Comparison of Granitoid Characteristics West Kalimantan and Karangsambung Based On Mineralogical And Geochemical Aspects

Indonesia was included in the ring of fire so that it has various types of tectonic products, one of which is granitoid. Granitoid is very complex rock and many are found in Indonesia. Some of them are found in West Kalimantan and Karangsambung. Basis of the reasearch is there is no research that compares granitoid in two regions. The purpose of this study was to compare rock characteristics and granite petrogenesis of West Kalimantan and Karangsambung. The research method used was collecting data on field, also laboratory analysis of rock samples using a polarization microscope, refraction microscope, and X-Ray Fluorescence analysis. The mineralogical characteristics of each study area tend to be almost the same. The predominant composition of the main minerals is quartz, plagioclase and orthoclase. But specifically the rock samples from West Kalimantan have been altered from phylic-silicification-propylitic. The entire study area contained accessory minerals, namely apatite, zircon, titanite, and for monazite only in the West Kalimantan sample. There was mineralization up to the supergene stage in the presence of the characteristic minerals for the supergene covelite and chalcocytes in the West Kalimantan sample. Geochemical analysis of both regions shows the same magma affinity, namely Calc Alkaline High K Calc Alkaline. For West Kalimantan, the value of A / CNK <1.1 has a type metaluminious and > 1.1 a type peraluminious. Meanwhile, Karangsambung A / CNK value <1.1 has a type metaluminious. So that West Kalimantan granite has two I-type and S-type. While Karangsambung is I-type. West Kalimantan granite is formed in continental arc granite (CAG) and continental collision granite (CCG). Meanwhile, Karangsambung in Volcanic Arc Granite (VAG). It can be concluded that the granites of the two regions have quite different characteristics even though they belong to a relatively similar tectonic environment.


Introduction
Indonesia is an archipelagic country surrounded by two oceans, namely the Pacific Ocean and the Indian Ocean, two continents, called the Asian continent and the Australian continent, and is included in the ring of fire. Therefore, the tectonic process greatly affects the product, one of the products of tectonism is granitod. Granite rocks are granular igneous rocks that generally contain quartz and two types of feldspar (Barbarin, 1999). Granitoids are classified into several types based on mineral content, field appearance and petrography as well as chemical characteristics (Streckeisen, 1976;Pearce, Harris and Tindle, 1984;Maniar and Piccoli, 1989;Barbarin, 1999).
The location of the research was carried out in two different area called West Kalimantan and Karangsambung. According to (Ilmawan, 2019) in the West Kalimantan, especially Bengkayang, is included in low to medium sulphide epithermal mineralization, but does not discuss in detail about the rock of origin. Meanwhile, according to (Setiawan and Novian, 2015) Karangsambung granitoid of the Cordilleran type is derived from a normal volcanic arc product and the possibility of a Caledonian type granitoid which is the product of a posttectonic collision of partial melting in the continental crust. Based on (Isyqi, Hastria and Ansori, 2016) classified the tectonic setting of Karangsambung granite into volcanic arc granite (VAG) with metaluminious magma of dominant origin.
The absence of research that compares the characteristics of the granitic rocks of Karangsambung and West Kalimantan is what underlies the authors to conduct research. This study aims to compare the mineralogical and geochemical characteristics of granitic rocks.
the Continental Block. Tectonic processes that produce magmatic arcs occur in the Eocene-Early Oligocene, which can be seen from Sintang to Kelian along Central Kalimantan.  (Suwarna et al., 1993)

Regional Geologi of Karangsambung
Based on the division of physiographic zone according to (Van Bemmelen, 1949), the study area is a part in the South Serayu Mountains Zone and is located in the southern part of Central Jawa can be seen in fig 2. Based on stratigraphy conditions from (Prasetyadi, 2007) in fig 3, the research are include in Melange Luk Ulo Complex consist of Metamorphic rock, igneous rocks and also pelagic sediment (Asikin et al., 1992) The subduction process between the Indo-Australian Plate and the micro-Sundanese resulted in the formation of three tectonic patterns on the island of Java. The dominant structures found on the island of Java include the Java pattern with an east-west direction (EW), the Sunda pattern with a north-south direction (NS), and the Meratus pattern with a northeast-southwest direction (NE-SW) with the Javanese pattern as the youngest pattern (Pulunggono and Martodjojo, 1994) Fig 3. Regional Stratigraphy of Karangsambung (Prasetyadi, 2007)

Research Methods
Sampling was carried out in two different areas. Samples in the West Kalimantan area were taken as representatives of the granitoid samples. For the Karangsambung area samples were taken on a representative river flow from the granitoid sample. The methods used in this analysis are petrographic analysis and geochemical analysis.  (Setiawan and Novian, 2015) and (Isyqi, Hastria and Ansori, 2016). The results of this XRF analysis are in the form of rock geochemical data in the form of data on major elements, trace elements, and rare earth elements.

