Hasil untuk "Petrology"

A. Philpotts, J. Ague

Building upon the award-winning second edition, this comprehensive textbook provides a fundamental understanding of the formative processes of igneous and metamorphic rocks. Encouraging a deeper comprehension of the subject by explaining the petrologic principles, and assuming knowledge of only introductory college-level courses in physics, chemistry, and calculus, it lucidly outlines mathematical derivations fully and at an elementary level, making this the ideal resource for intermediate and advanced courses in igneous and metamorphic petrology. With over 500 illustrations, many in color, this revised edition contains valuable new material and strengthened pedagogy, including boxed mathematical derivations allowing for a more accessible explanation of concepts, and more qualitative end-of-chapter questions to encourage discussion. With a new introductory chapter outlining the “bigger picture,” this fully updated resource will guide students to an even greater mastery of petrology.

R. Folk

G. Kocurek

M. Marsset, P. Vernazza, M. Brož et al.

Context. The origin of the petrologic diversity observed in ordinary chondrites (OCs), the most common meteorites on Earth, remains debated. Competing models invoke either depth-dependent sampling of a single thermally stratified ("onion-shell") parent body or contributions from multiple distinct parent bodies. Aims. We aim to determine which of the two models is preferred for LL chondrites. These are unique among OCs in exhibiting a bimodal petrologic distribution, with most meteorites being LL3 or LL6. Methods. We compare the spectral and mineralogical properties of LL chondrites and corresponding LL-chondrite-like near-Earth objects (NEOs) with their possible sources in the main asteroid belt. We also model the thermal histories of the proposed parent bodies, based on revised estimates of parent-body sizes. Results. The spectral and mineralogical diversity of LL chondrites is consistent with contributions from the bright, S-type component of the Nysa family (NysaS) and the Flora family, with NysaS supplying mainly low-petrologic-type material and Flora higher-grade material. Unequilibrated, LL3 chondrites appear to originate exclusively from NysaS. Similarly, LL-chondrite-like NEOs form two distinct subpopulations consistent with origins in these same families. Conclusions. Our results favour multiple parent bodies for LL chondrites. The petrologic differences between the NysaS and Flora parent bodies indicate that planetesimal accretion within the OC reservoir extended over 0.5-0.7 Myr.

B. Yardley

1. The concepts of metamorphism. 2. Chemical equilibrium in metamorphism. 3. Metamorphism of pelitic rocks. 4. Metamorphisms of basic igneous rocks. 5. Metamorphism of marbles and calc-silicate rocks. 6. Metamorphic textures and processes. 7. The relationships between regional metamorphism and tectonic processes.

H. C. Connolly, D. Lauretta, T. McCoy et al.

The OSIRIS‐REx mission returned a sample of regolith from the carbonaceous asteroid Bennu in September 2023. We present preliminary in situ investigations of the petrology and petrography of selected particles ranging in size from 0.5 to 3 mm. Using a combination of optical and electron beam techniques, we investigate whole specimens and polished sections belonging to morphologically and visually distinct categories of particles. We find that morphological differences in the particles are reflective of petrographic and petrologic differences, leading to the conclusion that we have at least two distinct major lithologies in the bulk sample. Our findings support predictions from remote sensing, suggesting that the morphological differences observed in the boulder population of Bennu correspond to petrologic differences. Our data provide insight into the geologic activity on Bennu's parent body and the petrographic framework needed to contextualize the detailed analyses of this pristine asteroidal material.

E. Garzanti

Ahmed Zoeir, Najme Talebi, Yousef Kazemzadeh et al.

Abstract Parameters like sediment’s origin, transport distances or next influencing factors such as cementation or dissolution, cause almost all natural porous media to exhibit some degree of anisotropy. Using the X-ray CT scanning approach to provide a virtual environment for the calculation of such properties has its own issues, including its low resolution, which gives an incomplete description of internal structure, along with its relatively high costs. Porous media can be reconstructed with the help of statistical techniques from existing high-resolution thin section images. In this work, in this article, a micro-CT file available on the Imperial College website is first selected, which has been obtained from a disordered anisotropic sandstone core sample. specific statistical algorithms are applied to the top and side images of the core sample, which represent the input images for the Multiple-Point Statistics (MPS) technique. After that, to construct artificial anisotropic media models, Optimization algorithms are used to polarize the phase occurrence potentials in the principal directions, which are obtained from the two thin-section images. Results show that applying optimization algorithms to polarize occurrence potential functions can effectively develop artificial porous media that exhibit tensor properties closely matching those calculated from high-resolution micro-CT images of the actual sandstone core sample, such as permeability and thermal conductivity tensors.

