640.243 0.610 0.395 0.21110.284 11.219 10.287 10.5929.727 11.449 10.652 9.66810.554 8.504 8.833 9.09410.891 8.180 9.225 10.40310.853 11.105 11.254 11.40110.919 11.468 11.293 10.95659.595 56.936 57.465 58.36157.918 58.405 57.684 56.991

RIM CORE CORE RIM5 6 7 81 2 3 4

26123 26123 26123 2612326123 26123 26123 26123

RIM CORE CORE





Si 8.075 7.832 8.003 7.778 8.010 7.812 8.038 7.818 8.105 7.846 8.030 7.833 7.994 7.793 8.028 7.831Al 1.623 1.574 1.678 1.631 1.690 1.648 1.709 1.662 1.594 1.543 1.622 1.582 1.719 1.676 1.680 1.639Fe+3 0.000 1.387 0.000 1.294 0.000 1.133 0.000 1.256 0.000 1.471 0.000 1.131 0.000 1.156 0.000 1.132Fe+2 1.430 0.000 1.332 0.000 1.162 0.000 1.291 0.000 1.520 0.000 1.160 0.000 1.186 0.000 1.160 0.000Mg 1.928 1.869 2.066 2.008 2.204 2.150 1.961 1.907 1.841 1.782 2.235 2.180 2.151 2.097 2.148 2.095Ca 0.029 0.029 0.063 0.061 0.052 0.051 0.043 0.042 0.019 0.018 0.090 0.088 0.043 0.042 0.070 0.068Na 2.054 1.992 2.033 1.976 2.055 2.005 2.131 2.073 2.038 1.973 2.044 1.994 2.106 2.053 2.091 2.040






Si 8.011 7.798 7.948 7.735 8.000 7.732 8.065 7.781 8.038 7.780 7.929 7.782 7.908 7.762 8.041 7.763Al 1.726 1.680 1.689 1.643 1.561 1.509 1.389 1.340 1.554 1.504 1.863 1.828 1.892 1.857 1.710 1.651Fe+3 0.000 1.221 0.000 1.232 0.000 1.539 0.000 1.616 0.000 1.475 0.000 0.855 0.000 0.853 0.000 1.587Fe+2 1.254 0.000 1.266 0.000 1.592 0.000 1.675 0.000 1.524 0.000 0.871 0.000 0.869 0.000 1.644 0.000Mg 2.053 1.999 2.188 2.129 1.923 1.858 1.999 1.929 1.954 1.891 2.337 2.293 2.372 2.328 1.658 1.601Ca 0.061 0.059 0.061 0.060 0.101 0.098 0.128 0.124 0.090 0.087 0.141 0.138 0.116 0.114 0.029 0.028Na 2.044 1.990 2.113 2.056 2.085 2.016 1.969 1.900 2.050 1.984 1.998 1.961 1.976 1.939 2.045 1.974


Fe3/Fe3+Al0.395 0.271 0.233 0.4680.349 0.302 0.408 0.3790.137 0.000 0.072 0.0990.082 0.159 0.147 0.246

2.039 1.998 1.970 2.0362.037 2.099 2.073 1.9500.090 0.141 0.116 0.0290.061 0.061 0.100 0.1271.943 2.337 2.365 1.6512.047 2.173 1.911 1.9801.270 0.871 0.720 1.4501.095 0.941 1.316 1.2100.246 0.000 0.146 0.1870.154 0.317 0.267 0.4491.546 1.863 1.886 1.7031.720 1.677 1.552 1.3757.995 7.930 7.883 8.0087.984 7.893 7.954 7.986

96.602 91.822 93.035 92.47796.351 96.806 95.099 95.6307.493 7.125 7.144 7.1437.545 7.810 7.473 7.0780.596 0.909 0.761 0.1820.406 0.409 0.655 0.8339.290 10.839 11.157 7.5369.859 10.518 8.961 9.34812.912 7.199 7.282 13.31710.731 10.846 13.229 13.9609.346 10.928 11.254 9.82810.479 10.267 9.201 8.21156.965 54.823 55.437 54.47157.331 56.955 55.580 56.201

10f 1 2 310b 10c 10d 10e26125 56141 56141 5614126125 26125 26125 26125

0.415 0.308 0.319 0.3390.390 0.337 0.297 0.3970.118 0.092 0.094 0.0330.110 0.143 0.120 0.000

