Alteration and Mineralization in the Coppo Village, Barru District, South Sulawesi Province

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INTRODUCTION
The Indonesian archipelago is a region traversed by three plate passes tectonics i.e. Indo-Australian plate, Pacific and Asia also called with the ring of fire. These three plates which forms the subduction pathway begins North Sumatra shifted northward passing through Nusa Tenggara to Sulawesi and Maluku. The existence of zones It is this subduction that causes the formation of volcanoes and activate volcanism activity and magmatism, especially on the island of Java which stretches along the coast south. Magmatism activity of a The area is closely related to the process hydrothermal alteration of rocks Forming mineral and mineral ore alteration (Suteja, et all, 2016).
Alteration and mineralization processes are very closely related to process phenomena chemistry and physics that occur in rocks due to the interaction of rocks with hydrothermal solution. Hydrothermal solution is a high-temperature liquid (100-500 o C) residual cooling of magma able to change existing minerals previous and forming minerals changes to the original rock and the formation of mineralized deposits metal sulfides under certain conditions (Bateman, 1981). Hydrothermal alteration is a process that occurs due to the interaction between the hot fluid and the side rocks through which it passes, so that the exposed primary minerals will be converted into secondary mineral series which are then called alteration minerals and under certain circumstances and conditions will produce a collection certain minerals are also called mineral assemblage or mineral assemblage, thus reflecting the chemical and physical conditions at the time of its formation (Sutarto, 2004). Hydrothermal alteration is a complex process because it occurs 4 changes in mineralogy, chemistry and texture due to the interaction of hydrothermal solutions with wall rocks that pass under certain physical chemical

METHODS
In general, research methodology is carried out in two stages, namely field data collection and laboratory analysis (Wakila, et all, 2021). This stage of research begins with sampling at the location of alterated rock outcrops. Then take a hand-sized alteration sample Spiceman as many as 3 samples with using the chip sampling method. In addition to collection samples at several points were also observed on the geological conditions around the study area, and descriptions of rock samples to obtain information in the form of rock position, direction of rock distribution, outcrop coordinates, and mineral content of rocks megascopically (Wakila, et, all, 2021). The sampling process can be seen in the following figure (Figure 1).

Figure 1. Sampling Process
After sampling, the next analysis is carried out Petrography Analysis and X-Ray Diffraction (XRD). Petrography analysis is carried out to determine the set of minerals which will then be the basis for determining the type of alteration. XRD analysis is performed to determine the name of the mineral contained in the sample and its grade (percentage). Altered minerals indicated to be altered analyzed by XRD (Chalik, et all, 2022). The results of both methods will be combined to obtain the better results.

Sample 1
Sample 1 shows a weathered white to greenish-gray color in the rock and shows an altered texture. The minerals seen are quartz, and plagioclase (figure 2). Megascopically, these rock samples show textures that have undergone alteration with white to brownish weathered color, visible minerals are quartz minerals, and clay minerals such as kaolinite, illite, montmorilonite and others (Figure 3). Megascopically, these rock samples show textures that have undergone alterations with a weathered white to yellowish-brown color, visible minerals namely quartz and clay minerals such as kaolinite, illite, and others ( Figure 4). Under microscope, a thin incision of sample 1, showing a collection of minerals alteration, namely chlorite (chl) is present as a mineral characterizing alteration and is circumvented in Rock samples that are faded green, epidote (ep) present as Alteration minerals from feldspar characterized as constituents of igneous rocks, quartz (qtz) is present as an associated mineral in rock sample and opaque minerals (opq) that sample 1 is characterized as metallic minerals that carry sulfide mineralization in the study area. Sample 1 polished incision photomicrograph can see in Figure 5. Under microscope observation, a thin incision of sample 2, showing a collection of minerals Plagioclase (plg) is present as a common mineral forming igneous rocks and dominating rock samples, K-feldspar is part of the mineral Plagioclase is present as phenocryst in rock samples, clay minerals are minerals that have undergone alteration from plagioclase and quartz minerals (qtz) is present as an associated mineral commonly found in rock samples. Photomicrograph of sample 2 polished incision can be seen in Figure 6.

X-Ray Diffraction (XRD) Analysis
XRD analysis is performed to determine the mineral content of the rock sample. Minerals that cannot be seen in later microscopy analyzed using XRD (X-Ray Diffraction) method. The working principle of the tool for mineralogical analysis methods known as XRD (X-ray diffraction) which is by using X-rays derived from metals with its wavelength, thus forming an angle of reflection of light that can be detected. According to Bragg's law, diffraction data is used to calculate the distance of the atomic plane that produces a certain angular magnitude (Fatimah, 2017). Most explanations of XRD address techniques for analyzing and identifying the crystalline phase of the material. The form of crystalline varies greatly in each material or mineral, so it is these are used as anomalous characteristics of certain minerals (Heriansyah, 2018).

Types of Alteration
Types of hydrothermal alterations are generally divided into several types based on alteration mineral sets. The results of the analysis then showed some minerals can be classified as alterationtype characterizers. Based on the presence of alteration minerals present, it can tabulated alteration mineral sets and alteration types based on type diagrams alteration by Corbett & Leach, 1996 as in Table 1, the alteration types that develop in the study area are propilitic and argylic.