scholarly journals Preliminary Study of Geology, Alteration and Ore Mineralisation at East Motoling Area, South Minahasa District, North Sulawesi, Indonesia

2021 ◽  
Vol 921 (1) ◽  
pp. 012034
Author(s):  
F R Hakim ◽  
A Idrus
Keyword(s):  
Middle Miocene ◽  
Geological Mapping ◽  
Petrographic Analysis ◽  
North Sulawesi ◽  
Late Middle Miocene ◽  
Geological Conditions ◽  
Ore Mineralization ◽  
Preliminary Study ◽  
Lapilli Tuff ◽  
Low Sulfidation

Abstract The East Motoling area is one of the prospect areas in the Minahasa region of North Sulawesi, which has indications of low sulfidation epithermal-type mineralization. The research was conducted as a preliminary study to determine the characteristics of geological conditions, alteration, and ore mineralization in the epithermal system. The research method is divided into two main parts, such as fieldwork including surface geological mapping (lithology, stratigraphy, geomorphology, structural geology, alteration and mineralization) and laboratory analysis methods including petrographic analysis. The stratigraphy of the study area consists of altered volcaniclastic breccia, altered lapilli tuff, altered tuff, limestone, welded lapilli tuff, and andesitic breccia. Volcaniclastic breccia, altered lapilli tuff, and altered tuff, member of the Volcanic Rock Formation which is Late – Middle Miocene age, are the host rock for ore mineralization and hydrotermal alteration process. There are 3 types of alterations that have developed, namely argillic (illite + quartz ± kaolinite), sericitic (sericite + illite ± chlorite), and propylitic (chlorite + epidote ± illite). The dextral slip fault with NW – SE trend present as a main control structure to formation of extention fracture/vein. The epithermal veins are relatively north-northeast – south-southwest, north-northwest – south-southeast, and northwest – southeast. The textures of the veins divided into 7 main groups, namely that is bladed-quartz, breccia, calcedony, colloform, comb, mold, and massive quartz. Ore mineralization is forms in the veins as pyrite and banded sulfide. Apart from that, the disseminated pyrite also limitedly found around the veins.

scholarly journals Investigation of Aquifer Zone in Tambakromo Village, Ponjong Subdistrict, Gunung Kidul Regency, Yogyakarta, Indonesia

2021 ◽  
Vol 6 (3) ◽  
pp. 216
Author(s):  
Al Hussein Flowers Rizqi ◽  
Oky Sugarbo
Keyword(s):  
Research Area ◽  
Unconfined Aquifer ◽  
Groundwater Exploration ◽  
Geological Mapping ◽  
Petrographic Analysis ◽  
Stratigraphic Correlation ◽  
Geological Conditions ◽  
Drought Disaster ◽  
Limestone Rock ◽  
Geoelectrical Resistivity

The presence of surface water is always being a primary issue in Gunung Kidul regency. An aquifer investigation would support groundwater exploration. The research area is located in Tambakromo village, Ponjong subdistrict, Gunung Kidul Regency, Daerah Istimewa Yogyakarta Province. The aim of this research is about geological and subsurface conditions based on geological data and geoelectrical resistivity methods. By resistivity value interpretation, the position, depth, and thickness of aquifer could be determined. The purpose of this research is to identification of geological conditions that supported being aquifer rock. The method in this research is used geological mapping combined with petrographic analysis. The geophysics method is used to identification of aquifer in research area. Three locations were selected to acquisition geoelectrical resistivity survey. In Grogol village, there is no aquifer based on resistivity values of more than 10000 ohmmeters (andesitic breccia). An akuifuge is interpreted there in andesitic breccia instead of the presence of aquifer. The tuffaceous is interpreted as lapillistone that contained the glass with resistivity value of 43.63 and 340.11 ohmmeters. The Garon and Sumberejo village have aquifer at depth of 50 to 80 meters with a thickness of 13 to 70 meters. The type of aquifer in both area is included an unconfined aquifer, specifically located in between the limestone rock layer and andesitic breccia. By regional stratigraphic correlation, tuffaceous lapillistone is interpreted as derived from Semilir Formation. In addition, the presence of aquifer in research area could recommend for local people and government to reduce the drought disaster.

scholarly journals Geological Mapping of the Longkeyang and Surrounding Regions, Bodeh District, Pemalang Regency, Central Java

