scholarly journals Hubungan Antara Fasies Batugamping Terhadap Kualitasnya Sebagai Bahan Baku Semen Portland Menurut Kadar CaO dan Senyawa Terkait di Kuari B dan C, PT Indocement Tunggal Prakarsa Tbk Unit Palimanan, Cirebon

2020 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Ahmad Syauqi Hidayatillah ◽  
Tri Winarno ◽  
Rofiatun Khasanah
Keyword(s):  
Back Reef ◽  
X Ray ◽  
Reef Lagoon

Batugamping merupakan sumberdaya alam kategori bahan galian industri nonlogam. Penelitian mengenai fasies dan kualitas batugamping di PT Indocement Tunggal Prakarsa Tbk Unit Palimanan dilakukan untuk mengetahui hubungan antara jenis fasies terhadap kualitas batugamping sebagai bahan baku semen portland. Penelitian dilakukan dengan pengamatan sampel batugamping secara makroskopis dan mikroskopis terhadap 20 singkapan batugamping Kuari B dan C. Setiap singkapan batugamping dilakukan pengambilan sampel hand speciment untuk analisis kualitas kimia menggunakan X-Ray Fluorescence dan analisis fasies lebih spesifik. Hasil analisis menyatakan bahwa batugamping Kuari B diklasifikasikan menjadi 3 fasies, yaitu packstone, bafflestone, dan rudstone yang terbentuk pada zonasi fasies reef core dan back-reef lagoon. Batugamping Kuari C diklasifikasikan menjadi 4 fasies, yaitu mudstone, wackestone, packstone, dan grainstone yang terbentuk pada zonasi fasies back-reef lagoon. Analisis kualitas kimia menunjukkan bahwa 8 sampel batugamping Kuari B berkualitas baik (kadar CaO>49%), sedangkan pada Kuari C didapati sebanyak 8 sampel berkualitas baik (kadar CaO >49%), 2 sampel berkualitas sedang (kadar CaO 40-49%) dan 2 sampel berkualitas rendah (kadar CaO<40%). Hasil penelitian menunjukkan bahwa jenis fasies batugamping yang bersifat grain supported seperti grainstone, packstone, bafflestone, dan rudstone cenderung menghasilkan batugamping dengan kualitas baik, sedangkan fasies batugamping yang bersifat matrix supported seperti mudstone dan wackestone akan menghasilkan batugamping dengan kualitas yang lebih buruk.

Growth rates and ecology of coralline rhodoliths from the Ras Ghamila back reef lagoon, Red Sea

2016 ◽  
Vol 37 (4) ◽  
pp. 713-726 ◽  
Author(s):  
Annalisa Caragnano ◽  
Daniela Basso ◽  
Graziella Rodondi
Keyword(s):  
Red Sea ◽  
Growth Rates ◽  
Back Reef ◽  
Reef Lagoon

Selective Elimination of Rooted Plants from a Tropical Seagrass Bed in a Back-Reef Lagoon: A Hypothesis Tested by Hurricane Wilma (2005)

2008 ◽  
Vol 241 ◽  
pp. 278-281 ◽  
Author(s):  
Brigitta I. van Tussenbroek ◽  
M. Guadalupe Barba Santos ◽  
Jent Kornelis van Dijk ◽  
S. N. Marisela Sanabria Alcaraz ◽  
M. Lourdes Téllez Calderón
Keyword(s):  
Back Reef ◽  
Seagrass Bed ◽  
Hurricane Wilma ◽  
Reef Lagoon ◽  
Selective Elimination

Siliciclastic—carbonate transitions in surface sediments of a back-reef lagoon north of Dar es Salaam (Tanzania)

1992 ◽  
Vol 78 (1-2) ◽  
pp. 49-57 ◽  
Author(s):  
Mario Fay ◽  
Desiderius C.P. Masalu ◽  
Alfred N.N. Muzuka
Keyword(s):  
Surface Sediments ◽  
Dar Es Salaam ◽  
Back Reef ◽  
Reef Lagoon

scholarly journals Lithological and isotopic (δ 13C and δ 18O) features of the Upper Silurian back-reef lagoon deposits of the Ilych River Basin, the Northern Urals

2021 ◽  
Vol 11 ◽  
pp. 43-54
Author(s):  
E. S. Ponomarenko ◽  
Keyword(s):  
River Basin ◽  
Isotopic Fractionation ◽  
Wide Distribution ◽  
Back Reef ◽  
Clastic Material ◽  
Reef Lagoon ◽  
Northern Urals ◽  
Rock Types ◽  
Δ 13C ◽  
Upper Silurian

