Mathematics – Logic
Scientific paper
Dec 2003
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003trgeo...1..269g&link_type=abstract
Treatise on Geochemistry, Volume 1. Editor: Andrew M. Davis. Executive Editors: Heinrich D. Holland and Karl K. Turekian. pp. 71
Mathematics
Logic
5
Scientific paper
The most ancient organic molecules available for study in the laboratory are those carried to Earth by infalling carbonaceous chondrite meteorites. All the classes of compounds normally considered to be of biological origin are represented in carbonaceous meteorites and, aside from some terrestrial contamination; it is safe to assume that these organic species were produced by nonbiological methods of synthesis. In effect, carbonaceous chondrites are a natural laboratory containing organic molecules that are the product of ancient chemical evolution. Understanding the sources of organic molecules in meteorites and the chemical processes that led to their formation has been the primary research goal. Circumstellar space, the solar nebulae, and asteroidal meteorite parent bodies have all been suggested as environments where organic matter may have been formed. Determination of the provenance of meteoritic organic matter requires detailed structural and isotopic information, and the fall of the Murchison CM2 chondrite in 1969 enabled the first systematic organic analyses to be performed on comparatively pristine samples of extraterrestrial organic material. Prior to that, extensive work had been undertaken on the organic matter in a range of meteorite samples galvanized, in part, by the controversial debate in the early 1960s on possible evidence for former life in the Orgueil carbonaceous chondrite (Fitch et al., 1962; Meinschein et al., 1963). It was eventually demonstrated that the suggested biogenic material was terrestrial contamination ( Fitch and Anders, 1963; Anders et al., 1964); however, the difficulties created by contamination have posed a continuing problem in the analysis and interpretation of organic material in meteorites (e.g., Watson et al., 2003); this has significant implications for the return of extraterrestrial samples by space missions. Hayes (1967) extensively reviewed data acquired prior to the availability of Murchison samples.Developments in the analysis of meteoritic organic matter have largely been driven by progress in analytical capabilities. The limited availability of samples, often restricted to a few grams at most, has presented a series of analytical challenges and significant advances were made in the late 1960s and early 1970s when the coupling of gas chromatography with electron impact mass spectrometry (GCMS) enabled detailed structural information to be obtained on individual compounds (e.g., Hayes and Biemann, 1968). Light-element stable-isotope measurements of meteoritic organic matter can provide important information on its origins and the potential of such measurements has long been recognized ( Boato, 1954). Indeed, meteoritic research has led to significant improvements in stable-isotope-ratio mass spectrometry (see Pillinger (1984), for a review). The 1970s saw the start of extensive quantitative analysis of solvent extractable compounds from Murchison together with the first attempts to resolve isotopic heterogeneities in the stable isotopes of carbon, hydrogen and nitrogen and this work has been the subject of regular detailed reviews ( Anders et al., 1973; Hayatsu and Anders, 1981; Mullie and Reisse, 1987; Cronin and Chang, 1993; Sephton and Gilmour, 2001b).The principal focus of this review is on the analysis of the organic matter in the Murchison CM2 chondrite, together with data from other meteorites, where it can be shown that they have not been compromised by terrestrial contamination. It primarily covers work undertaken since 1980, a period that has seen the increasing use of stable-isotopic techniques to elucidate the sources of meteoritic organic matter, improved methods to study the structure of organic matter such as NMR, and the first in situ examinations of organic matter in meteorites; these approaches have provided significant advances in our understanding of the processes involved in the synthesis of extraterrestrial organic matter.
No associations
LandOfFree
Structural and Isotopic Analysis of Organic Matter in Carbonaceous Chondrites does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Structural and Isotopic Analysis of Organic Matter in Carbonaceous Chondrites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structural and Isotopic Analysis of Organic Matter in Carbonaceous Chondrites will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1732119