Fine Calcite Research Articles

Discovery of the world longest known intra-till cave (Jura mountains, France): Age and formation processes

We describe an atypical cave network in the Jura mountains (eastern France), currently the only one known worldwide to be entirely excavated within a subglacial deposits. Extending over 600 m of mapped galleries, this natural cavity developed entirely within a large impermeable drumlin shaped during last glacial stage MIS 2 (Wurm). By using lidar topography, petrophysical, sedimentological and geochemical measurements, as well as U-Th dating, this cave is mainly attributed to mechanical erosion processes (piping cave). The network's morphogenesis seems to be characterized by two main phases. Firstly, thin mini-pipes were probably dug along shear planes previously formed within the drumlin. The first mini-pipes may have appeared under the ice cover during the last glaciation in response to differential hydraulic pressures on either side of the drumlin. They may also have appeared later when the drumlin was free from its glacial cover, forming a natural earth dam across a thalweg and obstructing the flow of surface water. A second phase would correspond to the development of mega-pipes, resulting from sequential capture of flows from mini-pipes. Mega-pipes appeared >2500 years ago, as indicated by U-Th dating of one speleothem. In other regions of the world, intra-till caves have been documented, but are <20 m long. This limitation is mainly attributed to instability of the materials constituting subglacial tills, disfavoring a durable existence of galleries without collapses. In the Jura calcareous mountains the subglacial till contains a high proportion of very fine calcite matrix produced by subglacial abrasion, which was indurated by compaction under several hundred meters of ice. These particular petrographic features appear to be required for the creation and the preservation of this long intra-till cave. Similar caves may likely be found in other regions of the world displaying limestone bedrock and where subglacial till with abundant carbonate matrix was formed.

Effect of calcium lignosulfonate on the interaction forces between fine calcite and fluorite

The separation of fluorite and calcite during flotation is challenging due to the complex interfacial forces that cause capping of fine-grained calcite on coarse-grained fluorite. In this paper, the micro flotation test, Zeta potential test, contact Angle test, scanning electron microscope and E-DLVO theoretical calculation were used to investigate the combination of sodium hexametaphosphate (SHMP) and calcium lignosulphonate (CLS) to disperse calcite on fluorite surface. The test results show that SHMP and CLS alone cannot effectively remove the cover, but the combination of the two can achieve good dispersion effect. In addition, Zeta potential shows that SHMP can significantly enhance the electrical properties of mineral surface, while CLS has a negligible effect on it. The contact Angle test proved that CLS adsorbed on the surface of mineral enhanced the hydrophilicity and hydration force of mineral. E-DLVO theoretical calculation further proves that CLS can not only enhance the hydration force between minerals, but also generate steric hindrance effect. When the distance between minerals is less than 1.8 nm, the steric hindrance force is greater than the repulsion force of hydration, and the steric hindrance force plays a dominant role.

Hydrolytic polymaleic anhydride as a depressant for flotation separation of fine smithsonite from calcite: An experimental and MD study

In this study, the effects of hydrolytic polymaleic anhydride (HPMA) on the flotation separation of fine smithsonite from fine calcite in the Na2S-Pb(II)-xanthate system were investigated. The micro-flotation tests showed that the floatability of fine calcite was significantly decreased after the addition of 40 mg/L of HPMA, while only a slight effect was observed on smithsonite. The inductively coupled plasma optical emission spectrometry (ICP-OES) analysis revealed that the addition of 50 mg/L HPMA dissolved 16.62 mg/L of Ca2+ ions from the calcite surface into the pulp. The analysis of total organic carbon (TOC) and Fourier transform infrared spectroscopy (FTIR) revealed that the HPMA could also chemical adsorption onto the calcite surface. The ultraviolet-visible spectroscopy and zeta potential results indicated that the HPMA blocked the formation of Pb(Ⅱ)-S species on the calcite surface, thus reducing the adsorption of xanthate. The X-ray photoelectron spectroscopy (XPS) analysis further confirmed that the HPMA achieved chemisorption and formed Ca-COOM onto the calcite surface, and the Pb and S contents on the calcite surface decreased significantly after HPMA treatment in the Na2S-Pb(II) system. The molecular dynamics simulation results agreed with the flotation test and measurements analysis results in this work, which explains that HPMA shows stronger adsorption performance on the calcite surface.

