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1.
政和-大埔深(大)断裂带中段地质构造特征及其演化探讨   总被引：4，自引：0，他引：4  
聂童春  朱根灵 《福建地质》2004,23(4):186-194
政和—大埔深(大)断裂带为划分福建省内一级构造单元的断裂带,通过各类资料综合分析,初步认为该断裂带自中晚元古代形成以来,持续活动至今,是一条深(大)断裂带,其活动位置不断迁移,各期的构造特征也不尽相同。该断裂带的活动对其两侧地质构造格局有较大的影响,在控岩、控矿等方面具有明显的表现。  相似文献   

2.
The interactions between cementitious materials and a clayey deep formation were investigated by studying the specific in situ context of the Tournemire Underground Research Laboratory (URL) of the French Institute for Radioprotection and Nuclear Safety and by reactive transport modelling using the HYTEC code. The study forms part of the safety assessment framework for the deep geological disposal of high to intermediate level long-lived radioactive waste. The in situ context investigated in the Tournemire URL corresponds to an engineered cemented borehole crosscutting the Toarcian argillite formation. The argillite/CEM II cement paste contacts have been in place over 18 a and were sampled in a saturated context outside the excavated disturbed zone (EDZ). Studies of the mineralogy (XRD, carbonatometry, SEM and TEM), petrophysical properties (BET) and geochemistry (TOC, Sr contents, C, O and Sr isotopes, EDS analyses) were carried out both on the argillite and on the cement paste in contact. Alteration of the cement paste is clearly expressed by decalcification and the opening of macroporosity. These modifications are mainly due to the dissolution of portlandite. The neoformation of C–S–H phases was identified in the first few micrometre next to the argillite interface, along with secondary carbonates at the outermost contact. Geochemical measurements argue for the introduction of a sedimentary fluid into the macroporosity of the cement paste to explain the formation of part of these secondary phases. This hypothesis is considered and tested using the HYTEC code, which indicates that such transport could have occurred near the argillite/cement paste contact at a very early stage. After this stage, the transport was reversed and ‘cementitious’ fluids flowed from the cement paste to the argillite. The changes brought about by these fluids are observed over a thickness of 11–13 mm in a so-called ‘black rim’, in which carbonates and C–S–H secondary phases are identified in the matrix of the sediment. An illitization process may also be observed in this altered rim, reaching its maximum development towards the inner part. Geochemical analyses show that the argillite disturbances are strictly confined to the black rim. Theoretical mineralogical profiles based on thermodynamic equilibria defined by the HYTEC code are in good agreement with the observations, and are used to achieve a better understanding of transport processes.  相似文献   

3.
鄂尔多斯块体新生代构造活动和动力学的讨论   总被引：54，自引：1，他引：53  
鄂尔多斯块体除西南边界为挤压边界外,四周被共轭剪切拉张带所围限,东西和南北两侧分别为右旋和左旋剪切拉张带,全新世水平和垂直滑动速率分别达5mm/a和0.3~3mm/a。鄂尔多斯块体自始新世起从西南挤压边界两端开始发育,逐渐向远端发展,至上新世最后形成山西断陷盆地带。新生代以来块体不断缓慢上升,距今1.40Ma以来的隆起总量为160m.形变测量说明块体现代隆升速率为1~2.8mm/a,周缘断陷盆地带现代下降速率为-4~-5mm/a。块体内部莫霍面变化平缓,埋深40km~42km,上地幔高导层埋深123km~131km,它们在周缘断陷盆地带相对隆起,前者隆起幅度1.5km~6km,后者埋深仅70km~100km.6级以上地震均发生在块体周边活动构造带内,块体内部无6级以上地震发生,4~5级地震也很少。震源机制、地应力和断层滑动矢量测量等得到的主压应力方位为NE-NEE向,与控制块体周边活动构造的区域应力场一致,主要与青藏块体的NE向挤压作用相关,盆地地下深部物质上涌产生的垂直力也起着重要作用。所以,区域性水平应力场和深部物质运动产生的垂直力联合作用是本区新构造活动的动力条件。   相似文献   

