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ABSTRACTThis book provides a comprehensive introduction to the field of geochemistry. The book first lays out the 'geochemical toolbox': the basic principles and techniques of modern geochemistry, beginning with a review of thermodynamics and kinetics as they apply to the Earth and its environs. These basic concepts are then applied to understanding processes in aqueous systems and the behavior of trace elements in magmatic systems. Subsequent chapters introduce radiogenic and stable isotope geochemistry and illustrate their application to such diverse topics as determining geologic time, ancient climates, and the diets of prehistoric peoples. The focus then broadens to the formation of the solar system, the Earth, and the elements themselves. Then the composition of the Earth itself becomes the topic, examining the composition of the core, the mantle, and the crust and exploring how this structure originated. A final chapter covers organic chemistry, including the origin of fossil fuels and the carbon cycle's role in controlling Earth's climate, both in the geologic past and the rapidly changing present.Geochemistry is essential reading for all earth science students, as well as for researchers and applied scientists who require an introduction to the essential theory of geochemistry, and a survey of its applications in the earth and environmental sciences.Additional resources can be found at."

"Gunung Api Krakatau merupakan salah satu gunung api aktif yang terbagi menjadi tiga periode letusan. Aktivitas vulkanik yang terjadi setelah letusan pembentuk kaldera pertama (diperkirakan sekitar abad ke-5) hingga letusan pembentuk kaldera kedua pada tahun 1883 termasuk dalam periode Krakatau Muda. Penelitian pada produk sebelum 1883 dilakukan pada lokasi penelitian Danan dan Pulau Rakata dengan total sampel berjumlah empat. Aktivitas vulkanisme yang terjadi pada 1883 membentuk kaldera dan mengakibatkan hilangnya Pulau Perbuatan dan sebagian Danan, sehingga penelitian pada produk sebelum 1883 terbilang sangat terbatas. Penelitian ini dilakukan melalui pendekatan petrologi, petrografi dan analisis geokimia dan kaitannya pada proses magmatisme periode Krakatau Muda. Periode Krakatau Muda menunjukkan karakteristik batuan berkomposisi mafik hingga felsik dengan jenis batuan basaltik hingga dasitik, dengan analisis geokimia batuan menunjukkan afinitas magma dalam seri kalk-alkali dan toleiitik, serta seri magma sub-alkali dengan seri K rendah hingga sedang dan evolusi magma yang berasal dari island arc. Analisis kimia mineral menunjukkan proses magmatisme yang terjadi di Krakatau Muda dipengaruhi oleh proses kristalisasi fraksional dan pencampuran magma dari terbentuknya mikro-tekstur zonasi dan glomerokris pada plagioklas.

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Mount Krakatoa is one of the active volcanoes that can be divided into three eruption periods. The volcanic activity that occurred after the first caldera-forming eruption (estimated around the 5th century) until the eruption forming the second caldera in 1883 is part of the Young Krakatau period. Research on products from before 1883 was conducted at the Danan research location and Rakata Island with a total of four samples. The volcanic activity in 1883 formed a caldera and caused the disappearance of Perbuatan Island and parts of Danan, so that research on volcanic products before 1883 are quite limited. This study was conducted using petrology, petrography, and geochemical analysis approaches, focusing on the magmatic processes of the Young Krakatoa period. The Young Krakatoa period is characterized by rocks with compositions ranging from mafic to felsic, including basaltic to dacitic rocks. Geochemical analysis of the rocks indicates a magma affinity within the calcalkaline and tholeiitic series, as well as a sub-alkaline magma series with low to medium potassium series and magma evolution originating from an island arc. Geochemical analysis of minerals shows that the magmatic processes in Young Krakatoa were influenced by fractional crystallization and magma mixing, as evidenced by the formation of microtextures, zonation, and glomerocrysts in plagioclase."

