Hasil untuk "Petrology"

D. L. Anderson

E. Middlemost

R. Gomes, R. Gomes, H. Levison et al.

The petrology record on the Moon suggests that a cataclysmic spike in the cratering rate occurred ∼700 million years after the planets formed; this event is known as the Late Heavy Bombardment (LHB). Planetary formation theories cannot naturally account for an intense period of planetesimal bombardment so late in Solar System history. Several models have been proposed to explain a late impact spike, but none of them has been set within a self-consistent framework of Solar System evolution. Here we propose that the LHB was triggered by the rapid migration of the giant planets, which occurred after a long quiescent period. During this burst of migration, the planetesimal disk outside the orbits of the planets was destabilized, causing a sudden massive delivery of planetesimals to the inner Solar System. The asteroid belt was also strongly perturbed, with these objects supplying a significant fraction of the LHB impactors in accordance with recent geochemical evidence. Our model not only naturally explains the LHB, but also reproduces the observational constraints of the outer Solar System.

R. Carver

Jaber B. Al Jaberi, Badr Bageri, Salaheldin Elkatatny

Abstract In high-density water-based drilling fluids, optimizing filtration behavior, filter cake characteristics, and rheological properties is essential for efficient and safe drilling operations. This study investigates the impact of perlite addition on these critical properties using three mud formulations with varying densities. Filtration tests were conducted using filter paper and ceramic disks, while rheological properties were evaluated using industry-standard models. Results revealed that increasing mud density leads to higher filtration volumes and thicker filter cakes, which potentially compromises wellbore stability and increasing the risk of pipe sticking. However, the incorporation of perlite significantly enhanced performance by reducing both filtration volume and filter cake thickness across all densities. Rheological models’ assessments illustrated that the perlite had minimal impact on plastic viscosity (PV) and yield point (YP), but a notable improvement in gel strength behavior, indicating better management of cuttings and entrapped air in drilling operations. Among the tested rheological models, the Herschel-Bulkley models offered the closest fluid behavior to the experimental data without and with the perlite addition. These findings highlight perlite’s potential as a valuable additive for enhancing water-based drilling fluids, enhancing operational efficiency and minimizing drilling complications. This study demonstrates perlite effectiveness as a primary additive in Micromax-weighted fluids, extending the operational density range and offering a practical, low-cost solution for HPHT conditions.

Junliang Li, Lili Ji, Wenbin Jiang et al.

Abstract Multiscale pore-slit structures, non-linear flow and complex lithofacies of continental shale in Dongying Sag present significant challenges for reservoir evaluation and sweet spots identification. This study establishes a comprehensive analytical framework through integrated physical experiments and high-resolution imaging to characterize pore-slit structures and flow dynamics across various lithofacies. Firstly, a novel PSD (pore size distribution) splicing technique is developed by combining multiscale feature extraction and a transformed method, seamlessly uniting nitrogen adsorption data with SEM (scanning electron microscopy) image analysis. Compared with traditional methods, this advanced technique provides a more comprehensive representation of shale pore size distribution and structural characteristics. Three permeability indexes, including the non-Darcy index (K non−D ), anisotropy index (K a ), and slit index (K f ), are proposed to quantify flow behavior based on the cubic-block and matrix permeability experiments. These innovative indexes allow us to explore the complex non-linear flow behaviors, the anisotropic flow properties and pore-slit crossflow characteristics of shale. Comparative analysis reveals distinct pore structure and flow characteristics among different lithofacies: clay-rich shale exhibits high porosity and matrix permeability, while carbonate-rich shale demonstrates stronger nonlinear flow capacity and anisotropic permeability. Finally, the intrinsic relationship between mineral composition, pore structure, and complex flow has been investigated, and the identification charts for porosity and permeability have been established. These findings provide valuable tools for enhanced reservoir evaluation and sweet spot identification in the continental shale formations of Dongying Sag.

W. Johannes, F. Holtz

Wladimir Neumann, Ning Ma, Audrey Bouvier et al.

