ABSTRACT A PETROCHEMICAL STUDY ON THE LATE CENOZOIC GRANITIC ROCKS IN SULAWESI, INDONESIA

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1 ABSTRACT A PETROCHEMICAL STUDY ON THE LATE CENOZOIC GRANITIC ROCKS IN SULAWESI, INDONESIA by Adi Maulana Chairperson of the Supervisor Committee: Professor Koichiro Watanabe Department of Earth Resources Engineering Sulawesi, with its unusual K-shape consisting of four arms that merge in the central part of the island, is composed of an intricate collage of metamorphic complexes, ophiolite terranes, volcanic arcs, granitoid belts, and sedimentary basins. This represents a complex history of subduction, accretion, ophiolite obduction and collision. Together they form four major litho-tectonic units comprising the Eastern, Northern and Western Sulawesi Provinces and the Banggai-Sula Microcontinent. One of the most widely distributed rock units in this island are granitic rocks, which cover almost 20% of the island stretching from the southern part of the Western Sulawesi Province to the central part of the Northern Sulawesi Province. Some granitic rocks have been identified on the basis of geochemical characteristics, but to date no detailed examinations of the granitic rock units have been undertaken. This dissertation is based on field sampling of granitic rocks from 11 areas in the Western and Northern Sulawesi Provinces. Over 110 granitic samples including some enclaves were systematically collected from various localities in the studied areas. Of these, 80 thin sections were prepared and studied petrographically to determine the rock types, mineral assemblages, fabric and textural relations. Concentrations of major elements of 84 fresh samples were analyzed using the X-ray fluorescence spectrometer (XRF), whereas trace and rare earth elements were determined by the inductively couple mass spectrometer (ICP-MS) method. Isotopic ratios of Sr, Nd, Pb and O were determined for 12 samples using i

2 a Thermofisher Triton RPQ multicollector mass spectrometer (for radiogenic isotope) and VG Optima mass spectrometer (for oxygen isotope). In order to get the cooling age, the argon-argon dating method was used for geochronologic analyses of 3 samples. Mineral chemistry analysis was conducted on the basis of electron microprobe analysis (EPMA) using a JEOL JXA-8800R to determine the mineral composition used for geotermobarometry calculation. Magnetic susceptibility of the rocks was measured in the field with a portable KT-10 Magnetic Susceptibility Meter of Terraplus. XRD analysis was conducted in order to determine the mineral composition and clay mineral in the weathered samples. Petrographical and geochemical study shows that the granitic rocks have a considerable compositional range from granodiorite through quartz monzonite, monzonite, monzodiorite, syenite to granite with enclaves of diorite. Major element composition (SiO 2 and K 2 O) indicates that the plutons can be classified as high-k or shoshonitic (HK) which are concentrated in the southern and central-western (CW) part of the Western Sulawesi Province, high-k calc-alkaline (CAK) which are found in the central and north-western (NW) part of the province and low-k to tholeiitic series which are dominated in the central part of the Northern Sulawesi Province. However, some samples from Masamba and Mamasa Pluton which are located in the CW part of the Western Sulawesi Province show a low-k to tholeiitic affinity. Most of the granitic rocks are metaluminous I-type granitic rocks. With an exception of tonalitic rocks in Gorontalo, all granitic samples resemble the upper continental crust pattern in their trace and rare earth element patterns. Enrichment of large ion lithophile elements (Rb and Sr) and depletion of high field strength elements (especially Nb and Ta) suggests an arc magma affinity. Negative Eu anomaly in most of the samples shows plagioclase fractionation during magmatic differentiation. Most of the samples show a high 87 Sr/ 86 Sr values but a low 143 Nd/ 144 Nd, suggesting a strong upper crustal component sources. In addition, they have high 206 Pb, 207 Pb and 208 Pb isotope ratios. However, microdioritic ii