"Gunung Pancar merupakan daerah yang memiliki potensi panas bumi yang terletak di Kabupaten Bogor, Jawa Barat. Potensi panas bumi pada daerah tersebut dibuktikan dengan keberadaan manifestasi permukaan seperti mata air panas dan batuan alterasi. Hal tersebut merupakan indikasi adanya suatu aktivitas panas bumi aktif pada daerah tersebut yang menarik untuk diteliti. Tujuan dari penelitian ini adalah untuk mengetahui sistem panas bumi Gunung Pancar dengan menggunakan metode analisis geokimia air manifestasi berupa analisis anion, kation, isotop, survei geologi berupa data struktur geologi, litologi, dan geomorfologi serta data pendukung geofisika berupa data MT dan gravity, sehingga didapat gambaran umum sistem panas bumi yang utuh direpresentasikan melalui model konseptual. Gunung Pancar tersusun atas Formasi Jatiluhur berumur Miosen Awal didominasi oleh batuan lanau hingga lempung kemudian terdapat batuan yang lebih muda berumur Miosen Tengah yaitu berupa batuan andesit hasil aktivitas vulkanisme Gunung Pancar. Gunung Pancar memiliki ketinggian 850 mdpl termasuk ke dalam sistem panas bumi relief tinggi. Terdapat tiga titik manifestasi berupa mata air panas yaitu Kawah Merah, Kawah Hitam dan Kawah Putih, keberadaan manifestasi tersebut dikontrol oleh adanya struktur patahan berupa sesar mendatar dengan arah N 195oE/77o dan ditemukan manifestasi berupa alterasi batuan tipe argilik. Kawah Merah memilki tipe air klorida-sulfat, temperatur air 67oC, pH 7,0. Pada Kawah Hitam tipe air merupakan tipe sulfat, temperatur air sebesar 51,8 oC, pH 7,04-8,0. Tipe air pada Kawah Putih adalah tipe air sulfat, temperatur permukaan sebesar 49 oC. Ketiga manifestasi tersebut berada pada zona outflow sistem panas bumi Gunung Pancar. Hasil perhitungan geotermometer silika didapatkan temperatur reservoir berkisar antara 113,5 oC hingga 118,4 oC. Dikategorikan sebagai sistem panas bumi temperatur rendah. Analisis isotop stabil 18O dan 2D menunjukkan sumber air sistem panas bumi Gunung Pancar berasal dari air meteorik.

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Gunung Pancar is located in Bogor Regency, West Java and with potential geothermal prospect. Geothermal potential in the area is proven by the presence of surface manifestations such as hot springs and surface alteration. The purpose of this study is to determine the Gunung Pancar geothermal system by integrating 3G data (water geochemical analysis-anion, cation, and isotope analysis, structural, lithological and geomorphological data and supporting MT and gravity secondary data). Gunung Pancar consists of Jatiluhur Formation of the Early Miocene age dominated by silt rock and clay where the youngest lithology is andesite as the product of volcanism activity from Middle Miocene. Gunung Pancar lies at 850 mdpl indicating a high-relief geothermal system. The presence of three surface manifestations of Kawah Merah, Kawah Hitam and Kawah Putih, is controlled by the presence of fault structures in the form of strike slip fault with N 195oE/770 direction. Kawah Merah is sulphate-chloride water manifestation, with temperature 67oC, pH 7.0. Kawah Hitam is sulphate water, with temperature 51.8 oC, pH 7.04-8.0. Kawah Putih is sulphate water, surface temperature 49 oC. The three manifestations are located in the outflow zone of Gunung Pancar geothermal system. Silica geothermometry calculation reveals that reservoir temperatures range from 113,5-118,4 oC. Gunung Pancar can be categorized as a low temperature geothermal system. Stable isotope analysis 18O and 2D shows that the water source of Gunung Pancar geothermal system originates from meteoric water. A conceptual model of Gunung Pancar geothermal system is successfully constructed based on the integration of data."