Mount Endut is a volcano located in the eastern part of Banten Province. Previous studies revealed that Mount Endut consists mainly of Quaternary volcanic and Tertiary plutonic igneous rocks respectively. This research focuses on the petrology of igneous rocks found in the southern region of Mount Endut in order to determine the type of igneous rocks, evolution of magma, and reconfirming historical geological process occurring in Mount Endut area. Petrographic analysis was performed on 11 samples and geochemical analysis was performed on 30 samples. Petrographic analysis revealed three types of igneous rocks, andesite porphyry, diorite porphyry, and dacite porphyry. Furthermore, geochemical analysis revealed that the igneous rocks in Mount Endut are comprised of basaltic andesite, andesite, dacite, basaltic trachy-andesite, trachy-andesite, and trachyte or trachydacite which originated from calc-alkaline magma series. The integration of petrographic and geochemical analysis supports the regional geological process where Mount Endut was formed either in an island arc or an active continental margin. The first section in your paper.

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Kajian Air Tanah di Jakarta Barat untuk mengetahui kualitas air tanah yang biasa digunakan warga Jakarta Barat untuk kebutuhan sehari-hari seperti air minum, bersih-bersih dan lain-lain. Kajian ini penting dilakukan karena air yang dikonsumsi warga belum tentu memenuhi standar baku kualitas air minum yang ditetapkan oleh pemerintah melalui Permenkes No. 492 Tahun 2010, melalui parameter Fisik dan kimia. Penelitian ini berfokus pada pengukuran akuifer bebas di perumahan padat penduduk dengan menggunakan analisis hidrogeologi dan hidrokimia. Penelitian ini bertujuan untuk memetakan kualitas airtanah dengan metode hidrogeologi dan hidrokimia. Analisis hidrogeologi digunakan untuk memetakan muka air tanah berdasarkan pengukuran kedalaman air tanah yang diukur pada sumur masyarakat dengan satuan meter di bawah permukaan tanah (mbmt) dan meter di bawah permukaan laut (mdpl). Data hidrokimia menggunakan dua data, yaitu data primer dan data sekunder. Data primer adalah data yang diambil penulis di lapangan pada tahun 2021 dengan fokus pada sumur air tanah akuifer bebas yang diambil di perumahan padat penduduk. Data sekunder adalah data yang diambil oleh BKAT pada tahun 2018-2020 dengan fokus pada sumur air tanah untuk ruang publik seperti SPBU, taman, dan rumah ibadah. Sedangkan analisis hidrokimia dilakukan untuk melihat kondisi salinitas, jenis air, serta tingkat intrusi air laut di daerah penelitian. Berdasarkan pengukuran yang dilakukan penulis pada bulan Maret 2021, kedalaman air tanah terdalam adalah di Kelurahan Semanam dengan kedalaman 9,3 mbmt, dan yang paling dangkal berada di Kelurahan Rawa Buaya dengan kedalaman 0,2 mbmt. Berdasarkan pengukuran penulis, kualitas airtanah di Jakarta Barat sangat memprihatinkan. Kelurahan Roa Melaka memiliki air yang bau, juga Klorida, Sodiun, dan Natrium, yang tinggi. Kelurahan Duri Kepa dan Jelambar memiliki pencemaran besi yang tinggi, melalui pengukuran memiliki kadar 0,4 mg/l dan 1,65 mg/l.

Hydrothermal alteration is an interaction between rock and hydrothermal fluid by means changing the mineralogical composition of the rock. This process is controlled by permeability, chemical composition, temperature, pressure, and duration of the hydrothermal alteration. Gunung Pancar, located in West Java, is considered an outflow for Gunung Gede Geothermal System. Typical geothermal surface manifestations found around Gunung Pancar are hot springs, warm ground and surface alteration. Basic geological mapping was conducted followed by water and altered rock sampling. Petrographic and diffraction methods are completed to confirm altered protolith. Water analyses were conducted to determine water type and origin. Alteration zonation is then inferred based on the water type, intensity of alteration and then cross referenced with indication of structural geological features. Zonation reveals that the intensity of alteration gets weaker as it moves away from the apparent faults. The result suggested that the permeability of the host rock affects thermal fluid movement around Gunung Pancar and subsequently the local geothermal conceptual model.

Citarum River, the longest river in West Java, is one of the most strategic rivers yet one of the most polluted rivers causing a series of floods throughout history. Understanding shallow flood deposits characteristics may infer the past flooding episode and predict future flood deposits distribution. This research aims to analyze grain size and elemental distributions of flood deposits found in the Citarum Riverbank Area at several districts in Bandung Regency, West Java. Shallow coring resulted in soil samples showing that the samples were dominated by clay and silt. Element analysis revealed that Si and Al are the major elements followed by high concentrations of Fe-oxide in all soil samples. Based on these findings, it is presumed that there were two major episodes of past-floods that occurred in the research area.