4.
Opalinus clay (OPA) is currently being investigated as a potential host rock for radioactive waste repository. The construction of this repository will lead to an excavation-damaged zone (EDZ) in the surrounding. Its sealing ability is crucial for the safety assessment of the geological repository. The sealing ability of OPA has a close relationship with its water retention and gas permeability behaviours. For this purpose, the water retention and gas permeability of OPA and its comparison with the artificial barrier (i.e. bentonite) were investigated in this study. The results show that OPA absorbed less water than granular bentonite material with equal suction. Compared with the other two similar materials (Boom clay and COx argillite), which were selected as natural engineering barriers for nuclear waste storage in Belgium and France, the suction behaviours of OPA are similar to those of COx argillite but notably different from those of Boom clay. The gas permeability tests show that OPA sample is quite sensitive to the changes in confining pressures but is less sensitive to applied gas pressures. Further, it is found that the OPA is more permeable than bentonite barrier after 10.5 years of hydration. Then, the OPA samples were artificially water-saturated. We find that the sealing ability can be recovered after long-time water saturation. However, when comparing with bentonite barrier, it is still a weak zone. This indicates that the EDZ should be paid more attention for the assessment the performance of the nuclear repository.  相似文献   

5.
Although the flux of molecular O2 between the atmosphere and the subsurface is intrinsically linked to the net soil production of greenhouse gasses, few studies have focused on the controls affecting the isotopic composition of O2 in the subsurface. Here, we developed and tested a stable oxygen isotope tracer technique and gas transport modeling approach to evaluate O2 cycling and fluxes from the subsurface that used an environmentally controlled soil mescosm. We measured the O2 and δ18O2 profiles in a model unsaturated soil zone and quantified the O2 consumption rates and the O2 isotope fractionation factors resulting from the combined processes of subsurface microbial (including bacteria, fungi, and protozoa) consumption of O2 and diffusive influx of O2 from the atmosphere. We found that at high respiration rates in the mesocosm, there appeared to be very little isotope fractionation of O2 by soil microorganisms. Although the mesocosm respiration rates are not typical of natural soils in northern temperate climes, they may be more representative of soils in warm and moist tropical environments. Our findings caution against the indiscriminate application of laboratory-determined oxygen isotope fractionation factors to field settings. The oxygen isotope tracer and modeling approach demonstrated here may be applied to gain a better understanding of biogenic gas production and O2 cycling in subsurface systems and soils.  相似文献   

6.
In this paper, we investigate the influence of the excavation damaged zone (EDZ) on the geomechanical performance of compressed air energy storage (CAES) in lined rock caverns. We conducted a detailed characterization of the EDZ in rock caverns that have been excavated for a Korean pilot test program on CAES in (concrete) lined rock caverns at shallow depth. The EDZ was characterized by measurements of P- and S-wave velocities and permeability across the EDZ and into undisturbed host rock. Moreover, we constructed an in situ concrete lining model and conducted permeability measurements in boreholes penetrating the concrete, through the EDZ and into the undisturbed host rock. Using the site-specific conditions and the results of the EDZ characterization, we carried out a model simulation to investigate the influence of the EDZ on the CAES performance, in particular related to geomechanical responses and stability. We used a modeling approach including coupled thermodynamic multiphase flow and geomechanics, which was proven to be useful in previous generic CAES studies. Our modeling results showed that the potential for inducing tensile fractures and air leakage through the concrete lining could be substantially reduced if the EDZ around the cavern could be minimized. Moreover, the results showed that the most favorable design for reducing the potential for tensile failure in the lining would be a relatively compliant concrete lining with a tight inner seal, and a relatively stiff (uncompliant) host rock with a minimized EDZ. Because EDZ compliance depends on its compressibility (or modulus) and thickness, care should be taken during drill and blast operations to minimize the damage to the cavern walls.  相似文献   

7.
地质微生物学中几项最新研究进展   总被引：3，自引：0，他引：3  
董海良  于炳松  吕国 《地质论评》2009,55(4):552-580
地质微生物学是地质学和微生物学之间的交叉学科,在过去的十几年中已取得了突飞猛进的发展。该研究领域涉及全球许多种极端环境,例如从地下深部结晶岩、古沉积岩、到现代超盐度湖泊、干旱的沙漠和热液喷口系统等。因为地质微生物学进展的综述可能要用一本专著方可阐述清楚,作者在此仅对地质微生物学几个活跃的前缘研究领域进行了综述,包括大陆深部、盐碱环境、干旱沙漠等极端环境中的微生物生态,白云石的微生物成因,古代沉积岩中的微生物古DNA及其环境意义以及海洋地质微生物学等几个方面。这些研究证明了将地质过程和微生物作用联系起来的重要性。  相似文献   

