AbstrakKabupaten Nunukan termasuk wilayah yang signifikan menyumbang cadangan batubara di Indonesia dengan cadangan hipotetik mencapai sepuluh juta ton. Salah satu data yang dibutuhkan dalam tahapan eksplorasi lanjut batubara adalah informasi lingkungan pengendapan. Penelitian ini bertujuan untuk menentukan lingkungan pengendapan batubara Miosen di Kabupaten Nunukan, Kalimantan Utara. Metode yang dilakukan dalam penelitian yaitu analisis petrografi mencakup analisis maseral dan mineral, pengukuran vitrinite reflectance, plotting Tissue Preservation Index (TPI) terhadap Gelification Index (GI). Komposisi batubara di daerah penelitian tersusun dari dominasi vitrinit (68%-91%) juga dijumpai mineral pirit (0,9%-6,6%). Berdasarkan hasil analisis, batubara di daerah penelitian adalah lignit (Ro= 0,39%-0,44%). Plot Tissue Preservation Index (TPI) dan Gelification Index (GI) menunjukkan bahwa pada saat mengendapkan gambut, daerah penelitian berada pada lingkungan lower delta plain, lahan gambut wet forest swamp dan clastic marsh, serta pada kondisi lingkungan pengendapan telmatic dan limno-telmatic. Kehadiran pirit framboidal mengindikasikan formasi pembawa batubara mengalami reduksi sulfat, yang berasal dari lingkungan anoxic, dengan ion besi pada saat pembatubaraan. Kata kunci :Maseral; Nunukan; Reflektansi Vitrinit; TPI-GI. AbstractNunukan Regency, North Borneo, significantly contributes coal reserves in Indonesia with hypothetical reserves reaching ten million tons. One of the data required in the next stage of coal exploration is information of depositional environment. This study aims to determine the Miocene coal depositional environment in Nunukan Regency. The method used in this research are petrographic analysis including observation of minerals and minerals, measurement of vitrinite reflectance, plotting tissue preservation index (TPI) of Gelification Index (GI). The composition of coal in the study area composed of vitrinite dominance (68% -91%), pyrite minerals are also identified (0.9% -6.6%). Based on the analysis, coal in the study area is lignite (Ro = 0.39% -0.44%). Tissue Preservation Index (TPI) and Gelification Index (GI) plot shows that the study area is in the lower delta plain environment, wet forest swamp and clastic marsh peatlands, and in the telmatic and limno-telmatic depositional environment during peat accumulation. The presence of ramboidal pyrite indicates the coal bearing formation experienced reduction of sulfates, from anoxic environment, with iron ions during coalification.

The beach is a favorite tourist destination for the Indonesian people. As Indonesia is blessed with many beaches which attracts people to visit. Indonesians usually come to the beach in the holiday to fish, see beautiful scenery, and play around. Central Java Province in Indonesia has a beach cluster situated to the north and south of the Java Island. Jatimalang Beach is the south coast of Java which has excellent natural beauty, which is located in Purworejo Regency. This research is focused on the beach facilities and infrastructures, tourist’s ecotourism awareness, and environmental sustainability management of the Jatimalang Beach Purworejo. The study was carried out in November till December 2019 by using the qualitative research method. Information discovered during fieldwork are used to direct data collection. Qualitative researchers, are closely engaging with the environment being examined. This work was conducted through observations and interviews with tourist at Jatimalang Beach, as well as a literature review. The results showed that the facilities and infrastructure found in Jatimalang Beach were the presence of lifesavers, waste, parking lots, freshwater swimming pools for children, toilets, electrical facilities, and worship places. In addition, tourists are often willing to preserve nature and the sustainability of marine tourism on the Jatimalang Beach, however many of them do not understand the importance of ecotourism and need to be educated again.

