a preliminary view of metamorphic rocks from schwaner ......metamorphic rocks are intruded by...
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A Preliminary View of Metamorphic Rocks from Schwaner Mountains, West
Kalimantan and Bantimala Complex, South Sulawesi in Indonesia
Nugroho I Setiawan, Y. Osanai, N. Nakano, T. Adachi, K. Yonemura, A. Yoshimoto (Kyushu University), and Joko
Wahyudiono (GRDC Indonesia)
Kyushu University UI project Kyudai Taro,2007
Location of Indonesia 95° - 141°E and 6°N – 11°S. Boundaries three major plates: Eurasia, Indo-Australia, and Pacific-Philippine Sea
Japan
Indonesia
Papua Sulawesi
Kalimantan Sumatera
Java Timor
Seram
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Tectonic framework on the Indonesia region
Hall, 2008
Japan
Indonesia
Kalimantan
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Study Area Japan
Indonesia
Schwaner Mountains West Kalimantan
South Sulawesi
Central Java
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Regional Geology of West Kalimantan Williams, et al. (1988) divided
geology of West Kalimantan into three geological domains:
1. Schwaner Mountains in the south: granitic and metamorphic rocks
2. Northwest Kalimantan domain: schist and deformed granite
3. Melange and associated accretionary deposits
2
1
3
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Regional Geology of West Kalimantan Schwaner Mountains
! Chemical composition indicate I-type calc-alkaline nature ! There is a gap in composition from 67% SiO2 to 72% SiO2, which suggests at least two
batholiths are present also supported by K-Ar ages data ! Haile, et al (1977) obtained K-Ar ages ranging from Jurassic (157 Ma) to Late Cretaceous (77
Ma) ! Williams, et al (1988) obtained K-Ar ages on 33 specimens ranging from Early Cretaceous (129
Ma) to Late Cretaceous (87 Ma)
Northwest Kalimantan domains ! Metamorphic rocks comprising schist, phyllite and quartzite with garnet grade greenschist facies ! Metamorphic rocks are intruded by deformed biotite granite, which yields K-Ar ages from Permian (320
Ma) to Late Triassic (204 Ma) (Williams, et al., 1988)
Melange and associated accretionary deposits ! Comprise of deformed flysch, melange and marine outer shelf deposits ! Dominantly east-trending outcrop belts ! Two zones of melange defined in this region are Boyan and Lubok Antu melange
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Radiometric Age Data Granitoids of West Kalimantan
Williams, et al (1988)
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General Strat igraphy of West Kalimantan
Williams, et al (1988)
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Current Samples Location
1. 84MS89A (Metatonalite) 2. 841U22A (Metatonalite) 3. 84BH236A (Metagranitoid) 4. 84BH354B (Biotite schist)
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Mineral Assemblages
From the textures and mineral assemblages, can be divided into two groups: 1. Metatonalite sample no.84MS89A and 841U221A 2. Metagranitoid (84BH236A) and Biotite schist (84BH354B)
No# Sample#No# Loca,on# Rock#Type#Mineral#Assemblages#
Major#Minerals# Minor#Minerals# Others# Relict#Qz# Pl# Kfs# Hbl# Bt# Bt# Opq# Ttn# Ep# Ap# Ms# Chl# Ser# Cpx#
1" 84MS89A"Nangataman"/"Schwaner"Mountain" Metatonalite" " # �� " /" �� �� # /" �� /" /" /" (#)"
2" 841U221A"Nangataman"/"Schwaner"Mountain" Metatonalite" " # �� # # /" �� �� /" �� /" /" /" /"
3" 84BH236A"Nangataman"/"Schwaner"Mountain" Metagranitoid" " # �� /" # /" �� �� �� �� /" �� �� /"
4" 84BH354B"Nangataman"/"Schwaner"Mountain" BioCte"Schist" " �� # /" " /" �� /" �� /" �� /" /" /"
" Abundant,"# Moderate,"��Poor,"/""absent,"("")"in"relict"minerals"or"inclusion"
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Representative Photomicrograph
Metagranitoid Biotite schist
Metatonalite
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Chondrite normalizing value are from Thompson (1982). Upper continental crust are from Taylor and McLennan (1981). Lower continental crust are from Waver and Tarney (1984)
Diagrams of Bulk Chemical Analysis
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Age Determination by Zircon LA-ICPMS on Metatonalite (84MS89A)
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Tentative Conclusion of metamorphic rocks from Schwaner Mountains
Metatonalite from the Schwaner Mountains (Central Kalimantan) suggests the same group with NW Kalimantan metamorphic rocks
The evidence of age dating, metamorphism on metatonalite from Schwaner Mountains suggests simultaneous synmetamorphic igneous activity
Field observation and comprehensive field sampling are needed in order to understanding more detail metamorphism and tectonic condition in Schwaner Mountains
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Geological Background of South Sulawesi
Barru
Bantimala
Modified from Sukamto, 1982
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Simplified Geological Map of Bantimala Area
Modified from Sukamto, 1982
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Simplified Geological Map of Barru Area
Modified from Sukamto, 1982
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Outcrop Photograph of Bantimala Complex Grt blueschist
Grt blueschist Eclogite
Grt-Jd-Qtz rock
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Representative Photomicrograph of Eclogites in Bantimala
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Qtz
Qtz
Jd
Jd
Grt
Ph
Ab
Amp
Ab
Ep
Grt
Ph
Mineralogy of Grt – Jd rock
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Ternary Cpx Nomenclature of Eclogite and Grt-Jd rock
Okamoto, et al. (2000)
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Matrix
Inclusion
Leake, B. E., et al. (1997)
Amphibole Nomenclature of Eclogite and Grt-Jd rock
Eclogite Eclogite Grt-Jd rock
Grt-Jd rock Eclogite Eclogite
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Ternary Diagrams for Grt compositions
Grt-Jd rock
Eclogite Grt-Jd rock
Eclogite
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Zoning Profile in Garnet
Grt-Jd rock [110309T01D] Eclogite [110310T03F]
Eclogite [110310T03I] Eclogite [UNHAS 3] Eclogite [UNHAS 5]
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Tentative P-T Path Diagram on Bantimala Area
• The Jd-Grt rock from Bantimala Complex, South Sulawesi suggests that the rock passed through Jd + Qz stability field during metamorphic evolution
• Pseudomorph of coesite indicates that the eclogite passed through Coe stability field
• Peak of metamorphism of Eclogite represented by garnet rim and omphacite in the matrix
• Grt – Cpx thermometer (Krogh, 1988., Pattison & Newton, 1989., and Ravna, 2000) yield a temperature of 670 ± 20 °C for pressure of 25 kbar on the sample of eclogite UNHAS 2.