2.028 2.037 2.098 2.0892.045 2.021 2.045 2.1310.018 0.090 0.043 0.0700.029 0.062 0.052 0.0431.832 2.227 2.143 2.1451.919 2.054 2.193 1.9611.301 0.992 1.004 1.1011.225 1.046 0.926 1.2910.212 0.163 0.178 0.0580.200 0.278 0.229 0.0001.587 1.616 1.712 1.6781.616 1.668 1.681 1.7098.068 8.002 7.963 8.0188.040 7.955 7.970 8.039

95.269 96.867 96.933 96.09495.922 96.724 95.734 95.8867.374 7.605 7.834 7.7207.502 7.505 7.562 7.8140.122 0.608 0.290 0.4660.195 0.418 0.349 0.2888.665 10.813 10.410 10.3139.159 9.922 10.547 9.35312.751 10.001 10.228 9.93112.115 11.398 9.909 10.9779.489 9.923 10.520 10.2049.756 10.194 10.228 10.30856.869 57.918 57.651 57.46157.195 57.287 57.138 57.147

RIM CORE7 8 9 10a3 4 5 6

26125 26125 26125 2612526125 26125 26125 26125

Fe2/Fe2+Mg





Si 7.978 7.836 7.932 7.788 7.986 7.806 7.972 7.814 7.923 7.788 7.982 7.819 8.007 7.817 7.985 7.791Al 1.872 1.838 1.875 1.841 1.895 1.852 1.895 1.857 1.904 1.871 1.900 1.861 1.869 1.824 1.837 1.793Fe+3 0.000 0.820 0.000 0.836 0.000 1.034 0.000 0.912 0.000 0.781 0.000 0.944 0.000 1.091 0.000 1.118Fe+2 0.835 0.000 0.851 0.000 1.058 0.000 0.931 0.000 0.795 0.000 0.963 0.000 1.118 0.000 1.146 0.000Mg 2.318 2.277 2.399 2.356 2.089 2.042 2.256 2.212 2.399 2.358 2.192 2.147 2.021 1.973 2.063 2.013Ca 0.128 0.126 0.108 0.106 0.041 0.040 0.040 0.040 0.110 0.108 0.034 0.034 0.051 0.049 0.074 0.072Na 1.909 1.875 1.930 1.895 1.998 1.954 1.971 1.932 1.991 1.957 1.989 1.948 1.986 1.939 1.981 1.933





Stoichiometry [Cations Bases on 23 Oxygens]All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric All Ferrous All Ferric

Si 8.050 7.835 7.968 7.831 7.953 7.813 8.031 7.809 8.019 7.823 7.758 7.497Al 1.805 1.757 1.846 1.814 1.896 1.862 1.790 1.741 1.742 1.699 0.559 0.540Fe+3 0.000 1.227 0.000 0.790 0.000 0.811 0.000 1.270 0.000 1.126 0.000 1.550Fe+2 1.260 0.000 0.804 0.000 0.825 0.000 1.306 0.000 1.155 0.000 1.604 0.000Mg 1.890 1.840 2.388 2.347 2.356 2.314 1.849 1.798 2.031 1.982 3.122 3.017Ca 0.044 0.043 0.115 0.113 0.078 0.077 0.030 0.029 0.180 0.175 1.691 1.634Na 1.996 1.943 1.974 1.940 1.980 1.945 2.137 2.078 1.968 1.919 0.456 0.440



1.976 0.454

0.010 0.012 0.054 0.000 0.000 0.214

1.995 1.973 1.976 2.141

0.000 0.152

1.889 2.387 2.350 1.853 2.040 3.112

0.019 0.023 0.107 0.000

7.364 1.630

8.046 7.964 7.935 8.045 8.052 7.733

7.500 7.606 7.620 8.115

10.723 3.286

9.238 11.968 11.792 9.135 9.889 14.523

11.158 11.702 12.002 11.185

12c 12d10d 11 12a 12b

0.345 0.3340.262 0.213 0.315 0.246 0.232 0.2740.036 0.067 0.028 0.0570.007 0.097 0.048 0.092