3 enclaves and tonalitic rocks from Gorontalo Pluton in the Northern Sulawesi Province show lower 87 Sr/ 86 Sr values but higher 143 Nd/ 144 Nd and relatively higher 206 Pb, 207 Pb and 208 Pb values, suggesting a more basic source. Whole-rock δ 18 O values from the granitic rocks are in the range of +5.7 to +9.6 permil (outlier three samples lower than +5.1 permil and two samples higher than +12 permil). The low δ 18 O value can be attributed to the introduction of meteoric hydrothermal alteration whereas the higher δ 18 O value indicates the significant involvement of high δ 18 O metasedimentary rocks in the melting process. 40 Ar/ 39 Ar ages of hornblende and biotite separated from the granitic rocks in Sulawesi range between 9.5 and 3.12 Ma suggesting that the cooling occurred during the Late Miocene to Late Pliocene. The magnetic susceptibility of the granitic rocks varies between 0.08 x 10-3 SI to 18.5 x 10-3 SI, corresponding respectively to ilmenite-series (< 3x 10-3 SI; reduced type) and magnetite-series (> 3x 10-3 SI; oxidized type) granite. Geothermobarometry condition was calculated for 5 different plutons; including the Mamasa and the Masamba Plutons from CW of Western Sulawesi Province; the Lalos-Toli and the Sony Pluton from NW of Western Sulawesi Province and the Gorontalo Pluton from Northern Sulawesi Province. Pressure and temperature of crystallization estimation were based on the Al-in-hornblende geobarometry whereas the temperature of formation were calculated using the hornblende and plagioclase geothermometry. The results show that the Mamasa and Masamba Plutons were crystallized at 0.91 to 1.2 kbar with the formation temperature of 677 to 729 C and 2.3 to 2.8 kbar with temperature range of 756 to 774 C, respectively. The Lalos-Toli and Sony Plutons were crystallized at 3.1 to 3.3 and 3.2 to 3.4 kbar at temperature of 731 to 736 C and 601 to 609 C, respectively whereas the Gorontalo Pluton were crystallized at pressure of 2.6 to 2.7 kbar and temperatures of 662 to 668 C. The crystallization depths were estimated from the pressure of crystallization and the results coupled with the Ar-Ar age were used to calculate the tentative exhumation rate. iii

4 Crystallization depth of 3.2 to 4.3 km and 8.2 to 10 km were estimated from the Mamasa and Masamba Pluton respectively whereas the Lalos-Toli and Sony Plutons show deeper crystallization depth (11.3 and 11.6 km, respectively). The Gorontalo Pluton shows an average emplacement depth of 9.3 km. The exhumation rate estimation shows that the Mamasa and Masamba Plutons were exhumed at a rate of 0.39 and 1.68 mm/year respectively, whilst Lalos-Toli and Sony Plutons at 1.69 and 2.69 mm/year, respectively and Gorontalo Pluton was exhumed at 0.51 mm/year. The rapid exhumation rate of the Sony Pluton is attributed to the active vertical movement of the Palu-Koro Fault Zone. The oxygen fugacity calculation showed that the Mamasa, Masamba and Lalos-Toli Pluton are classified as reduced- and contaminated- I type features consistent with their magnetic susceptibility values, whereas the Sony and Gorontalo Pluton show a normal I type rocks. The occurrence of reduced (ilmenite-series) - I-type granitic rocks were resulted from reduced magmas related to carbon-bearing metasedimentary rocks. The exhumations of the granitic rocks in the Western Sulawesi Province were mainly triggered by the collision of the Banggai-Sula microcontinent with eastern Sulawesi in the Late Miocene to Pliocene whereas the exhumation of the granitic rocks in the Northern Sulawesi Province was attributed to the subduction of Celebes Sea Basin. The crystallization depth estimates refute the low-angle extensional type of emplacement model. Study on geochemistry of REE in the weathering crust from granitic rocks, particularly from Mamasa and Palu region shows that the weathered crusts can be divided into horizon A (lateritic profile) and B (weathered horizon) in Mamasa and horizon C (weathering front) in Palu region. Quartz, kaolinite, halloysite and montmorillonite prevail in the weathered crust and weathering front. Both weathered profiles show that the total REE increased from the parent rocks to horizon B, but significantly decrease towards the upper part (horizon A). The total REE content of the weathered crust are relatively elevated iv

