An investigation of the structure of abelsonites from the Uinta Basin of Utah

Abelsonite has been obtained from five widely separated cores in the Green River Formation of Utah. Each occurrence was in fractures or bedding plane partings of lean oil shales. High resolution mass spectra show that the abelsonite samples are vitually identical from core to core and consist largely of the nickel complex of a C-31 porphyrin of DPEP type. ¹H-NMR spectra of some of the samples have been recorded and are compared with spectra of several model nickel porphyrin complexes. From these spectra it is deduced that abelsonite is largely the nickel complex of a nor-DPEP. Abelsonite is believed to differ from nickel DPEP in having a methyl substituent in place of an ethyl substituent at either carbon 3 or 8. Abelsonite is shown not to have a hydrogen substituent on any pyrrolic carbon. A chlorophyll origin of abelsonite is thus indicated. Abelsonite appears to have been introduced into the fractures and bedding planes of the rocks in which it is found subsequent to their lithification, as porphyrins different from abelsonite were extracted from shales associated with abelsonite.     

Nickel porphyrins in the bedding planes of a Colorado lean oil shale

A Colorado lean oil shale was found to have red-colored material on the faces of bedding planes and fractures. This red material is almost entirely the nickel chelate of a single C-29 porphyrin of deoxophylloerythroetioporphyrin type. The molecular weight of the chelate is 490 or 492, depending on which of the two major isotopes of nickel is chelated. A small amount of a methylene homologue 14 mass units higher in molecular weight is also present. Porphyrins extracted from the powdered shale are an extended homologous series of deoxophylloerythroetioporphyrin-type and possibly etio-type nickel porphyrins, as determined by mass spectrometry. The origin of the red porphyrins coating the shale fractures and bedding planes therefore was exogenous to these particular shale samples.     

卟啉的研究现状及其应用

在前人研究资料及作者近年来的研究成果的基础上，综述了卟啉化合物地球化学研究的现状，包括金属卟啉的类型，卟啉的化学结构系列，高度脱链基卟啉和高碳数咔琳等及其它们在沉积物(如油页岩、煤和现代沉积物)中的分布特征和成因机理。指出了今后需要加强研究的领域，如沉积物中新的金属卟啉类型探讨和卟啉化学结构的确定等。文章还综述了卟啉化合物地球化学指标在地质勘探中的应用，如:评价生油岩质量，油源对比，油气运移研究，古沉积环境研究和有机质热成熟度研究等。     

Iron porphyrins in the Permian Kupferschiefer of the lower Rhine Basin, N.W. Germany

Immature samples of the Permian Kupferschiefer from the Lower Rhine Basin in N.W. Germany were analysed for tetrapyrrole pigment type and abundance. The sediment, thought to have been deposited in a marine regime with enhanced salinity, was found to contain high concentrations of metalloporphyrins. The porphyrins are complexed to nickel (Ni) and oxovanadium (V=0), but high abundances of iron (Fe) porphyrins were also detected using UV/visible spectroscopy and mass spectrometry. The presence in the latter of series of aetioporphyrins, cycloalkanoporphyrins, di-cycloalkanoporphyrins and benz-cycloalkanoporphyrins was confirmed by accurate mass measurements; HPLC co-injection of deoxophylloerythroetioporphyrin (C₃₂ DPEP) with the demetallated iron porphyrins indicated its presence in the sediment as an iron complex. The study provides the first evidence for the occurrence of Fe porphyrins in geological samples other than coals and lignites, and reports the highest concentrations in sedimentary organic matter to date.     

Identification and occurrence of 25-norbenzohopanes in biodegraded bitumen from Palaeozoic carbonates in northern Alberta

In addition to the previously reported 25-norhopanes and 25-norhopanoic acids, for the first time we report the identification of 25-norbenzohopanes. The hydrocarbon composition of the bitumen from Palaeozoic carbonates in northern Alberta displays molecular evidence for severe levels of biodegradation characterised by the removal of C₃₀–C₃₅ hopanes. Biodegradation is also indicated by the removal of C₃₂ and C₃₃ benzohopanes. The appearance of C₃₁ and C₃₂ 25-norbenzohopanes corresponds to the decrease in C₃₂ and C₃₃ benzohopanes, suggesting that 25-norbenzohopanes originate by demethylation of benzohopane counterparts. Demethylation at C-10 in the hopanoids affects a broader class of compounds that so far includes the hopanes and hopanoic acids, as well as the benzylated hopanoid species.     