New insight into the structure nature for Pb-starch colloidal depressant from experiments and DFT calculations

Starch is a traditional depressant for fine minerals, whilst this depressant difficultly inhibits fine calcite and chlorite. This study presents that the chelation of starch with lead ions could significantly increase the inhibiting ability, which effectively decrease the recovery of fine calcite and chlorite to 28.81 % and 20.11 %. When the starch coordinates with lead ions, the particle size and the surface charge are increased obviously. Meanwhile, the Fourier transform infrared spectroscopy illustrate the shift of initial functional group, and the O-Pb functional group appears at wavelength of 3513.72 cm−1. The X-ray photoelectron spectroscopy determine the Pb atoms concentration increases to 9.59 %, and the Pb-group characteristic peaks generate at binding energy of 138.23 eV and 143.11 eV. Furthermore, the cluster calculation presents the trans-glucose of single starch molecule is easier chelated with lead ions than the cis-glucose. And the optimal configuration of Pb-starch is the lead ions chelate the O6 and O1 atoms of trans-glucose structure to form the O1-Pb-O6 structure with a shortest average band length and a lowest interaction energy. Besides, during the chelation, the Pb contributes empty orbitals to accept the donated electrons of glucose. Therefore, this study deeply determines the structure nature of Pb-starch colloidal depressant.

Depression performance and mechanism of a novel reagent (Pb-starch) for calcite: Experimental and DFT study

The fine calcite is difficult to inhibit due to the high activity and large specific surface area, and its inhibition is the crucial to achieve the flotation separation of valuable minerals. This study releases that the Pb-starch is an effective depressant for calcite flotation to significantly decrease the flotation kinetics, which is better than the effect of starch. The surface charge of calcite obviously increases with the increase of mass ration of Pb2+ ions and starch. The FTIR spectra indicate the starch is chemisorbed on the calcite surface through hydroxyl groups, while the chemisorption of Pb-starch is relied on Pb-O group. Meanwhile, the XPS measurement determines that starch mainly react with the Ca active site, whilst the Pb-starch mainly react with O active site. Furthermore, the single Pb-starch molecule adsorb on the (104) cleave surface of calcite to form two covalent bonds of Pb2+ and O atom, and the adsorption energy is much less than that of starch. The analysis of electronic property and electrons density confirm during the adsorption, the Pb2+ ions of Pb-starch accept the electrons from O atoms on calcite surface, and the hybrid orbital is the electronic states of Pb 6s6p with that of O 2s2p.

CHARACTERIZING THE PAINTED WALL RELIEFS FROM THE ANCIENT EGYPTIAN ROCK TOMBS OF MEIR AT ASSIUT, EGYPT

The present research was designed to characterize the main components of ancient Egyptian wall reliefs of Meir rock tombs at Assiut of Egypt using severalµ-destructive analytical methods. The microscopic characterization included optical examination on painted surfaces and petrographic examination on thin sections of rock fractions. The morphology of pigments and their chemical structure were investigated by scanning electron microscopy and energy dispersive X-ray spectrometry (SEM-EDX). Fourier transform infrared spectroscopy (FTIR) was used for the investigation of the molecular composition of the render layer and the blue pigment. The mineralogical composition by X-ray diffractometry (XRD) helped to study the stone, underlying preparation layer, and some pigments. The results showed that the petrographic features of the rock samples are based mainly on fine calcite grains. The identified pigments were Egyptian blue (synthetic cuprorivaite), red ochre (iron oxides and clay minerals), and carbon black. While for the green colour, a mixture of Egyptian blue and yellow ochre was created. Since the materials used in the abovementioned tombs were never been previously analyzed, this research will be a valuable start for a future complex study related to painting materials used in the Meir necropolis of ancient Egypt

Isothermal Hydrogen Reduction of a Lime-Added Bauxite Residue Agglomerate at Elevated Temperatures for Iron and Alumina Recovery.

The hydrogen reduction of bauxite residue lime pellets at elevated temperatures was carried out to recover iron and alumina from the bauxite residue in a new process route. Prior to the H2 reduction, oxide pellets were initially prepared via the mixing of an industrial bauxite residue with fine calcite powder followed by calcination and high-temperature sintering. The chemical, compositional, and microstructural properties of both oxide and reduced pellets were studied by advanced characterization techniques. It was found that iron in the oxide pellets is mainly in the form of brownmillerite, and calcium–iron–titanate phases, while upon reduction they are converted to wüstite and shulamitite intermediate phases and further to metallic iron. Moreover, it was found that the reduction at lower temperature of 1000 °C is faster than that at higher temperatures of 1100 °C and 1200 °C. The slower rate and extent of reduction at the higher temperatures is attributed to the porosity loss and reduction mechanism change to a diffusion-controlled process step. In addition, it was found that Al-containing phases in the raw materials are converted mainly to gehlenite in sintered pellets and further to the leachable mayenite phase. The alkaline leaching of selected reduced pellets by a sodium carbonate solution yielded up to 87% Al recovery into the solution, while the metallic iron was not affected.

