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1.
Compound-specific stable carbon isotopic composition of petroleum hydrocarbons as a tool for tracing the source of oil spills 总被引：1，自引：0，他引：1
With the increasing demand for and consumption of crude oils, oil spill accidents happen frequently during the transportation of crude oils and oil products, and the environmental hazard they pose has become increasingly serious in China. The exact identification of the source of spilled oil can act as forensic evidence in the investigation and handling of oil spill accidents. In this study, a weathering simulation experiment demonstrates that the mass loss of crude oils caused by short-term weathering mainly occurs within the first 24h after a spill, and is dominated by the depletion of low-molecular weight hydrocarbons (相似文献
2.
Oil, refined product, and pyrogenic hydrocarbons are the most frequently discovered contaminants in the environment. To effectively determine the fate of spilled oil in the environment and to successfully identify source(s) of spilled oil and petroleum products is, therefore, extremely important in many oil-related environmental studies and liability cases. This article briefly reviews the recent development of chemical analysis methodologies which are most frequently used in oil spill characterization and identification studies and environmental forensic investigations. The fingerprinting and data interpretation techniques discussed include oil spill identification protocol, tiered analytical approach, generic features and chemical composition of oils, effects of weathering on hydrocarbon fingerprinting, recognition of distribution patterns of petroleum hydrocarbons, oil type screening and differentiation, analysis of “source-specific marker” compounds, determination of diagnostic ratios of specific oil constituents, stable isotopic analysis, application of various statistical and numerical analysis tools, and application of other analytical techniques. The issue of how biogenic and pyrogenic hydrocarbons are distinguished from petrogenic hydrocarbons is also addressed. 相似文献
3.
This study demonstrates that petroleum and source rocks are enriched in Pt and Pd to the ppb level, and that the 187Os/188Os composition coupled with the Pt/Pd value permits the fingerprinting of petroleum to its source. Oils from the United Kingdom Atlantic Margin (sourced from the Upper Jurassic Kimmeridge Clay Fm.) as well as source rock samples have been analysed for Pt and Pd. When the Pt/Pd value is compared with 187Os/188Os (calculated at the time of oil generation; Osg) the values from both the known source and the oils are similar, demonstrating that they can be used as an oil to source fingerprinting tool. This inorganic petroleum fingerprinting tool is particularly important in heavily biodegraded petroleum systems where traditional fingerprinting techniques (e.g. biomarkers) are severely hampered, e.g. the world's largest oil sand deposit, the West Canadian Oil Sands (WCOS). This has caused the source of the WCOS to be hotly debated, with no present day consensus between inputs from potential source units e.g. Exshaw and Gordondale Fms. 187Os/188Os and Pt/Pd fingerprinting of the oil sands shows that the majority of the petroleum have similar 187Os/188Os and Pt/Pd values, supporting the hypothesis of one principal source. Analysis of the potential source rocks establishes that the principal source of the oil sands to be from the Jurassic Gordondale Fm., with a minor Exshaw Fm. input. Thus, the combination of previously pioneered Re–Os petroleum geochronology with 187Os/188Os and Pt/Pd values of petroleum permits both a temporal and spatial understanding of petroleum systems. 相似文献
4.
In 2002, 13 years after the Exxon Valdez spill, mussels and clams were examined for lingering oil exposure and damage. Known oil patches were sampled at four locations, and compared to nearby reference areas (same bay), and were also compared to "hot reference" sites to verify the methods used (Cordova harbor and fresh diesel spill at Port Chalmers). Passive samplers deployed for a month at the sites, along with tissue samples, confirmed that the oiled sites were oiled (fingerprinting back to Exxon Valdez oil) and that reference sites were clean. The highest PAH loads were detected in sub-surface interstitial waters at oiled sites. Exposure at the surface was generally low level, and probably intermittent. DNA damage was assessed in blood cells using sensitive comet analyses. DNA strand breakage was detected in both mussels and clams, with the highest level of damage detected at "hot reference" sites of Cordova harbor and Port Chalmers. Bioavailability and DNA damage at the oiled sties was low, indicating there has been substantial progress in recovery from the spill 13 years before, yet low level bioavailability and damage were still detectable. 相似文献
5.
