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A hydroxy-sodalite/cancrinite zeolite composite was synthesized from low-grade calcite-bearing kaolin by hydrothermal alkali-activation method at 160 C for 6 h. The effect of calcite addition on the formation of the hydroxy-sodalite/cancrinite composite was investigated
using artificial mixtures. The chemical composition and crystal morphology of the synthesized zeolite composite were characterized by X-ray powder diffraction, infrared spectroscopy, scanning electron microscopy, and N2 adsorption/desorption analyses. The average specific surface area is around 17–20 m2g-1, whereas the average pore size lies in the mesoporous range (19–21 nm). The synthesized zeolite composite was used as an adsorbent for the removal of heavy metals in aqueous solutions. Batch experiments were employed to study the influence of adsorbent dosage on heavy metal removal eciency. Results demonstrate the effective removal of significant quantities of Cu, Pb, Ni, and Zn from aqueous media. A comparative study of synthesized hydroxy-sodalite and
hydroxy-sodalite/cancrinite composites revealed the latter was 16–24% more effcient at removing heavy metals from water. The order of metal uptake effciency for these zeolites was determined to be Pb > Cu > Zn > Ni. These results indicate that zeolite composites synthesized from natural calcite-bearing kaolin materials could represent effective and low-cost adsorbents for heavy metal removal using water treatment devices in regions of water hortage.
Tourism is booming on global level since many decades and developing countries often capture tourism as a lever to push up their economy. Many regions in Vietnam invest lots of money in this development hoping to change the traditional economic structure. Located in the North Central Vietnam, about 170 km from Ha Noi capital to the south at the coastline, Sam Son is known as an ideal location for holiday makers. Currently the number of tourist has been counted to millions. Realizing its potential, the local authorities decided to enlarge and improve tourism to become the biggest tourism center in the North Central part of Vietnam. As many mass tourism destinations, Sam Son is facing several hidden drawbacks, which are generated by a (too) fast growth. Thats why unexpected problems may occur very soon. One path to mitigate weaknesses and to strengthen the positive impacts of tourism is to develop tourism in a more sustainable manner. As the very first step Sam Son needs to delineate a proper strategy and to establish a powerful "Destination Management System". Although several studies have been conducted already, the destination lacks reliable empirical data. This research intends to fill the gap by supplying concrete information with specific focus on “making tourism more sustainable”. In the study methodological triangulation has been applied to collect data and information. Besides literature review and secondary data analysis, two surveys - statistically well secured - have been conducted: A household survey with more than one thousand questionnaires to record the situation and opinion of local people and a visitor survey with 1139 face-to-face interviews to collect structural data about current guests in Sam Son as well as to explore their behaviour. Moreover expert and stakeholder interviews were included to supplement the information basis. As the research acquired the information directly from local people and from tourists by face-to-face interviews several weaknesses could be unveiled which official statistical data cannot show. There are three facets out of balance in terms of economic benefit: Compared with the political awareness and the financial support the tourism sector does not ensure the livelihood of an adequate number of people; the economic benefits from tourism are very unequally distributed and also the spatial dimension indicates a strong imbalance - only people living directly in the core area of tourism participate in tourism sector, the positive impact of tourism does not reach till the outskirts. In addition social and environmental problems are recognized by a majority of local people as consequences of tourism in the region. Regarding the touristic demand side a very low level of satisfaction has been detected: A small variety and low quality of touristic offers are the main reasons of dissatisfaction. The most exiting finding is that tourists treasure environment in the destination, whereas this aspect is underestimated in the locals view. In addition, tourists are really willing to pay for an improvement of environmental and touristic quality! Even if the amount of voluntary payments is very low, the total sum can enable the local government to develop the destination in a very proper way. Although this is a case study the results deliver valuable information and furthermore a concrete delineated roadmap for all destinations, which are in the same situation as Sam Son today. It is an example how to analyze and evaluate the present condition and how to continue in a proper way towards a more sustainable tourism development.
Growth corridors have been an instrument of
economic development for decades but have gained new
attention in regional economic development policies in recent years, e.g., in Sub-Saharan Africa or Southeast Asia.