Al-caustic starch coordination compounds: A new depressant for fine calcite

The flotation separation of scheelite from fine calcite is difficult due to the larger specific surface area and higher activity with flotation collectors. The selectivity of caustic starch as the depressant is poor, due to the -OH functional group reacting with the similar Ca2+ active sites of scheelite and calcite. In this paper, a novel structure of Al-caustic starch is prepared by the reaction of Al3+ and caustic starch, which has a new functional group of -CH2-O-Al2+. The Al-caustic starch is an effective depressant for the fine calcite particles, contributing to the efficient flotation separation of scheelite from the fine calcite particles. All the flotation kinetics of scheelite and fine calcite is first-order uniform distribution model, and the flotation rate of calcite decreases significantly after the treatment of Al-caustic starch. The zeta potential of Al-caustic starch is much higher than that of caustic starch, and Al-caustic starch can selectively change the surface charge of fine calcite, instead of scheelite. The X-ray photoelectron spectroscopy (XPS) spectrum of Al-caustic starch appears the peak of Al atom, which chemisorb on the calcite surface and make the peak of characteristic atoms shift. Moreover, Al-caustic starch reacts with the anion of CO32- on fine calcite surface, instead of cation of Ca2+, which obviously improves the selective adsorption on mineral surface.

Upcycling sintering red mud waste for novel superfine composite mineral admixture and CO2 sequestration

To utilize the sintering red mud waste（SRM）on a large scale and sequester CO2, a room temperature in-situ wet carbonation method was proposed for activation of SRM. The wet carbonation reaction process of SRM was investigated, and the evolution of phase composition, microstructure and pore structure during carbonation of the SRM was revealed by XRD, TG/DTG, FT-IR, NMR, SEM and nitrogen adsorption. Moreover, the feasibility of carbonated SRM (C-SRM) as a high value-added mineral admixture was explored. The results showed that the carbonation of SRM produced a large number of fine calcite crystals and silica-alumina gel with high polymerization. After 3 h of carbonation, the SRM achieved a CO2 sequestration rate of 15.3%, calcite (Cc) yield of 86.5% and Na+ leaching rate of 81.8%. The C-SRM possessed a high pozzolanic reactivity and fine particle size, showing its potential as a cement mineral admixture.

Strength improvement of rock fractures and aggregates cemented with bio-slurry

Microbially induced carbonate precipitation (MICP) is a new environmentally friendly technique for grouting rock fractures and aggregates. However, this method can achieve only a limited degree of strength increase and low treatment efficiency. To address these limitations, an improved treatment method was designed and tested using bio-slurry (i.e., bacterial suspension with fine calcite particles), and the treatment effectiveness and strength of cemented rock fractures and aggregates were enhanced. The experimental results show that the rock specimens with fractures grouted using bio-slurry exhibited significantly higher shear strength values than those treated using the conventional MICP method, owing to a nearly six times higher filling ratio. The uniaxial compressive strength of the rock aggregates cemented using bio-slurry was two times higher than that treated using the conventional method, owing to the formation of more calcite crystals near the contact points between adjacent particles. The proposed bio-slurry method was demonstrated as an effective technique for cementation of rock fractures and aggregates with a higher efficiency than the traditional method.

Miocene Phosphatization of Rocks From the Summit of Rio Grande Rise, Southwest Atlantic Ocean

AbstractMarine phosphorites are an important part of the oceanic phosphorus cycle and are related to the effects of long‐term global climate changes. We use petrography, mineralogy, rare earth elements contents, and 87Sr/86Sr‐determined carbonate fluorapatite (CFA) and calcite ages to investigate the paragenesis and history of phosphatization of carbonate sediments, limestones, ferromanganese crusts, and ironstones from the summit of Rio Grande Rise (RGR), Southwest Atlantic Ocean. Phosphatization of all the rock types occurred throughout the Miocene from 20.2 to 6.8 million years ago (Ma), and occasionally during the Quaternary, mainly through the cementation of carbonate sediments by cryptocrystalline CFA, likely involving the dissolution of the smaller size fraction of foraminifera‐nannofossil ooze. Porosity/permeability and abundance of fine calcite material were important factors determining the intensity of phosphatization of the various rock types. Phosphatization was initiated during a transition to a more dynamic circulation system in the South Atlantic Ocean, which remobilized phosphorus from deeper waters and increased primary productivity that culminated with the middle‐Miocene Climatic Optimum between ∼17 and 14.8 Ma. The relatively shallow‐water depth of RGR summit during the Miocene provided proximity to the oxygen minimum zone, a reservoir for reactive phosphorus, especially during periods of enhanced phosphorus cycling spurred by surface primary productivity. The cessation of phosphatization at RGR resulted from a rapidly cooling and dry climate that characterized the Miocene‐Pliocene transition. Our results support previous observations that periods of broadly intensified ocean circulation and local hydrodynamic changes were the key paleoceanographic links to phosphorite formation.