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Irwan Firmansyah ◽  
Adi Candra ◽  
Fajar Rizki Widiatmoko
Keyword(s):  
Middle Miocene ◽  
Research Area ◽  
Geological Structure ◽  
Geological Mapping ◽  
Research Activity ◽  
River Sand ◽  
Geological Disasters ◽  
Central Java ◽  
Geological Conditions ◽  
River Deposits

Geological mapping is one of the important things as part of a field study to obtain geological knowledge. This is due to the need for a geologist who is required to be able to understand the geological conditions of an area, one of which is by conducting mapping activities in the field. In conducting this research activity, it is divided into two stages, namely the field stage and the laboratory stage. The purpose of this research is to determine the characteristics and geological conditions, identify resource potentials and potential geological disasters in the research area. Based on the analysis, it was found that the geomorphological units of the study area were divided into 4 (four), namely the Mount Ketos Homocline Hills Unit, the Polaga River Anticline Valley Unit, the Sarangkadu Cycline Hills Unit, and the Mount Lanji Intrusion Hills Unit. The geology of the study area consists of three rock units in order from oldest to youngest, namely the claystone-sandstone unit and the sandstone-claystone unit and the diorite intrusion unit. The geological structure of the pinnacle area is in the form of folds and faults, namely, Polaga River Anticlines, Sarangkadu Synclines, Polaga River Right Shear Fault, Polaga River Left Shear Fault. The geological history of the study area begins with the deposition of claystone-sandstone units during the Middle Miocene in the Upper Bathyal environment. Furthermore, after the claystone-sandstone units were deposited, during the Middle Miocene – Late Miocene in the Deep Neuritic environment, sandstone-claystone units were deposited with a turbidity deposition mechanism. As well as the geological resource potential of the research area in the form of utilization of river deposits in the form of chunks of igneous rock, river sand deposits and indications of the presence of gold. Meanwhile, the potential for geological disasters in the form of landslides.

scholarly journals The distribution of <i>Triebelina raripila</i> and <i>Carinocythereis carinata</i> (Ostracoda) from the Middle Miocene of the Central Paratethys and their palaeogeographic implications

1998 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
J. Szczechura
Keyword(s):  
Shallow Water ◽  
Late Miocene ◽  
Middle Miocene ◽  
Early Miocene ◽  
Central Paratethys ◽  
Eastern Paratethys ◽  
Main Species ◽  
Late Middle Miocene ◽  
The Mediterranean

Abstract. Late Middle Miocene (Upper Badenian) strata of the Fore-Carpathian Depression of Poland yield a shallow-water ostracod fauna which contains the species Triebelina raripila (G. W. Müller, 1894) and Carinocythereis carinata (Roemer, 1838). The palaeobiogeographic distribution of the two main species suggests, that in the late Middle Miocene, Central Paratethys was still connected to the Mediterranean, although still separated from the Eastern Paratethys and from southeastern Eurasia. The continuous occurrence of Triebelina raripila and Carinocythereis carinata in the Mediterranean basins, from the Early Miocene to Recent, indicates that marine conditions existed throughout, thereby allowing them to survive the Late Miocene salinity crisis.

scholarly journals New record of Neosaimiri (Cebidae, Platyrrhini) from the late Middle Miocene of Peruvian Amazonia

2020 ◽  
Vol 146 ◽  
pp. 102835 ◽  
Author(s):  
Laurent Marivaux ◽  
Walter Aguirre-Diaz ◽  
Aldo Benites-Palomino ◽  
Guillaume Billet ◽  
Myriam Boivin ◽  
...  
Keyword(s):  
New Record ◽  
Middle Miocene ◽  
Late Middle Miocene ◽  
Peruvian Amazonia

scholarly journals Ag-Pb-Sb Sulfosalts and Se-rich Mineralization of Anthony of Padua Mine near Poličany—Model Example of the Mineralization of Silver Lodes in the Historic Kutná Hora Ag-Pb Ore District, Czech Republic

Minerals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 430 ◽  
Author(s):  
Pažout ◽  
Sejkora ◽  
Šrein
Keyword(s):  
Solid Solution ◽  
Czech Republic ◽  
Chemical Element ◽  
Hydrothermal Fluids ◽  
Tectonic Events ◽  
Mineral Phases ◽  
Ore Mineralization ◽  
Ore Mineralogy ◽  
Low Sulfidation ◽  
Ore District