They are seen by policy makers and private businesses as
catalysts of regional economic integration, pushing traditional businesses into increasingly complex international
value chains. However, the outcomes of such development
initiatives are still barely understood. Critics argue that development policies are based on simplified models that are
unable to sufficiently address the complexity of regional
development. Policies on value-chain development, for
example, can lead to conflicts, external dependencies,
land rush, and a polarization of wealth. Growth corridors
often go hand-in-hand with socio-economic transformations and land-use conflicts. This paper first discusses the
theoretically possible desired and undesired regional socio-economic effects of modern corridors. Second, we illustrate the potential and challenges to realize integrative
(or inclusive) development by contrasting three growth
corridors: the SAGCOT growth corridor in Tanzania, the
Walvis Bay-Ndola-Lubumbashi Development Corridor
(WBNLDC) in Namibia, Zambia and Zimbabwe, and the
growth corridors in the Greater Mekong Subregion (GMS)
Multiproxy investigations of lacustrine sediments from Laguna Azul (52 °S) document multi-millennial Holocene influences of Southern Hemispheric Westerlies (SHW) on the hydroclimatic variability of south-eastern Patagonia. During the last 4000 years, this hydroclimatic variability is overprinted by centennial warm/dry periods. A cool/wet period from 11,600 to 10,100 cal. BP is succeeded by an early Holocene dry period (10,100–8300 cal. BP) with a shallow lake, strong anoxia, methanogenesis and high salinity. Between 8300 and 4000 cal. BP the influence of SHW weakened, resulting in a freshwater lake considered to be related to less arid conditions. Since 4000 cal. BP, regional temperature decreased accompanied by re-intensification of SHW reaching full strength since 3000 cal. BP. Centred around 2200, 1000 cal. BP and in the 20th century, Laguna Azul experienced century-long warm/dry spells. Between these dry periods, two pronounced moist periods are suggested to be contemporaneous to the ‘Dark Age Cold Period’ and the ‘Little Ice Age’. Different from millennial SHW variations, centennial fluctuations appear to be synchronous for South America and the Northern Hemisphere. Changes in solar activity, large volcanic eruptions and/or modulations of ocean circulation are potential triggers for this synchronicity.
Tourism is a multifaceted economy and based on existing nature, as well as on culture in a geographical space to become a successful destination for tourism. The topic of this survey is how tourism in the transitioning country of Vietnam influences culture and nature or vice versa. A special focus will be on the transitioning aspect. This study gives insights about how in the transitioning country of Vietnam, tourism can act as an additional driver of change in terms of nature and culture or if tourism is only adapting to these changes. Therefore in the beginning the subject of ‘social-ecological transformation’ is described and furthermore the situation in Vietnam will be introduced. The key aspects here will be within the range of geography and sociology. It becomes evident, that scientific views on this topic are rather diverse, but nevertheless many theoretical aspects can be observed also in the investigation area Vietnam. Within the country several aspects of economic transition already became reality, while others, like social, ecological or political reforms, are still at the beginning. The empirical part of this study deals with existing thoughts, according to the topic of transition, in relation to tourism development and respectively to environmental understanding, by analyzing and comparing positions of 21 international and Vietnamese experts, 569 international tourists and 710 Vietnamese students. By doing so, similarities within opinions about tourism development and the environmental situation in the country became observable. While tourism is rated as a mostly positive development, the current environmental situation has mostly been criticized by all survey participants. Apart from that, connections between both aspects (tourism economy and nature) are often of no importance or the relationship is identified to be just a rudimentary one. In case of these opinions, involvement within one social group and personal experience is of larger importance than cultural conditioning (European or Asian), e.g. own travels, own jobs and own education. This fact becomes visible by very similar ratings of environmental problems on the one hand and the beauty of natural landscapes on the other hand, done by both survey groups; namely international tourists and Vietnamese students.
Coastal and marginal seas – like the Baltic Sea – serve as natural reaction sites for the turnover and accumulation of land-derived inputs. The main location for the modification and deposition of the introduced material is, in most cases, not the water mass, but the sediment. Its key function as central reactor in the interaction between land and sea has so far been insufficiently studied and assessed. This study was part of the interdisciplinary SECOS project that aimed to identify and evaluate the service functions of sediments in German coastal seas in the context of human use with a focus on the Baltic Sea. One of its goals was to assess sediment functions related to the intermediate storage or final sink of imported material like nutrients and contaminants, and quantify their inventory as well as their mass accumulation rates on multi-decadal to multi-centennial time scales. For that, a detailed examination of the natural and anthropogenic processes that interfere with sediment accumulation in the south-western Baltic Sea basins is essential.