Deformation mechanisms accommodating progressive simple shear thrusting of quartzite and metacarbonate in the southwestern Espinhaço Range, Brazil

The accommodation of low-temperature ductile deformation in foreland fold-and-thrust belts is often described in terms of outcrop-based geometric analysis, but microtextural observations are also important, as they relate stress, strain, fluids and temperature and thus the rheology in the peripheral part of the orogen. Such microtextural observations are lacking from the foreland part of the Araçuaí orogen in Brazil, and are here investigated through EBSD-based textural analysis of quartzites and metacarbonate samples from the southwestern Espinhaço Range. The quartzites overthrust the metacarbonates, and deform solely by the activation of dissolution-precipitation creep, whereas the metacarbonates show a much greater variety of deformation mechanisms that closely relate to grain-size, composition and strain, in the long (low-angle) and short (steep) limbs of shear-related folds. The metacarbonates show a centimeter-scale alternation of coarse-grained domains of calcite and quartz, and fine-grained domains of a mix of phases (calcite, dolomite, phyllosilicates, quartz, and apatite). In the strongly sheared long limbs, coarse calcite was deformed by dislocation creep with slip on (c)<a>, whereas fine calcite displays evidence of oriented dissolution-precipitation creep, with both cases displaying <c> axis orientations consistent with the top-to-the-west thrusting. Coarse calcite shows evidence of recovery by subgrain rotation and grain boundary migration. Coarse-grained calcite in the short limbs was deformed by dislocation creep, assisted by twin boundary migration recrystallization with twinning on {e}, indicating simple shear-dominated deformation. In contrast, fine-grained calcite was deformed by fluid-assisted grain boundary sliding. Dissolution-precipitation in both short and long limbs produced random textures, with the exception of coarse quartz in the short limbs, where dissolution-precipitation creep led to <c> axis orientation parallel to X. This study demonstrates that the foreland thrust zone of the Araçuaí orogen underwent consistent W-directed progressive thrusting, and that this deformation produced a wide variety of texture types in the metacarbonates while a simpler structural and textural pattern developed in adjacent quartzitic metasediments.

Novel bioceramics from digital light processing of calcite/acrylate blends and low temperature pyrolysis

Porous bioceramic composites with complex shapes were easily fabricated starting from fine calcite (CaCO3) particles (<10 μm) immersed in a liquid photocurable polymer. The building of 3D structures, layer-by-layer, was achieved by means of Digital Light Processing (DLP), using a commercial stereo-lithography 3D printer. The pyrolysis of the hardened photosensitive polymer, in nitrogen atmosphere (at 500 °C), left calcite powders embedded in an amorphous carbon matrix, without any degradation of the main phase, which retained its biocompatibility, according to the cell culture studies. In addition, calcite was successfully converted into hydroxyapatite (HAp), by simple immersion of samples in a phosphatizing bath (aqueous solution of sodium phosphate), for 2 weeks, obtaining HAp-pyrolytic carbon composite scaffolds. The developed structures, after phosphatization, exhibited an adequate strength-to-density ratio (compressive strength of 1.4 MPa with porosity of about 80 vol%).

Effects of the calcite on quartz flotation using the reagent scheme of starch/dodecylamine

Quartz and calcite are the representative gangue minerals exited in the hematite ores while the interactions between these gangue minerals are still unknown. The roles of calcite slimes on the quartz flotation using corn starch as the depressant and dodecylamine (DDA) as the collector were studied though micro-flotation tests, zeta potential measurements and DLVO theory calculations. The micro-flotation results showed that calcite significantly affected the quartz flotation. The flotation recovery of quartz largely reduced with the addition of fine calcite particles under the starch/DDA reagent scheme. The zeta potential results illustrated that there is an electro-steric attraction between quartz and calcite slimes, leading to the coating of calcite on quartz surface. The depressant starch could be absorbed onto the surface of coated calcite slimes and prevented the adsorption of DDA collector, thereby decreased the floatability of quartz. DLVO calculation confirmed the hetero-coagulation in the quartz-calcite slimes system.