Significant selenium enrichment associated with selenides and previously unknown Ag-Pb-Sb, Ag-Sb and Pb-Sb sulfosalts has been discovered in hydrothermal ore veins in the Anthony of Padua mine near Poličany, Kutná Hora ore district, central Bohemia, Czech Republic. The ore mineralogy and crystal chemistry of more than twenty silver minerals are studied here. Selenium mineralization is evidenced by a) the occurrence of selenium minerals, and b) significantly increased selenium contents in sulfosalts. Identified selenium minerals include aguilarite and selenides naumannite and clausthalite. The previously unknown sulfosalts from Kutná Hora are identified: Ag-excess fizélyite, fizélyite, andorite IV, andorite VI, unnamed Ag-poor Ag-Pb-Sb sulfosalts, semseyite, stephanite, polybasite, unnamed Ag-Cu-S mineral phases and uytenbogaardtite. Among the newly identified sulfides is argyrodite; germanium is a new chemical element in geochemistry of Kutná Hora. Three types of ore were recognized in the vein assemblage: the Pb-rich black ore (i) in quartz; the Ag-rich red ore (ii) in kutnohorite-quartz gangue; and the Ag-rich ore (iii) in milky quartz without sulfides. The general succession scheme runs for the Pb-rich black ore (i) as follows: galena – boulangerite (– jamesonite) – owyheeite – fizélyite – Ag-exces fizélyite – andorite IV – andorite VI – freieslebenite – diaphorite – miargyrite – freibergite. For the Ag-rich red ore (ii) and ore (iii) the most prominent pattern is: galena – diaphorite – freibergite – miargyrite – pyragyrite – stephanite – polybasite – acanthite. The parallel succession scheme progresses from Se-poor to Se-rich phases, i.e., galena – members of galena – clausthalite solid solution – clausthalite; miargyrite – Se-rich miargyrite; acanthite – aguilarite – naumannite. A likely source of selenium is in the serpentinized ultrabasic bodies, known in the area of “silver” lodes in the South of the ore district, which may enable to pre-concentrate selenium, released into hydrothermal fluids during tectonic events. The origin of the studied ore mineralization is primarily bound to the youngest stage of mineralization of the whole ore district, corresponding to the Ag-Sb sequence of the ´eb´ ore type of the Freiberg ore district in Saxony (Germany) and shows mineralogical and geochemical similarities to low-sulfidation epithermal-style Ag-Au mineralization.

Evolutionary adaptation and geographic spread of the Cenozoic buccinid genus Lirabuccinum in the North Pacific

2003 ◽  
Vol 77 (5) ◽  
pp. 863-872 ◽  
Author(s):  
Kazutaka Amano ◽  
Geerat J. Vermeij
Keyword(s):  
North Pacific ◽  
Middle Miocene ◽  
Eastern Pacific ◽  
Early Pleistocene ◽  
Northwestern Pacific ◽  
The North ◽  
Early Oligocene ◽  
Rocky Bottom ◽  
Late Middle Miocene ◽  
The Western Pacific

The Early Oligocene to Recent genus Lirabuccinum Vermeij, 1991, is a North Pacific clade of rocky-bottom predatory buccinid gastropods. A re-examination of all available material from eastern Asia and comparison of this material with western American species leads us to recognize four northwestern Pacific species: L. fuscolabiatum (Smith, 1875) from the Pliocene to Recent; L. japonicum (Yokoyama, 1926) from the Pliocene and Early Pleistocene; L. branneri (Clark and Arnold, 1923) from the early Middle Miocene, also known from the Oligocene in the eastern Pacific; and Lirabuccinum sp. from the late Middle Miocene. The genus originated in the eastern Pacific and subsequently spread to the western Pacific by late Early Miocene to early Middle Miocene time. Lirabuccinum exemplifies a common pattern among rocky-bottom North Pacific gastropods in that the early species have a thick, internally strongly ribbed or denticulate outer lip. As they adapted to the colder boreal realm during the Pliocene and Pleistocene, Lirabuccinum and such other clades as Nucella, Ceratostoma, and Ocinebrellus (all Muricidae) evolved thinner, less heavily reinforced outer lips.

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