Facies

SARI Berdasarkan bentuk bentang alam dan asosiasi batuan penyusun, suatu kerucut gunung api komposit dapat dibagi menjadi fasies sentral, fasies proksimal, fasies medial, dan fasies distal. Secara bentang alam, pembagian tersebut dimulai dari pusat erupsi di bagian puncak, menurun ke arah lereng, kaki, serta dataran di sekelilingnya. Fasies sentral gunung api dicirikan oleh asosiasi batuan beku intrusi dangkal, kubah lava, dan batuan ubahan hidrotermal. Fasies proksimal tersusun oleh perselingan aliran lava dan breksi piroklastika. Fasies medial terutama berupa breksi piroklastika, breksi lahar, dan konglomerat, sedangkan fasies distal lebih banyak disusun oleh batuan epiklastika berukuran butir pasir-lempung. Tuf dapat tersebar mulai dari fasies proksimal sampai distal karena berbutir halus dan ringan. Pembagian fasies gunung api di dalam batuan berumur Tersier atau lebih tua dilakukan dengan pendekatan inderaja-geomorfologi, stratigrafi batuan gunung api, vulkanologi fi sik, struktur geologi, serta petrologi-geokimia. Pembagian fasies gunung api ini dapat dimanfaatkan dalam rangka pencarian sumber baru di bidang mineral dan energi, penataan lingkungan, serta mitigasi bencana geologi. Kata kunci: kerucut gunung api komposit, fasies gunung api ABSTRACT Based on the nature and rock association, a composite volcanic cone can be divided into central facies, proximal facies, medial facies and distal facies. Physiographically, those begin from central eruption at the summit, going down to upper slope, lower slope, and foot plain in the surrounding area. Central facies is characterized by the presence of subvolcanic intrusions, lava domes, and hydrothermally altered rocks. Proximal facies consists of alternating lava fl ows and pyroclastic breccias. Medial fasies mainly is composed of pyroclastic breccias, laharic breccias, and conglomerates. Whereas, distal facies is dominated by fi ne-grained epiclastic rocks having sand to clay size. Tuff can be widely distributed from proximal to distal facies due to its fi ne grain and lightness. Methodological approachs for classifi cation of volcanic facies in Tertiary and older rocks are remote sensing and geomorphology, volcanic stratigraphy, physical volcanology, structural geology, and petrology-geochemistry. This volcanic facies division is useful for supporting new discovery on energy and mineral resources, environmental geology, and geologic hazard mitigation.

Stratigraphic exposures, fluvial archives and borehole data have been allowed to reconstruct the alluvial history of Late Pleistocene to Late Holocene and climate changes in the monsoonal wet – dry region of lower Damodar Basin (West Bengal, India). The facies architectures and climate proxies suggest that five to six climate changes occurred in between ~ 14 ka and 6 ka. Supporting evidence from the floodplain of Damodar River demonstrates that the successive phases of aggradation and incision were linked to the south-west monsoonal variability of Late Quaternary period. The onset of semi-arid climate was associated with caliches, pond and backswamp deposits of wanning low energy floods. The relatively warm-humid climate was associated with sandy bedforms, valley fills, slack water deposits and ferruginous nodules. This paper presents a synthesis of the available palaeoclimatic records from the lower Ganga Basin and the rivers of western and central India for the palaeoenvironmental significance of Late Quaternary deposits and discusses the influence of palaeoclimatic controls on the fluvial architectures and archives that developed below the floodplain of Damodar River. We have taken some representative studies from the region to reveal the spatial variability in fluvial successions in response to climate changes during this period.

The Asmari Formation, a thick carbonate succession of the Oligo-Miocene in Zagros Mountains (southwest Iran), has been studied to determine its microfacies, paleoenvironments and sedimentary sequences. Detailed petrographic analysis of the deposits led to the recognition of 10 microfacies types. In addition, five major depositional environments were identified in the Asmari Formation. These include tidal flat, shelf lagoon, shoal, slope and basin environmental settings and are interpreted as a carbonate platform developed in an open shelf situation but without effective barriers separating the platform from the open ocean. The Asmari carbonate succession consists of four, thick shallowing-upward sequences (third-order cycles). No major hiatuses were recognized between these cycles. Therefore, the contacts are interpreted as SB2 sequence boundary types. The Pabdeh Formation, the deeper marine facies equivalent of the Asmari Limestone is interpreted to be deposited in an outer slope-basin environment. The microfacies of the Pabdeh Formation shows similarities to the Asmari Formation.