Abstract The formation of planets in our solar system encompassed various stages of accretion of planetesimals that formed in the protoplanetary disk within the first few million years at different distances to the sun. Their chemical diversity is reflected by compositionally variable meteorite groups from different parent bodies. There is general consensus that their formation location is roughly constrained by a dichotomy of nucleosynthetic isotope anomalies, relating carbonaceous (C) meteorite parent bodies to the outer protoplanetary disk and the non-carbonaceous (NC) parent bodies to an origin closer to the sun. It is a common idea, that in these inner parts of the protoplanetary disks, planetesimal accretion processes were faster. Testing such scenarios requires constraining formation ages of meteorite parent bodies. Although isotopic age dating can yield precise formation ages of individual mineral constituents of meteorites, such ages frequently represent mineral cooling ages that can postdate planetesimal formation by millions or tens of millions of years, depending on the cooling history of individual planetesimals at different depths. Nevertheless, such cooling ages provide a detailed thermal history which can be fitted by thermal evolution models that constrain the formation age of individual parent bodies. Here we apply state-of-the-art thermal evolution models to constrain planetesimal formation times particular in the outer solar system formation region of C meteorites. We infer a temporally distributed accretion of various parent bodies from $$<0.6$$ < 0.6 Ma to $$\approx 4$$ ≈ 4 Ma after solar system formation, with 3.7 Ma and $$2.5-2.75$$ 2.5 - 2.75 Ma for the parent bodies of CR1-3 chondrites and the Flensburg carbonaceous chondrite, and $$<0.6$$ < 0.6 and $$<0.7$$ < 0.7 Ma for the parent bodies of differentiated achondrites NWA 6704 and NWA 011, respectively. This implies that accretion processes in the C reservoir started as early as in the NC reservoir and were operating throughout typical protoplanetary disk lifetimes, thereby producing differentiated parent bodies with carbonaceous compositions in addition to undifferentiated C chondrite parent bodies. The accretion times correlate inversely with the degree of the meteorites’ alteration, metamorphism, or differentiation. The accretion times for the CM, CI, Ryugu, and Tafassite parent bodies of 3.8 Ma, 3.8 Ma, $$1-3$$ 1 - 3 Ma, and 1.1 Ma, respectively, fit well into this correlation in agreement with the thermal and alteration conditions suggested by these meteorites. Our results indicate that individual planetesimals formed rapidly (i.e., within $$<1$$ < 1 Ma), however, distinct planetesimals formed recurrently throughout the total lifetime of the protoplanetary disk. Rapid individual formation is consistent with streaming instabilities assisted by gravitational collapse. However, obviously not the total dust inventory was consumed at early disk evolution stages, so there must have been some delay mechanisms, e.g. collisional destruction of precursor aggregates due to high impact velocities induced by radial drift phenomena. This counterbalance enabled late ( $$>2-3$$ > 2 - 3 Ma) accretion of C planetesimals beyond the snow line which escaped severe planetesimal heating and volatile loss, hence, preserving their volatiles, especially water. Only this delayed formation of water-rich planetesimals allowed Earth to accrete sufficient water to become a habitable planet, preventing it from being a bone dry planet.

Longfei LU, Guoliang TAO, Junyu WAN et al.

Using techniques such as ultra-microscopic organic petrology, the study explores the relationship between bioclasts such as siliceous and calcareous skeleton-wall-shell organism and high-quality hydrocarbon source rocks in terms of their biomolecular composition and stability. Common organisms containing biosilica and siliceous derivatives are mainly radiolarians and other protozoa, sponges, diatoms, chrysophytes, and the siliceous skeleton-wall-shell and debris of some planktonic algae like scales-bearing dinoflagellates. The biogenic calcium preserved in high-quality hydrocarbon source rocks is mainly derived from calcareous skeleton-wall-shell and their debris of animals such as planktonic foraminifera and pteropods and planktonic algae like coccolithophores or acritarchs. These biogenic siliceous and calcareous skeleton-wall-shell debris particles often contain varying amounts of organic matter (pectin or scleroprotein, equivalent to type Ⅲ organic matter), which can generate a certain amount of hydrocarbons at high to over-mature stages and can be preserved in the native pores of biological structures.

