OFIOLIT ?v Ofiolit adalah sisa kerak samudra purba dan
mantel atas yang alih tempat / penempatannyake tepian benua secara tektonik ;
v Berumur maksimum 170jt th
v Ophios : ular ;lithos :batu -à batu ular
Alexandre Brongniart (1740 – 1847)1813 : ofiolit adalah serpentinit di mélange1821 : redefinisi ofiolit mencakup himpunan batuan ultramafik,
gabbro, diabas, dan batuan volkanik (di Peg.Alpen)
Gustav Steinmann (1856–1929)1927 : - Ofiolit adalah himpunan batuan beku intrusi insitu
di sumbu geosinklin.
- Kehadiran himpunan batuan peridotit (serpentinit), gabbro,dan diabas-spilit (spilit : lava dengan albitisasi plagioklas),berasosiasi dengan batuan sedimen laut dalam (rijang,batulumpur serta batugamping) di Rangkaian PegununganMediteran,diinterpretasikan sebagai hasil diferensiasimagma di lantai samudra.
- Ko magmatik.
Steinmann Trinity : serpentinit, diabas -spilit, rijang
- "Ofiolit Semail" di Oman (Mesozoikum), Ofiolit Troodos di Siprus
(Mesozoikum), “Ofiolit Papua " di Papua Nugini (Mesozoikum), dan
“Ofiolit Bay of Islands " di Newfoundland (Paleozoic) ; lain-lain
di Jepang ofiolit Yakuno (Paleozoic), Hirakanai (Mesozoikum) dan
Poroshiri (Mesozoikum) , di Indonesia Meratus-Bobaris Kalimantan,
Bantimala Sulawesi Selatan, lengan timur Sulawesi, Halmahera,
Ciletuh, Karangsambung, Talaud, Timor, dll.
Penrose Conference 1972 Terdiri dari pseudo stratigrafi batuan beku
v basalt (di bagian atas), v anggota gabbro (diabas dan gabbro) dibagian tengah
danv anggota peridotit (lersolit, serpentin, harsburgit) dibagian
bawah.
KLASIFIKASI BERDASARKAN TATANAN TEKTONIK
Terbentuk di MOR (divergent plate boundaries) - lersolitTerbentuk di Supra subduction zone (SSZ) : busur kepulauan dantepian cekungan (marginal basins) --- convergent plate boundaries- Harsburgit
Data kimia dari batuan dan mineral
There are incompatible-rich and incompatible-poor mantle source regions for MORB magmas
– N-MORB (normal MORB)
§ Mg# > 65: K2O < 0.10 TiO2 < 1.0
§ Depleted in LREE, Low LILE e.g. K+
– E-MORB (enriched MORB, P-MORB for plume)
§ Mg# > 65: K2O > 0.10 TiO2 > 1.0
§ Rich in LREE, higher in LILE e.g. K+
E-MORBs (squares) enriched in LREE over N-MORBs (red triangles): regardless of Mg#
Lack of distinct break suggests three MORB types
E-MORBs La/Sm > 1.8N-MORBs La/Sm < 0.7
T-MORBs (transitional) intermediate values
Manfaat ofiolit
v Mekanisme “pertemuan” lempeng----à geodinamika
v Ofiolit : endapan mineral logam dan non logamlogam mulia : emas,peraklogam berat : besi, kromit, nikel,grup platinummineral non logam : jade, asbes
Distribution of Cretaceous accretionary-collision complexes. 1 = Ciletuh, 2 = Karangsambung, 3 = Jiwo Hills, 4 = Meratus, 5 = Pulau Laut, 6 = Bantimala, 7 = Barru, 8 = latimojong, 9 Pompangeo, 10 = Palu
( modified from Metcalf, 1990; Wakita, 2000)
Sumatra
Java
Kalimantan
SulawesiPapua
Jakarta
Bandung
Yogyakarta
Luh Ulo
Semarang
Java Sea
INDONESIA
MALAYSIA
AUSTRALIA
PHILIPINES
Surabaya
Luh Ulo area, Central Java
Waturanda Fm.
Totogan Fm.
Karangsambung Fm.
Black clay
Graywacke
Meta graywace/Meta arkose ?