5 compared to the parent rocks, particularly in the lower part of horizon B in the Mamasa profile and in horizon C in Palu profile. The mass transfer illustration using isocon diagram shows a different transfer trend from Mamasa and Palu weathering profiles. The positive Ce anomaly in the horizon A of Mamasa profile indicated that Ce is rapidly precipitated during weathering and is retained at the upper soil horizon. Geochemical data shows that the petrogenesis of the granitic rocks was controlled not only by fractional crystallization processes but also by crustal contamination, particularly for the HK and CAK granitic rocks in the Western Sulawesi Province. Magnetic susceptibility suggests that country rocks bearing reduced organic carbon may have played an important role in the reduction of normal I-type granitic rocks to reduced- I-type. Radiogenic isotopic data suggests that the HK and CAK granitic rocks were derived from partial melting of lower crustal sources with an arc signature. Low-K to tholeiitic series magma in the Gorontalo have originated from amphibolite in the lower to mid crust which were partially melted and mixed with a crustal source producing low Sr and high Nd isotopic values. The HK and CAK granitic rock occurrences were linked to the geodynamic setting of collision to subduction between microcontinent derived from Australia and Sundaland (Eastern Sulawesi) particularly in the CW and NW Western Sulawesi Province from Late Miocene to Late Pliocene. The low-k to tholeiitic granitic rocks in Masamba and Mamasa plutons share a similarity with the Lamasi Complex which originated from oceanic floor basalt. The low-k to tholeiitic series in the Gorontalo Pluton suggests an origin from subduction of lower crustal segment in the Celebes Sea. Although regionally, the granitic rocks from Sulawesi are dominated by ilmenite-series granites, the ratio of ilmenite/magnetite series granites decreases substantially from the southern part to the northern part of the island, indicating various magmatic processes and sources. The occurrence of the ilmenite-series v

6 with I-type character (reduce I-type) in the southern and CW part of the Western Sulawesi Province may be explained by an assimilation process between magma and crustal materials containing a variable quantity of reduced C- and S-bearing sediments whereas the occurrences of the normal- I type magnetite-series in the NW part of the West Sulawesi Province and in the Northern Sulawesi Province resulted by contamination of more basic sources. The differences in oxygen fugacity, source rock composition, country rocks, petrogenesis and mineral chemistry play a key part in the genesis of mineralization in Sulawesi. It is suggested from this study that both granitic series are associated with Au Cu and base metal (Pb, Zn and Cu) mineralization. vi

7 TABLE OF CONTENTS Abstract Table of contents List of Figures List of Tables Acknowledgements i v x xvii xviii Chapter I: Introduction 1 I.1. Background 1 I.2. Objectives 3 I.3. Structure of Dissertation 4 I.4. Notes 5 Chapter II: Tectonic Setting and Geology of Sulawesi and field occurrences of the granitic rocks Historical background Tectonic evolution Tectonic provinces Western Sulawesi Province Eastern Sulawesi Province Northern Sulawesi Province Banggai-Sula and Tukang Besi Microcontinent Field occurrences of the granitic rocks Barru Pluton Polewali and Mamasa Plutons Latuppa Pluton Masamba Pluton West Sulawesi, Emu-Lab and Parigi Plutons Sony and Lalos-Toli Plutons Gorontalo Pluton 40 Chapter III: Petrography, geochemistry, Ar-Ar dating age and magnetic susceptibility of the granitic rocks in Sulawesi, Indonesia 43 Abstract 43 vii

8 3.1. Introduction Analytical methods Results Petrography Whole-rocks and trace element geochemistry Sr-Nd-Pb and O isotopes Ar/ 39 Ar Geochronology Magnetic Susceptibility Conclusions 76 Chapter IV: Geothermobarometry of the granitic rocks: implication on exhumation process. 79 Abstract Introduction Analytical methods Results Whole rocks composition Mineral chemistry Geothermobarometry Hornblende-Plagioclase geothermometry Al- in Hornblende geobarometry Discussions Crystallization depth estimation Oxygen fugacity Magma typology Exhumation rate estimation Tectonomagmatic implication Conclusions 100 Chapter V: Geochemistry of rare earth elements (REE) in weathered crust of the granitic rocks 102 Abstract Introduction Regional Geology Description of the parent rocks and weathering profile Mamasa granites Palu granites Analytical method 108 viii