The Upper Silurian is widely developed in the Northern Urals, where it is represented by various facies. The continental slope facies and the reef shoal facies are well documented in the geological literature, while as back-reef lagoon facies have not yet been characterized in detail. The studied objects included two sections of the back-reef deposits in the Ilych River basin. In this work, we characterize rock types the make up the sections, and their isotopic characteristics. The Late Silurian back-reef lagoon was characterized by a mosaic sediments distribution, which included the island areas between which there were areas with a quiet hydrodynamic regime. In the latter, mainly muddy carbonates were accumulated, represented by clotted fenestral limestones. The area of small islands was characterized by a wide distribution of lime sands, which clastic material was derived from probable paleosoil carbonates. They are characterized by slightly increased δ 13C values, which, probably, reflects isotopic fractionation at the evaporative geochemical barrier. Dolomitization and karstification are described among secondary alterations in the studied sections. Cementstones is interpreted as karst cavities precipitates.

Growth and population dynamics of Thalassodendron ciliatum in a Kenyan back-reef lagoon

1996 ◽  
Vol 55 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Carlos M. Duarte ◽  
Marten A. Hemminga ◽  
Nuria Marbà
Keyword(s):  
Population Dynamics ◽  
Back Reef ◽  
Reef Lagoon ◽  
Thalassodendron Ciliatum

scholarly journals Analisis Litofasies dan Sistem Terumbu Batuan Karbonat Berdasarkan Data Log dan Core, Cekungan Banggai, Sulawesi Tengah

2020 ◽  
Vol 1 (01) ◽  
Author(s):  
Fachry Muhammad ◽  
Benyamin Benyamin ◽  
Firman Herdiansyah
Keyword(s):  
Back Reef ◽  
Fore Reef ◽  
Reef Lagoon ◽  
Reef System ◽  
Data Log

<p>Lokasi daerah penelitian berada pada lapangan “FM” terletak pada Cekungan Banggai, Sulawesi Tengah. Tujuan dari penelitian ini adalah mengidentifikasi fasies dan lingkungan pengendapan yang berkembang pada Anggota Mentawa yang berada di Formasi Minahaki yang merupakan suatu reef system pada batuan karbonat. Metodologi penelitian yang dilakukan yaitu dengan cara analisis kuantitatif menggunakan data log dan analisis fasies menggunakan data petrografi dan mudlog. Dari hasil analisis kuantitatif berupa peta kedalaman daerah penelitian dan hasil analisis litofasies berdasarkan deksripsi dari litologi yang terdapat pada seluruh sumur terbagi menjadi beberapa fasies yaitu fasies mudstone, fasies wackstone, fasies skeletal wackstone, fasies skeletal packstone dan fasies coarse skeletal wackstone-packstone. Lingkungan pengendapan pada sistem terumbu yang berkembang berdasarkan jenis dari fasies dan biota yang hadir pada daerah penelitian diperkirakan diendapakan pada lingkungan back reef lagoon dan fore reef. Berdasarkan hasil analisis lingkungan pengendapan tersebut menunjukan geometri dari sistem terumbu yaitu isolated reef.</p>

Space and Time Distribution of Hard X-Ray Emission in a Loop at the Beginning of a Flare

1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux
Keyword(s):  
Time Distribution ◽  
Electron Bombardment ◽  
Spatial Evolution ◽  
Superthermal Electrons ◽  
Flare Loop ◽  
X Ray ◽  
Superthermal Electron ◽  
Flare Loops ◽  
Chromospheric Evaporation ◽  
Temporal And Spatial

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.

Some Problems in Understanding the Solar Corona

1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel
Keyword(s):  
Solar Corona ◽  
Solar Atmosphere ◽  
Theoretical Modelling ◽  
Total System ◽  
Major Advance ◽  
X Ray ◽  
Proper Perspective ◽  
Space Observations

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.

White-Light Coronal Structures: Streamers and CMEs

1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner
Keyword(s):  
Emission Line ◽  
Electron Density ◽  
White Light ◽  
Coronal Mass Ejections ◽  
X Rays ◽  
Solar Cycles ◽  
Temperature Function ◽  
X Ray ◽  
Eclipse Observations ◽  
Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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