Holoprosencephaly (HPE) is genetically heterogeneous. Variable phenotypic manifestations within families with normal and affected patients have been attributed to the number and type of HPE gene mutations. Environmental agents may also contribute to the severity as well as the requirement of multiple hits. Clinical expression is extremely variable ranging from minor facial signs to complex craniofacial anomalies such as cyclopia. Main genes involved include SHH, GLI2, PTCH1, TGIF, ZIC2, TDGF1, SIX3; however, several other candidates have been proposed. Recently it was established that the human growth arrest specific gene 1 (GAS1) is a potential locus for several human craniofacial malformations. Here, we report on four Brazilian patients with GAS1 DNA sequence change who presented variable phenotypical manifestations ranging from classic HPE to HPE-like signs. Two patients had single DNA sequence change in the GAS1 gene, while in other two, an additional mutation in the SHH gene was observed. Clinical manifestations presented by these patients suggest that GAS1 could be considered a candidate locus for one of the types of human HPE. © 2010 Wiley-Liss, Inc.

The Middle Miocene Marnoso-arenacea Formation at Deruta in the northern Apennines of Italy rests unconformably on an orogenic wedge adjacent to the Adriatic foredeep. Based on a detailed facies analysis, the succession reveals two genetically related depositional systems: a distal delta-fed sand-rich system and a more proximal fan-delta slope system. Petrographic data confirm the genetic relationship between the two depositional systems, with the fan-delta slope feeding the basinward sand-rich system. The Deruta depositional setting shows a multi-step sedimentary evolution controlled by tectonically induced relative sea-level changes. The first stage, corresponding to a sea-level rise, promoted deposition in a wedge-top basin of pebbly sand and sand lobes (delta-fed). The second stage, characterized by intense tectonic activity (uplift) and sea-level fall, promoted accumulation of a prograding fan-delta slope replacing the sand-rich lobes. This phase was dominated by mass failures a...

The Upper Ordovician (late Whiterockian to Mohawkian) Lourdes Formation represents a narrow (tens of kilometers), short-lived [∼5–7 million years (my)], open-ocean (high-energy) mixed siliciclastic-carbonate ramp that onlapped allochthonous strata along the orogen side of the local Taconic foreland basin. Platform development followed a 6–8 my hiatus during which weathering had concentrated chemically mature siliciclastics that were admixed with initial carbonate sediments. A cross-platform facies gradient contains paleokarst and peritidal carbonates and sandstones, shallow-ramp carbonate bioherms and skeletal shoals, and deeper ramp calcareous shales. Transgressive systems tracts are marked by ramp-wide sheets and shoals of skeletal grainstone and low accumulation rates, and highstand systems tracts are marked by significant admixture and interbedding of siliciclastics with cross-ramp carbonate facies. Platform demise coincides with increased siliciclastic input, which is likely tectonically influenced. The Lourdes platform is equivalent to epicontinental foreland ramps along eastern Laurentia, but its narrower width precluded formation of oceanographically restricted platform-interior facies.

Thin-section analysis of Late Aptian/Early Cenomanian limestones was carried out in respect to the distribution of components and biota. All the sedimentological data were used for interpreting the depositional environment. The sequence starts with Early Cretaceous sandstones; sandy dolomites form the transition to massive limestones, which prevail in the middle and upper parts of the section. They indicate shallow marine carbonate platform conditions at the northern rim of the African Craton: Thick accumulations of tidal carbonate shoals interfinger with quiet-water subtidal and intertidal to supratidal strata. The paleogeographic importance of the sequence is emphasized by comparison with contemporaneous strata in Israel and northern Egypt. Orbitolinids are most important fossils for stratigraphic analysis:Dictyoconus algerianus, Orbitolina (M.) texana, O. (M.) subconcava andO. (M.) aperta were joined by other minor foraminifera and a diverse algal flora. The youngest dateable sample withO. (M.) aperta andO. (M.) subconcava indicates a Late Albian age (Fig. 5); the overlying sequence ranges to the Cenomanian. Abfolge beginnt mit unterkretazischen Sandsteinen-sandige Dolomite leiten über zu massiven Kalken, die in den mittleren und oberen Profilabschnitten überwiegen. Sie zeigen eine flachmarine Karbonatplattform am Nordrand des Afrikanischen Kratons an, die durch Verzahnung von mächtigen Kalksandbarren mit subtidalen Ruhigwasserab-lagerungen ininter- bis supratidalen Bereichen gekenn-zeichnet ist. Die paläogeographische Bedeutung dieses Profiles wird durch Vergleiche mit zeitgleichen Ablagerungen in Israel und Nordägypten verdeutlicht. Die stratigraphische Einstufung erfolgte mit Orbitoliniden:Dictyonconus algerianus, Orbitolina (M.) texana, O. (M.) subconcava undO. (M.) aperta wurden durch weitere Foraminiferen und Algen ergänzt. Die jüngste datierbare Probe zeigt mitO. (M.) aperta undO. (M.) subconcava oberes Alb an (Fig. 5); die überlagernde Abfolge reicht ins Cenoman.

