Petrography

The petrography and mineralogy form an integral part of Petrological studies of any area. The petrographical and mineralogical data is very useful in mapping and correlating the flow sequences and in establishing the flow stratigraphy. The petrographic and mineralogical studies also play an important role identification of various petrogenetic processes that may be responsible for producing them. In the present study an attempt has been made to understand the preliminary petrography and mineralogy of lava pile of Muktagiri. The detailed geological mapping of the study area was done, and number of filed traverses were carried out the to identify the various lava flows along with their extensions. The field specimens were collected along all the traverses. The megascopic and microscopic studies were done to identify the petrographic and mineralogical characters. About 15 lava flows were identified in the study area. These lava flows, based on mineralogical and petrographic characters were divided in to four formations namely A, B, C and D formation. Further, the lava flows can be classified into aphyric and phyric lava flows. Mineralogical study revels that the lava flows are composed of plagioclase, clinopyroxene and opaque (mostly Fe-Ti oxide). At few places places primary glass with very small proportion of olivine is also observed.

In this paper, we describe the application of Object Based Image Analysis for the knowledge-based, automated mineral
classification from petrographic micrographs. Digital color images, acquired by an optical, petrographic microscope at
different stage rotations and with parallel and crossed polarization filters, are the input to a sequence of different image
segmentation and fuzzy classification steps. As compared with traditional, pixel-based algorithms, Object Based Image
Analysis incorporates not only the spectral characteristics of various mineral phases, but also their topological and genetic
properties, resulting in superior image classification results. By means of rule sets, image analysis can be flexibly adapted
to different rock types.

A growing collection (now close to 1500 videos highlighting close to 400 samples) of short (~30s each) videos showing a variety of both common and rare minerals in thin section through 360° rotations.  These videos illustrate distinctive optical properties in plane polarized light (PPL; both stage and lower polarizer rotation versions), under crossed polarizers (XP; stage rotation), and where appropriate, will also include an optic figure rotation.  The featured minerals are cross referenced to PPL and XP scans of the source thin section and to accompanying microprobe data, to provide for greater petrologic context.  Additionally, where possible, multiple examples of particular species are provided to highlight how optical properties may vary with compositional diversity.  My goal with producing this collection is two-fold: first, to provide beginning petrography students with a one-stop educational remote-learning resource to complement determinative tables and in-class microscope time, and second, to document the optical properties of less common minerals and unusual compositional variants that may not be otherwise available.  Note: this online resource is a website, so the "download" here (an image of a lamprophyllite BxA figure showing amazing r>v dispersion) is just a single still image for illustrative purposes. Look for the library to be continually expanding, with new batches of videos typically added every few months.

See: https://www.rockptx.com/video-atlas-of-minerals-in-thin-section/

The petrographic and geochemical composition of the Dharla River sediments has been examined to infer their sediment type, degree of weathering, provenance, and tectonic settings. Petrographically the sediments are characterized by the high quartz content (64.97 to 74.24 wt%), followed by feldspar (7.04 to 15.20 wt%), mica (5.38 to 19.92 wt%), lithic fragment (3.46 to 8.14 wt%), and heavy minerals (1.98 to 6.94 wt%). Geochemical composition shows marked enrichment of SiO 2 (mean ~ 74.16%) and a strong negative correlation with the other major oxides because of quartz dilution. The Chemical index of alteration (CIA, 45.52 to 63.51); Plagioclase index of alteration (PIA, 43.13 to 66.55); W index (20.15 to 32.86) and Rb/Sr ratios (0.35 to 0.98) suggest low to moderate intensity of chemical weathering in the source area. Geochemical classifications of the studied samples show mostly litharenitic immature type of sediments also reflects high index of compositional variability (ICV, 0.96 to 1.72). The ternary diagrams of Al 2 O 3-(CaO + Na 2 O)-K 2 O (or A-CN-K) and of mafic rocks, felsic rocks and degree of weathering of the source rocks (or MFW) and several immobile trace element ratios (e.g. light rare earth element/heavy rare earth element or LREE