Open and analysis-ready data, as well as methodological and technical advancements have resulted in an unprecedented capability for observing the Earth’s land surfaces. Over 10 years ago, Landsat time series analyses were inevitably limited to a few expensive images from carefully selected acquisition dates. Yet, such a static selection may have introduced uncertainties when spatial or inter-annual variability in seasonal vegetation growth were large. As seminal pre-open-data-era papers are still heavily cited, variations of their workflows are still widely used, too. Thus, here we quantitatively assessed the level of agreement between an approach using carefully selected images and a state-of-the-art analysis that uses all available images. We reproduced a representative case study from the year 2003 that for the first time used annual Landsat time series to assess long-term vegetation dynamics in a semi-arid Mediterranean ecosystem in Crete, Greece. We replicated this assessment using all available data paired with a time series method based on land surface phenology metrics. Results differed fundamentally because the volatile timing of statically selected images relative to the phenological cycle introduced systematic uncertainty. We further applied lessons learned to arrive at a more nuanced and information-enriched vegetation dynamics description by decomposing vegetation cover into woody and herbaceous components, followed by a syndrome-based classification of change and trend parameters. This allowed for a more reliable interpretation of vegetation changes and even permitted us to disentangle certain land-use change processes with opposite trajectories in the vegetation components that were not observable when solely analyzing total vegetation cover. The long-term budget of net cover change revealed that vegetation cover of both components has increased at large and that this process was mainly driven by gradual processes. We conclude that study designs based on static image selection strategies should be critically evaluated in the light of current data availability, analytical capabilities, and with regards to the ecosystem under investigation. We recommend using all available data and taking advantage of phenology-based approaches that remove the selection bias and hence reduce uncertainties in results.
Recent geochemical and mineralogical alteration processes in tropical coastal sediments of Vietnam
(2006)
The dissertation contains two main parts: (i) Syn-sedimentary hydrodynamic processes & relationship with elemental distribution, clay matter, (ii) Short-term mineral alteration during early diagenes. Samples were taken from the uppermost one metre (<50 year old in RRD, < 300 y old in south central VN). In part one, three principal hydrodynamic factors can be revealed based on End-Member Modelling Algorithm (EMMA), for the polymodal grain-size distribution patterns in coastline of VN (i) Accumulation factor: accumulation of terrigenous sediments linked with a grain size separation (distance dependence), (ii) Erosion factor: synsedimentary erosion by wave activities, (iii) Aeolian factor: deposition from neighbour sand bar by wind (typically only for low sedimentation rate, like in South Central Coast but not to detect in RRD). Distributions of clay matter and chemical elements in the coastal sediments in Vietnam are strongly influenced by hydrodynamic forces (distance from the coastline). In part two, particle-wise analysis by TEM allowed to determined four main mixed layer series: di-Vermiculite/Smectite-ml, Kaolinite/ Expandable-ml, Illite/Smectite-ml, Chlorite/Saponite-ml. Three principal mineral alteration processes can be detected in coastal sediments during early diagenesis: Dissolution, Smectitization, Kaolinitization, based on XRD (CSD, peak area) & TEM-EDX (particle morphology, chemical formula, polytype, particle frequency). Dissolution process of clay matter is typically in the coastal alkaline condition. It is a function of diagenetic time. Dissolution begins with a higher degree of dislocation and is followed by step-wise delamination & dissolution of the first stacks Smectitization (mirrored in diVS-ml series) alters mica-like structures (illite, dioctahedral vermiculite) to smectitic structures (Beidellite, Montmorillonite). Smectitization process occurs in group-wise layer by layer transforming mechanism (mica-like layer to smectitic layer). Each step is indicated by a gauss-like distribution of the octahedral layer charge with K as trigger. Kaolinitization of KE series alters smectitic structure (beidellite, smectitic KE-ml) to kaolinitic structure (kaolinitic KE-ml, kaolinite) "interlayer by interlayer" transformation of KE-ml series is comparable to kaolinitization mechanism discussed by Dudek et al. (2006).OH- groups in ambient could be the trigger. Mangroves biota influences the sediments in two main pathways: Nutrients supply & trapping function (clay matter, heavy metals)Interaction of active root-layer: intensification of dissolution, smectitization & kaolinitization: uptake of K, Na by mangrove root is possible trigger Human activities like shrimp cultivation have stopped the influences of the former active roots.Besides, erosion process related to water discharge gives rise to dispersion of clay species & heavy metals => more toxic for ecosystem.