8.
The performance and safety assessment and technology demonstration are the main objectives of research programs for feasibility studies for deep geological repository of radioactive waste. In this context, the French national radioactive waste management agency (ANDRA) started to develop the Meuse/Haute-Marne underground research laboratory (URL) at Bure, nearly 300 km East of Paris. The host formation consists of a Callovo-Oxfordian claystone found between 420 and 550 m below ground, overlain and underlain by poorly permeable carbonate formations. One of the major concerns related to performance assessment is the excavation-induced fractures which may provide groundwater preferential pathway for radionuclide migration. The extent of the fractures possibly acting significantly in the radionuclide migration is known as the excavation damaged zone (EDZ). A scientific study on the EDZ characterization is performed at the main level of the URL (?490 m). Observations such as structural analysis on core, overcored resin-filled samples, geological survey of the drift face and sidewalls, were made to better understand the fracture network characteristics, extent and its generation. Pulse and constant head test hydraulic conductivity measurements were performed with multi packer system to estimate the extension of the EDZ hydraulic conductivity. Fractures exhibited high transmissivity near the excavation walls, but farther from the exaction walls, shear fractures showed hydraulic conductivity values reflecting values of undisturbed or slightly disturbed rock mass condition. The major findings in terms of geometry and properties of excavation-induced fractures are discussed in detail in this paper. For example, it is observed that the shape of the fracture network depends on the orientation of the drift in relation to the orientation of the in situ stress field.  相似文献   

9.
袁静  王乾泽 《矿物岩石》2001,21(1):43-47
东营凹陷下第三系埋深大于 30 0 0 m的深部碎屑岩储层普遍发育 2～ 4个次生孔隙带 ,Φ=10 %～ 30 % ,K=0 .1× 10 - 3μm2～ 30× 10 - 3μm2 ,为中孔低渗低孔低渗油气储层。综合有机质热演化过程、成岩作用和构造断裂等分析 ,认为东营凹陷埋深大于 30 0 0m碎屑岩地层中 ,第一、二个次生孔隙带埋深在 30 0 0 m～ 390 0 m之间 ,其形成主要与有机质成熟过程释放有机酸对长石等颗粒的溶解有密切关系 ,在深大断裂附近储层同时受到大气淡水的影响 ,而深陷带包裹于暗色泥岩中的浊积砂岩的次生孔隙发育情况还与泥质岩异常压力带有关 ;第三个次生孔隙带埋深一般为 390 0 m～ 430 0 m,主要成因于粘土矿物转化造成的还原环境 ,同时受到硫酸盐热化学氧化还原反应的影响。这三个次生孔隙发育带对储集油气有效。第四个孔隙发育带埋深在 470 0 m以下 ,主要是构造成因的微裂缝 ,较难成为有效的油气储层。  相似文献   

10.
依(兰)-伊(通)断裂带和密(山)-抚(顺)断裂带(又称敦-密断裂带)斜穿辽吉黑三省(图1),穿过了中朝淮地台和吉黑地槽系,被认为是郯庐断裂北延部分的两个分支。前者长约1000km,后者长近800km,在两个断裂带内发育了一系列含煤、含油盆地。这些盆地多为断陷盆地,具有地堑或反地堑性质,很多都是半地堑,它们的成堑活动主要发生在第三纪,其构造发展过程与断裂带内的沉积环境变化、生物演变有密切关系。本文讨论范围除依-伊断裂带外,包括了密抚断裂带南段的抚顺盆地。  相似文献   

11.
The surface microlayer population of two estuarine sites was sampled to determine the numbers of bacteria present. Random isolates from one site were examined taxonomically, with subsurface and sediment samples taken for comparison. There were 130 to 5000 times more bacterial cells per ml in the surface microlayer as compared to the subsurface water, agreeing with the observations of other investigators. The surface population was found to be different taxonomically from the subsurface and sediment isolates. Pseudomonads predominated among the surface isolates while ca. onethird of the subsurface isolates werePseudomonas species.Alcaligenes species were found only in the subsurface population and comprised nearly one-half of these isolates. The majority of the surface and subsurface bacteria required no salts for growth, whereas most of the sediment bacterial isolates required either Na+ or Mg++.  相似文献   