Schist
a. Diabasb. Basalt
Gabbro, peridotite
Serpentinite
Detail observation
PETA GEOLOGI DAERAH LUH ULO (Sukendar,1974)
Pillow basalt and radiolarian chert
Diabase
Massive gabro
Cummulate gabro
HarsburgiteSerpentinite
Dacite
Sediments
Melange
Milonites and breciatedrock
Faults
Pakuruhan River Section
Sediments (chert)Pillow lava
Diabase
Massive gabro
Cummulate gabro
HarburgiteSerpentinite
LEGEND :
Scale 1:12.500
CurugdawaRiver Section
Pillow basalt
Diabase
Massive gabro
Cummulate gabro
HarsburgiteSerpentinite
Metamorphic rocks
Sediments
Melange
Milonites
Faults
Basalt
Diabase
Massive gabro
Cummulate gabro
HarburgiteSerpentinite
LEGEND :
Scale 1:12.500
Basalt
Diabase
Massive gabro
HarburgiteSerpentinite
LEGEND :
Basalt and chert
Diabase
Massive Gabbro
Metamorphic rocks
Mylonite and Brecciated rocks
Harzburgite, Serpentinite
ParakansubahRiver Section
Scale 1:12.500
Massive gabbro outcrops showing some blocks of diabase . (Loc : Medana River)
Diabase outcrop showing white spotted plagioclase phenocrysts(Loc : Medana River)
Altered &deformed gabbro. Notes the presence of veins of quartz or carbonate, and epidote veins . (Loc : Medana River)
a. b.
epidotequartz or carbonate
Boulder basalt in diabase outcrop (a); commonly show mixing of diabase, gabbro and basalt (Loc : Lokidang River)
a. b.
Basalt lava with pillow structures; close up photograph of outcrop (b); (Loc : Lokidang River)
a. b.
Pillow Lava
Diabase
Massive gabbro
Cummulategabbro
HarzburgiteSerpentinite
Pelagic Sediments
Pillow Lava
Pelagic Sediments
Pillow Lava
Pelagic Sediments
Pillow Lava
Pelagic Sediments
Pillow Lava
Pelagic Sediments
Massive gabro Massive gabro Massive gabbro Massive gabbro
Diabase Diabase Diabase Diabase
Cummulategabro
Cummulategabbro
Cummulategabbro
Cummulategabbro
HarzburgiteSerpentiniteLherzolite
HarburgiteSerpentinite
HarzburgiteSerpentiniteLherzolite
Pakuruhan River Curug Dawa River Medana River Lokidang River Parakan Subah River
Pseudostratigraphic Column of the Cretaceous Ophiolite Complex of Luh Ulo area
Pillow Lava
Diabase
Massive gabro
Cummulategabro
HarburgiteSerpentinite
Sediments
Pillow Lava
Sediments
Pillow Lava
Sediments
Pillow Lava
Sediments
Pillow Lava
Sediments
Massive gabro Massive gabro Massive gabro Massive gabro
Diabase Diabase Diabase Diabase
Cummulategabro
Cummulategabro
Cummulategabro
Cummulategabro
HarburgiteSerpentiniteLersolit
HarburgiteSerpentinite
HarburgiteSerpentiniteLersolit
Pakuruhan River Curug Dawa River Medana River Lokidang River Parakan Subah River
Pillow Lava
Sediments
Trondhjemite
Diabase dike
Olivine gabro
HarburgiteSerpentinite
Trondhjemite &
Quartz diorite
Unconformity
Schisst & serpentinite
Gabro
Peridotite
Imbricated peridotite
Pillow Lava
Sediments
Massive gabro
Diabase
Cummulategabro
Harburgite
Serpentinite
Lersolit
Gabro
Piroxenite
Peridotite
OPHIOLITES
(Penrose, 1972)
Meratus Ophiolites(Sikumbang, 1986)
Luh Ulo Ophiolites(Suparka, 1988)
OPHIOLITE
(Penrose, 1972)
MERATUSSoutheast Kalimantan
(Sikumbang, 1986)
LUH ULONorth Karangsambung
(Suparka, 1989)
SedimentsSediments
Pillow Lava
Diabase dike
Trondhjemite
Gabbro
Olivine gabro
Pyroxenite
Peridotite
Peridotite
HarzburgiteSerpentinite
Trondhjemite &
Quartz diorite
Gabbro
Peridotite
Imbricated Peridotite,
Peridotite
Schisst & serpentinite
Pillow Lava
Diabase
Massive Gabbro
CummulateGabbro
Penampang kolom ofiolit daerah penelitian dibandingkan dengan penampang kolom ofiolit Semailmenurut Boudier dan Nicolas (1985)
Litologi dan ketebalan ofiolit pada ofiolitSemail menurut Boudier dan Nicolas(1985)
PERBANDINGAN OFIOLIT DAERAH PENELITIAN VSMODEL OFIOLIT SEMAIL
Gabbro, showing intercalation of plagioclase and pyroxene lamination(X nicol)
Gabbro, plagioclase as intercumulate crystals altered to sericite, where pyroxene represent as cumulate crystals.(X nicol)
Gabbro, display recrystalization as the result of alteration and deformation. Prenhite aggregate filled along the fracture (a) or partly replaced the plagioclase. Carbonate also occurred. (X nicol).