Underground hard coal mining operations irreversibly disrupt the pre-existing mechanical equilibrium of the geological media. The employment of high-recovery methods modifies the stress field of the sedimentary sequence, generating movement and faulting of the rock layers above and below mined seams. These new fracture zones do affect the original conditions of the hydrogeological system by modifying flow pathways and increasing the permeability of the rock sequence. Moreover, the surface area of rock exposed to air and water is increased, conditioning the water-rock interaction. Despite this rather clear conceptualization, flow and reactive transport processes in fractured overburdens are rarely modeled simultaneously. Discrete setups that consider fractures and porous matrix require extensive characterization of both media, which is impractical for regional case studies. As a result, most post-mining models explicitly ignore fracture structures by employing the equivalent porous approach or even both media with lumped parameter models. However, omitting either medium represents a delicate simplification, considering that mining-related fractures control the rate and direction of water flow within moderately permeable but relatively highly porous rock sequences.
In this dissertation, the specific contribution of fractured and matrix continua to the transient discharge and water quality of a post-mining coal zone is quantified and evaluated. For this purpose, dual and multiple interacting continua models are employed to simulate fluid flow and reactive mass transport in fractured and variable water-saturated rock sequences. The effectiveness of the models is evaluated by simulating the origin, generation and transport of acid mine drainage (i.e., water with elevated concentrations of hydrogen, iron, sulfate and chloride) within the shallow overburden of the Ibbenbüren Westfield. Compared to other coal districts in Germany, this area is strongly delimited by the local geology and topography, resulting in a well-defined hydrogeological system to test the models. Petrographic and chemical analyses performed on core samples from the area show the strong influence of mining-derived fractures on the water-rock interaction within the Carboniferous sequence. The presence of oxidized pyrite along with amorphous iron hydroxide phases in weathering fronts on both sides of the fractures demonstrates the exchange of solutes and gases between the fractured and the porous matrix media.
Based on the previous evidence, the TOUGHREACT software is employed to characterize flow and reactive transport processes in the Westfield. However, each of the two processes is simulated at separate stages to have more control in the adjustment of sensitive parameters for which little information is available. For the flow component, a dual continuum model, with Richard’s equations is used to characterize the unsaturated water flow in both fractured and matrix media. Under this approach, the model adequately reproduces the bimodal flow behavior of the discharges measured in the mine drainage for the years 2008 and 2017. Simulation results show how the fractured continuum generates intense discharge events during the winter months while the rock matrix controls smooth discharge limbs in summer, when water is slowly released back to the fractures. With the flow component calibrated, the second part of the study incorporates the geochemical processes into the model based on actual data from the rock samples. Their simulation requires extending the two-continuum setup to a multiple continua model with five nested block strings: one for the fractures and four for the rock matrix. This further subdivision prevents under-representations of kinetic reactions with short equilibrium length scales and numerical instabilities due to lack of chemical and flow gradients. As a result, the new multiple continua model provides good agreement with respect to long- and short-term concentrations and discharge trends measured in the mine drainage. The flow of oxygen and meteoric water through the fractured continuum leads to a high and steady release of hydrogen, iron and sulfate ions derived from pyrite oxidation in the matrix continua closest to the fractures. Moreover, high chloride concentrations result from the mixing and gradual release of relatively immobile solutes in the matrix as they interact with percolating water in the fracture. Both findings are equally congruent with the reactive pyrite oxidation and iron hydroxide precipitation fronts identified in the fractured core samples.
In the end, the multiple continua models, the simulation procedure and the results of the benchmark and sensitivity analysis scenarios developed for the Westfield pave the way for the application of the approach in other mining zones. The first candidate emerges in the Ibbenbüren Eastfield, where a coupled elemental-isotopic approach included in this thesis has confirmed that water-conducting fracture zones are primary elements for solute generation and transport in the first 300 meters of the overburden. In the latter case, calibration and verification of the models can be complemented with measurements of δ34S in sulfates and δ18O, δ2H, and Tritium in water.