Tetrapyrrole pigments in United States humic coals

Analyses of forty-two United States humic coals have revealed a striking divergence between chlorophyll diagenesis in coals when compared to the more widely studied marine sediments, shales, asphalts and petroleums. Porphyrins of humic coals have been found to be dominated by the ETIO-series, to lack members above C-32, and, in lower ranked samples (e.g. Sub-bituminous-B, high volatile C) to exhibit mass spectral envelopes with unique even-carbon number predominances. The weighted average mass, as well as the carbon number maximum (viz. mode), of these coal porphyrin homologies has been found to decrease as rank increases. The generation of porphyrins of the ETIO-series is suggested as occurring both during early coal formation, including oxidative scission of the isocyclic ring at the phorbide stage, and later during the catagenic alteration of surviving DPEP-series porphyrins. A preliminary study of chlorophyll diagenesis in a South Florida peat partially substantiates this suggestion and has further shown that the coal porphyrins can be derived from bacterial, as well as higher plant, chlorophylls.     

Novel side chain methylated and hexacyclic hopanes: Identification by synthesis, distribution in a worldwide set of coals and crude oils and use as markers for oxic depositional environments

Novel side chain methylated and hexacyclic hopanes have been identified in coals and oils from around the world. Extended hopanes (>C₃₂) with an additional methyl in the side chain (“isohopanes”) were identified by comparison with synthetic standards. The major C₃₃-C₃₅ isohopanes are 31-methylbishomohopanes, 32-methyltrishomohopanes and 33-methyltetrakishomohopanes. Extended hopanes methylated at C-29 were not detected. The 17α(H),21β(H)-31-methyltrishomohopanes show four peaks on gas chromatography because of the extra asymmetric carbon at C-31. Like regular hopanes, the isohopanes extend beyond C₃₅. Low concentrations of novel hexacyclic hopanes having 35 or more carbons were also detected in oils and coal extracts. The C₃₅ hexacyclic hopanes were identified as 29-cyclopentylhopanes. Isohopanes are released from the kerogen by hydrous pyrolysis and hydropyrolysis. The 22S/(22S + 22R) ratio for 31-methylbishomohopanes and other isohopanes is around 0.60 at equilibrium in geological samples. They isomerize slightly more slowly than regular C₃₃ hopanes. Isohop-17(21)-enes, 2α-methylisohopanes and two series of rearranged isohopanes were tentatively identified. Isohopanes can be biodegraded to form the corresponding 25-norhopanes. When 25-norhopanes are not formed, the isohopanes are much more resistant to biodegradation than regular hopanes. In biodegraded oil seeps from Greece, 30-norisohopanes were tentatively assigned. The composition and relative abundance of C₃₃ and C₃₄ isohopanes in a worldwide set of coals and crude oils was determined. Isohopanes are abundant in coal and coal-generated oils, where they can account for more than 5% of all extended hopanes, and low in abundance in oils from source rocks deposited under anoxic conditions.     

Characterisation of fossil porphyrins of the “di-DPEP” type

Four basic structural types of alkyl porphyrins have been reported frequently to occur in sedimentary organic matter as metallocomplexes. The purpose of this note is: i) to report the structural assignment of two representatives (C₃₂, C₃₃) of the so-called “di-DPEP” series, isolated from El Lajjun shale, a bituminous limestone of central Jordan (Upper Cretaceous, El Lajjun Basin); ii) to evaluate a previous suggestion that this type of compound and sedimentary monobenzoporphyrins are related in structure and origin.     

Petroporphyrins in Gaosheng crude oil

China's Gaosheng crude oil is characterized as being high in nickel and low in vanadium. Nickel porphyrins were extracted with dimetrylformamide, concentrated by absorption chromatography and demetallized with methylsulfonic acid. The concentrate of demetallized porphyrins was then separated by centrifugal thin-layer chromatography, in which DPEP, ETIO, Di-DPEP, Rhdo-ETIO, Rhdo-DPEP and Rhodo-Di-DPEP types of porphyrin were identified by mass spectrometry and UV-VIS spectroscopy. The possible geochemical pathways from DPEP to Di-DPEP and from Di-DPEP to Rhodo-DPEP series are discussed.     

Carbon and nitrogen isotopic compositions of alkyl porphyrins from the Triassic Serpiano oil shale

The carbon and nitrogen isotopic compositions of seven of the most abundant alkylporphyrins from the Serpiano oil shale (marine, Triassic) were determined. For the C31 and C32 butanoporphyrins, values of delta 13CPDB and delta 15NAIR averaged -24.0% and -3.1%. In contrast, the C31 and C32 methylpropanoporphyrins, DPEP, and a C30 13-nor etioporphyrin had delta 13C and delta 15N values averaging -27.5 and -3.3%, respectively. Carbon and nitrogen isotopic values for kerogen averaged -30.8 and -0.9, whereas those for total extract averaged -31.6, and -4.0%. The butanoporphyrins apparently derive from a biological source different from that giving rise to the other porphyrins, their 13C enrichment not being related to carbon isotopic fractionation accompanying diagenetic reactions. The delta 15N values for all the porphyrins indicate that the depletion of 15N observed in the kerogen is of primary origin. Consistent with the very high abundance of hopanoids and methyl hopanoids in the aliphatic hydrocarbon fraction, it is suggested that cyanobacterial fixation of N2 may have been the main cause of 15N depletion.     