Predicting porosity of binary mixtures made out of irregular nonspherical particles: Application to natural sediments

Predicting porosity or packing density of sediments made of coarse and fine components of arbitrary geometry is critical to many science and engineering applications. Well-established analytical models for packing of spheres express porosity of the binary mixture as a function of fine-to-coarse particle size ratio. Nevertheless, the applicability of such models to natural granular materials is limited given the nonspherical and irregular nature of the particles whose packing depends on both particle size and shape. The objective of this study is to develop a model that predicts the porosity of binary mixtures made up of irregular nonspherical particles. We modified a previously developed linear sphere-packing model so that it takes into account the effect of both the particle size and shape. As an input, the modified model uses the coarse-to-fine particles specific surface area ratio instead of using the particle size ratio required by the sphere-packing model. We tested the modified model by predicting the porosities of a binary mixture composed of coarse and fine calcite aggregates. We further validate the model by using published data on the porosity of binary mixtures made of synthesized, cubical and cylindrical particles. Our model predictions show good agreement with the measured porosity.

Characteristics, formation periods and genetic mechanisms of tectonic fractures in the tight gas sandstones reservoir: A case study of Xujiahe Formation in YB area, Sichuan Basin, China

The main target for hydrocarbon exploration of terrestrial strata in Sichuan Basin is the tight gas sandstone reservoir of the Upper Triassic Xujiahe Formation. Xujiahe Formation in YB area is a major discovery of hydrocarbon exploration in recent years, which is characterized as tight with ultralow porosity, ultralow permeability, and intensive heterogeneity. The tectonic fractures have important influence on accumulation and productivity of gas in the area. In the paper, analysis data of outcrop, core, imaging logging and other experiments were used to determine the characteristics, formation periods and genetic mechanisms of tectonic fractures. There are mainly high-angle and low-angle shear fractures in the area, which caused by tectonic stress. The length of the fractures is mainly 0–4 m from the outcrop and 10–20 cm from the cores and fracture frequencies (number per meter) is mostly 2-7 m−1, 2-4 m−1 respectively. The fracture fillings are mainly calcite, argillaceous and carbonaceous, about 60% of the fractures is unfilled or incompletely filled. Without considering the diagenetic fractures, there are three periods of the fractures: the middle-late Yanshanian tectonic movement, the early-middle Himalaya tectonic movement and the late Himalaya tectonic movement. The first period of the fractures are mainly filled with fine calcite, homogenization temperature of inclusion is 75–85 °C and the maximum effective principal stress of paleostress is 71.64 Mpa. The second period of the fractures are half-filled (or unfilled) with coarse calcite, homogenization temperature of inclusion is 150–175 °C and the maximum effective principal stress of paleostress is 74.91 Mpa. The third period of the fractures are low filling degree and cuts formed fractures clearly, the maximum effective principal stress of paleostress is 86.52 Mpa. For these tectonic movement, there are four sets of the plane “X” shear fractures in the area: NE strike fractures, NW strike fractures, NEE strike fractures, SN strike fractures. There are one set of the profile shear fractures of NWW strike. Finally, the complex fault system of nearly NS, NW and NE strike are formed in YB area.

Mechanics, microstructure and AMS evolution of a synthetic porphyritic calcite aggregate deformed in torsion

In order to investigate the mechanical, microstructural and AMS evolution of porphyritic mylonites, we made a synthetic aggregate composed of 70% fine calcite (<50μm) and 30% coarse calcite (200–700μm), and deformed cylindrical specimens in torsion at 300MPa, 727°C, a constant strain rate of 3.0E−4s−1, to shear strains γ≈1 and 5. After peak stress, dynamic recrystallization of porphyroclasts resulted in grain size reduction and weakening till a mechanical steady state was reached. Microstructural, AMS and EBSD analyses show the consistent evolution of pre-torsion (cold-pressed) planar fabric from perpendicular to sample cylinder axis at γ≈0, to oblique at γ≈1, and finally to low angle to the shear plane at γ≈5, as expected for approximate simple shear. At γ≈1, stretched calcite grains >3mm in length defined a conspicuous foliation, and showed aligned twins. At γ≈5, calcite porphyroclasts were highly stretched (aspect ratio around 20), and had rotated towards the shear plane. Between γ=1 and 5, a composite fabric formed, one at low and the other at high angle to the shear plane, from which shear sense can be deduced. The AMS patterns were sensitive to increasing shearing, and tracked strain reasonably well, despite the reduced size and low susceptibility of specimens. From the CPO and the microstructure, we infer that a balance compatible with an optimal dissipation of the applied stress was achieved between grain growth and grain reduction processes.