Maurizio Petrelli

The present manuscript reports on the state-of-the-art and future perspectives of Machine Learning (ML) in petrology. To achieve this goal, it first introduces the basics of ML, including definitions, core concepts, and applications. Then, it starts reviewing the state-of-the-art of ML in petrology. Established applications mainly concern the so-called data-driven discovery and involve specific tasks like clustering, dimensionality reduction, classification, and regression. Among them, clustering and dimensionality reduction have been demonstrated to be valuable for decoding the chemical record stored in igneous and metamorphic phases and to enhance data visualization, respectively. Classification and regression tasks find applications, for example, in petrotectonic discrimination and geo-thermobarometry, respectively. The main core of the manuscript consists of depicting emerging trends and the future directions of ML in petrological investigations. I propose a future scenario where ML methods will progressively integrate and support established petrological methods in automating time-consuming and repetitive tasks, improving current models, and boosting discovery. In this framework, promising applications include (a) the acquisition of new multimodal petrologic data, (b) the development of data fusion techniques, physics-informed ML models, and ML-supported numerical simulations, and (c) the continuous exploration of the ML potential in petrology. To boost the contribution of ML in petrology, our main challenges are: (a) to improve the ability of ML models to capture the complexity of petrologic processes, (b) progressively link machine learning algorithms with the physical and thermodynamic nature of the investigated problems, (c) to start a collaborative effort among researchers coming from different disciplines, both in research and teaching.

Tomáš Hrstka, P. Gottlieb, R. Skála et al.

The collection of representative modal mineralogy data as well as textural and chemical information on statistically significant samples is becoming essential in many areas of Earth and material sciences. Automated Scanning Electron Microscopy (ASEM) systems provide an ideal solution for such tasks. This paper presents the methods and techniques used in the recently developed TESCAN Integrated Mineral Analyzer (TIMA-X) with Version 1.5 TIMA software. The benefits from the use of a fully integrated quantitative energy-dispersive X-ray spectrometry (EDS) and an advanced statistical approach to ASEM systems are demonstrated. Typically, the system can handle more than 500,000 X-ray events per second. Using a common spectral total of 1000 events this represents the acquisition of 500 spectra per second. A number of measurement modes is available to make the most effective use of these spectra depending on the application. For a back-scattered electrons (BSE) map combined with EDS data with spatial resolution of 10 μm, this represents the high-resolution measurement of c. 1 cm2 of a thin section or a polished rock surface in 30 minutes. A patented X-ray spectrum clustering algorithm that lowers the chemical detection limit is described and an example of its use is shown. The modal and textural (liberation, association, size etc.) data produced are statistically robust and provide information across a broad range of Earth and material sciences. A comparison with some other available instruments is also provided together with a number of case studies.

Keith D. Putirka

This chapter begins with some basic concepts regarding the structure and mineralogy of rocky planets, how to read and construct ternary diagrams, and why partial melting occurs when plate tectonics is operative. Partial melting is a key concept in that it governs crust and core formation, which in turn control mineralogy. These sections are for astronomers, or geologists new to the study of igneous petrology. From there, computational approaches for estimating planetary mineral assemblages will be introduced. These quantitative methods are simple, consonant with the level of information currently available on exoplanet compositions, and while largely intended for mineralogists, should be accessible to non-specialists as well. Such methods are followed by a study of error when plotting mineral abundances in ternary diagrams, for mineralogists and petrologists who construct such diagrams. The chapter concludes with caveats, and the ways in which exoplanets might surprise us.

Elishevah van Kooten, Xuchao Zhao, Ian Franchi et al.

Knowledge of the nucleosynthetic isotope composition of the outermost protoplanetary disk is critical to understand the formation and early dynamical evolution of the Solar System. We report the discovery of outer disk material preserved in a pristine meteorite based on its chemical composition, organic-rich petrology, and 15N-rich, deuterium-rich, and 16O-poor isotope signatures. We infer that this outer disk material originated in the comet-forming region. The nucleosynthetic Fe, Mg, Si and Cr compositions of this material reveal that, contrary to current belief, the isotope signature of the comet-forming region is ubiquitous amongst outer Solar System bodies, possibly reflecting an important planetary building block in the outer Solar System. This nucleosynthetic component represents fresh material added to the outer disk by late accretion streamers connected to the ambient molecular cloud. Our results show that most Solar System carbonaceous asteroids accreted material from the comet-forming region, a signature lacking in the terrestrial planet region.

Carlos Rodriguez-Navarro, Kerstin Elert, Aurelia Ibañez-Velasco et al.