9 5.5. Results XRD identification of minerals Geochemistry of parent rocks and weathered granitic rocks Discussions Distribution of REE in the weathering profile Mass transfer during weathering process Ce anomaly Conclusions 120 Chapter VI: Discussion: petrogenesis, origin and geodynamic setting of the granitic rocks Tectonic discrimination of the granitic rocks Petrogenesis of the granitic rocks: fractional crystallization and crustal contamination Nature of possible source materials High-K and CAK sample Low-K to tholeeitic sample Geodynamic setting: spatial and temporal granitic rocks series Regional Metallogeny Province Conclusions 140 Chapter VII: Conclusions 142 References 146 Appendix ix

10 LIST OF FIGURES Figure 1.1 Shuttle radar tomography mission (SRTM) map of the Indonesian archipelagoes in a global tectonic setting showing location of Sulawesi Island in the archipelago. 1 Figure 2.1 Tectonic map of the Southeast Asian region. Sulawesi is located in the central part of the region which is surrounded by some plates interaction boundaries (inset). 8 Figure 2.2 Regional geology and tectonic provinces division of Sulawesi Island (Sukamto, 1975; van Leeuwen and Pieters, 2011). 21 Figure 2.3 Distribution of granitic rocks in Sulawesi Island (modified from Sukamto, 1975). 22 Figure 2.4 (a) Sample locality map of the Barru Pluton. (b) and (c) Field photograph of fine- to medium-grained equigranular quartz monzonite from the Barru Pluton. 26 Figure 2.5 Sample locality map of the granitic rock from the Mamasa and Polewali Plutons. 27 Figure 2.6 Field photographs and outcrop of Polewali and Mamasa Plutons. (a) A mountain range formed by granitic pluton in Mamasa. (b) Outcrop of granitic rocks in Mamasa which has been fractured due to intense faulting. (c) Quartz vein filling the fractured in the granitic rocks in Mamasa. (d) Medium- to coarse grained texture of the granodiorite from Polewali Pluton and (e) Outcrops of granitic rocks in Mamasa River. 28 Figure 2.7 (a) Sample locality map and (b) field photograph of granodiroite in Latuppa Pluton. (c) Outcrop of granitic rocks cut by aplite (very fine-grained texture). 30 Figure 2.8 Sample locality map of the Masamba Pluton 32 x

11 Figure 2.9 (a) Field photographs of an outcrop of the granitic rocks in Rongkong River. (b) The granitic rocks showing a light color with plagioclase, K-feldspar and quartz as the major minerals. (c) Mafic enclaves found in the granitic rocks from Masamba Pluton. 33 Figure 2.10 Sample locality map of West Palu (WP), Parigi (PAR) and Emu-Lab Plutons (EMU). 35 Figure 2.11 (a) Field photograph of quartz monzonite sample (WP-29B) in West Palu containing some enclaves (b) Plagioclase occur as phenocryst in a coarse-grained granitic rocks in West Palu. (c) Gabboric enclaves found in coarse-grained quartz monzonite (PAR-28ENC) at Parigi Pluton. (d) Boulder of medium- to coarse grained granitic rocks in West Palu Pluton. (e) Granitic body forming a mountain range which reached up to 2000 meters in West Palu. 36 Figure 2.12 Sample locality map of Sony (SO) and Lalos-Toli (LA) Plutons. 38 Figure 2.13 Field photograph and outcrops of the Lalos-Toli and Sony Plutons. (a) Sony Pluton reaches an altitude of more than 3000 m. (b) Close up picture of Lalos-Toli pluton (LA-17AB) containing plagioclase as phenocryst. (c) Outcrops of Sony Pluton (SO-21B) and (d) granodiorite surface of sample SO-25. (e) Highly fractured outcrops of Sony Pluton. Note that some fractures have been filled by quartz vein. 39 Figure 2.14 Sample locality map of Gorontalo Pluton 41 Figure 2.15 Fig (a) Bird s eye view of granitic rocks pluton in Gorontalo Gulf. (b) Granodioritic outcrops (GR-2) along road near Gorontalo Port. (c) Enclave in fine- to medium grained granitic rocks. (d) Outcrops of granitic rocks showing a weathering process and (e) Boulder of granitic rocks used as industrial material. 42 Figure 3.1a Photomicrograph of granodiorite (MA-45) from Mamasa consisting mainly of plagioclase, quartz, hornblende and biotite. Accesory of titanite and opaque oxide are common (cross-polorized). b. Biotite in monzogranite (MA-41) showing reddish brown color xi