12.
史春潇  雷怀彦  赵晶  张劼  韩超 《沉积学报》2014,32(6):1072-1082
本研究应用微生物16S rRNA-DGGE和T-RFLP技术,结合环境参数,对我国天然气水合物潜在区南海九龙甲烷礁附近973-4柱状样沉积物中3个层位12个不同深度(表层20 cm至382 cm,中层552 cm至796 cm,深层862 cm至1 196 cm)细菌群落结构及其分布进行了对比研究.其中T-RFLP实验表明,细菌丰度、香农指数和均匀度变化趋势相同,由深层到716 cm处先降后升,中层716 cm深度范围处微生物群落丰度、均匀度、香农指数相对较高,716 cm至表层先降后升.DGGE图谱和T-RFLP色谱峰聚类分析表明:表层20 cm至192 cm相似性较高,表层236 cm至382 cm与深层1 082 cm、1 196 cm群落结构相似性较高,但中层沉积物中微生物群落结构与表层及深层均有较大差异.环境参数表明中层甲烷含量较高,推测甲烷是影响微生物群落结构差异的主要因素之一.T-RFLP色谱峰与微生物数据库比对及DGGE条带测序也表明了:本区变形杆菌(Proteobacteria)为优势菌群,其中α-、γ-、δ-变形杆菌(Proteobacteria)为主要的细菌亚群,其他细菌包括放线菌(Actinobacteria)、厚壁菌门(Firmicutes)、绿弯菌门(Chloroflexi)为次优势菌群.甲烷含量较高的中层,甲烷氧化菌(Methanotrophs),硫还原菌(Sulfate-reducing bacteria)等与甲烷密切相关的细菌均有被检测到,表明该区域存在与天然气水合物的分解释放相关的微生物群落.  相似文献   

13.
The monotony of the surface and of the deep structure of the Sahel domain in eastern Tunisia (low topographic area covered by a Quaternary series) induces the possible existence of an important subsiding collapsed block and associated faulted zones. Gravity data analyses have permitted the reconnaissance of the crustal and gravimetric setting of the northern part of the Sahel domain and the discussion of main outlines of subsurface structures. The deep structure of a particular zone (Kairouan–Sousse–Monastir area) demonstrates the existence of an east-west en-doigt-de-gant crustal thinning confirmed by the gravity data. This deep structuring is perfectly showed by the high-resolution second-order enhanced analytic signal technique developed to image geologic boundaries such as contacts and faults. This technique, correlated with the distribution of all seismic events in the last century, has permitted to define an important east–west Kairouan–Sousse–Monastir tectonic corridor (CKSM). This corridor corresponds to major faults oriented east-west, were some folded structures can be developed. To cite this article: H. Gabtni, C. R. Geoscience 337 (2005).  相似文献   

14.
Metasomatic reaction zones which developed at marble-pelitic schist contacts in a granulite facies terrane in West Greenland contain a consistent sequence of five mineralogical zones. Outward from the carbonates the zones are characterized by the assemblages grossular-diopside-meionite (I), meionite-anorthite-diopside (II), anorthite-diopside-edenitic hornblende (III), anorthite-enstatite (IV), plagioclase-almandine-sillimanite (V). Sphene is superceded by ilmenite between zones (II) and (III); quartz is present in all zones except zone I. Scapolite, plagioclase, clinopyroxene and mica exhibit a small degree of compositional variation which correlates with distance from the carbonate. These small compositional variations are superimposed on a strong CaO chemical potential gradient. Compositional features, zone distributions and CaO activity calculations demonstrate that the zones developed in response to CaO diffusion along a chemical potential gradient of 2 kcal/m. The CaO source appears to be carbonate rocks which release calcium as decarbonation reactions proceed. The maximum volume of CO2 released in this process, and that released during discontinuous reactions in the marbles, will contribute a total volume of CO2 approximately equivalent to the volume of carbonate in the rock. Calculations demonstrate that a terrane consisting of as little as 8% carbonate will release sufficient CO2 to result in complete dehydration of an amphibolite terrane, at deep crustal conditions. Dehydration through CO2 release will be accomplished either through rapid burial, which would prevent both equilibration of mineral assemblages and CO2 release at intermediate crustal levels, or through diffusion-driven metasomatic reactions which would lead to CO2 release primarily at the high temperatures of deep crustal environments. The latter process would be the dominant CO2 source at deep crustal levels if carbonate rocks occur predominately as relatively thin layers.  相似文献   

