scholarly journals COASTAL DYNAMICS OF SINGKAWANG, WEST KALIMANTAN

2016 ◽  
Vol 27 (2) ◽  
pp. 77
Author(s):  
Yudi Darlan ◽  
Udaya Kamiludin
Keyword(s):  
Coastal Region ◽  
Granitic Rocks ◽  
Physical Oceanography ◽  
Adjacent Area ◽  
Coastal Dynamics ◽  
West Kalimantan ◽  
Shallow Marine ◽  
Level Change ◽  
Erosion Coast ◽  
Global Sea Level

Morphologically, Singkawang and adjacent area consist of zones beaches, undulating hills, and steep hills. Granitic rocks and alluvium as a based rock of Singkawang coasts. Generally, Singkawang coasts was developed for coastal farms, fishery pond, and beach resorts, where most of these area have been eroded. Geological and physical oceanography condition are the aspects that build the characteristics of Singkawang coast. Human activities also play an important role in managing the equilibrium and dynamics of this coastal region. This research is to determine the dynamics and coastline changes of Singkawang coasts based on the characteristics of the coastal element and sediment. The high erosion was occurred at Semalagi–Cape Bajau. The Cape Bajau - Cape Banjar is relatively stable due to headlands of this coast is characterized by igneous rocks which resistant to the erosion. The Cape Banjar – South Coasts is very intensive erosion coast. Modern shorelines of the Singkawang coast might be as a shallow marine environment which were occurred thousands years ago (pre-Recent). The high of sedimentation process is generated by global sea level change, where was occurred at that time, and might be changed the area become part of the mainland coast of Singkawang. Keywords: coastal dynamics, erosion, sedimentation, Singkawang, West Kalimantan Secara morfologi, Singkawang terdiri atas daerah patai, perbukitan bergelombang, dan perbukitan curam. Batuan granit dan alluvium mengalasi kawasan pesisir Singkawang. Pesisir Singkawang sebagian besar berupa daerah pertanian, tambak ikan, dan tempat wisata yang umumnya merupakan kawasan pantai erosi. Geologi dan oseanografi fisika merupakan aspek yang membentuk karakteristik pantai Singkawang. Aktifitas manusia juga memainkan peranan penting di dalam mengelola kesetimbangan dan dinamika pesisir daerah ini. Penelitian ini untuk mengetahui dinamika dan perubahan garispantai Singkawang berdasarkan karakteristik dan sedimen pantai. Pantai Semalagi – Tanjung Bajau merupakan kawasan pantai erosi kuat. Tanjung Bajau – Tanjung Banjar merupakan kawasan pantai nisbi stabil ujung-ujung TanjungTanjungnya dicirikan oleh batuan beku yang tahan terhadap erosi. Tanjung Banjar – Pantai Selatan merupakan kawasan pantai erosi sangat kuat. Garispantai Singkawang pada saat ribuan tahun sebelum sekarang (pra-Recent) diperkirakan berupa kawasan lingkungan laut dangkal. Karena proses sedimentasi cukup kuat yang ditimbulkan oleh perubahan muka laut global pada saat itu mengubah kawasan tersebut menjadi daratan pantai Singkawang. Kata kunci: Dinamika pantai, erosi, sedimentasi, Singkawang, Kalimantan Barat.

scholarly journals Identifikasi Keterdapatan Mineral Radioaktif pada Urat-Urat Magnetit di Daerah Ella Ilir, Melawi, Kalimantan Barat

EKSPLORIUM ◽  
2019 ◽  
Vol 40 (1) ◽  
pp. 33
Author(s):  
Ngadenin Ngadenin ◽  
Frederikus Dian Indrastomo ◽  
Widodo Widodo ◽  
Kurnia Setiawan Widana
Keyword(s):  
Iron Ore ◽  
Biotite Granite ◽  
Ore Deposits ◽  
Geological Mapping ◽  
Granitic Rocks ◽  
Metamorphic Rocks ◽  
West Kalimantan ◽  
The North ◽  
Iron Ore Deposits ◽  
Radioactive Minerals