The Mexican Ixtoc oil well blew out on 3 June, 1979. Since then more than 3.5 × 105 tonnes of crude oil have entered the Gulf of Mexico. This is probably the largest oil spill in the world's history. Two months later (7 August, 1979), the spilled oil began moving to the Texas coastal waters and the well is not yet capped. Although laboratory tests showed that the aged oil was not acutely toxic to some marine invertebrates, further work needs to be conducted to determine its possible chronic effects on sensitive ecosystems such as the Laguna Madre. 相似文献
6.
Lemkau KL Peacock EE Nelson RK Ventura GT Kovecses JL Reddy CM 《Marine pollution bulletin》2010,60(11):2123-2129
Understanding the fate of heavy fuel oils (HFOs) in the environment is critical for sound decisions regarding its usage and spill cleanup. To study weathering of HFOs, we examined the M/V CoscoBusan spill (November 2007; San Francisco Bay, CA, USA). In this baseline report, we identified which ruptured tank (port tank 3 or 4) was the source of the spilled oil and characterized changes in the oil composition across location and time. Samples from three impacted shorelines, collected within 80 days of the spill, were analyzed using one- and two-dimensional gas chromatography (GC and GC × GC, respectively). Weathering varied across sites, but compounds with GC retention times less than n-C16 were generally lost by evaporation and dissolution. Changes in n-C18/phytane and benz[a]anthracene/chrysene ratios indicated some biodegradation and photodegradation, respectively. 相似文献
7.
Time series changes in chlorophyll a concentration before and after the Hebei Spirit oil spill that occurred in December 2007 were analyzed using NCEP wind and SeaWiFS/MODIS ocean color data. Prevailing southwesterly winds and northeast/southwestward tidal currents pushed the oil towards Korea’s West Sea coast of Taean. After the oil spill, daily chlorophyll a concentration decreased about 45-50% compared to the normal condition before the oil spill, and this decrease continued for about two weeks. Monthly mean chlorophyll a concentration in December 2007 was lower compared to the average value for the same month between 1998 and 2007, but, in October and November 2007 before the spill and in January-February 2008 after the spill, the concentration value was higher than average for the same period between 1998 and 2007. 相似文献
8.
Oil spill detection with fully polarimetric UAVSAR data 总被引：3，自引：0，他引：3
In this study, two ocean oil spill detection approaches based on four scattering matrices measured by fully polarimetric synthetic aperture radar (SAR) are presented and compared. The first algorithm is based on the co-polar correlation coefficient, ρ, and the scattering matrix decomposition parameters, Cloud entropy (H), mean scattering angle (α) and anisotropy (A). While each of these parameters has oil spill signature in it, we find that combining these parameters into a new parameter, F, is a more effective way for oil slick detection. The second algorithm uses the total power of four polarimetric channels image (SPAN) to find the optimal representation of the oil spill signature. Otsu image segmentation method can then be applied to the F and SPAN images to extract the oil slick features. Using the L-band fully polarimetric Uninhabited Aerial Vehicle – synthetic aperture radar (UAVSAR) data acquired during the 2010 Deepwater Horizon oil spill disaster event in the Gulf of Mexico, we are able to successfully extract the oil slick information in the contaminated ocean area. Our result shows that both algorithms perform well in identifying oil slicks in this case. 相似文献
9.
Mary Jo Baedecker Robert P. Eganhouse Haiping Qi Isabelle M. Cozzarelli Jared J. Trost Barbara A. Bekins 《Ground water》2018,56(5):797-809
The composition of crude oil in a surficial aquifer was determined in two locations at the Bemidji, MN, spill site. The abundances of 71 individual hydrocarbons varied within 16 locations sampled. Little depletion of these hydrocarbons (relative to the pipeline oil) occurred in the first 10 years after the spill, whereas losses of 25% to 85% of the total measured hydrocarbons occurred after 30 years. The C6‐30 n‐alkanes, toluene, and o‐xylene were the most depleted hydrocarbons. Some hydrocarbons, such as the n‐C10–24 cyclohexanes, tri‐ and tetra‐ methylbenzenes, acyclic isoprenoids, and naphthalenes were the least depleted. Benzene was detected at every sampling location 30 years after the spill. Degradation of the oil led to increases in the percent organic carbon and in the δ 13C of the oil. Another method of determining hydrocarbon loss was by normalizing the total measured hydrocarbon concentrations to that of the most conservative analytes. This method indicated that the total measured hydrocarbons were depleted by 47% to 77% and loss of the oil mass over 30 years was 18% to 31%. Differences in hydrocarbon depletion were related to the depth of the oil in the aquifer, local topography, amount of recharge reaching the oil, availability of electron acceptors, and the presence of less permeable soils above the oil. The results from this study indicate that once crude oil has been in the subsurface for a number of years there is no longer a “starting oil concentration” that can be used to understand processes that affect its fate and the transport of hydrocarbons in groundwater. 相似文献
10.