15.
A combined geochemical, geological and microbiological analysis of an actively biodegrading 24.5 m thick oil column in a Canadian heavy oil reservoir has been carried out. The reservoir properties associated with the cored vertical well are characterised by a 15.75 m thick oil column and an 8.75 m zone of steadily decreasing oil saturation below the oil column, referred to as the oil–water transition zone (OWTZ), grading down into a thin water leg. The oil column exhibits systematic gradients in oil physical properties and hydrocarbon composition and shows variations in biodegradation level throughout the reservoir consistent with the notion that the biodegradation of oil is focussed in a bioreactor zone at the base of the oil column. Through the oil column, the dead oil viscosity measured at 20 °C ranged from 50,000 cP (0.05 McP) at the top of the oil column to 1.4 McP at the oil–OWTZ contact, and continued to increase to 10.5 McP within the OWTZ. The saturated and aromatic hydrocarbons are characterised by systematically decreasing bulk fraction and component concentrations down through the oil column. Different compound classes decreased to levels below their detection limit at different depths within the OWTZ, defining a likely bioreactor extent of over 5 m in depth with, for example, n-alkanes being reduced to their detection limit concentration at the bottom of the oil column/top of the OWTZ, while branched isoprenoid alkanes were not completely degraded until well into the OWTZ.Core samples from the oil column and the lower part of the OWTZ were estimated to contain ca. 104–105 bacterial cells/g, based on qPCR of bacterial 16S rRNA genes, while samples from a narrow interval in the OWTZ immediately below the oil column contained on the order of 106–107 cells/g of sediment. Interestingly, these latter numbers are typical of those observed in active deep subsurface biosphere systems with the notion that microbial activity and abundance in the deep subsurface is elevated at geochemical interfaces. The numbers of organisms are not constant throughout the OWTZ. The highest bacterial abundance and geochemical gradients of, for example, methylphenanthrene biodegradation define a zone near the oil–water contact as likely the most active in terms of biodegradation. The largest bacterial abundances in the upper part of the OWTZ are in line with the trend of bacterial abundance with depth that has emerged from extensive analysis of microbial cells in deep subsurface sediments, implying that in terms of deep biosphere cell abundance, oil reservoirs are similar to other deep subsurface microbial environments. This is puzzling, given the atypical abundance of organic carbon in petroleum reservoirs and may imply a common large scale control on microbial abundance and activity in the deep biosphere, including in oilfields.  相似文献   

16.
渤海湾盆地隐性断裂带识别及其地质意义   总被引：1，自引：0，他引：1       下载免费PDF全文
周维维  王伟锋  安邦  胡瑜 《地球科学》2014,39(11):1527-1538
隐性断裂带是区域或局部应力场、基底断裂体系活动、潜山块体扭动影响下在沉积盆地盖层中产生的断裂趋势带, 它是断裂带的一种类型, 与显性断裂伴生于沉积盆地, 但由于其不具有显性断裂的固有特征, 隐蔽性强而常常被忽略.可以通过以下7个方面有效识别隐性断裂带: ①小型显性构造(小断层、小褶皱、断块)呈雁列式、断续状、错位对称式反映的大型隐性断裂带; ②基底断裂体系活动在沉积盆地盖层中产生的隐性断裂带; ③潜山、凹陷分布形成的线状、调节型或者侧列式隐性断裂带; ④砂体分布反映的隐性断裂带; ⑤油藏排列、分布、走向反映的隐性断裂带; ⑥相干体切片显示的隐性断裂带; ⑦断层叠覆端、末端、深大断裂分段活动等局部应力场变化形成的隐性断裂带.应用上述方法开展渤海湾盆地隐性断裂带识别研究, 综合国内外的调研结果, 建立了隐性断裂带的类型划分方案体系并阐述了不同级别构造单元中隐性断裂带的类型特征.研究表明, 隐性断裂带具有多方面的地质意义, 可以作为调节构造带调节盆地不均匀伸展活动, 分隔凹陷、隆起等构造单元; 控制盆地沉积相带发育分布, 影响断陷湖盆砂体的展布范围; 控制圈闭组合排列、改造输导体系, 形成串珠状、带状油气富集区; 深断裂活动触发地震的过程中会在地表形成隐性断裂带, 因此, 隐性断裂带的识别和分析具有现实意义.   相似文献   