Petrography
The results of petrographic observations of the research area produced several characteristics. Mineralogical characteristics have holocrystalline crystallinity, phaneritic granularity, but there are 3 samples that have porphyroafanitic granularity, subhedral crystal form. Most of the samples have undergone quite high rock alteration and deformation. There is a special texture in the form of consertal which has a characteristic indicating that there is intergrowth between quartz and feldspar. As well as the typical micrographic and granophyric where the quartz mineral grows randomly on the feldspar. The main minerals such as quartz, plagioclase, K-feldspar are replaced by secondary minerals in the form of alteration minerals. There are accessory minerals in the form of apatite, zircon, monazite, titanite. The phyllicpropylitic alteration zone.
Based on plotting on the IUGS (Streckeisen, 1976) the analyzed incisions tend to have the name monzogranite except for two incisions, namely sample codes I/080312/M-01 and III/110312/M-05 which have the name syenogranite, and alterted stone can be seen in fig 6.  (Streckeisen, 1976) 1. Syenogranite This type of naming is only found in two rock samples. With an average mineral composition of 13% plagioclase, 17% quartz, 22% orthoclase, 3% opaque mineral. With a consertal texture. There is a secondary mineral sericite 40%, secondary quartz 5%. So this rock has undergone quite intense alteration. With selective pervasive alteration style, and moderate alteration intensity of 45% (Browne, 1991) it belongs to the philic alteration type can be seen fig 7.

Monzogranite
This naming type is dominantly found in West Kalimantan rock samples. With a composition of 23% plagioclase, 30% quartz, 17% orthoclase, 18% biotite, 2% opaque mineral. With a special texture in the form of concertal, poikilitic, secondary minerals in the form of 20% epidote. The presence of secondary minerals indicates that this rock has undergone alteration with a style alteration non-pervasive, with a low alteration rate of 20% (Browne, 1991). Has a propylitic alteration type can be seen in fig 8.

Altered Stone
This type of naming is based on the appearance on a polarization microscope, the dominance of the main mineral has been replaced but is still granitic. With a composition of 50% secondary quartz, 35% base mass, 13% clay minerals, and 2% opaque minerals. style alteration Pervasive, with a high intensity level of 100% alteration (Browne 1991). Based on its appearance, it is included in the silicification alteration type in fig 9. The presence of accessory minerals as a marker and can be used as an indicator of petrogenesis. Accessory minerals found in West Kalimantan granitoid samples include zircon, monazite, apatite, titanite can be seen in fig 10.

Mineragraphy
Special for sample west Kalimantan doing a mineragraphy analysis. Based on the observation of the optical properties of the rock samples in the study area, they are divided into several groups including native element and sulfide minerals. Native element are founded, namely gold (Au). The appearance of gold (Au) was found with small grains as free grains that did not stick to the others seen in Fig    Ore mineral paragenesis discusses the sequence of ore mineral formation stages. Based on the presence of covelite and chalcocite minerals, the mineralization of the study area has undergone a supergene stage.