《Marine pollution bulletin》2009,58(6-12):895-898
Experimentally, a feasibility study for adsorption and catalytic pyrolysis of spill oils on Cu/ZSM-5 for recycling of light oils has been conducted in the present work. The adsorption and pyrolysis of model compounds such as heptane, toluene, and diesel (to stimulate the spill oils) on Cu/ZSM-5 have been investigated on a continuous fixed-bed reactor. By component fitted X-ray absorption near edge structural (XANES) spectroscopy, catalytic active species such as metallic copper (Cu) (77–84%) and Cu2O (6–7%) are found in the channels of ZSM-5 during pyrolysis of heptane or toluene. Pyrolysis of diesel effected by Cu/ZSM-5 yields gas (C1–C5) (32%) and light oil (68%) that can be used as auxiliary fuels. 相似文献
11.
The Tiribí Tuff covered much of the Valle Central of Costa Rica, currently the most densely populated area in the country (∼2.4 million inhabitants). Underlying the tuff, there is a related well-sorted pumice deposit, the Tibás Pumice Layer. Based on macroscopic characteristics of the rocks, we distinguish two main facies in the Tiribí Tuff in correlation to the differences in welding, devitrification, grain size, and abundance of pumice and lithic fragments. The Valle Central facies consists of an ignimbritic plateau of non-welded to welded deposits within the Valle Central basin and the Orotina facies is a gray to light-bluish gray, densely to partially welded rock, with yellowish and black pumice fragments cropping out mainly at the Grande de Tárcoles River Gorge and Orotina plain. This high-aspect ratio ignimbrite (1:920 or 1.1×10−3) covered an area of at least 820 km2 with a long runout of 80 km and a minimum volume outflow of 25 km3 (15 km3 DRE). Geochemically, the tuff shows a wide range of compositions from basaltic-andesites to rhyolites, but trachyandesites are predominant. Replicate new 40Ar/39Ar age determinations indicate that widespread exposures of this tuff represent a single ignimbrite that was erupted 322±2 ka. The inferred source is the Barva Caldera, as interpreted from isopach and isopleth maps, contours of the ignimbrite top and geochemical correlation (∼10 km in diameter). The Tiribí Tuff caldera-forming eruption is interpreted as having evolved from a plinian eruption, during which the widespread basal pumice fall was deposited, followed by fountaining pyroclastic flows. In the SW part of the Valle Central, the ignimbrite flowed into a narrow canyon, which might have acted as a pseudo-barrier, reflecting the flow back towards the source and thus thickening the deposits that were filling the Valle Central depression. The variable welding patterns are interpreted to be a result of the lithostatic load and the influence of the content and size of lithic fragments. 相似文献
12.
Tectonic and geochemical characteristics and reserved conditions of a mantle source gas accumulation zone in eastern China 总被引：8，自引：0，他引：8
Along both sides of the Tancheng-Lujiang Fracture Zone in eastern China, a series of mantle source gas pools constitute a
massive-scale tectonic accumulation zone in NNE direction, with the mantle geochemical characteristics of high concentrations
of C02 and He, high3He/4He-40Ar/36Ar ratio system and high δ13Coo2 ratios (the main frequency, -3.4%— 4.6%), showing no difference from the tectonic framework of the area. In the area, the
tectonic environment is a rift formed as a result of diapiric mantle injection and crust thinning to form graben-type basins
and lithospheric fractures. The mantle-derived volcanic rocks and inclusions are well-developed and a high geothermal zone
(mantlesource) exists in the area. The characteristics of the three components (solid, liquid and gas) of mantle, concentrated
all over the same tectonic space zone, show that the rift system is of a good tectonic environment or passage for mantle degassing
and gas migration. The main types of the gas pools are volcano, fault-block, anticline, buried hill and so on, but most of
them are combination traps closely related with fracture. For the mantle source gas pools, rift is an optimum tectonic region,
and nearby lithospheric fracture, mantle source volcanic rocks or basement uplifts are a favourable structural location when
reservoir-caprock association develops. 相似文献
13.