12 (plane-polarized). c. Calcite veins cross cut the highly sericitized plagioclase in quartz monzonite (M-1) from Mamasa (cross-polarized). d. Plagioclase occurs as phenocrysts showing oscillatory zoning in granodiorite (WP-30B) from West Palu (cross-polarized). e. Biotite in quartz syenite (SO-25) from Sony Pluton showing greenish brown (plane-polarized). f. Accessory minerals including zircon and titanite set in a groundmass of quartz, plagioclase, hornblende and biotite in a granodiorite from Lalos-Toli (LA-17B) (cross-polarized). g. Highly sericitized plagioclase along with quartz, hornblende and biotite in monzogranite (61 MAL) from Gorontalo (cross-polarized). h. Granodiorite from Gorontalo (62 GTL), consisting of a quartz and plagioclase groundmass with hornblende and chloritized biotite. 54 Figure 3.2 Sample location map showing the distribution and classification of granitic rocks according to their geochemical character in Sulawesi Island. 59 Figure 3.3 The granitic rocks from Sulawesi plotted in diagram of Cox et al. (1979). 62 Figure 3.4 A/CNK [(Al 2 O 3 /(CaO+Na 2 O+K 2 O) molar] vs A/NK (Al 2 O 3 /(Na 2 O+K 2 O) molar] diagram of granitic rocks from Sulawesi. Symbols as in Fig Figure 3.5 SiO 2 vs K 2 O (wt%) diagram of Pecerillo and Taylor (1979) which divided the granitic rocks into three groups; HK, CAK and low-k to tholeiitic groups. Some plutons show combination of more than one series (composite). Symbols as in Fig Figure 3.6 Primitive-mantle normalized trace element (Sun & McDonough, 1989) of granitic rocks from Sulawesi. Symbols as in Fig Figure 3.7 Chondrite normalized trace element (Sun & McDonough, 1989) of granitic rocks from Sulawesi. Symbols as in Fig Figure 3.8 (a) 87 Sr/ 86 Sr vs 143 Nd/ 144 Nd; (b) SiO 2 vs 143 Nd/ 144 Nd and (c) SiO 2 vs and 87 Sr/ 86 Sr of granitic rocks from Sulawesi with respect to the field of xii