Geochemical
Harker diagram plotting was carried out by comparing the ratio of the main elements on the Y axis with SiO2 on the X axis. Since the study area had undergone quite intense alteration, plotting was carried out at a value of 66%. LoI value (Lost on Ignition) < 2.5 or quite fresh. The tendency of all elements decreases with the increase in SiO2. Elements MgO, Fe2O3, TiO2 decrease. These three elements are found in mafic minerals. This means that the crystal national fraction runs normally because the main composition of mafic minerals tends to decrease followed by an increase in SiO2. The CaO element also decreased with the addition of SiO2, and was followed by a relative increase in Na2O content. It is interpreted that these two elements are the composition of plagioclase minerals. Due to the decrease in CaO levels and an increase in the relative levels of Na but not too significant, it indicates that there is a replacement or substitution between Ca and Na components when SiO2 is added can be seen in fig 13. Plotting the magma affinity diagram shows that the magma in the granite sample of the study area is formed from magma that is High K Calc Akaline and Calc Alkaline. (Fig 14). Fig 14. Plotting the classification of rock alkalinity levels (Peccerillo and Taylor, 1976) The magma type diagram was made by (Chappel and White, 1974) to determine the type of granite which was then used as an indicator of granite petrogenesis parameters. Data is used in the form of moles of each selected main element, namely Al2O3, Na2O, CaO, K2O can be seen in table 2.
Based on the results of plotting on the magma type diagram according to (Chappel and White, 1974) the tested granite rock samples have almost the same characteristics or transition from metaluminious to peraluminious. <1.1 and >1.1 then the type of granite in the study area is a mixed type, namely type I granite and type S graniteType I granite implies a source rock of magma composition which is mafic to intermediate or infracrustal derivational (Chappel and White, 1974;Chappell and Stephens, 1988) can bee seen in fig 15. While this type of S granite indicates that the source rockis sedimentary rock or protolith crust (supracrast protolith (Chappell and Stephens, 1988).  (Chappel and White, 1974) This geochemical analysis also produces trace elements and rare rearth elements. For plotting, a normalized chondrite spider diagram and a normalized extend spider diagram of the primitive mantle were used to eliminate the Oddo-Harkins effect.  Sun, 1989) Based on plotting in fig 16 This negative anomaly on the Eu element is related to subduction on the island arc or active continental margin. This negative anomalous pattern in Eu indicates that the granitoid was formed from magma remaining from the frozen solution after the plagioclase separation process (Gromet and Silver, 1987;Widana and Priadi, 2015) The elements Nb, Ta and Sr tend to be depleted or reduced to LREE. The Nb element has a negative anomaly. This is interpreted as the tectonic setting is still related to the volcanic arc. Sr element experiencing negative anomaly indicates a change of plagioclase Ca into plagioclase Na and K-Feldspar in late fractionation.
Based on the plotting in Aluminum saturation indeks diagram (Shand, 1943) in fig 17 found that samples of rocks scattered on the metaluminous towards peraluminous. When viewed overall, the dominant trend is towards peraliuminous, although there is a metaluminious magma type, so that the rock samples are classified as peraluminious and metaluminious. Tectonic environment ranging from CCG (continental collision granitoids), CAG (continental arc granitoids).  (Shand, 1943)