This thesis describes a series of experiments on oxidising sandstone from a yard owned by the City of Sydney Council which is part of the old Saunders Quarries; Hell Hole, which was shut down 130 years ago. These tests were conducted to characterize the properties of the stone in order to determine whether the stone is of adequate quality for the restoration of Heritage-listed sandstone buildings such as Town Hall. The tests conducted include bulk specific gravity, water absorption, compressive strength, rupture of modulus test (flexural tensile strength), Brazil test (splitting tensile strength) and soundness (or salt attack). Brazil testing was conducted also on the quartz-rich specimens from the University of Sydney Clock Tower to provide a comparison of sandstone used in a Heritage-listed building. Petrographic analysis was also conducted on both sandstones to determine the microstructure and mineral composition and to find reasons for the behaviour of the stones in the different tests.
Though the sandstone from Hell Hole met the requirements for bulk density and water absorption, its failure to meet the other requirements, especially in wet conditions, as well as its friability and weathering observable from the petrography, means that it cannot be recommended for use in the restoration of Town Hall.

Lucrarea de faţă tratează analiza petrografică şi geochimică a gresiilor din Fm. de Şard. Prin intermediul datelor obţinute din analiza petrografică şi geochimică au fost determinate tectofaciesuri, ce au rolul de a furniza informaţii despre cadrul tectonic în care s-au format aceste depozite şi despre posibilele arii sursă pentru depozitele siliciclastice din această formaţiune.

Il volume è il risultato di un progetto di ricerca interdisciplinare che ha visto coinvolti due dipartimenti dell’Università di Cagliari (Dip. di Scienze Chimiche e Geologiche e il Dip. di Storia, Beni Culturali e Territorio) e l’Istituto di Scienze dell’Atmosfera e del Clima (U.O.S. di Cagliari) del ConsiglioNazionale delle Ricerche (CNR-ISAC), con la collaborazione del Dipartimento di Architettura dell’Università di Firenze e dell’Istituto di Geoscienze e Georisorse (IGG-U.O.S. di Firenze) del Consiglio Nazionale delle Ricerche (CNR). Il presente lavoro è finalizzato alla focalizzazione dei rapporti fra il monumento architettonico e il territorio di riferimento, nella prospettiva storica e in quella attuale, attraverso lo studio di alcuni casi studio rappresentati dalle chiese romaniche edificate in
Sardegna nell’età giudicale (dal XI al XIII secolo).
A tal fine è stata elaborata ed applicata una metodologia di studio dei manufatti architettonici che ha visto l’apporto congiunto di discipline
di ambito umanistico (archivistica, storia dell’architettura, storia
dell’arte) con altre di ambito scientifico (geologia, mineralogia, petrografi a, petrofisica, geochimica), insieme alle tecnologie di rilievo laser-scan volta a comprendere su quali connessioni territoriali si sia fondata la relazione fra gli edifici ecclesiastici romanici e il paesaggio circostante. L'incrocio dei dati minero-petrografici-geochimici dei materiali costruttivi con quelli derivati dall’attività di ricognizione delle cave di estrazione della pietra ha consentito di precisare quali fossero, durante l’età giudicale, i fattori che sovrintendevano alla scelta dei materiali (e quindi delle cave) e come e quanto questi fattori si siano correlati con le esigenze di tipo politico, estetico o, più semplicemente, di tipo pratico.

Pour la caractérisation pétrophysique et pétrographique des roches du système mixte carbonaté, siliciclastique et évaporitique du Desmoinesien supérieur du Bassin du Paradox (Utah, USA), trois affleurements de terrain et six carottes de forage ont été visités. Les données pétrophysiques mesurées sur échantillon sont la densité, la porosité, la perméabilité, et les vitesses ultrasoniques des ondes P et S. Pour la pétrographie, les observations en lame mince (texture, composants, porosité, types de pores et diagenèse) sont complétées par la minéralogie en diffraction X. Ce travail débouche sur deux applications. D'une part, la base de données constituée permet de mieux comprendre les propriétés pétrophysiques en relation avec la pétrographie. D'autre part, la calibration pétrophysique en laboratoire a servi pour mettre au point une méthode de prédiction de lithofaciès et faciès pétrophysiques. Cette technique, basée sur des statistiques multivariées classiques, permet d'interpréter les diagraphies de puits en intervalles non carottés.