Modern limnology, sediment accumulation and varve formation processes in Lake Żabińskie, northeastern Poland: comprehensive process studies as a key to understand the sediment record

Reconstructions of paleoclimatic and paleoenvironmental data from sediment records require a thorough knowledge of the physical, chemical and biological factors that influence sediment-formation processes and signal preservation in lake sediments. Lake Żabińskie, an eutrophic hardwater lake located in northeastern Poland (Masurian Lake District), provides an unique environment for the investigation of processes that lead to the varve formation. During a two-year long observation period we investigated limnological and hydrochemical conditions within the water column, recent sediment fluxes and laminations preserved in the sediments of this lake to understand the relationship between the lake water properties and the sediment formation processes. We demonstrate that different mixing patterns may occur in Lake Żabińskie, from dimictic to meromictic depending on the meteorological conditions. Regardless of the water mixing pattern, the lake was stratified during much of the year which led to significant differences between surface and near-bottom water environments. The hypolimnion was characterized by higher conductivity and anoxic conditions with only short periods of better oxygenation, which created conditions ideal for the formation and preservation of biogenic varves. The material collected from the sediment trap revealed notable changes in sediment fluxes with characteristic spring maxima and, optionally, a second late fall maxima. Considerable variability was also observed for the fluxes of total organic carbon, biogenic silica and calcite. Microscopic investigation of the topmost sediments revealed a complex structure of the varves showing a distinct spring calcite lamina followed by several fine calcite laminae interbedded with diatom-rich laminae and, finally, by an organic-rich lamina with minerogenic admixtures deposited during winter. This seasonal variability was also reflected in the chemical composition inferred from high-resolution XRF measurements which allowed for the recognition of individual seasons within one varve. A characteristic annual succession of elemental composition followed a distinct pattern: spring was marked with a silica peak followed by a major calcium peak; during summer and fall minor calcium peaks occurred as well as maxima in iron and sulphur; winter was characterized by a peak in potassium. This study shows a remarkable potential of the sediment record from Lake Żabińskie as a high-resolution paleoenvironmental archive.

Preparation of Alternative Hydraulic Binder Based on Secondary Raw Materials

Reusing and recycling of secondary raw materials from high-volume industrial productions (especially form construction materials and binders fabrications) is very important way of conserving environment and it is also interesting from the economical point of view. The production of common hydraulic binders, especially Portland cement, burdens the environment with considerable amount of combustion gases and consumes energy in massive scale. Alternative (low – energy) binder can be used as Portland cement substitution in applications with lower mechanical properties requirements. Mined limestone wash sediments contain large amount of clay components, but there is also indispensable share of fine calcite. This composition makes these sediments a promising material for the preparation of hydraulic binders as Roman cement or hydraulic lime.

Coseismic microstructures of experimental fault zones in Carrara marble

Experimental fault zones developed in Carrara marble that were deformed at seismic slip rates (1.18–1.30 m s−1) using a high-velocity-rotary-shear apparatus exhibit very low friction (friction coefficient as low as 0.06) at steady state due to nanoparticle lubrication of the decomposition product (lime). The fault zones show a layered structure; a central slip-localization layer (5–60 μm thick) of lime nanograins mantled by gouge layers (5–150 μm thick) and a plastically deformed layer (45–500 μm thick) between the wall rock and gouge layer in the marginal portion of cylindrical specimens. Calcite grains of the wall rock adjacent to the slip zone deform by dislocation glide when subjected to frictional heating and a lower strain rate than that of the principal slip zone. The very fine (2–5 μm) calcite grains in the gouge layer show a foam structure with relatively straight grain boundaries and 120° triple junctions. This foam structure is presumed to develop by welding at high temperature and low strain once slip is localized along the central layer. We suggest that a seismic event can be inferred from deformed marbles, given: (i) the presence of welded gouge with foam structure in a fault zone where wall rocks show no evidence of thermal metamorphism and (ii) a thin plastically deformed layer immediately adjacent to the principal slip zone of a cataclastic fault zone.