岩浆侵入体对有机质生烃(成熟)作用的影响及数值模拟   总被引：3，自引：1，他引：2  

王民  卢双舫  薛海涛  武静  刘大为 《岩石学报》2010,26(1):177-184

火山作用带来的热源对有机质的成烃进程和成烃量产生了重要影响,这种热效应一方面可以加速烃源岩的成熟和成烃作用,另一方面可以破坏先期形成的油藏。目前国内外对火山作用的生烃热效应方面的研究主要在热成熟度参数变化描述及岩浆侵入体引起的围岩热蚀变程度的讨论。火山作用对成烃/成藏的利弊,影响的时/空范围、程度的定量研究尚未报道。本次在前人研究基础上,建立了描述岩浆侵入体散热的热传导模型,进一步结合EasyRo%模型和前人报道的实测Ro数据进行了模型检验。通过调整模型的参数和岩浆侵入体厚度、位置及个数等进行了火山作用对有机质成熟作用及生烃影响的研究。模拟结果表明:岩浆侵入体的热作用范围是有限的,但是不同地质情况,影响的范围广度也不相同,对于相同厚度的侵入体,初始温度越高,作用范围越广,但是一般X/D3(X/D代表离接触面的距离与侵入体厚度的比值)。对于不同厚度侵入体而言,在侵入体热作用影响的范围内,侵入体越厚,热作用的范围越广。同时数值模拟结果也表明岩浆侵入体的存在可以改变烃源岩生烃期。  相似文献   

The fight for Kanaky: decolonisation in the South Pacific     

John Connell 《The Australian geographer》1987,18(1):57-62

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Kerosene-like tainting in Australian mullet     

D. W. Connell 《Marine pollution bulletin》1971,2(12):188-190

A preliminary report on the chemical composition of substances causing a kerosene-like taint in mullet. These substances are kerosene-like in composition and may originate from similar substances isolated from aquatic areas.  相似文献   

Long-term declines in two apex predators,bull sharks (<Emphasis Type="Italic">Carcharhinus leucas</Emphasis>) and alligator gar (<Emphasis Type="Italic">Atractosteus spatula</Emphasis>), in Lake Pontchartrain,an oligohaline estuary in southeastern Louisiana     

Martin T. O’Connell  Travis D. Shepherd  Ann M. U. O’Connell  Ransom A. Myers 《Estuaries and Coasts》2007,30(4):567-574

We analyzed historic and current fishery independent data to determine if the abundance of two apex predators, bull sharks (Carcharhinus leucas) and alligator gar (Atractosteus spatula), in Lake Pontchartrain had changed significantly over the last half century. Lake Pontchartrain is an environmentally degraded oligohaline estuary in southeastern Louisiana that has experienced considerable changes in fish assemblage composition over this interval. Using gillnet, beach seine, and trawl data collected during three time periods (1953–1955, 1977–1978, and 1996–2005), we analyzed trends in abundance forC. leucas andA. spatula using generalized linear models with a negative binomial error structure and a log link. Lake Pontchartrain data were divided into four spatial locations (northwest, northeast, southwest, southeast) since each region represents a unique combination of anthropogenic and natural influences that could affect catches. For each species and gear type, we produced log-likelihood profiles for the instantaneous rate of change in relative abundance through time. Raw catches were generally lower for both species in the later surveys.C. leucas were not captured in beach seines since the 1950s andA. spatula were rarely captured in trawls or seines since the 1970s. Likelihood profiles of changes in abundance forC. leucas andA. spatula showed very large declines in both species since 1953.C. leucas declined by 98.6% (95% CI: 73.4–99.9%) in gillnets and became functionally extirpated in beach seines with a decline of 99.9% (95% CI: 23–99.9%). Among all gears,C. leucas declined by the same rate as in gillnets. The decline inA. spatula was also large with a decrease of 98.6% (95% CI: 73.4–99.9%) in beach seines and a decline of 99.2% (95% CI: 54.8–99.9%) in trawls since 1953. Catches ofA. spatula in gillnets did not show a significant change over the study period. The continued decline of these two apex predators could seriously affect efforts to restore this degraded estuarine ecosystem.  相似文献   

A theoretical model for gas adsorption-induced coal swelling   总被引：6，自引：2，他引：6  

Zhejun Pan  Luke D. Connell 《International Journal of Coal Geology》2007,69(4):243-252

Swelling and shrinkage (volumetric change) of coal during adsorption and desorption of gas is a well-known phenomenon. For coalbed methane recovery and carbon sequestration in deep, unminable coal beds, adsorption-induced coal volumetric change may cause significant reservoir permeability change. In this work, a theoretical model is derived to describe adsorption-induced coal swelling at adsorption and strain equilibrium. This model applies an energy balance approach, which assumes that the surface energy change caused by adsorption is equal to the elastic energy change of the coal solid. The elastic modulus of the coal, gas adsorption isotherm, and other measurable parameters, including coal density and porosity, are required in this model. Results from the model agree well with experimental observations of swelling. It is shown that the model is able to describe the differences in swelling behaviour with respect to gas species and at very high gas pressures, where the coal swelling ratio reaches a maximum then decreases. Furthermore, this model can be used to describe mixed-gas adsorption induced-coal swelling, and can thus be applied to CO₂-enhanced coalbed methane recovery.  相似文献   

Devensian glacial events in Buchan (NE Scotland): A progress report on new OSL dates and their implications     

Alastair M.D. Gemmell  Andrew S. Murray  E.R. Connell 《Quaternary Geochronology》2007,2(1-4):237-242