13 Lamasi Complex and Miocene intrusive igneous rocks and volcanic rocks (Bergman et al., 1996), Mariana Trench sediments (Woodhead, 1989), Solomon sediments (Woodhead et al., 1998), Celebes Sea basement (Serri et al., 1991), Volcanic rocks from New Britain volcanic arc (Woodhead et al., 1998), mantle array (Nelson & DePaolo, 1985), GLOSS (Langmuir & Plank, 1998) and Upper crust (De Paolo & Waaserburg, 1979). 70 Figure Pb/ 204 Pb isotope plot against 207 Pb/ 204 Pb, 208 Pb/ 204 Pb and 143 Nd/ 144 Nd of granitic rocks from Sulawesi compared with those of Pacific Ocean sediments (Kay et al., 1978), East Indonesia sediments (Vroon et al., 1996), Sulawesi sediments (Elburg et al., 2003), North and South New Guinea Basement (Bergman et al., 1996), Volcanic rocks from the New Britain Arc volcanic rocks (Woodhead et al., 1998). Also shown are value from Indian-MORB (Simonetti et al., 1998), Pacific-MORB (White et al., 1987), and GLOSS (Plank & Langmuir, 1998). NHRL value is from Hart (1998). Symbols as in Fig Figure 3.10 (a) δ 18 O vs 87 Sr/ 86 Sr values and (b) δ 18 O vs SiO 2 diagram of granitic rocks in Sulawesi. Symbol as Fig Figure Ar/ 39 Ar apparent age and apparent Ca/K spectra for a. Hornblende concentrate from granodiorite (MA-45B) at Mamasa area, Western Unit. b. Biotite separate from monzogranite (PAR-27B) at Parigi area and c. Hornblende separate from quartz monzonite (LA-18C) at Toli-toli. Analytical uncertainties (2σ, intralaboratory) are represented vertical width of bar whereas horizontal width of bars show % Ar released during each successive heating stage. Experimental temperatures increase from left to right. 73 Figure 3.12 Result of magnetite susceptibility measurement from the granitic rocks in Sulawesi, Indonesia. 75 Figure 3.13 Distribution of granitic rocks in Sulawesi based on their magnetic susceptibility values. 76 Figure 4.1 Sample and granitic rocks distribution map for EPMA analysis 82 xiii

14 Figure 4.2 a. AFM diagram of the studied samples. All samples were plotted in calc-alkaline field. b. A/CNK vs A/NK diagram of the granitic rocks. All samples were classified as I-type and metaluminous granitic rock 84 Figure 4.3 Ternary diagram of feldspar for granitic rocks from Sulawesi 86 Figure 4.4 Amphibole composition diagrams according to nomenclature of Leake et al. (1997) of granitic rocks from Sulawesi. 88 Figure 4.5 Diagrams showing the classifications of biotite in granitic rocks from Sulawesi, according to the nomenclature of Speer (1984) (left) and Deer et al. (1986) (right). 88 Figure 4.6 Diagrams showing the classification of magmas based on biotites composition, after Abdel-Rahman (1994). A = alkaline, P = peralkaline, C = calc-alkaline. 90 Figure 4.7 Temperature versus oxygen fugacity diagram for the granitic rocks from Sulawesi. The solid line show the fo 2 T conditions for the redox buffer Hm-Mt (hematite and magnetite), NiO-Ni, QFM (quartz, fayalite and magnetite), and CO 2 -CH 4 (from Candela, 1989). I-SCR = strongly contaminated reduced I-type granitoid (after Ague and Brimhal, 1988). Oxidized, reduced and contaminated I-type rocks fields are from Yang and Lentz (2005), S-type rocks, Mo deposit and porphyry Cu+Au deposit fields are from Yang et al. (2006). 96 Figure 4.8 Triangular diagram showing the relationship between the contents of MgO, Al 2 O 3 and Total FeO for biotite from granitic rocks in Sulawesi. Field I = biotite associated with muscovite; II = biotite associated with pyroxene and garnet; III = biotite associated with hornblende. 97 Figure 5.1 Geologic map and location of studied area of (a) Mamasa and (b) Palu. 105 Figure 5.2 Profile of weathered crust in (a) Mamasa and (b) Palu granitic rocks. Note the weathering profile of Palu granite (b), consisting of horizon A, B1 and B2 whereas Mamasa profile only consists of horizon A and B. 108 xiv