For petrophysical and petrographic characterization of rocks from the mixed carbonate, siliciclastic and evaporite system of Upper Desmoinesian in Paradox Basin (Utah, USA), three outcrops and six drilling cores have been visited.  Petrophysical data measured on rock samples are density, porosity, permeability, and ultrasonic P- and S-wave velocities.  Regarding petrography, thin section observations (texture, components, porosity, pore types and diagenesis) are complemented by X-ray diffraction mineralogy.  This work results in two applications.  On one hand, the dataset that has been built allows to better understand the development of petrophysical properties in relation with petrography.  On the other hand, petrophysical calibration in the laboratory serves to establish a method to predict lithofacies and petrophysical facies.  This technique, based on classical multivariate statistics, allows to interpret wellbore logs along uncored intervals.

This work focuses on the physical structure and processes of the Italian coasts and takes advantage of the original joint research recently carried out by the Department of Earth Sciences of the University of Parma and the ENEA Marine Research Centre of Santa Teresa. On such base, several specific databases (e.g. Coastal Cells) were created and the available data (e.g. Morpho-sedimentological types) were adapted to the requirements of the research. This was accompanied by the production of a homogenous set of petrographic and granulometric data on beach sands of the Italian coasts. GIS technologies (geodatabase ©ESRI, ArcMap) were applied through extensively. These original data are complementary to the relevant literature identifying coastal petrographic provinces on numerous coastal tracts. The sampling of beach sands was then planned on the remaining part of the Italian coastline. A total of 137 samples were collected; 135 of them were analysed for granulometry and thin-section o...

Die Lage der Gemeinde Winden zwischen
den Abhängen des Leithagebirges und
dem Westufer des Neusiedler Sees weist
nicht nur in historischer, sondern auch aus geowissenschaftlicher
Sicht überaus interessante Aspekte
auf. Die Positionierung an einer uralten Nord-Süd
Hauptverkehrsader, der Bernsteinstraße1, sowie
die Verfügbarkeit von diversen Rohstoffen und ein
fruchtbarer Boden stellten günstige Bedingungen
für eine prosperierende Gemeinde dar. Neben dem
Weinbau war in der Vergangenheit aber vor allem
die Gewinnung von Baugesteinen von großer
wirtschaftlicher Bedeutung. Vor allem die nahezu
weißen, fein- bis grobkörnigen miozänen Leithakalke
wurden in mehreren, bis in römische Zeiten
zurückgehenden Steinbrüchen in großer Menge
abgebaut. Die morphologischen und bodenkundlichen
Eigenheiten der Gemeinde stehen naturgemäß
in engem Zusammenhang mit dem geologischen
Aufbau dieser Region. Die Beschreibung
der geologischen Verhältnisse des Windener Untergrundes
erfordert ein etwas weiteres Ausholen,
da die vorliegende Situation eng mit der jüngsten
geologischen Geschichte des Ostalpen–Karpaten–
Gebirgssystems im Neogen zusammenhängt. Besonders
hervorzuheben sind hier die Entstehung des
Wiener Beckens, des Eisenstädter Beckens und der
Kleinen Ungarischen Tiefebene.

Publikasi provenan batupasir vulkanik formasi Semilir yang diendapkan pada submarine fan masih
terbatas. Komposisi batupasir Formasi Semilir dianalisa menggunakan teknik sayatan tipis dan klasifikasi
Dickinson & Suczek (1979) untuk menentukan sumber batuan dan susunan tektoniknya.
Dua belas  sampel dianalisa dengan metode point counting untuk mendapatkan komposisi mineralogi.
Hasil analisa diplot pada segitiga diagram QFL dan QmFL Dickinson & Suczek (1979). Penelitian ini juga
menggunakan klasifikasi kuarsa Krynine (1940) untuk membedakan antara kuarsa vulkanik dan kuarsa plutonik.
Kuarsa vulkanik dicirikan dengan struktur embayment, bentuk pipih memanjang dan berbentuk hexagonal
idiomorfik sedangkan kuarsa batuan plutonik dicirikan dengan xenomorphic, monokristalin dan bentuk
memanjang yang meyudut di kedua tepi dengan sedikit lekukan.
Hasil analisis petrografi menunjukkan bahwa komposisi batupasir Semilir terdiri dari mineral kuarsa
yang berasal dari batuan beku vulkanik sebesar 1.8 % - 20 %, batuan beku plutonik sebesar 0.2 % - 2 %, mineral
opak sebesar 23 % - 67 % dan mineral feldspar sebesar 16 % - 62 %. Berdasarkan hasil analisa tersebut,
kedudukan tektonika provenan batupasir Semilir  berasal dari Transition Arc dalam sistem busur magmatik.