Petrography
Mineralogical characteristics based on petrography have holocrystalline crystallinity, phaneritic, granularity, subhedral crystal form. There is a special texture in the form of consertal which has a characteristic indicating that there is intergrowth between quartz and feldspar. Then there is a special texture of pertite caused by the dissolution process to make pertite a phenocryst in K feldspar. As well as a typical antipertite where the quartz mineral grows randomly on the feldspar. The main minerals such as quartz, plagioclase, K-feldspar. There are accessory minerals in the form of apatite, zircon, titanite. Based on plotting on the IUGS Streckeisen classification (1967) (Streckeisen, 1976) 1. Monzogranite This type of naming is the naming of the entire granitoid sample being analyzed. Based on petrographic analysis, it has phaneric granularity, holocrystalline crystallinity degree, relationship between hypidiomorphic crystals, special texture in the form of consertal intergrowth, pertite, antipertyte, primary mineral composition in the form of plagioclase (An42) 20% , quartz 35%, orthoclase 20%, muscovite 25%. Can bee seen in fig 19. The presence of accessory minerals as a marker and can be used as an indicator of petrogenesis. Accessory minerals found in West Kalimantan granitoid samples include zircon, monazite, apatite, titanite can be seen in fig 20.
Major element used by harker diagram. This analysis uses a Harker diagram by comparing the SiO2 element with other main elements. The plotting of (Setiawan and Novian, 2015) with (Isyqi, Hastria and Ansori, 2016) has pattern trend a relatively similar. It can be seen that the value of MgO, Fe2O3, TiO2 decreased along with the increase in SiO2. If you look at the three elements, it is interpreted that the content is found in mafic minerals. This means that the crystal fractionation is running normally. The CaO element also decreased with the addition of SiO2, and was followed by a relative increase in Na2O content. It is interpreted that these two elements are the composition of plagioclase minerals. For the trend overall, all elements have decreased but some have increased significantly. This can be interpreted to mean that they are still in the same genetic (Mustafa and Usman, 2016) can bee seen in fig 21.   Fig 21. Comparison of the principal elements with SiO2 on the Harker diagram by (A) (Setiawan and Novian, 2015) (B) (Isyqi, Hastria and Ansori, 2016) Plotting the magma affinity diagram shows that the magma in the granite sample in the study area is formed from magma that is High K Calc Akaline and Calc Alkaline can be seen in fig 22.  Fig 22. Plotting the classification of rock alkalinity levels by (a) (Setiawan and Novian, 2015) (b) (Isyqi, Hastria and Ansori, 2016) (Peccerillo and Taylor, 1976) Based on the results of plotting on the magma type diagram according to (Chappel and White, 1974) granite rock samples have almost the same characteristics as metaluminious. this plotting spread but dominant in the metaluminious. For the type of granite, the research area is granite type I. This type of granite indicates that it implies a source rock from magma composition that is mafic to intermediate or infracrustal (Chappell and Stephens, 1988) can be seen in fig 23.  (Isyqi, Hastria and Ansori, 2016) (Chappel and White, 1974) This geochemical analysis also produces trace elements and rare rearth elements. For plotting, a normalized chondrite spider diagram and a normalized extend spider diagram of the primitive mantle were used to eliminate the Oddo-Harkins effect.
The plot by (Setiawan and Novian, 2015) (Setiawan, et al 2015) (McDonough andSun, 1989) Based on pengeplotan by (Isyqi, Hastria and Ansori, 2016) on the normalization MORB there is enrichment of elements K, Rb , Ba, Th, Ce, and Sm, but depleted elements Ta, Nb, P, Hf, Zr, Ti, Y and Yb. Positive anomalies in low ionic potential incompatible elements such as K, Tb, Ba and Th were caused by the metasomatism process in the mantle of the solution agent which was released in theprocess subduction slab. Then negative anomalies in high ionic potential incompatible elements such as (Ta, Nb, P, Hf, Zr, Ti, Y and Yb caused by theprocess partial melting with a high degree of intensity used in the formation of stable mantle residues (Wilson, 1989). For the normalization of chondrite by (Sun and McDonough, 1989) shows apattern depleted on the element Eu. This negative anomaly in Eu is related to subduction at the island arc or active continental margin. This negative anomalous pattern on Eu indicates that the granitoid is formed from magma remaining from the frozen solution after the plagioclase separation process (Gromet and Silver, 1987;Widana and Priadi, 2015) (Isyqi, Hastria and Ansori, 2016) (Sun and McDonough, 1989) Based on the results of plotting the tectonic discriminant diagram from (Pearce, Harris and Tindle, 1984) from the diagram (Yb +Nb) vs Rb, Y vs Nb, Yb vs Ta, it was found that according to (Setiawan and Novian, 2015) and (Isyqi, Hastria and Ansori, 2016) this Karangsambung granitoid has atectonic environment. volcanic arc granite (VAG) can be seen in fig 26.  (Setiawan et al, 2015) (Chappell and White, 1974)

Comparison of Granitoid Characteristics
Analysis has been carried out in the form of petrographic analysis, mineragraphy, as well as geochemical analysis of the granite rock samples in the study area. Then obtained several comparisons on the samples that have been analyzed from the two research areas can be seen in table 3.

Conclusion
Based on the mineralogical aspects of the petrographic analysis of granite in West Kalimantan and Karangsambung, there is quite a difference. West Kalimantan granite has a specialtexture micrographic, granophyric with altered rock conditions so that it has a phyllic-silicified-propyltic alteration zone. Has three types of naming synogranite, monzogranite, altered stone. With the presence of opaque minerals that can be analyzed for mineralization. The accessory minerals are zircon, moderate apatite, monazite, titanite. Karangsambung granite has a special texture that is typical of perite and antipertyte without the presence of secondary minerals. For the presence of the most accessory minerals, namely zircon. It has thename monzogranite.
Based on geochemical analysis, West Kalimantan granite has an affinity for Calc-High K Calc alkaline, magmawith metaluminious and peraluminious magma types resulting in granite types I and S, interpreted to be formed from different parental magmas. Formed inenvironments continental arc granite (CAG) and continental collision granite (CCG). Geochemistry of Karangsambung granite has an affinity Calc-High K Calc alkaline, magmawith a metaluminious magma type. So it has type I granite. Formed on volcanic arc granite (VAG).