15 Figure 5.3 Representative X-ray diffraction pattern of weathered crusts of Mamasa granites. K= kaolinite, Qtz = Quartz, Mon = montmorillonite 110 Figure 5.4 Representative X-ray diffraction pattern of weathered crusts of Palu granites. K= kaolinite, Qtz = Quartz, Alb = Albite, Kfs = K-feldspar, Hal= halloysite 111 Figure 5.5 Total LREE, HREE and Y of weathered crusts at Mamasa and Palu. 113 Figure 5.6 Variation in major element oxide, trace element and REE in Mamasa and Palu weathering profile. 119 Figure 5.7 Chondrite normalized rare earth element pattern of parent rocks and weathered granitic rocks from Mamasa and Palu. 120 Figure 5.8 Normalized isocron diagrams for the weathering profile in the granitic rocks from Mamasa and Palu regions using the normalization solution. The thick line indicates the unified isocon defined by TiO 2 and the number before the oxide and REE symbol represent the scaling coefficients. 120 Figure 6.1 Diagram of Frost et al. (2001) showing an I-type character of granitic rocks in Sulawesi. Symbols as in Fig Figure 6.2 Tectonic discrimination of the granitic rocks from Sulawesi plotted based on diagrams of Pearce et al. (1984). The granitic rocks have been classified as HK (blue color), CAK (green color) and low-k to tholeiitic series (red color). The samples are mostly clustered into the volcanic arc granitoid field. WPG: within plate granites, VAG: volcanic arc granites, ORG: oceanic ridge granites, syn-colg: syncollisional granites. Symbols as in Fig Figure 6.3 a. (Th/Yb) vs (Ta/Yb) diagram for the granitic rocks in Sulawesi. Most of HK and CAK granitic rocks are plotted in the active continental margin field. b. Yb vs Th/Ta diagram for the granitic rocks in Sulawesi. The boundaries of active continental margin, oceanic arc and within plate volcanic zones are from Gorton and Schandl (2000). Symbols as in Fig xv

16 Figure 6.4 Variation diagrams of major oxide with respect to SiO 2 content (in wt%) for the granitic rocks in Sulawesi Island. Symbols as in Fig Figure 6.5 Variation diagrams of trace elements (in ppm) with respect to SiO 2 content (in wt%) of the granitic rocks in Sulawesi Island. Symbols as in Fig Figure 6.6 Zr/Nb versus Zr diagram of the granitic rocks from Sulawesi. Note that most of high-k to shoshonitic and high-k calc-alkaline samples are followed fractional crystallization trend whereas most of low-k to tholeiitic samples were mainly concentrated around partial melting trend. 128 Figure 6.7 Nb versus Nb/Ta diagram of the granitic rocks in Sulawesi. Chondritic, average MORB and average continental crust (Schmidt et al. 2004) and average GLOSS (Plank & Langmuir, 1998). Most of the samples are concentrated near average continental crust field and average GLOSS. 134 Figure 6.8 Diagram of Fe 2 O 3 /FeO vs. Rb/Sr (Blevin, 2006) showing the igneous metallogenesis correspond to magma properties. 139 Figure 6.9 Proposed metallogenic province associated with a granitic rock map in Sulawesi. 140 xvi

17 LIST OF TABLES Table 1.1 List of commonly used acronyms in this dissertation 6 Table 2.1 Main lithologies and mineral assemblages of the plutons in Sulawesi 24 Table 3.2 Selected major (wt%) and trace element (ppm) concentration of granitic rocks from Sulawesi. 60 Table 3.3 Sr, Nd, Pb and O isotope data of granitic rocks in Sulawesi. 69 Table 3.4 Magnetic Susceptibility (MS) measurement results from the granitic rocks. 75 Table 4.1 Whole rock composition and CIPW normative mineral assemblage of the granitic rocks from the studied area. 84 Table 4.2 Representatives feldspar composition of the granitic rocks from Sulawesi 87 Table 4.3 Representative hornblende composition of the granitic rocks from Sulawesi 89 Table 4.4 Representative biotite composition of the granitic rocks from Sulawesi 90 Table 4.5 Estimations of pressures, depth of emplacement, oxygen fugacity value (log fo 2 ) and exhumation rate estimation of the granitic rocks from Sulawesi 95 Table 5.1 Concentration of major elements, trace elements, REE and Y of parent rocks and weathered crust from granitic rocks at Mamasa region 114 Table 5.2 Concentration of major elements, trace elements, REE and Y of parent rocks and weathered crust from granitic rocks at Palu region 115 xvii