Benjamin Jacobsen Qing-zhu Yin Frederic Moynier Yuri Amelin Alexander N. Krot Kazuhide Nagashima Ian D. Hutcheon Herbert Palme 《Earth and Planetary Science Letters》2008,272(1-2):353-364
The precise knowledge of the initial 26Al/27Al ratio [(26Al/27Al)0] is crucial if we are to use the very first solid objects formed in our Solar System, calcium–aluminum-rich inclusions (CAIs) as the “time zero” age-anchor and guide future work with other short-lived radio-chronometers in the early Solar System, as well as determining the inventory of heat budgets from radioactivities for early planetary differentiation. New high-precision multi-collector inductively-coupled plasma mass spectrometry (MC-ICP-MS) measurements of 27Al/24Mg ratios and Mg-isotopic compositions of nine whole-rock CAIs (six mineralogically characterized fragments and three micro-drilled inclusions) from the CV carbonaceous chondrite, Allende yield a well-defined 26Al–26Mg fossil isochron with an (26Al/27Al)0 of (5.23 ± 0.13) × 10− 5. Internal mineral isochrons obtained for three of these CAIs (A44A, AJEF, and A43) are consistent with the whole-rock CAI isochron. The mineral isochron of AJEF with (26Al/27Al)0 = (4.96 ± 0.25) × 10− 5, anchored to our precisely determined absolute 207Pb–206Pb age of 4567.60 ± 0.36 Ma for the same mineral separates, reinstate the “canonical” (26Al/27Al)0 of 5 × 10− 5 for the early Solar System. The uncertainty in (26Al/27Al)0 corresponds to a maximum time span of ± 20 Ka (thousand years), suggesting that the Allende CAI formation events were culminated within this time span. Although all Allende CAIs studied experienced multistage formation history, including melting and evaporation in the solar nebula and post-crystallization alteration likely on the asteroidal parent body, the 26Al–26Mg and U–Pb-isotopic systematics of the mineral separates and bulk CAIs behaved largely as closed-system since their formation. Our data do not support the “supra-canonical” 26Al/27Al ratio of individual minerals or their mixtures in CV CAIs, suggesting that the supra-canonical 26Al/27Al ratio in the CV CAIs may have resulted from post-crystallization inter-mineral redistribution of Mg isotopes within an individual inclusion. This redistribution must be volumetrically minor in order to satisfy the mass balance of the precisely defined bulk CAI and bulk mineral data obtained by MC-ICP-MS.The radiogenic 208Pb/206Pb ratio obtained as a by-product from the Pb–Pb age dating is used to estimate time-integrated 232Th/238U ratio (κ value) of CAIs. Limited κ variations among the minerals within a single CAI, contrasted by much larger variations among the bulk CAIs, suggest Th/U fractionation occurred prior to crystallization of igneous CAIs. If interpreted as primordial heterogeneity, the κ value can be used to calculate the mean age of the interstellar dust from which the CAIs condensed. 相似文献
14.
The aim of this work was to detect the impact of Prestige oil spill on meiobenthic community structure at higher levels of taxonomic aggregation. In addition, the relationship between sediment individual polycyclic aromatic hydrocarbon (PAH) concentration and meiofauna community structure was investigated. Six months after the Prestige oil spill, meiobenthos community and sediment PAHs content from seven shallow subtidal localities along the Galician coast were studied. Two sites presented differences in community structure, characterized by high densities of nematodes, gastrotrichs and turbellarians, and low densities of copepods. Chrysene and triphenylene were only found at these two disturbed sites and could be responsible for differences of meiobenthos community structure. However, differences in community structure of sites could be linked with sedimentary parameters, and discrimination between the effect of PAHs and sedimentary parameters was impossible due to the lack of baseline studies on meiobenthos and PAHs contents in this area. 相似文献
15.