Abstract Crystallization of monosodium urate monohydrate (MSU) leads to painful gouty arthritis. Despite extensive research it is still unknown how this pathological biomineralization occurs, which hampers its prevention. Here we show how inflammatory MSU crystals form after a non-inflammatory amorphous precursor (AMSU) that nucleates heterogeneously on collagen fibrils from damaged articular cartilage of gout patients. This non-classical crystallization route imprints a nanogranular structure to biogenic acicular MSU crystals, which have smaller unit cell volume, lower microstrain, and higher crystallinity than synthetic MSU. These distinctive biosignatures are consistent with the template-promoted crystallization of biotic MSU crystals after AMSU at low supersaturation, and their slow growth over long periods of time (possibly years) in hyperuricemic gout patients. Our results help to better understand gout pathophysiology, underline the role of cartilage damage in promoting MSU crystallization, and suggest that there is a time-window to treat potential gouty patients before a critical amount of MSU has slowly formed as to trigger a gout flare.

M. Pankhurst, J. Scarrow, Olivia A. Barbee et al.

How and why magmatic systems reactivate and evolve is a critical question for monitoring and hazard mitigation efforts during initial response and ongoing volcanic crisis management. Here we report the first integrated petrological results and interpretation provided to monitoring authorities during the ongoing eruption of Cumbre Vieja, La Palma, Canary Islands, Spain. The first eruptive products comprised simultaneous Strombolian fountain-fed lava flows and tephra fall from near-continuous eruption plumes. From combined field, petrographic and geochemical analyses conducted in the 10 days following sample collection, we infer low percentage mantle melts with a variably equilibrated multimineralic crystal-cargo and compositional fractionation by winnowing during eruptive processes. Hence ‘rapid response’ petrology can untangle complex magmatic and volcanic processes for this eruption, which combined with further study and methodological improvement can increasingly assist in active decision making.

Junjie Dong

Nominally anhydrous minerals (NAMs) are the primary carriers of water in rocky planet mantles. Therefore, studying water solubilities of major NAMs in the mantle can help us estimate the water storage capacities of rocky planet mantles and indirectly constrain the actual water contents of their interiors. By using data science methods such as statistics and statistical learning algorithms, in this paper, current modeling studies on the mantle water storage capacities of Earth, Mars, and exoplanets have been introduced and summarized. Firstly, the thermodynamic model for mantle water storage capacity has been reviewed. Then, based on the two case studies on Earth and Mars, how to translate atomic-scale experimental data of water solubility and their measurement errors into planetary-scale models of mantle water storage capacity has been explored by using robust regression, Monte Carlo methods, and bootstrap aggregation algorithms. Thirdly, how the large sample data from the exoplanet observational campaigns can help us understand the statistical properties of the mantle water storage capacities of rocky exoplanets has been introduced. Finally, the application limitations of data science methods in mineral physics research have been discussed, and how to better combine statistics and statistical algorithms with mineral physics data research has been prospected.

Jiang Y., Kang J. T., Liao S. Y. et al.

The Chang'E 5 (CE-5) samples represent the youngest mare basalt ever known and provide an access into the late lunar evolution. Recent studies have revealed that CE-5 basalts are the most evolved lunar basalt, yet controversy remains over the nature of their mantle sources. Here we combine Fe and Mg isotope analyses with a comprehensive study of petrology and mineralogy on two CE-5 basalt clasts. These two clasts have a very low Mg# (~29) and show similar Mg isotope compositions with Apollo low-Ti mare basalts as well as intermediate TiO2 and Fe isotope compositions between low-Ti and high-Ti mare basalts. Fractional crystallization or evaporation during impact cannot produce such geochemical signatures which otherwise indicate a hybrid mantle source that incorporates both early- and late-stage lunar magma ocean (LMO) cumulates. Such a hybrid mantle source would be also compatible with the KREEP-like REE pattern of CE-5 basalts. Overall, our new Fe-Mg isotope data highlight the role of late LMO cumulate for the generation of young lunar volcanism.

D. Schmidlin, L. Scheiber, M. Teixidó et al.

<p>Groundwater is a vital resource for the development of urban areas, where the problem focuses on the quantity and on the quality of this freshwater resource. Barcelona is a good example as because currently groundwater is used for irrigation of parks and gardens and street cleaning due to its poor quality as drinking water source. Among the pollutants found in groundwater, of special interest are contaminants of emerging concern (CEC), as they pose a high risk to the aquatic environment and human health. The behaviour, spatial distribution and processes that control them in the aquatic environment are still uncertain and most of them are unregulated. In this paper we study the inputs and processes controlling the hydrochemistry of Barcelona urban groundwater with special emphasis on the CEC. We selected 29 CEC that were detected at high concentrations of up to 1 <span class="inline-formula">µ</span>g L<span class="inline-formula">⁻¹</span> (e.g. gemfibrozil, benzotriazole, among others). Towards the higher zones we identify groundwater with relative low mineralization more proximate to the natural recharge composition, while towards the urban area the anthropic inputs are evident (e.g. nitrate concentrations range from 50 to 200 mg L<span class="inline-formula">⁻¹</span>). Near the Besòs river there is a clear contribution from this superficial water highly polluted, mostly from wastewater treatment plant (WWTP) discharges, and reducing conditions. The main contributor of CEC pollution in groundwater was the river-aquifer interaction (Besòs river), while towards the urban area it might come from sewage seepage and probably a minor input from urban runoff. The redox state of these waters seems to control the fate and occurrence of several of these CEC. The limitations of this study are restricted to a single sampling campaign, therefore these results should be corroborated with other sampling campaigns, including the seasonal variations, which would allow establishing more robust conclusions.</p>

Ковалев Дмитрий Петрович, Ковалев Петр Дмитриевич, Зарочинцев Виталий Сергеевич et al.