D. Kim, C. Duran, D. Giardini et al.

Abstract We report observations of Rayleigh waves that orbit around Mars up to three times following the S1222a marsquake. Averaging these signals, we find the largest amplitude signals at 30 and 85 s central period, propagating with distinctly different group velocities of 2.9 and 3.8 km/s, respectively. The group velocities constraining the average crustal thickness beneath the great circle path rule out the majority of previous crustal models of Mars that have a >200 kg/m3 density contrast across the equatorial dichotomy between northern lowlands and southern highlands. We find that the thickness of the Martian crust is 42–56 km on average, and thus thicker than the crusts of the Earth and Moon. Considered with the context of thermal evolution models, a thick Martian crust suggests that the crust must contain 50%–70% of the total heat production to explain present‐day local melt zones in the interior of Mars.

János Szanyi, Ladislaus Rybach, Hawkar A. Abdulhaq

In an era of accelerating energy transition and growing demand for critical metals essential for clean technologies, the innovative integration of geothermal energy with critical metal extraction stands as a paradigm shift in sustainable resource utilization. This comprehensive review unravels the synergistic potential of coupling geothermal energy systems with critical metal extraction, thereby transforming a dual crisis of energy and resource scarcity into an opportunity for circular economy. Through rigorous analysis of existing geothermal technologies, and extraction methodologies, the study establishes a coherent framework that merges energy production with environmental stewardship. It scrutinizes current extraction techniques, and evaluates their compatibility with geothermal brine characteristics, proposing optimized pathways for maximum yield. Through detailed case studies and empirical data, the paper elucidates the economic and environmental advantages of this multifaceted approach, from reduced carbon footprint to enhanced energy efficiency and resource recovery. It concludes that combined heat and mineral production technology can open new, unexplored resources, increasing the supply of previously untapped resources, while the potential of geothermal energy for sustainable mineral extraction and energy production is in line with Sustainable Development Goal 7, which aims to ensure access to affordable, reliable, sustainable and modern energy for all.

Mohamed W. Ali-Bik, Safwat S. Gabr

The initial phase of the Gulf of Suez rifting in the late Oligocene was accompanied by the eruption of continental basaltic magmas, which continued to the early Miocene. Within the rift zone at Abu Zenima area, west-central Sinai, several km-scale Oligo-Miocene basaltic exposures in the form of dykes, sills and lava flows intruded/extruded the Phanerozoic sedimentary successions. These basaltic outcrops were successfully discriminated from their country rocks by remote sensing techniques, using the Landsat-8 dataset. The basalts are evolved tholeiitic, Ti-rich varieties and exhibit narrow compositional range with absence of any felsic counterparts, suggesting equilibrium crystallization process in their evolutions rather than fractional crystallization mechanism. Simulations of equilibrium crystallization process and evolution trajectories of these basalts have been modeled.

Anett Blischke, Bryndís Brandsdóttir, Martyn S. Stoker et al.

Abstract Volcanostratigraphic and igneous province mapping of the Jan Mayen microcontinent (JMMC) and Iceland Plateau Rift (IPR) region have provided new insight into the development of rift systems during breakup processes. The microcontinent's formation involved two breakup events associated with seven distinct tectono‐magmatic phases (∼63–21 Ma), resulting in a fan‐shaped JMMC‐IPR igneous domain. Primary structural trends and anomalous magmatic activity guided initial opening (∼63–56 Ma) along a SE‐NW trend from the European margin and along a WNW‐ESE trend from East Greenland. The eastern margin of the microcontinent formed during the first breakup (∼55–53 Ma), with voluminous subaerial volcanism and emplacement of multiple sets of SSW–NNE‐aligned seaward‐dipping reflector sequences. The more gradual, second breakup (∼52–23 Ma) consisted of four northwestward migrating IPR (I–IV) rift zones along the microcontinent's southern and western margins. IPR I and II (∼52–36 Ma) migrated obliquely into East Greenland, interlinked via segments of the Iceland‐Faroe Fracture Zone, in overlapping sub‐aerial and sub‐surface igneous formations. IPR III and IV (∼35–23 Ma) formed a wide igneous domain south and west of the microcontinent, accompanied by uplift, regional tilting, and erosion as the area moved closer to the Iceland hotspot. The proto‐Kolbeinsey Ridge formed at ∼22–21 Ma and connected to the Reykjanes Ridge via the Northwest Iceland Rift Zone, near the center of the hotspot. Eastward rift transfers, toward the proto‐Iceland hotspot, commenced at ∼15 Ma, marking the initiation of segmented rift zones comparable to present‐day Iceland.

