Fluid-rock interfaces as revealed by cryo-scanning electron microscopy

Mann, Ulrich; Neisel, J. D.; Burchard, W.-G.; Heinen, Vernon O.; Welte, Dietrich H.

doi:10.3997/1365-2397.1994010

Cited by 16 publications

(8 citation statements)

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“…2007) but applications in Geosciences are as yet limited to studies of fluid inclusions and wettability (Fassi‐Fihri et al. 1992; Mann et al. 1994; Chenu & Tessier 1995; Robin et al.…”

Section: Introductionmentioning

confidence: 99%

“…One of the recent developments to study wet grain boundaries is with high-resolution cryogenic SEM after stabilization of the water phase in the grain boundaries at cryo-temperatures. Cryo-SEM is widely used in Life Sciences (Echlin 1978;Sargent1988;Erlandsen et al 1997;Fauchadour et al 1999;Walther & Muller 1999;Frederik & Sommerdijk 2005;Marko et al 2007) but applications in Geosciences are as yet limited to studies of fluid inclusions and wettability (Fassi-Fihri et al 1992;Mann et al 1994;Chenu & Tessier 1995;Robin et al 1995;Tritlla & Cardellach 1997;Durand & Rosenberg 1998;Shepherd et al, 1998;Vizika et al 1998;Barnes et al 2003;Negre et al 2004;Kovalevych et al 2005Kovalevych et al , 2006Schenk et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Cryogenic vitrification and 3D serial sectioning using high resolution cryo‐FIB SEM technology for brine‐filled grain boundaries in halite: first results

Desbois¹,

Urai²,

Burkhardt³

et al. 2008

Geofluids

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The structure of brine films in grain boundaries of halite has been the subject of much controversy over the past 20 years; although a number of innovative methods have been developed to study these structures, much is still unknown and fundamental information is missing. In this study, we investigated different methods of plungefreezing to vitrify the brine fill of grain boundaries for natural salt polycrystal. This was followed by a preliminary study of the 3D morphology of a vitrified grain boundary in a natural rock salt sample with a focused ion beam (FIB) excavation system. We have shown that brine-filled grain boundaries in rock salt can be efficiently well frozen when dimensions are less than about 1 mm. Coupled with an ion beam tool, cryo-SEM allows 3D observation of the well-frozen grain boundaries in large volumes and high resolution. Initial results of brine-filled natural halite grain boundaries show non-faceted crystal-brine interfaces and unexpectedly low dihedral angles at room temperature and pressure.

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“…2007) but applications in Geosciences are as yet limited to studies of fluid inclusions and wettability (Fassi‐Fihri et al. 1992; Mann et al. 1994; Chenu & Tessier 1995; Robin et al.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cryogenic vitrification and 3D serial sectioning using high resolution cryo‐FIB SEM technology for brine‐filled grain boundaries in halite: first results

Desbois¹,

Urai²,

Burkhardt³

et al. 2008

Geofluids

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“…Small rock chips are shock‐frozen to a very low temperature (approximately −190°C) and can be used for chemical characterizations (Samson & Walker, 2000; Timofeeff et al. 2001) and for visualization of the distribution of fluids in rocks, in particular to investigate qualitatively fluid–mineral interfaces (Durand & Rosenberg 1998; Mann et al. 1994;Monma et al.…”

Section: Introductionmentioning

confidence: 99%

“…To do this we studied samples using the cryo-SEM. Small rock chips are shock-frozen to a very low temperature (approximately )190°C) and can be used for chemical characterizations (Samson & Walker, 2000;Timofeeff et al 2001) and for visualization of the distribution of fluids in rocks, in particular to investigate qualitatively fluid-mineral interfaces (Durand & Rosenberg 1998;Mann et al 1994;Monma et al 1997). In order to characterize the crystallographic orientations of grain boundaries we used electron backscatter diffraction (EBSD) analysis.…”

Section: Introductionmentioning

confidence: 99%

Structure of grain boundaries in wet, synthetic polycrystalline, statically recrystallizing halite – evidence from cryo‐SEM observations