17.
赵俊杰  黄云飞  吉霞  楚道亮  童金南 《地球科学》2022,47(11):4210-4221
为了定量化恢复晚二叠世末期生物大灭绝对底栖群落的物种多样性和功能多样性的影响,对浅海碎屑岩台地相区的贵州水城仲河剖面开展宏体化石采集和分析,识别和划分古群落,选择优势度、香农指数、均匀度等代表物种多样性指数,生态功能群数量和功能均匀度代表功能多样性指数. 共采集1 340枚化石标本,经鉴定得到30属33种,其中双壳类可归纳为两个生物带:晚二叠世长兴期的Hunanopecten exilis顶峰带和早三叠世Griesbachian早期的Pteria ussurica variabilis顶峰带. 根据化石属种的地层分布、保存状况,结合聚类分析方法识别出3个古群落:Astartella obliqua-Tethyochonetes quadrata群落、Pteria ussurica variabilis-Claraia wangi群落和Pteria ussurica variabilis-Unionites canalensis群落. 自晚二叠世长兴期末期至早三叠世Griesbachian早期,古群落的优势度上升、香农指数降低、均匀度下降,功能群丰富度降低,功能均匀度上升,这指示晚二叠世末生物大灭绝对浅海碎屑岩相区的底栖群落的组成和功能均有显著的破坏. 此外,结合华南浅海和深海相区的古群落数据,发现底栖群落的物种多样性指数和功能多样性指数在晚二叠世末生物大灭绝中均遭受损失,但是浅海底栖群落受影响较高.   相似文献   

18.
程关文  陈从新  沈强 《岩土力学》2014,35(5):1421-1429
在对矿区地质条件、采矿情况以及监测资料分析的基础上,提出了悬臂梁的力学模型。该悬臂梁是由NWW向节理切割下盘的花岗岩岩体而产生。地下采矿引起的岩层移动分为两个阶段,筒状破坏延伸到地表之前为第1阶段;筒状破坏延伸到地表后,则进入第2阶段。筒状破坏延伸到地表使水平构造应力释放,悬臂梁受力发生变化,而发生弯曲折裂变形和破坏,从而形成了深部岩体破坏的4个区:破裂岩体区、破裂过渡带、变形区和未扰动岩体区。通过对矿区地表测点所测数据进行分析,结合上述岩层移动机制和裂缝产生过程,将变形区域划分为:变形累积区、裂缝产生区、裂缝扩展区和裂缝闭合区。随着采矿的进行,深部岩体4区将逐渐向下延伸,地表4区将逐渐向外扩展。  相似文献   

19.
Carbon capture and sequestration (CCS) is one of the important options available for partially stemming greenhouse gas emissions from large point sources. The possibility of leaking from deep storage needs to be addressed. The Wadi Namaleh area in southern Jordan provides an interesting case study of how excess CO2 can be trapped in the form of carbonates in the near surface, even when the local geology is not obviously conducive for such a process.Carbonate veins are formed in surface alteration zones of rhyolite host rock in this arid region. The alteration zones are limited to areas where surface soil or colluvium are present. Oxygen, deuterium and carbon isotopes of the carbonates and near-surface ground water in the area suggest that the source of carbon is deep seated CO2, and that the carbonate precipitated in local meteoric water under ambient temperature conditions. Analysis of strontium in the carbonate, fresh rhyolite and altered host shows that the source for calcium is aeolian. Trace elements show that metal and REE mobility are constrained to the alteration zone.Thus, interaction of H2O, CO2 and atmospheric wet and dry deposition lead to the formation of the clayey (montmorillonite) alteration zone. This zone acts to trap seeping CO2 and water, and thus produces conditions of progressively more efficient trapping of carbon dioxide by means of a positive feedback mechanism. Replication of these conditions in other areas will minimize CO2 leakage from man-made CCS sites.  相似文献   

20.
In recent years the widespread occurrence of microorganisms was demonstrated in deep marine and terrestrial sediments. With this discovery inevitably the question of the potential carbon and energy sources for this deep subsurface microbial life arises. In the current study a new method for the investigation of low molecular weight (LMW) organic acids linked to the kerogen matrix is presented. These LMW organic acids form a potential feedstock for deep microbial populations. Twelve coal samples of different maturity (vitrinite reflectance (R0) of 0.28–0.80%) from several coal mines on the North and South Island of New Zealand (NZ) were examined to assess the amount of bound LMW organic acids. Formate, acetate and oxalate were detected in significant amounts whereas the amounts of these compounds decrease with increasing maturity of the coal sample. This decrease of LMW organic acids mainly correlates to the phase of diagenetic alteration of the organic matter characterized by the release of oxygen containing compounds. Concomitantly, it coincides with temperature conditions assumed to be still compatible with microbial life in the deep subsurface. First assessments of the feedstock potential and generation rates of LMW organic acids indicate that the NZ coals investigated exhibit the potential to feed deep terrestrial microbial life with appropriate substrates over geological time spans.  相似文献   

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