1.988 1.983 1.984 1.9761.908 1.922 1.994 1.9630.110 0.034 0.051 0.0740.128 0.108 0.041 0.0402.395 2.186 2.019 2.0582.318 2.389 2.085 2.2470.722 0.825 1.064 1.0330.822 0.646 0.960 0.7350.071 0.135 0.053 0.1100.013 0.201 0.096 0.1921.901 1.895 1.867 1.8331.871 1.867 1.891 1.8877.910 7.959 7.998 7.9667.976 7.897 7.969 7.939

98.521 98.812 99.256 98.47792.443 98.592 98.724 98.1537.650 7.636 7.613 7.5156.889 7.410 7.635 7.5240.763 0.239 0.352 0.5090.835 0.752 0.281 0.27911.989 10.946 10.077 10.17810.885 11.980 10.381 11.2057.079 8.575 9.934 10.0776.889 7.574 9.367 8.23812.031 12.001 11.783 11.46611.114 11.841 11.910 11.90159.009 59.414 59.499 58.73155.832 59.035 59.150 59.007

CORERIM9c 10a 10b 10c4 8 9a 9b

56141 56141 56141 5614156141 56141 56141 56141

56141 5614156141 56141 56141 56141

CORE RIM

58.642 59.527 59.339 59.128 58.188 53.789

10.979 7.183 7.363 11.497 10.018 13.293

1.804 1.845 1.891 1.794 1.749 0.557

1.241 0.781 0.716 1.308 1.159 1.446

0.044 0.115 0.078 0.030 0.180 1.686

0.301 0.802 0.545 0.204 1.217 10.944

97.817 98.788 98.661 99.264 97.399 97.465

0.396 0.247 0.234 0.414 0.362 0.317

Note: Arrows from rim to core indicates mineral analyses along indivigual crystals transects

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Appendix 2. Prophyroblastic Systems

Date Collected Location Thin Section Sigma Delta symetrical undetermined6/9/03 26 Katergaki 1691 15 0 16 206/9/03 26 Katergaki 1692 6 0 10 11

6/10/03 31 Katergaki 16101 7 1 2 16/10/03 32 Katergaki 16103 * 11 0 2 26/12/03 38 North Ermopoli 16121 6 13 37 206/12/03 39 North Ermopoli 16122 11 0 22 36/23/03 63 North Ermopoli 36231 8 0 34 36/12/03 39 North Ermopoli 26122a 9 1 13 116/12/03 39 North Ermopoli 16123.1* 17 2 20 56/12/03 39 North Ermopoli 16123.2 7 2 7 146/12/03 39 North Ermopoli 26125 * 2 0 2 66/23/03 63 North Ermopoli 26231 5 0 3 16/13/03 42 Airport 36131 4 1 1 396/13/03 41 Airport 16131 0 0 12 46/13/03 44 Airport 56131 5 3 23 66/13/03 43 Airport 46131 3 0 3 106/14/03 48 Charrasonis Hill 56141 * 0 0 12 126/14/03 45 Charrasonis Hill 16141 0 0 35 206/14/03 47 Charrasonis Hill 36141 8 0 7 76/14/03 47 Charrasonis Hill 36142 0 0 11 46/14/03 48 Charrasonis Hill 46141 1 1 2 66/14/03 48 Charrasonis Hill 56142 3 1 10 36/17/03 50 Perdiki 26171 7 0 2 136/17/03 51 Perdiki 36171 10 2 23 66/19/03 52 Paradice 26191 3 0 14 56/19/03 53 Paradice 36191 0 0 6 126/19/03 52 Paradice 16191 0 2 2 06/20/03 55 San Michael 16203 14 0 5 676/20/03 55 San Michael 16201 16 2 19 156/20/03 55 San Michael 16202 8 0 9 226/21/03 57 Kini 26211 8 0 2 76/21/03 57 Kini 26212 0 0 3 86/21/03 56 Kini 16212 1 8 14 136/21/03 56 Kini 16211 2 8 53 226/22/03 58 Kastri 16221 18 2 13 96/22/03 59 Kastri 26221 1 1 8 76/22/03 59 Kastri 36221 0 5 6 26/23/03 62 Windmill Hill 16231 3 0 3 16/23/03 62 Windmill Hill 16232 0 0 4 0

totals 219 55 470 417Note: * Thin sections analyzed on Smith College's SEM with EDS

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Microstructures associated with deep crustal subduction

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