A. Reyes

R. Rudnick, Shan Gao, W. Ling et al.

R. Mitchell, S. Bergman

Gay Aurélien, Favier Alexiane, Potdevin Jean-Luc et al.

The giant Jurassic-aged pockmark field of Beauvoisin developed in a 800 m wide depression for over 3.4 Ma during the Oxfordian; it formed below about 600 m water depth. It is composed of sub-sites organized in clusters and forming vertically stacked carbonate lenses encased in marls . This fine-scale study is focused on a detailed analysis of petrographical organization and geochemical signatures of crystals that grew up in early to late fractures of carbonate lenses, surrounding nodules, and tubes that fed them. The isotopic signature (C, O and Sr) shows that at least three different episodes of fluid migration participated to the mineralization processes. Most of the carbonates precipitated when biogenic seepage was active in the shallow subsurface during the Oxfordian. The second phase occurred relatively soon after burial during early Cretaceous and thermogenic fluids came probably from underlying Pliensbachian, Late Toarcian or Bajocian levels. The third phase is a bitumen-rich fluid probably related to these levels reaching the oil window during Mio-Pliocene. The fluids migrated through faults induced by the emplacement of Triassic-salt diapir of Propiac during the Late Jurassic and that remained polyphased drain structures over time.

Emmanuel U. Akpan, Godpower C. Enyi, Ghasem G. Nasr

Abstract Xanthan gum is commonly used in drilling fluids to provide viscosity, solid suspension, and fluid-loss control. However, it is sensitive to high temperatures and not tolerant of field contaminants. This paper presents an experimental study on the effects of an eco-friendly biopolymer (diutan gum) on xanthan gum (XC) in a water-based bentonite mud. Laboratory experiments were carried out for different compositions of the biopolymers in water-based bentonite muds formulated without salt and in water-based bentonite muds containing sodium chloride (NaCl). The rheological properties of the water-based bentonite muds formulated with XC (2 Ibm) and those of the water-based bentonite muds prepared using XC (1Ibm) and diutan gum (1Ibm) were measured using Model 1100 viscometer after aging at 25 °C, 100 °C, and 120 °C for 16 h. The API fluid loss and filter cake of the mud formulations were measured using HTHP filter press. The properties of the water-based bentonite muds containing only XC were compared with those of the water-based bentonite muds containing XC and diutan gum. Presented results show that combining diutan gum and xanthan gum in a ratio of 1:1 in a water-based bentonite mud enhances its performance with respect to fluid properties—apparent viscosity, gel strength, yield points, YP/PV ratio, LSRV, n, and K. The fluid formulations also showed favorable mud cake building characteristics. Experimental data also indicate a 16%, 19%, and 34% reduction in API fluid loss values for the water-based benitoite muds containing XC in the presence of diutan gum after aging at 25 °C, 100 °C, and 120 °C for 16 h, respectively. Experimental results also show that the water-based benitoite mud containing XC and diutan gum would cause less formation damage and was tolerant of contamination with a monovalent cation (Na+). The synergy of xanthan gum and diutan gum can, therefore, improve the performance of water-based drilling fluids.

Y. Niu, M. O'hara

Giovanni Mongelli, Ariadne Argyraki, Mari Luz García Lorenzo et al.