Summary  New dates and analysis of 12 deep and 57 shallow cores allow a more detailed interpretation of the Pleistocene shelf edge of the Florida Platform as found in various facies of the Key Largo Limestone beneath the Florida Keys. In this study a three-phase evolution of the Quaternary units (Q1–Q5) of the Key Largo is presented with new subdivision of

The Aladağ Unit is one of the main tectonic units in the Tauride Belt, located in southern Turkey. It includes a continuous Paleozoic carbonate sequence encompassing the mid-Carboniferous boundary, with outcrops being especially well exposed in the Hadim region. The boundary succession lithology is mainly composed of carbonates with intercalated quartz arenitic sandstone layers. Based on foraminifers, four biostratigraphic zones have been defined in the interval from the Upper Serpukhovian to the Lower Bashkirian. These zones are, in ascending order: the Eostaffella ex gr. ikensis—E. postmosquensis Zone (Zapaltyubinsky Horizon, Upper Serpukhovian); the Plectostaffella jakhensis—P. bogdanovkensis Zone, and the Millerella marblensis Zone (Bogdanovsky Horizon, lower Bashkirian); and the Semistaffella sp. Zone (Syuransky Horizon, lower Bashkirian). The mid-Carboniferous boundary occurs between the Eostaffella ex gr. ikensis—E. postmosquensis Zone and the Plectostaffella jakhensis—P. bogdanovkensis Zone. Boundary beds are characterized by eight, repeatedly occurring microfacies types, namely: (1) coated crinoidal packstone; (2) coated bioclastic grainstone; (3) oolitic grainstone; (4) oolitic packstone-grainstone; (5) intraclastic grainstone; (6) mudstone-wackestone; (7) quartz-peloidal packstone; and 8) quartz arenitic sandstone. Based on microfacies stacking patterns, various types of shallowing-upward cycles have been recognized. Depositional sequences and sequence boundaries are correlatable with those described from North America and Russia and Carboniferous global sea-level curves. The duration of cycles has been estimated as 100 ky, suggesting that cycle periodicities correspond to the Milankovitch eccentricity band.

Different types of builing stones have been macro-scopically and petrographically characterized at the ancient city of Sagalassos (SW Turkey). The natural building stones include limestone, conglomerate, breccia, marble, travertine, granite and sand-to siltstone of different qualities. The provenance of most of the building stones may be related to local lithological units, both in the immediate area of the city and on its territory. Also, some stone types were clearly imported from considerable distance. Throughout the history of the city, local beige and pink good quality limestone remained the most important building stone. Both the high quality white limestone from the territory of the city and the marbles imported from a distance of 250 km, represent only a small fraction of the total amount of building stones used. While the use of the white limestone can be considered to form a clear but limited trend from the Trajanic period (98–117 AD) onwards, the import of the marbles must be considered as a rare event. The selection of building stone went hand in hand with the appreciation for structural strength and suitability for carving complex architectural decoration, together with the desire to obtain a polychrome architecture.

Ernst, A., & May, A., & Marks, S. (2012): Bryozoans, corals, and microfacies of Lower Eifelian (Middle Devonian) limestones at Kierspe, Germany. - Facies, 58: 727-758, 11 figs., 8 tabs.; Erlangen.

http://link.springer.com/article/10.1007/s10347-011-0289-6 ---  Abstract The Lower Eifelian Meinerzhagener Korallenkalk  (= upper Cultrijugatus Beds) at Kierspe, Sauerland,  contains a rich reefal fauna. Eight bryozoan species are  described, two of them are new: the cystoporate Fistuliporella  kierspensis n. sp. and the trepostome Leptotrypella sophiae n.  sp. The bryozoans from the Meinerzhagener Korallenkalk shows distinct similarities to the Lower–Middle Devonian of  Spain (Santa Lucía Formation, Emsian–Eifelian), and to the  Middle Devonian (Eifelian) of Transcaucasia. The coral fauna comprises five tabulate corals and one rugose coral that document a paleobiogeographic relationship between Central  and Eastern Europe and Central Asia. The associated fauna is  represented by brachiopods, ostracods, and echinoderms. The  studied limestones also commonly contain calcimicrobes  represented by three species. The faunal and microfacial  characteristics indicate a shallow marine depositional environment  just above the storm wave base, with a supposed  depth of 20 m, within the photic zone. The nutrient regimewas  at least a mesotrophic. The upper boundary of the Cultrijugatus  Beds coincides with the Chotecˇ-Event that strongly  affected brachiopods, whereas corals and bryozoans were  insensitive to this event. 

Keywords:  Middle Devonian  Germany  Microfacies   Bryozoa  Corals  Brachiopods  Calcimicrobes   Taxonomy  Paleoecology  Paleobiogeography