Schenk¹,

Urai²,

Piazolo³

2006

Geofluids

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It is well known from nature and experiments that the presence of brine strongly affects the microstructural evolution and the mechanical and transport properties of halite. Existing interpretations of the grain boundary structure in deformed, wet, salt samples annealed statically at room temperature are based on indirect evidence from reflected light microscopy and conventional scanning electron microscopy. This paper presents direct observations of fluid-filled grain boundaries using the cryogenic-scanning electron microscope (cryo-SEM) in which the grain boundary fluids were frozen before breaking the samples. The rapid cooling transforms the brine into two phases, i.e. ice and hydrohalite, which are easily recognized from characteristic segregation patterns. We studied samples of wet, synthetic, polycrystalline halite annealed under static conditions at room temperature. In coarse-grained samples, fine-scale segregation patterns were observed at the boundaries of the primary recrystallizing grains. These points indicate the existence of fluid films with a thickness in the range of 30 nm, but the finer scale structure of the fluid remains unknown. In fine-grained samples, the distribution and reorganization of fluids with annealing time is recorded by the combination of contact healing and successive accumulation of fluids in triple junction tubes. The contact healing is attributed to the small initial grain size, such that the fluid film necks down by accumulating the fluids into previously existing triple junctions via neck growth. Electron backscatter diffraction measurements of both primary and secondary recrystallized grains indicate that they are euhedral, i.e. the grain growth morphology is controlled by the anisotropy of the grain boundary energy of the growing grain, which results in planar growth faces.

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“…Once flash-frozen, such samples can subsequently be imaged in cryo-mode, using special cryo-transfer stages and TEM systems that can run at −165 • C. Both cryo-SEM and cryo-HR-TEM can be useful when phases need to be imaged during a process. Cryo-SEM techniques have extensively been used in earth science related research, specifically in freeze-fracture imaging of rock deformation processes by salt formation at grain boundaries (i.e., Mann et al, 1994;Samson and Walker, 2000;Schenk et al, 2006). However, cryo-SEM is naturally limited by resolution ( Fig.…”

Section: Imaging Techniquesmentioning

confidence: 99%

Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls

Benning

Waychunas

2008

Kinetics of Water-Rock Interaction

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The formation of any phase, whether natural or synthetic (Fig. 7.1), is usually a disequilibrium process that follows a series of steps until a thermodynamically stable state (equilibrium) is achieved. The first step in the process of creating a new solid phase from a supersaturated solution (either aqueous or solid) is called nucleation. A particle formed by the event of nucleation usually has a poorly ordered and often highly hydrated structure. This particle is metastable with respect to ordering into a well-defined phase, which can accompany growth of the particle. This process of initiation of a new phase is defined as a first order transition and can follow various pathways involving a host of mechanisms. One of these pathways occurs when individual nuclei coalesce into larger clusters, a process defined as aggregation, which itself can follow a series of different pathways. The new phase is thermodynamically defined when the growing nucleus or aggregate has distinct properties relative to its host matrix; for example, a well-defined crystal structure, composition and/or density. These processes depend on a plethora of chemical and physical parameters that control and strongly affect the formation of new nuclei, the growth of a new crystal, or the aggregation behavior of clusters, and it is these issues that will be the focus of this chapter. We will discuss the mechanisms and rates of each process as well as the methods of quantification or modeling from the point of view of existing theoretical understanding. Each step will be illustrated with natural examples or laboratory experimental quantifications. Complementary to the information in this chapter, a detailed analysis of the mechanisms and processes that govern dissolution of a phase are discussed in detail in Chap. 5 and more detailed information about molecular modeling approaches are outlined in Chap. 2.

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Fluid-rock interfaces as revealed by cryo-scanning electron microscopy

Cited by 16 publications

References 0 publications

Cryogenic vitrification and 3D serial sectioning using high resolution cryo‐FIB SEM technology for brine‐filled grain boundaries in halite: first results

Cryogenic vitrification and 3D serial sectioning using high resolution cryo‐FIB SEM technology for brine‐filled grain boundaries in halite: first results

Structure of grain boundaries in wet, synthetic polycrystalline, statically recrystallizing halite – evidence from cryo‐SEM observations

Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls

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