a. b.
Diabase, medium grain with ophitic / diabasic texture (a)Basalt, fine grain with intergranular – intersertal texture (b)
a. b.
Normalized by chondrite (Sun & McDonough (1989)) Normalized by average N-type MORB-(Saunders & Tarney (1984);Sun (1980))
100
101
102
10-1
Rb Ba Th U K Nb Ta La Ce Sr Nd P Hf Zr Sm Ti Tb Y
100
101
102
10-1
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
10-1
100
101
102
10-2
Rb Ba Th U K Nb Ta La Ce Sr Nd P Hf Zr Sm Ti Tb Y
101
102
100
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
100
101
10-1
Rb Ba Th U K Nb Ta La Ce Sr Nd P Hf Zr Sm Ti Tb Y
Basalt DiabaseGabbro
101
102
100
La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu
10^ 0
10^ 1
10^ 2
10^-1
Rb Ba Th U Ta Nb K La Ce Pb Sr Nd Zr Hf Sm Ti Tb Y
Primitive mantle by Sun and McDonough (1992)
BasaltDiabaseGabbro
Ba La Ba Nd Sm Eu Gd Dy Er Yb Lu
50
10
2
North Karangsambung
Mid Oceanic Ridge
BASALT
Fractionation REE pattern of basalt from Karangsambung compare to REE pattern of common basalt from Mid Oceanic Rigde (MORB)
10x chondrites; flat pattern; depleted in LREE
Eurasia Continental Plate
Hindia Oceanic Crust
North Karangsambung Ophiolite
Cartoon diagram for showing emplacement of ophiolite in North Karangsambung
(Suparka, 1988)
(A) Emplacement of North Karangsambung Ophiolites ( Suparka,E., 1988).(B) Geologic section along N-S trend of Seboro Melange based on gravity anomaly (Kamtono et.al, 1996)
Ophiolite complexMid Oceanic Ridge relict
Melange Luh Ulo
Metamorphic rocks sequent (Melange complex)
Oceanic crust sequent
Melange Luh Ulo
Geological setting of the Luh Ulo , Karangsambung area at present day
(Suparka, 1988)
Recent 90-70 MA
33 b
120 – 90 MA
M O
Continental crust
Oceanic crust
Slice of Islands arc ophiolite
Melange wedge
Ophiolites
Islands Arc
Subduction zone
Mid Oceanic Ridge(Age 82-112 ma)
Mid Oceanic Ridge(Age 70-82 ma)33 b
M O
LEGEND :
THE DEVELOPMENT SCENARIO OF JAWA AND KALIMANTAN ISLAND BASE ON BASEMENT ROCKS
recent 90-70jt
Kesimpulan
v Himpunan batuan mafik – ultramafic Karangsambung Utarav adalah kompleks Ofiolit (ko genetic / ko magmatik)
v Terdiri dari harsburgit ,lersolit,gabbro (kumulat & non kumulat),v Diabas, lava bantal
v Kelas II (Myashiro,1975)
v Ofiolit terpisah-pisah, termetamorfisme
v Basalt : tipe N (normal)