Iron porphyrins in coal from the United States

Iron porphyrins have been isolated from seven U.S. humic coals of various geological ages. Mass spectrometry shows that for the higher rank coals the porphyrins comprise an homologous series of alkyl derivatives (C₂₇-C₃₂). Mesoheme is detected in a Cretaceous lignite from Montana.     

The Preparation of Twenty Ore Standards, IGS 2O-39. Preliminary Work and Assessment Of Analytical Data

The first inter-laboratory investigation of accuracy in are analysis was carried out by the Institute of Geological Sciences in 1968. The preparation of the 19 samples involved in this study is briefly described and the results are summarised.
The second survey on twenty samples was initiated in 1972 and completed in 1976. The samples prepared are: IGS 20, nickel concentrate; IGS 21, nickel ore (norite); IGS 22, nickel ore (serpentinite); IGS 23, nickel ore (laterite); IGS 24, cobalt ore; IGS 25, wolframite; IGS 26, tin-tungsten ore; IGS 27, molybdenum-tungsten ore; IGS 28, lead-zinc concentrate; IGS 29, pyrolusite; IGS 30, chromite; IGS 31, ilmenite; IGS 32, rutile; IGS 33, columbite; IGS 34, tantalite; IGS 35, zircon; IGS 36, monazite; IGS 37, uraninite; IGS 38, baryte; IGS 39, fluorite. After proper grinding and homogenisation, aliquots of the samples were issued to over 50 laboratories in 14 countries for analysis. Methods used and problems encountered in dealing with the 5000 results are described. It is seen that neither purely statistical methods nor an empirical approach are entirely satisfactory in the interpretation of data that vary widely in both in quality and quantity. An important outcome of the work is that 55 elemental concentrations within the 20 samples have been given recommended values and confidence limits for use as standards.
Moisture values, analytical results and participating laboratories are listed in three appendices.     

Characterization of sedimentary humic matter by alkaline hydrolysis

Humic matter fractions from modern sediments of Lake Huron and Lake Michigan have been compared. Large yields of saccharinic acids from alkaline hydrolysis suggest that these fractions contain large portions of carbohydrate materials. Evidence for contributions of aquatic lipid (C-16 fatty acids) and of liginin (phenolic acids) to these sediments is also present in the hydrolysis products. Qualitative differences among fulvic acid, humic acid and humin from the same lake are minor, suggesting common (or similar) organic sources for these fractions. The lability of sedimentary humic matter to alkaline hydrolysis is inversely related to its degree of exposure to oxidative weathering. Lability may also be related to diagenetic state as fulvic acids generally yield greater quantities of hydrolysis components than humic acids which in turn yield more than humin.     

The stereochemistry of bound and extractable pentacyclic triterpenoids during closed system pyrolysis

The distributions of hopanoic acids, ranging from C₃₀ to C₃₄, in the Messel oil shale were characterized in both the free and bound states. The bound acids were released by thermochemolysis in the presence of tetramethylammonium hydroxide (TMAH). These were compared with the distributions of the hopanoic acids and hopanes released or generated from Messel oil shale kerogen following closed system microscale pyrolysis. This comparison revealed that epimerization had occurred at C-17, C-21 and C-22 during heating. It was also clear that the residual bound hopanoic acids had undergone configurational isomerization. During the pyrolysis there is a large loss of hopanoic acids following their rapid release from the kerogen into the free fraction even at 250 °C. In these particular experiments this loss does not appear to result in exclusive formation of hopanes, by way of decarboxylation or reduction reactions, unless the resulting hopanes are either themselves rapidly transformed into other compounds or the reaction rates are a function of the total number of carbon atoms in each hopanoic acid precursor.     

δC and δD identification of sources of lipid biomarkers in sediments of Lake Haruna (Japan)

Organic materials in lacustrine sediments are from multiple terrestrial and aquatic sources. In this study, carbon (δ¹³C) and hydrogen isotopic compositions (δD) of phytol, various sterols, and major n-fatty acids in sediments at Lake Haruna, Japan, were determined in their solvent-extractable (free) and saponification-released forms (bound). The δ¹³C-δD distributions of these lipid molecules in sediments are compared with those of terrestrial C3 and C4 plants, aquatic C3 plants, and plankton to evaluate their relative contributions. δ¹³C-δD of free phytol in sediments is very close to that of phytol in plankton samples, whereas δ¹³C-δD of bound phytol in sediments is on a mixing line between terrestrial C3 plant and plankton material. Unlike phytol, no significant δ¹³C-δD difference between free and bound forms was found in sterols and n-fatty acids. δ¹³C-δD values of algal sterols such as 24-methylcholesta-5,22-dien-3β-ol in sediments are close to those of plankton, whereas δ¹³C-δD of multiple-source sterols such as 24-ethylcholest-5-en-3β-ol and of major n-fatty acids such as n-hexadecanoic acid in sediments are between those of terrestrial C3 plants and plankton samples. Thus, δ¹³C-δD distributions clearly indicate the specific source contributions of biomarkers preserved in a lacustrine environment. Free phytol and algal sterols can be attributed to phytoplankton, and bound phytol, multiple source sterols, and major n-fatty acids are contributed by both terrestrial C3 plants and phytoplankton.     