Vesicle characteristics (vesicularity, largest vesicle size, number of vesicles/cm2), CO2-δ13C and CO2-4He-40Ar-40Ar/36Ar in vesicles and CO2-δ13C in the glass have been measured in 19 tholeiitic basalt glasses from the Easter Microplate East Ridge (East Pacific Rise) collected at 3 different sites (26°S East Ridge, Pito Seamount and Pito Deep at 23°S).Carbon supersaturation values (Cmelt/Csolubility) vary from 1.3 to 4.3. Carbon supersaturation values are strongly correlated with the number of vesicles/cm2. There is also a correlation between number of vesicles/cm2 and vesicle size. At the Pito Seamount site, there is a negative correlation between carbon supersaturation values and observed carbon isotope fractionation between CO2 in vesicles and carbon dissolved in the glass (Δ13Cobserved). High 4He/40Ar* ratios in vesicles (from 49 to 190) are observed in both the most and least carbon supersaturated samples, while samples with intermediate carbon supersaturation have the lowest 4He/40Ar* ratios (16±1). These correlations show that most quenched melts record different disequilibrium to equilibrium states during closed-system degassing.The samples showing the highest carbon supersaturation (4.3) have the highest 4He/40Ar* (from 94 to 190). This observation shows for the first time that the 4He/40Ar* ratio can be kinetically fractionated during incomplete degassing of magmas from the magma chamber to the seafloor. This result implies that high 4He/40Ar* ratios are not a systematic indicator of open-system degassing (Rayleigh distillation) and that caution should be taken when using this ratio for any degassing correction.A two-stage degassing model, with the first stage being a closed-system degassing occurring between the source and the magma chamber, and the second stage of degassing (with a mode varying from open-system degassing to different degrees of kinetic closed-system degassing) taking place between the magma chamber and eruption on the seafloor, is the most appropriate to describe the degassing of MORB. Reconstructing initial carbon content of the magma prior to degassing and extrapolating the results to the entire ridge system results in a carbon flux of 1.6-0.3+0.6×1014 g/year. This value implies vigorous exchange of carbon between the mantle and the surface throughout geological times. 相似文献
16.
Knowledge of long-term movements of water-masses in the English Channel has been substantially improved using hydrodynamic modelling coupled with radio-tracers studies; nevertheless, the precision of results so obtained is still largely dependent on measurement precision. New tools are now available to make more accurate determinations of radio-tracer distribution: (1) Repositioning of station locations at the same tide reference-time, giving a homogeneous spatial data set, coupled with the possibility of interpolating and quantifying the amounts of dissolved radioactivity flowing through the English Channel; (2) the first measurements of tritium (3H) in seawater on a large scale in the English Channel demonstrate that this fully conservative radionuclide is a clearly identifiable marker of industrial releases; (3) recent campaigns carried out during the FLUXMANCHE II CCE (1994) programme show the general distribution of dissolved radionuclides 137Cs, 134Cs, 60Co, 125Sb, 106Ru and 3H in the English Channel and the Irish Sea; and (4) the re-utilisation of data from previous campaigns (1983, 1986, 1988) provides indications, at any given location in the English Channel, about the average dilution and distribution of releases derived from the La Hague reprocessing plant. Excesses and losses of radionuclides are now quantified with respect to known source terms; estimates of losses are provided for non-conservative radionuclides, while an excess of 137Cs was observed in the English Channel during the period 1983–1994. This excess, which has the same order of magnitude as the quantities released from La Hague plant in the English Channel, could be explained by about 1% of the Sellafield reprocessing plant releases entering the Channel. These results confirm and give a more detailed picture of the previously known distribution of water masses in the English Channel. They lead to clear information about transit times and dilution at this scale, and provide directly comparable data for the validation of hydrodynamic models. 相似文献
17.
For the first time during a significant oil spill, aircraft were used in preference to surface vessels to apply chemical dispersants, following the tragic accident to the French registered tanker in Bantry Bay, south-west Eire. In this particular case, with an ideally situated landing strip, close to the source of the spill of fresh crude oil, the response proved to be highly effective and prevented the vast majority of the oil lost after the 6th day from reaching the nearby shorelines. The ability of the pilot of the spray aircraft to rapidly locate and to select for treatment only those slicks or parts of slicks posing a significant threat also resulted in the minimum amount of dispersant being used to maximum effect. 相似文献
18.
