collecting the fluid for conventional water analysisinductively coupled plasma techniques, ion chroma-tography.. Fluid inclusions are listed here since they are most commonly analysed by
Trang 1collecting the fluid for conventional water analysis
(inductively coupled plasma techniques, ion
chroma-tography) Fluid inclusions are listed here since they
are most commonly analysed by using a high powered
microscope and heating–cooling stage Most fluid
inclusions are composed of discrete liquid and vapour
phases even though they would have been trapped as
a single-phase liquid, which is typically assumed to
have been saturated with vapour at the time of
trap-ping During a heating cycle, the two phases
hom-ogenize; the precise temperature of homogenization
reveals the temperature at which the mineral grew
The salinity of the water can be assessed by
monitor-ing the temperature at which it starts freezmonitor-ing, since
this temperature can be related to salt content
(assum-ing that the water is dominated by dissolved NaCl)
A combination of thorough petrography and
thermo-metric studies of aqueous inclusions can help to reveal
details of the thermal and mineral-growth history as
well as the fluid evolution history
Related Geochemical Techniques
The techniques listed and briefly discussed here are
only some of the vast panoply of techniques that have
been employed during geochemical studies over the last
50 years or so Some have now fallen out of favour
For example, a technique called neutron activation
analysis was used for a long time to measure trace
elements in solids It has fallen out of favour mainly
owing to developments in ICP-OES and ICP-MS
The vast range of light and electron optical
tech-niques are routinely used in conjunction with a wide
range of solid-state and even organic geochemical
studies Scanning electron microscopy has recently
been extensively developed and can now give fabric,
mineralogy, mineral chemistry, and high-resolution
crystallographic information Transmission electron
microscopy can provide ultra-high spatial
resolu-tion (of the order of tens of nm) geochemical data
(using secondary X-rays) as well as fabric and
crystallographic data
A wide range of wet geochemical techniques have
been employed routinely in studies of natural waters
from all near-surface and surface environments
Titration, electrochemical techniques, and colorim-etry are essential techniques that are used routinely
in many geochemical studies
See Also
Clay Minerals Fluid Inclusions Minerals: Definition and Classification; Native Elements Petroleum Geol-ogy: Chemical and Physical Properties; The Petroleum System.Rocks and Their Classification
Further Reading
Emery D and Robinson AC (1993) Inorganic Geochemistry: Applications to Petroleum Geology Oxford: Blackwells Farmer VC (1974) The Infrared Spectra of Minerals London: Mineralogical Society
Faure G (1986) Principle of Isotope Geology New York: John Wiley and Sons
Goldstein RH and Reynolds TJ (1994) Systems of Fluid Inclusions Tulsa: Society of Sedimentary Geology Hagemann HW and Hollerbach A (1986) The fluorescence behaviour of crude oils with respect to their thermal maturation and degradation Organic Geochemistry 10:
473 480
Jarvis I and Jarvis KE (1992) Plasma spectrometry in the Earth sciences: techniques, applications and future trends Chemical Geology 95: 1 33
Jenkins R (1999) X ray Fluorescence Spectrometry New York: Wiley Interscience
Lico MS, Kharaka YK, Carothers WM, and Wright VA (1982) Methods for the Collection and Analysis of Geo pressured Geothermal and Oil Field Waters Water Supply Paper 2194 United States Geological Survey Moore DM and Reynolds RC (1997) X ray Diffraction and the Identification and Analysis of Clay Minerals Oxford: Oxford University Press
Rollinson HR (1993) Using Geochemical Data: Evalu ation, Presentation, Interpretation New York: Longman Scientific and Technical
Tissot B and Welte D (1984) Petroleum Formation and Occurrence Berlin: Springer Verlag
Tucker ME (1988) Techniques in Sedimentology Oxford: Blackwell Scientific
Weiss J (2000) Ion Chromatography New York: John Wiley and Sons
Zussman J (1967) Physical Methods in Determinative Mineralogy London: Academic Press
76 ANALYTICAL METHODS/Geochemical Analysis (Including X-ray)