ABSTRACT
A detailed geologic mapping coupled with petrographic mineral identification and description
were carried out on various rock types around NE Okene, Kogi State, south-central Nigeria.
The studied area is located between latitude 70
30’and 70
35’ North and between longitude 60
10’and 60
16’ East of the Greenwich Meridian and covers an approximate area of 92 Km2
.
Mapping was done by traverse mapping method together with systematic sampling of the
various outcrops encountered. The rock types within the area of study include migmatites,
gneisses, granitic rocks and charnockites. There were also minor occurrences of quartzitic,
quartzo-feldspathic and pegmatitic veins. Field relations observed on the rock samples
collected from the various outcrops, coupled with available information and literature, showed
that the oldest lithologic units in the mapped area are those belonging to the migmatite-gneiss-
quartzite complex of the Nigerian Basement Complex, and they are the various gneisses
(granodioritic and garnetiferous gneiss) and the migmatites (granite-gneiss), which were
intruded by the Pan-African granitoids (600 Ma). These lithologic units are characterized by
parallel layers consisting of alternation of felsic (light coloured) and mafic (dark coloured)
minerals in what is referred to as gneissic layering. Structural features such as faults, minor and
major folds observed on these outcrops are indications that the rocks have suffered more than
one episode of deformation. The charnockitic and granitic rocks occur as low lying outcrops in
association with these older units. Petrographic analysis of the charnockite show that it is
hypersthene-bearing which is as expected of charnockitic rocks except in cases where the
hypersthene have been converted to olivine. The granitic rocks are mainly felsic with mineral
assemblages of feldspar, quartz and biotite conspicuously observed both in hand specimen on
the field and under a polarizing microscope of their thin sections in the laboratory. Most of the
rocks in the mapped area has been affected by physical, chemical and biological weathering
which is characteristic of areas with high rainfall, humidity and high temperature.

This research deals with the economic and commercial Phoenician networks during the early Iron Age in the southern Levant. Optical Mineralogy (petrography) analysis was conducted on a large scale on three categories of early Iron Age ceramic vessels. The first category includes transport and storage vessels, mainly pithoi, jars, and small lentoid flasks; the second category comprises Phoenician decorated ware, namely Phoenician Monochrome and Phoenician Bichrome; and the third category are open vessels of various types selected as a control group in order to better understand local fabrics and technological aspects of productions in the different sites. Lastly a unique assemblage of Egyptian imports from Tel Dor offer an addition view of relation of Egypt and Phoenicia during this period. 
Vessels for analysis were collected from both Phoenician and non-Phoenician sites: the Phoenician sites include Tel Achziv, Tell Keisan and Tel Dor. Non-Phoenician sites include Tel Dan, Tel Rehov, Tel Megiddo ‛En-Haggit, Tell Qasile and Nahal Patish in the Negev; altogether, about 450 vessels.
In general, three main petro-fabric groups were identified that represent ceramic production centers on the Phoenician coast: petro-fabric group A is produced in sites along the coast between Haifa and Achziv; petro-fabric group B originated on the southern Lebanese coast between Tyre and Sidon; and petro-fabric group C represents the Carmel Coast.
Three main commercial circles of Phoenician involvement in trade were identified in the early Iron Age. The first one is the inner Phoenician circulation of ceramics between Phoenician sites along the sea routes of the Levantine coast. Movement of Phoenicians transport vessels of various types were identified up and down the coast: this includes mainly carinated jars and Phoenician decorated wares.
The second commercial circle is characterized by overland trade between the Phoenician coastal centers and sites that fall within their immediate hinterland. Vessels made in Phoenicia, especially small lentoid flasks and Phoenician decorated ware found deep inland and southwards in the land of Philistia. The Phoenician Carmel Coast shows a particular connection with the Jezreel Valley and the southern Lebanese coast shows ties to Rehov and Dan. The realization of this close connection is solidified in the local production of Phoenician Bichrome ware in the Jezreel Valley and Dan in the northern Hula Valley. In reciprocity, transport vessels, mainly oval jars of inland production travel to the Phoenician coast. In addition to that, jars of various types (but not carinated) were found to travel from Philistia and the Sharon Coast to Phoenician sites especially during the 10th century BCE; this is the first time this phenomenon is identified.
The third commercial circle is the traffic that existed between the Phoenician coastal cities and their old political master, now turned large consumer, Egypt. In the void left by retreating Egypt at the end of the 12th century, the Phoenician marinners step-in, building and negotiating a large multi-leveled commercial network, with themselves in the center. These networks in the so-called Dark Age of the 11th to early 9th centuries BCE mark the beginning of the Phoenician's market economy.
 