ABSTRAKElla Ilir secara administratif terletak di Kabupaten Melawi, Kalimantan Barat. Geologi regional daerah Ella Ilir tersusun atas batuan malihan berumur Trias–Karbon yang diterobos oleh batuan granitik berumur Yura dan Kapur. Keterdapatan mineral radioaktif di daerah tersebut terindikasi dari radioaktivitas urat-urat magnetit pada batuan malihan berumur Trias–Karbon dengan kisaran nilai 1.000 c/s hingga 15.000 c/s. Tujuan dari penelitian ini adalah menentukan jenis cebakan mineral bijih dan mengidentifikasi keterdapatan mineral radioaktif pada urat-urat bijih magnetit di daerah Ella Ilir. Metode yang digunakan adalah pemetaan geologi, pengukuran radioaktivitas, analisis kadar uranium, dan analisis mineragrafi beberapa sampel urat bijih magnetit. Litologi daerah penelitian tersusun oleh kuarsit biotit, metatuf, metabatulanau, metapelit, granit biotit, dan riolit. Sesar sinistral barat-timur dan sesar dekstral utara-selatan merupakan struktur sesar yang berkembang di daerah ini. Komposisi mineral urat-urat magnetit terdiri dari mineral-mineral bijih besi, sulfida, dan radioaktif. Mineral bijih besi terdiri dari magnetit, hematit, dan gutit. Mineral sulfida terdiri dari pirit, pirhotit, dan molibdenit sedangkan mineral radioaktif terdiri dari uraninit dan gumit. Keterdapatan urat-urat bijih magnetit dikontrol oleh litologi dan struktur geologi. Urat-urat magnetit pada metabatulanau berukuran tebal (1,5–5 m), mengisi rekahan-rekahan yang terdapat di sekitar zona sesar. Sementara itu, urat-urat magnetit pada metapelit berukuran tipis (milimetrik–sentimetrik), mengisi rekahan-rekahan yang sejajar dengan bidang sekistositas. Cebakan mineral bijih di daerah penelitian adalah cebakan bijih besi atau cebakan bijih magnetit berbentuk urat karena proses hidrotermal magmatik.ABSTRACTElla Ilir administratively located in Melawi Regency, West Kalimantan. Regional geology of Ella Ilir area is composed of metamorphic rocks in Triassic–Carboniferous age which are intruded by Jurassic and Cretaceous granitic rocks. Radioactive minerals occurences in the area are indicated by magnetite veins radioactivities on Triassic to Carboniferous metamorphic rocks whose values range from 1,000 c/s to 15,000 c/s. Goal of the study is to determine the type of ore mineral deposits and to identify the presence of radioactive mineral in magnetite veins in Ella Ilir area. The methods used are geological mapping, radioactivity measurements, analysis on uranium grades, and mineragraphy analysis of severe magnetite veins samples. Lithologies of the study area are composed by biotite quartzite, metatuff, metasilt, metapellite, biotite granite, and ryolite. The east-west sinistral fault and the north-south dextral fault are the developed fault structures in this area. Mineral composition of magnetite veins are consists of iron ore, sulfide, and radioactive minerals. Iron ore mineral consists of magnetite, hematit, and goetite. Sulfide minerals consist of pyrite, pirhotite, and molybdenite, while radioactive minerals consist of uraninite and gummite. The occurences of magnetite veins are controlled by lithology and geological structures. The magnetite veins in metasilt are thick (1.5–5 m), filled the fractures in the fault zone. Meanwhile, the magnetite veins in metapellite are thinner (milimetric–centimetric), filled the fractures that are parallel to the schistocity. The ore deposits in the study area are iron ore deposits or magnetite ore deposits formed by magmatic hydrothermal processes. 

Volume–area scaling parameterisation of Norwegian ice caps: A comparison of different approaches

The Holocene ◽  
2016 ◽  
Vol 27 (1) ◽  
pp. 164-171 ◽  
Author(s):  
Tron Laumann ◽  
Atle Nesje
Keyword(s):  
Water Resources ◽  
Sea Level Rise ◽  
Sea Level ◽  
Sea Level Change ◽  
Global Scale ◽  
Two Dimensional ◽  
Ice Caps ◽  
Level Change ◽  
Global Sea Level ◽  
Best Fit

Over the recent decades, glaciers have in general continued to lose mass, causing surface lowering, volume reduction and frontal retreat, thus contributing to global sea-level rise. When making assessments of present and future sea-level change and management of water resources in glaciated catchments, precise estimates of glacier volume are important. The glacier volume cannot be measured on every single glacier. Therefore, the global glacier volume must be estimated from models or scaling approaches. Volume–area scaling is mostly applied for estimating volumes of glaciers and ice caps on a regional and global scale by using a statistical–theoretical relationship between glacier volume ( V) and area ( A) ( V =  cAγ) (for explanation of the parameters c and γ, see Eq. 1). In this paper, a two-dimensional (2D) glacier model has been applied on four Norwegian ice caps (Hardangerjøkulen, Nordre Folgefonna, Spørteggbreen and Vestre Svartisen) in order to obtain values for the volume–area relationship on ice caps. The curve obtained for valley glaciers gives the best fit to the smallest plateau glaciers when c = 0.027 km3−2 γ and γ = 1.375, and a slightly poorer fit when the glacier increases in size. For ice caps, c = 0.056 km3−2 γ and γ = 1.25 fit reasonably well for the largest, but yield less fit to the smaller.

scholarly journals COASTAL MONITORING OF THE VERBYANAYA SPIT BY SATELLITE DATA

2020 ◽  
Vol 25 (3) ◽  
pp. 169-180
Author(s):  
Viacheslav V. Krylenko ◽  
◽  
Marina V. Krylenko ◽  
Keyword(s):  
Remote Sensing Data ◽  
Anthropogenic Factors ◽  
Adjacent Area ◽  
Coastal Dynamics ◽  
Modern Development ◽  
Exploration And Production ◽  
Combined Action ◽  
Underwater Slope ◽  
Kuban River ◽  
Natural And Anthropogenic Factors

The Verbyanaya spit is the south-western part of the sea edge of the Kuban river Delta, which was formed during the last 200 years. Сomplex monitoring studies including analysis of remote sensing data and cartographic material were performed for estimation of modern development trends of this accumulative form, coastal dynamics, the intensity of erosion-accumulative processes and the effectiveness of coast protection structures. The coastal dynamics of the Verbyanaya spit during last 150 years was determined by combined action of natural and anthropogenic factors. For last half a century the coastline of spit western part came forward to 200-400 m and the east spit coast retreated to 30-200 m. Economic development of adjacent area (natural gas exploration and production) has caused the need to stabilize the coast, and coastal protected dam was built in 2007. Monitoring showed that spit coast stabilized after creation of the dam, but changes of the underwater slope relief continued. Currently Verbyanaya spit develops as natural-anthropogenic system.

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