Abstract Stable isotopes are powerful research tools in environmental sciences and their use in ecosystem research is increasing. Stable isotope measurements allow the study of evapotranspiration fluxes, soil evaporation and leaf transpiration phenomena. Soil water and leaf water are the sources of the evapotranspiration that transfers large quantities of water from land to the atmosphere; as a result the isotopic composition of water left in the leaves is modified towards enrichment. Evaporation also changes the isotopic composition of water bodies creating a natural isotopic signal. The isotopic identity of soil water affects the oxygen isotopic signature of leaf and stem water. In this paper we present the isotopic data of bulk leaf water, showing the enrichment in isotopic value of oxygen due to evapotranspiration from leaves in conjunction with the isotopic signal of rainwater and other environmental factors such as humidity and temperature. Results suggest that the variation in the values of δ18O of Eucalyptus citriodora, Dalbergia sissoo, Melia azedarach and Pinus roxburghii is due to the seasonal changes in the δ18O of the source water for plants, i. e. rain. It is further observed that leaf water δ18O values are depleted during the months of July, August and September. This occurs due to the following reasons: (a) the sampling areas receive about 50% of the average annual rain during these months, and (b) rainfalls during these months are isotopically depleted compared with winter rains. Citation Butt, S., Ali, M., Fazil, M. & Latif, Z. (2010) Seasonal variations in the isotopic composition of leaf and stem water from an arid region of Southeast Asia. Hydrol. Sci. J. 55(5), 844–848. 相似文献
19.
Bill Bonnichsen William P. Leeman Norio Honjo William C. McIntosh Martha M. Godchaux 《Bulletin of Volcanology》2008,70(3):315-342
New 40Ar-39Ar geochronology, bulk rock geochemical data, and physical characteristics for representative stratigraphic sections of rhyolite
ignimbrites and lavas from the west-central Snake River Plain (SRP) are combined to develop a coherent stratigraphic framework
for Miocene silicic magmatism in this part of the Yellowstone ‘hotspot track’. The magmatic record differs from that in areas
to the west and east with regard to its unusually large extrusive volume, broad lateral scale, and extended duration. We infer
that the magmatic systems developed in response to large-scale and repeated injections of basaltic magma into the crust, resulting
in significant reconstitution of large volumes of the crust, wide distribution of crustal melt zones, and complex feeder systems
for individual eruptive events. Some eruptive episodes or ‘events’ appear to be contemporaneous with major normal faulting,
and perhaps catastrophic crustal foundering, that may have triggered concurrent evacuations of separate silicic magma reservoirs.
This behavior and cumulative time-composition relations are difficult to relate to simple caldera-style single-source feeder
systems and imply complex temporal-spatial development of the silicic magma systems. Inferred volumes and timing of mafic
magma inputs, as the driving energy source, require a significant component of lithospheric extension on NNW-trending Basin
and Range style faults (i.e., roughly parallel to the SW–NE orientation of the eastern SRP). This is needed to accommodate
basaltic inputs at crustal levels, and is likely to play a role in generation of those magmas. Anomalously high magma production
in the SRP compared to that in adjacent areas (e.g., northern Basin and Range Province) may require additional sub-lithospheric
processes.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.
This paper constitutes part of a special issue dedicated to Bill Bonnichsen on the petrogenesis and volcanology of anorogenic
rhyolites. 相似文献
20.
Chemical characterization of naturally weathered oil residues in the sediment from Yellow River Delta, China 总被引：2，自引：0，他引：2
With its close proximity to Shengli Oilfield, China’s second largest oilfield, the Yellow River Delta is at high risk for crude oil contamination. The massive oil discharge in oilfield may offer a chance for a natural experiment to investigate compositional changes of oil residues and study the stability of source- and weathering-dependent molecular parameters in oil residues after spills. The results demonstrate that the conventional diagnostic ratios, such as C2920S/(20S + 20R), C29/C30H, C30βα/αβ, C3122S/(22S + 22R), C2-DBTs/C2-PHENs, C3-DBTs/C3-PHENs, DBT/MCHRY, CHRY/PHENs, are also valid for oil source identification even after extensive weathering of spilled oils in terrestrial environment, although some exceptions were encountered for extensively weathered sample. Moreover, the ratios of selected specific biomarkers (the oleanane index, the gammacerane index) have been developed and assessed as source indicators. Finally, we find that some maturity parameters based on alkyl naphthalenes and methyl phenanthrenes in petroleum geochemistry, such as the methylnaphthalene ratios (TMNr, TeMNr, PMNr), the methylphenanthrene ratios (MPI-1, MPDF), can be applied for the source identification and correlation at their lightly to moderately weathered stage. 相似文献