超临界萃取技术在泥炭纤维素提纯中的应用与萃取组分特征

将超临界CO2萃取技术应用于泥炭纤维素中有机脂类物质的提纯工作,并对萃取物进行色—质联用分析。结果表明,在萃取物中检出了一系列甲酯类、乙酯类、少量有机酸及正构烷烃组分。首次检出的脂肪酸乙酯系列化合物多数呈高碳数分布,具偶碳优势。长链正构烷烃主峰碳为nC33或nC31,具有明显的奇碳优势,这在一定程度上反映了泥炭生成过程的气候条件,记录了气候变化的信息。同时也显示出超临界CO2萃取技术能够很好地完成除去纤维素中有机脂类这一重要环节,有利于提高泥炭纤维素δ13C值检测的准确度,为超临界流体萃取技术在地学中的应用开辟了一个新途径。     

A natural pyrolysis experiment — hopanes from hopanoic acids?

The formation or generation of hopanes are important processes during both the natural heating of organic-rich sediments and laboratory pyrolysis experiments. Molecular maturity parameters as well as the amounts (ng/g rock) of the C₃₁ hopanes and C₃₀–C₃₂ hopanoic acids were quantified in a Jurassic silty shale horizon (Isle of Skye, Scotland) as a function of distance from an igneous intrusion. The maturity profiles of the homohopanes and the hopanoic acids are comparable. There is also a correlation between the decreasing amounts of C₃₀–C₃₂ hopanoic acids and concomitant increases in C₂₉–C₃₁ hopanes suggesting that free hopanoic acids could be one potential source of hopanes in this particular horizon. Other possible sources could include hopanoic acids that are bound into the macromolecular fraction.     

吉林省红旗岭矿区7号岩体群地质特征及对地质找矿的指导意义

红旗岭矿区的南东部存在7、32、33号三个岩体,一般统称为7号岩体群。7号岩体是矿区发现含铜、镍矿最大的岩体,32与33号岩体分布在7号岩体的北西部。通过对这三个岩体的地质特征进行分析,利用3Dmine软件建模技术,对三个岩体、岩相、矿体建立三维模型。对模型进行观察、分析,结合成岩成矿地质理论,发现三个岩体是由来自7号岩体的南东部深部岩浆源生成的,岩浆由7号岩体的南东部深部向北西方向侵入,地质历史上三个岩体是一个大岩体,只是经过长期的风化剥蚀和地质构造改造形成目前的3个岩体,显示7号岩体的南东部深部具有找矿潜力。     

Comparison of the structures of humic substances from aquatic and terrestrial sources by pyrolysis gas chromatography-mass spectrometry

Four humic extracts isolated from terrestrial, mahne, plankton and freshwater sources have been investigated by pyrolysis-gas chromatography-mass spectrometry. The results show that substantial quantities of phenols (some not derived from lignin), pyrroles and nitrites (derived from proteins, nucleic acids or porphyrins) are decomposition products. Small amounts of furans (derived from carbohydrates) and unsaturated ketones (derived from polycarboxylic aliphatic acids) are also present. The results illustrate how parent material, transport factors and biological activity affect the composition of humic extracts.     

Constraining the genetic relationships of 25-norhopanes,hopanoic and 25-norhopanoic acids in onshore Niger Delta oils using a temperature-dependent material balance

Analysis of oil samples from the Niger Delta (Nigeria) revealed a range of structurally related hopanes, including 25-norhopanes, and hopanoic and 25-norhopanoic acids. 25-Norhopanes were detected in all medium and heavily biodegraded oils and were most abundant in the heavily degraded oils. Hopanoic acids (C₃₀-C₃₃) and 25-norhopanoic acids (C₃₀-C₃₁) were most abundant in moderately degraded oils and occurred in reduced concentration in heavily degraded oils but were absent from, or in trace concentration in, slightly degraded oils. Consideration of the structures suggests that 25-norhopanoic acids form via carboxylation of 25-norhopanes or demethylation of hopanoic acids. Mass balance for the onshore Niger Delta oils suggests that formation of 25-norhopanes operates independently of 25-norhopanoic acid formation and that 25-norhopanoic acids are likely transient intermediates for only a small proportion of the 25-norhopanes.