AbstrakSemburan lumpur Sidoarjo di Porong belum berhenti hingga saat ini, sehingga tahun 2019 Pusat Pengendalian Lumpur Sidoarjo (PPLS) berencana membangun tanggul baru di sisi timur tanggul utama setinggi 5 m yakni tanggul Wedok. Dalam pembangunan tanggul Wedok perlu diketahui kekuatan tanah dasar serta stabilitas tubuh tanggul. Untuk itu, dilakukan kajian mengenai kekuatan tanah penopang tanggul dan kestabilan tubuh tanggul mengunakan metode finite element dengan perangkat lunak Phase2 V8.0. Berdasarkan data pemetaan geologi lokasi penelitian tersusun oleh litologi endapan aluvial dan endapan lumpur Sidoarjo, sedangkan berdasarkan penyelidikan geologi teknik terbagi menjadi tiga satuan, yakni : satuan tanah urugan, satuan endapan lumpur Sidoarjo, dan satuan tanah asli. Tanah dasar pada lokasi rencana tanggul berupa lempung lunak yang tebal dengan kemampuan menahan beban tanggul setinggi 2,15 m. Pemasangan PVD (Prevabricated Vertical Drain) pada tanah dasar meningkatkan nilai faktor keamanan (FK) pada stabilitas tubuh tanggul.Kata kunci: Tanggul Wedok; kestabilan lereng; finite element; tanah dasar; PVD. AbstractThe Sidoarjo mudflow in Porong has not stopped until now, therefore in 2019 the Pusat Pengendalian Lumpur Sidoarjo (PPLS) plans to build a new embankment on the east side of the main embankment as high as 5 m, namely the Wedok embankment. In the consruction of Wedok embankment it is necessary to know the strength of the subgrade and the stability of the embankment body. For this reason, a study was conducted on the strength of the embankment supporting soil and the stability of the embankment body using the finite element method with Phase2 V8.0 software. Based on geological mapping data, the research site is composed of lithology alluvial sediment and Sidoarjo mud deposit, while based on technical geological investigation is divided into three units, namely: subgrade soil unit, Sidoarjo mud deposit unit, and original soil unit. The subgrade at the dike plan location is thick soft clay with the ability to withstand embankment loads as high as 2.15 m. Installation of PVD (Prevabricated Vertical Drain) on subgrade increases the value of safety factor (FK) on the stability of the embankment body.

Kabupaten Gunungkidul, salah satunya di Hargomulyo, Kecamatan Gedangsari, dikenal memiliki komoditas tambang non-logam zeolit. Diperlukan penelitian lanjut untuk mengetahui karakteristik zeolit tersebut. Daerah ini termasuk ke dalam bagian Pegunungan Selatan. Daerah penelitian pada Peta Geologi lembar Surakarta – Giritontro tahun 1992 tersusun dari Formasi Kebobutak Oligosen dan Formasi Semilir Miosen Awal yang tersusun oleh batuan sedimen dengan komposisi dominan vulkanik. Pada sebagian batuan sedimen vulkanik sudah teralterasi menjadi zeolit, yang berdasarkan peneliti terdahulu termasuk ke dalam Formasi Kebobutak. Penelitian bertujuan untuk mengetahui genesis, karakteristik, arahan pemanfaatan zeolit di daerah penelitian. Observasi lapangan dilakukan untuk memperoleh data geologi, dilanjutkan dengan analisis di laboratorium. Analisis yang dilakukan pada sampel zeolit berupa analisis petrografi untuk menentukan penamaan batuan, sedangkan analisis X-Ray Diffraction (XRD) dan X-Ray Fluorensence (XRF) untuk mengetahui jenis mineral penyusun. Zeolit pada daerah penelitian memiliki nama petrografis Vitric Tuff terubah (Pettijohn, 1975 dengan modifikasi). Hasil XRD dan XRF menyebutkan sampel zeolit di daerah penelitian didominasi mordenit, klinoptilolit dan heulandit. Genesis dari zeolit pada daerah penelitian merupakan hasil alterasi akibat kontak dengan airtanah, ditandai dengan mineral zeolit, yaitu mordenit dan klinoptilolit (Suhala dan Arifin, 1997). Faktor lain alterasi adalah pengaruh diagenetik, diindikasikan dengan keberadaan Heulandit. Dengan mineral zeolit yang dominan adalah mordenit, klinoptilolit dan heulandit, yang mendukung interpretasi genesis dari zeolit yang terbentuk dari alterasi airtanah dan proses diagenetik. Pemanfaatan yang tepat untuk zeolit dari daerah penelitian adalah untuk bidang pertanian, peternakan, dan perikanan.

Indonesia is an archipelago blessed with the wealth of coastal resources, but also with the risk of natural hazards including tectonic earthquake and tsunami. This potential risk is high in the Purwodadi Subregency, Purworejo Regency, Indonesia, because of its location in an active subduction zone at the edge of the Indian Ocean. Therefore, this study was conducted in the region located on the southern coast of Java Island. The high probability of disaster in the area needs a proper coastal management strategy and mitigation measures. Hence, this study aims to establish an appropriate policy using the strength-weakness-opportunity-threat (SWOT) analysis. Furthermore, the data obtained from this novel analysis include the population and social vulnerability, geological conditions, landuse allocation, and disaster strategies. Each is carefully assessed and then incorporated into the matrix to obtain the result. In addition, the alternative strategies used are the development of disaster mitigation facilities, infrastructure, and institutional strengthening.