Madagascar houses one of the Earth’s biologically richest, but also one of most endangered, terrestrial ecoregions. Although it is obvious that humans substantially altered the natural ecosystems during the past decades, the timing of arrival of early inhabitants on Madagascar as well as their environmental impact is still intensively debated. This research aims to study the beginning of early human impact on Malagasy natural ecosystems, specifically on Nosy Be island (NW Madagascar) by targeting the sedimentary archive of Lake Amparihibe, an ancient volcanic crater. Based on pollen, fungal spore, other non-pollen palynomorph, charcoal particle and diatom analyses combined with high-resolution sediment-physical and (in)organic geochemical data, paleoenvironmental dynamics during the past three millennia were reconstructed. Results indicate a major environmental change at ca. 1300 cal BP characterized by an abrupt development of grass (C4) dominated and fire disturbed landscape showing the alteration of natural rain forest. Further, increased soil erodibility is suggested by distinct increase in sediment accumulation rates, a strong pulse of nutrient input, higher water turbidity and contemporaneous increase in spores of mycorrhizal fungi. These parameters are interpreted to show a strong early anthropogenic transformation of the landscape from rain forest to open grassland. After ca. 1000 cal BP, fires remain frequent and vegetation is dominated by forest/grassland mosaic. While natural vegetation should be dominated by rain forest on Nosy Be, these last results indicate that human continuously impacted the landscapes surrounding the lake. At a local scale, our data support the “subsistence shift hypothesis” which proposed that population expansion with development of herding/farming altered the natural ecosystems. However, a precise regional synthesis is challenging, since high-resolution multi-proxy records from continuous sedimentary archives as well as records located further north and in the hinterland are still scarce in Madagascar. The lack of such regional synthesis also prevents precise comparison between different regions in Madagascar to detect potential (dis)similarities in climate dynamics, ecosystem responses and anthropogenic influences at the island’s scale during the (late) Holocene.
The present work is a paleolimnological orientated approach to refine and improve the indicator ability of freshwater ostracods from Holocene and Late glacial deposits in northeast Germany. The thesis follows two different approaches, one utilizes quantitative paleoenvironmental analysis, while the other evaluates ecological investigations of living specimens to extend the potential indicator group. For the first time quantitative ostracod analysis are carried out for a lacustrine basin (lake Krakower See) and a near-shore locality (Pudagla lowland) in the study area. The ecological investigation of living ostracods comprises 96 localities. The evaluation focused on environmental variables, which explain significantly the species composition. A canonical correspondence analysis identified at least four environmental parameters - water temperature, conductivity, pH-value, and mean water depth – which have an effect on ostracod assemblages. An extended analysis, which included only a subset of lake sites, revealed also that the former three environmental parameters affect the ostracod lake fauna, whereas the water temperature is the dominant factor. A temperature-transfer function could be regressed and calculated from the given trainingset by a weighted average model. These estimates can now be use in future paleolimnological investigations in northeast Germany to quantify the paleotemperature.
Thermally treated kaolinite is used to develop a range of alumino‐silicate‐based precursor materials but its behavior during plasma spraying has not been well‐researched. In this study, two types of kaolinite samples were investigated in the form of low defect (KGa‐1b) and high defect (KGa‐2) varieties. The extreme temperatures of the plasma stream (up to 20 000 K) induced flash melting to produce a highly porous alumino‐silicate glass without any crystallization of new Al−Si oxide minerals. The glass is comprised largely of intact or deformed spheres (average diameters 1.14–1.44 μm), which indicates rapid quenching and solidification before impact. The subspherical structures contain up to 40 % closed pore space caused by the rapid escape of water during melting. The low‐density, porous alumino‐silicate glass coatings with predicted specific surface areas (>0.95 m2/g) and hardnesses >1.8 GPa represent a potentially reactive but physically stable substrate ideal for further chemical functionalization.
Climate change has strongly affected mountain forests through an increasing intensity and frequency of disturbances and forest dieback in recent decades. However, given the strong relevance of forest dieback and potential impacts on forest stakeholders and local inhabitants, it is surprising that this research field is seldom investigated to date. Therefore, this study deals with the perception of climate change-related consequences as well as possible silvicultural adaptation strategies for the Bavarian Forest. Since it can be assumed that various forest ecosystem services will be increasingly in demand in the future, participation by all stakeholders is essential. Therefore, a sequential, mixed-method approach (qualitative and quantitative survey) allows developing concrete guidelines and strategies for adaptive management, in which the diverse social demands on forests can be adequately taken into account.
Perception of climate change-related forest dieback in mountain forests among the local population
(2023)
Mountain forests provide multiple benefits but are threatened by climate change-induced forest dieback. Although many studies summarize perceptions of forest ecosystem services, relatively few deal with mountain forests. The local population’s perception of forest dieback in mountain forests in relation to climate change has rarely been investigated so far. Their perspective is relevant as local people are often deeply attached to “their” forests, they actively use forest ecosystems and—as voters and taxpayers—they need to support the state’s adaptation and funding measures. Therefore, this study investigates the climate change and forest dieback perception of local inhabitants in two mountain areas of Southern Germany (the German Alps and the Bavarian Forest) with a quantitative survey based on representative online samples (n = 709). Relying conceptually on van der Linden’s (J Environ Psychol 41:112–124, 2015. https://doi.org/10.1016/j.jenvp.2014.11.012) climate change risk perception model, the results show that experiential processing, cognitive and socio-cultural factors are related to locals’ forest dieback and climate change perception, while socio-demographics show no or few connections. Nearly two-thirds (64.7%) of the respondents perceive moderate to strong forest dieback, while more than half (55.0%) of the respondents already observe consequences of climate change. The perceptions of climate change and forest dieback are positively correlated with medium to high strength. This shows that forest dieback could be interpreted as an indicator of climate change, which is difficult to observe due to its long-term nature. We identify three groups of respondents regarding preferred forest adaptation strategies to climate change. In general, respondents support nature-based forest adaptation strategies over intense measures.