Рассматриваются результаты изучения длинноволновых движений с периодами более 20 ч на шельфе юго-западного побережья о. Сахалин с использованием полученных в натурных экспериментах временных серий колебаний уровня моря с дискретностью 1 с и продолжительностью от 4 до 6 мес. Спектральный анализ временных серий колебаний уровня моря для диапазона периодов от 8 до 200 ч выявил наличие длинноволновых процессов с периодами от 26.1 до 46.7 ч, которые значительно превышают инерционный период 16.48 ч. Численное моделирование шельфовых волн для экспоненциально выпуклых профилей морского дна, проведенное с использованием дисперсионного соотношения В.Т. Бухвальда и Дж.К. Адамса для волн континентального шельфа, показало, что обнаруженные волновые процессы с периодами от 31.2 ч до 46.7 ч являются шельфовыми волнами. Их амплитуды увеличиваются во время штормов; показана возможность передачи энергии от атмосферных возмущений шельфовым волнам, которые вносят вклад в формирование уровня моря, что подтверждает ранее сделанное предположение. Путем расчета разности фаз шельфовых волн на расстоянии 12.4 км между Невельском и Горнозаводском, наблюдаемых и определенных по теоретической модели, установлено, что вторая мода шельфовой волны с частотой 0.152 цикл/ч близка к теоретической. Регистрируемая в Ильинском и Горнозаводске волна с периодом 26.1 ч при расстоянии между пунктами 173.6 км не может быть шельфовой, а является волной Кельвина. Это подтверждено рассчитанной дисперсионной диаграммой, согласно которой длина волны около 689 км хорошо соответствует разности фаз для расстояния Ильинский–Горнозаводск. Установлено, что шельфовые волны, одним из механизмов генерации которых является напряжение ветра вдоль берега, имеют разные амплитуды в летнее и зимнее время, что обусловлено сезонным направлением вдольберегового ветра. В летний период направления распространения шельфовых волн и ветра противоположны, что ослабляет шельфовые волны.

Junxin Shang, Mingyou Feng, Xingzhi Wang et al.

Abstract Middle Permian Qixia Formation in the southwestern region of Sichuan (SW China) has experienced multiphase fluidisation, resulting in an unclear understanding of the reservoir reconstruction effect. In this study, a systematic analysis of the Qi2 member in Wulong Town was carried out by combining field outcrop petrology and geochemistry. The results demonstrated that multiple sets of crystalline dolomite-bioclastic limestone cycles were stacked vertically in the Qi2 member, accompanied by the development of fractures and karst channels. The dolomite was mainly composed of silty-fine dolomite (D1) and recrystallised dolomite (D2). Furthermore, obvious multiphase dolomitic cements (Cd1-Cd2) were present in the fractures and pores. Early karst is known to have lithologic mutation surface development and karst channel development at the top of several secondary cycles. The vadose silt dolomites (Cd1) having karst channels developed dull luminescence under cathode luminescence (CL). Both the geochemical indicators of elements and rare earth element (REE) content indicated dysoxic-oxic environmental conditions. The hydrothermal solution displayed tectonic carniole characteristics in the strata burial stage. Fractures and pores were filled with hydrothermal minerals such as coarse dolomites-saddle dolomites (Cd2, with some caused by recrystallisation of the Cd1 hydrothermal solution) and fluorites. Coarse dolomites-saddle dolomites developed dull-red luminescence with a bright-red rim under CL and their δ18OVPDB values were more negative than those of middle Permian limestone samples. Both the geochemical indicators of elements and REE content indicated the suboxic-anoxic environmental conditions. Karstification had minor constructive impact on the reservoir of the Qi2 member in Baoxing in southwestern Sichuan. Most products of karstification were distributed as fillings in channels. Aside from creating certain networked fractures, the hydrothermal solution was mainly filled with hydrothermal minerals along the fractures, pores and early karst channels. Karst and the hydrothermal solution mainly damaged the middle and upper parts of the middle Permian Qixia Formation in Southwest Sichuan. The impact of episodic fluid on the restoration of the carbonate reservoir was mainly restricted by channels for fluid migration and thickness differences among the reservoir. However, certain thick-layered and massive crystalline dolomite may hold promise for exploration.