Aspek mikrofasies dan diagenesis batuan karbonat Anggota Batugamping Formasi Pamutuan telah dipelajari guna mengetahui mekanisme pengendapan batuan dan sejarah proses geologi paska pengendapan batuan. Sampel-sampel batugamping yang telah diambil secara sistematis berdasarkan pada runtunan stratirafi hasil pengukuran penampang stratigrafi rinci pada formasi batuan yang berumur Miosen Tengah tersebut dan telah dipakai untuk bahan pengujian petrografi di laboratorium. Analisis petrografi telah dilakukan terhadap empat belas sampel batugamping yang memperlihatkan bahwa jenisnya adalah wackestone, packstone, grainstone, floatstone, rudstone, dan framestone. Lingkungan pengendapan batuan karbonat Anggota Batugamping Formasi Pamutuan tersebut meliputi fasies landaian laut dalam, tepian cekungan, lerengan terumbu depan, dan terumbu organik di tepi paparan. Beragam proses diagenesis yang terjadi pasca pengendapan batuan yang meliputi : penyemenan, pemikritan, pemampatan, neomorfisme, dan pelarutan.

This study deals with the geology, petrography,
geochemistry and radioactive mineralization of older granites,
younger granites and associated pegmatites to record their
suitability for ceramic industry and other purposes in Wadi Abu
Sheih area, located between Latitudes 26º 30' and 26º 44' N and
Longitudes 33º 20' and 33º 30' E, North Eastern Desert of Egypt.
The rock types cropping out in the study area from the youngest
to the oldest are classified into acidic dikes, basic dikes and
pegmatites, younger granites and older granites.

From 2017, an unknown rural settlement in Contrada Castro at Corleone (Palermo Province, western Sicily) was investigated as part of the ‘Harvesting Memories Project’. The stratigraphic sequence, supported by radiocarbon dating, has demonstrated a reoccupation of a pre‐Roman site during the transition between the Byzantine and Islamic periods. In particular, the main occupation occurred in the late 8th–9th century when pottery kilns and a probable warehouse were constructed. During the 10th–11th century, a new structure with different orientations replaced the previous buildings that had already collapsed. Specifically focusing on a perspective of the household production and its relationship to the surrounding landscapes of this site, this paper presents the results of a geological survey and petrographic analysis of ceramic finds and lithic samples to identify the source area of the geomaterials used in the studied settlement. The ceramic finds were divided into different Paste Groups based on the characteristics of a polarizing microscope study. The use of some locally available raw materials was recorded both for ceramic and lithic samples. Such an approach enables us to better understand ceramic craft technology, clay and lithic procurement strategies and, more broadly, the consumption of household pottery in the Early Medieval site in Contrada Castro. Furthermore, this study verifies the close relationship that this rural settlement had with the surrounding resources in the area and reveals a connection with the city of Palermo during the Early Middle Ages