Optically stimulated luminescence (OSL) dating of a series of glaciofluvial/glaciodeltaic sediments in central Buchan and Aberdeen has recently been undertaken. The aims of this project are to test the chronological model proposed by the most recent regional review and the suggestion that parts of Buchan may have remained ice-free during the last glacial maximum (late marine isotope stage (MIS) 3 and MIS 2 29–15 ka). The preliminary results indicate that during the Devensian (ca. 116–12 ka), extensive areas of Buchan may have been glaciated earlier than previously believed (possibly during MIS 4, 72–60 ka), but parts of the region show no depositional evidence of later glaciation. Some waterlain sediments from the Ugie Valley have yielded OSL ages indicating deposition during MIS 5d to MIS 5a (116–72 ka). We discuss whether the absence of overlying glaciogenic sediments at these locations raises questions about the reliability of the OSL ages or about existing models of the Devensian glaciation of Buchan.  相似文献   

Islands, idylls and the detours of development   总被引：1，自引：0，他引：1  

John Connell 《Singapore journal of tropical geography》2007,28(2):116-135

A passing parade of paradigms imported from distant places has failed to bring development to small islands and island states in the Pacific. Insularity might once have suggested purity, but more extended resource frontiers and other external pressures have challenged illusory benefits of 'isolation'. Failures of development, seemingly crystallized in the 'arc of instability', have brought new and more direct external intervention as regional geopolitics have been recast, despite the failure of earlier 'foreign flowers'. These have been paralleled by a new outward urge and simultaneous emergence of alternative indigenous responses at various scales, mostly encapsulated within indigenous 'cultural turns' and 'economic turns'. Older versions of syncretism and hybridity have taken more cultural and economic forms, in various contexts of disengagement and restructuring, which offer positive development outcomes and suggest the need for new, more culturally relevant dimensions and directions for development practice and theory.  相似文献   

Errors and uncertainty in physically-based rainfall-runoff modelling of catchment change effects   总被引：1，自引：0，他引：1  

John Ewen  Greg O&#x;Donnell  Aidan Burton  Enda O&#x;Connell 《Journal of Hydrology》2006,330(3-4):641-650

The error in physically-based rainfall-runoff modelling is broken into components, and these components are assigned to three groups: (1) model structure error, associated with the model’s equations; (2) parameter error, associated with the parameter values used in the equations; and (3) run time error, associated with rainfall and other forcing data. The error components all contribute to “integrated” errors, such as the difference between simulated and observed runoff, but their individual contributions cannot usually be isolated because the modelling process is complex and there is a lack of knowledge about the catchment and its hydrological responses. A simple model of the Slapton Wood Catchment is developed within a theoretical framework in which the catchment and its responses are assumed to be known perfectly. This makes it possible to analyse the contributions of the error components when predicting the effects of a physical change in the catchment. The standard approach to predicting change effects involves: (1) running “unchanged” simulations using current parameter sets; (2) making adjustments to the sets to allow for physical change; and (3) running “changed” simulations. Calibration or uncertainty-handling methods such as GLUE are used to obtain the current sets based on forcing and runoff data for a calibration period, by minimising or creating statistical bounds for the “integrated” errors in simulations of runoff. It is shown that current parameter sets derived in this fashion are unreliable for predicting change effects, because of model structure error and its interaction with parameter error, so caution is needed if the standard approach is to be used when making management decisions about change in catchments.  相似文献   

Prediction of bioconcentration and related lethal and sublethal effects with aquatic organisms     

Des W. Connell 《Marine pollution bulletin》1995,31(4-12)

It is now well established that the octanol/water partition coefficient (K_0W) can be used to estimate bioconcentration of persistent organic compounds, such as the chlorohydrocarbons as well as PAHs and other hydrophobic substances. However, while these relationships are well established in the laboratory, use in the field often poses a number of problems. In recent studies of contaminants in fish from Australia, bioconcentration has been described using additional information on specimen size, lipid content and fish movement patterns.The use of internal biotic concentration provides an additional new and different perspective on toxicant behaviour as compared to the conventional ambient aqueous concentration-based toxicity measures. The internal lethal concentration for persistent organic compounds approaches a constant value for many compounds, and at these concentrations lethal effects are observed. This constant internal lethal concentration provides a basis for predicting toxicity and its relationship to exposure period. In addition, sublethal effects can be successfully related to the internal biotic concentration.  相似文献   

'You Gotta Love This City': The Whitlams and inner Sydney     

Jessica Carroll  John Connell 《The Australian geographer》2000,31(2):141-154

This analysis of music in cultural geography, in the context of the inner Sydney-based band, The Whitlams, traces the creative links between sounds, 'scenes' and places. Based in Newtown, The Whitlams are associated with political values, evident in the band's name, and social values tied to and opposed to urban changes, such as gentrification, where community is threatened. The band's lyrics emanate from their experiences, challenging commercialisation of city life at different scales and reflecting the anomie of city living, but defending its virtues, whilst also fostering place stereotypes. The audience was similarly inner-city based until the band's recent commercial success, which has challenged The Whitlams' identity and radicalism, and resulted in mainstream appropriation. Though The Whitlams continue to reaffirm their local identity, and local audiences have remained, the popularity and commodification of their music has challenged concepts of shared meaning, the link between bands and their fans, and the connection between music and its place of origin. The Whitlams' music nevertheless remains a means of evoking and sharing a sense of place.  相似文献