• The occurrence of Gln in the core and mantel inclusion of Grt on Bantimala eclogite indicates the former stability field of blueschist area
• Retrogression observed in the Bantimala eclogites represented by replacement of Omp and Gln by Bar, Wnc and Act
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Photomicrograph of metamorphic rocks from Central Java Eclogite
Grt-Mica schist
THANK YOU FOR YOUR ATTENTION
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Karangsambung
Bayat
Yogyakarta
Samples Location in Central Java
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Gambar-1. Peta geologi daerah Bayat (Prasetyadi, 2007).
Gambar-2: Kronostratigrafi Jawa Tengah selatan (termasuk Bayat)(Prasetyadi & Indranadi, 2007).
Simplified Geological Map of Bayat Area
Prasetyadi, 2007
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Simplified Geological Map of Karangsambung Area
Modified from Prasetyadi, 2007
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Mineral Assemblages of Metamorphic Rocks in Central Java
""
Loca,on# Rock#Name# Tot#
Mineral#Assemblages# ""No# Major#Minerals# Minor#Minerals# Secondary# Remark#
"" Grt# Gln# Qtz# Amp#Omp# Ep/Zoe# Ph# Srp# Ttn# Rt# Opq# Ap# Other# ## ""
1"Bayat,"Central"Java" SerpenCnite" 3" �� �� �� �� �� �� �� " �� �� �� �� Spl" Chl,"Cal" ""2"Bayat,"Central"Java" Greenschist" 2" �� �� " �� �� �� �� �� �� �� �� �� Tlc" Act" Chl"abundant"3"Bayat,"Central"Java" Carbonate"bg"schist" 2" �� �� " �� �� �� �� �� �� �� �� �� �� Cal" ""4"Bayat,"Central"Java" Metadolerite" 2" �� �� # �� �� �� # �� �� �� �� �� Act" Tlc,"Ab" Relict"of"Pl"and"Cpx"5"Karangsambung,"Central"Java" Eclogite" 1"# # # �� # �� Δ �� # �� �� �� �� Chl" ""6"Karangsambung,"Central"Java" Grt"Amphibolite" 14" Δ �� " # �� �� �� �� �� �� �� �� Pl" Chl,"Ab" ""7"Karangsambung,"Central"Java" Amphibolite" 6" �� �� # " �� # # �� �� �� �� �� �� Chl" ""8"Karangsambung,"Central"Java" Grt/"Mica"schist"(Fine"grain)" 8" �� �� " �� �� �� Δ �� # �� �� Δ Pl,"Act" Chl,"Cal,"Ab"""9"Karangsambung,"Central"Java" Blueschist" 11" �� Δ Δ �� �� " �� �� Δ �� �� �� �� Cal,"Chl" ""10"Karangsambung,"Central"Java" Greenschist" 4" �� �� " �� �� �� �� �� �� �� �� �� Act" Cal" Chl"abundant"11"Karangsambung,"Central"Java" SerpenCnite" 5" �� �� �� �� �� �� �� " �� �� �� �� Spl" Chl,"Cal" ""12"Karangsambung,"Central"Java" Grt"blueschist" 7"# " �� �� �� # # �� Δ �� �� �� �� Ab,"Chl" ""13"Karangsambung,"Central"Java" Grt/Mica"schist" 23"# �� " �� �� �� Δ �� # �� �� �� �� Chl,"Cal" ""14"Karangsambung,"Central"Java" Metagraywacke" 3" �� �� " �� �� �� �� �� �� �� �� �� Chl" Ab" Chl"abundant"15"Karangsambung,"Central"Java" Talc"schist" 1" �� �� " �� �� �� �� �� �� �� # �� Act,"Chl" Ab" Tlc"abundant"16"Karangsambung,"Central"Java" Metadolerite" 1" �� �� # �� �� �� # �� �� �� �� �� �� Tlc,"Ab" Relict"of"Pl"and"Cpx"17"Karangsambung,"Central"Java" Riversand" 1" �� �� $ �� �� �� $ �� �� �� �� �� �� "" ""
94#" Abundant,"Δ"Rich,"# Moderate,"��Poor,"/""absent,"±"occurs"in"some"sample"