18 ACKNOWLEDGEMENTS The writing of this dissertation has been one of the most significant academic achievements that I have ever had to gain in my life. I would not be able to write this acknowledgment section without the support, guidance and help of several individuals who in one way or another contributed and extended their valuable assistance in the preparation and completion of this works. Indeed, it is to them that I owe my deepest gratitude. First and foremost, my utmost gratitude to Professor Koichiro Watanabe, who undertook to act as my supervisor despite his many other academic and professional commitments. His wisdom, sincerity, knowledge, managerial skill and commitment to the highest standards inspired and motivated me. He has given me lots of opportunity to develop my educational experience during my study time and threated me as an independent learner rather than just being an ordinary student which will be very useful for my academic career in the future. I would like to express my heartfelt and sincere gratitude to my supervisor Professor Akira Imai from Akita University for the outstanding continues support of my PhD study and research, for his patience, enthusiasm, and immense knowledge. Although we have a distance constraint, his guidance, insightful comments, hard questions and fruitful critiques on my paper, journal and dissertation draft have pushed me beyond my limit and elevated my level of understanding in geology. He is the one who recommended me to pursue my PhD in Kyushu University about three years ago. My sincere thanks also go to Dr Kotaro Yonezu, an outstanding assistant professor in Economic Geology Lab who had kind concern and consideration regarding my research needs and academic requirements. His endless assistance and friendship during my academic year in Kyushu University has meant more to me than I could ever express. I wish to thank Dr. Mami Mampuku for providing valuable time of help and assistance not only related with my academic issue but also nonacademic problem that I faced during my study for my poor Japanese language. I must also thank Ms Miwa Hirajima and Minako Matsue for their assistance in arranging my research budget from GCOE program. Their kindness and assistance will always be remembered. Thanks are due to Prof. Takanori Nakano from Research Institute of Human and Dr. Shin Kicheoul from AIST for isotope analyses facility, Dr. Guibin Zhang from Peking University for EPMA analysis, Dr. Lauren Page and Andrew Schersten from Lund University for Ar-Ar dating analyses, Dr. Adrian Boyce from Glasgow University for oxygen isotope analyses, Dr. Theo van Leeuwen for suggestions and comments on the early draft, Prof. Robert Hall from xviii

19 London University for sharing his data and Dr. Steven Bergman from ARCO for his unpublished data. My PhD project has been supported by MEXT scholarship from Japanese Government, and benefited from some research grants including GCOE program, Society of Resource Geology and Hasanuddin University graduation assistance program. All their supports are greatly acknowledged. While travelling abroad for conference and short course, I had great budget support from ITP program and JSPS program as well as GCOE program for which I am thankful. I thank my fellow labmates in Economic Geology Lab, particularly member of room 421 for the stimulating discussions, for the sleepless night we were working together and for all the fun that we have in the last three years. Special thanks go to Thomas Tindell for excellent proof reading on this manuscript. I would like to express my deepest gratitude to my parent, Mansyur M and Hj Thahirah Sunu, for giving birth to me at the first place and supporting me spiritually throughout my lifetime. Their support forged my desire to achieve all that I could in this life. I owe them everything and I wish I could show them just how much I appreciate and love them. I will always pray to ALLAH the Omnipresent for their kindness. Last but not least, I would like to express my heartfelt gratitude to my beloved soul mate Kumalasari TD, who has unconditionally accompanied me cruising this life. Without her this effort would have been worth nothing. Her endurance love, support and constant patience have taught me so much about sacrifice, discipline and compromise. She is always ready to open our door house every night when I back with a bunch of burden from ITO campus, cheering me up and stood by me through the good time and bad. If I could write in the tears that flowed while I thought of what to put here, you might have a better idea of what it means to me. Finally, I would like to dedicate this work to my little angel ALMAIDAH who have already sacrificed her precious childhood time to support and accompany me in gaining all my ambitions from Canberra until Fukuoka. She had lost much of her precious time without me in the house and always stood by me and dealt with all of my absence from many family occasions with a smile though sometime with tears. She is a source of my strength to finish this job. This works is a testimony for her that never gives up in achieving your dream in this life. I believe you will reach higher achievement than what your father did. xix