The New Zealand coal covering the complete maturity range from peat to high volatile bituminous, thus from early diagenetic to catagenesis coalification levels, has been studied in order to bring out new insights into molecular alterations, macromolecular structural evolution, elemental-compositional changes as function of maturation and to propose which processes cause these changes. As particular note from the previous observations that many immature coals from around the world often have rather high extraction yields. It is uncertain whether or not bitumen affecting on petroleum potential and structural evolution of coals. My purposes were therefore to find out the possible interaction between kerogen and bitumen during pyrolysis, and to elucidate the role of bitumen in defining petroleum potential and structural evolution of coals. Furthermore, it is assumed that low rank coals appear to be well suited for feeding the deep subsurface microbes. The products are released as either CO2 or CO that could be substrates for microbial activity. Thus, in this dissertation, I have calculated the loss of CO2 during diagenesis to give the quantitative feeding potential link to deep biosphere, using a mass balance model. To achieve these purposes, at the primary step, the facies variability as well as the molecular compositional changes within the coal band sequence in regard to distinguish the influences of organofacies and maturity need to be clear. Hence, the first aim was to gather information about depositional environment and insights into the plant communities that have contributed to New Zealand coals. Numerous organic-geochemical techniques were used to analyse the free lipids and macromolecular organic matter. Total organic carbon determination (TOC), bulk δ13Corg isotope analysis, the Rock-Eval pyrolysis, pyrolysis- gas chromatography and infrared spectrometry were performed on the original samples and the residue after solvent extraction. The crude lipid extract was separated into fractions that were then analysed by gas chromatography and gas chromatography-mass spectrometry. The obtained data shows that organic matter of New Zealand coals contains mainly terrestrial higher plant material, with a more or less constant background supply of bacterial biomass, deposited in oxidising environment. Angiosperms contributed as the main proportion of the organic matters. Gymnosperms, particularly the Podocarpaceae, Cupressaceae, Taxodiaceae, Pinanceae and Araucariaceae conifer species, still dominated during the Cretaceous. New Zealand coal is classified as mixed gas- and oil-prone. Hydrogen index values increase from 120 to 280 (mg/g TOC) with increasing maturity, which has been explained by the loss of oxygen during diagenesis. A Transformation Ratio of CO2 (TRCO2) has been formulated here in order to quantify the loss of CO2 for any given coal type. It obviously shows CO2 generation is one of the major features of diagenesis that might feed the deep biosphere. In case of study, about 10 to 105 mg CO2 per gram of total organic carbon have been released during maturation from peat to high volatile bituminous. This is equivalent to 0.23 to 2.4 millimoles CO2 per g TOC. For methanogenesis via CO2 reduction, between 0.92 and 9.6 millimoles hydrogen would be required for complete CO2 reduction during diagenesis. Future work must determine if this is feasible or not. The important role of bitumen in defining the petroleum generation potential was elucidated. The presence of hydrogen transfer agents in bitumen helps to stabilize free radicals hence prevents recombination/ repolymerization processes thus preserving the petroleum generating potential in original coals. Specially, second-order reactions between kerogen and bitumen occurred during pyrolysis that reduce the primary gas yield, but increase the potential secondary gas as well as oil yields. Therefore, it is proposed that pre-extraction of source rocks before pyrolysis, especially coals where extraction yields are particularly high, is not recommended. The comparative investigation with previously studied higher rank Carboniferous German coals showed an excellent fit for both pyrolysis and infrared spectrometry data, suggesting that the New Zealand coals can be considered as natural precursors of the German coals. The structural evolution of coals during maturation is firstly characterized by the enrichment of the aliphatic structures in low rank, peat to high volatile bituminous, then decreases with further maturation. This enrichment of aliphatic carbon content in low rank is accompanied by an increase in the average aliphatic chain length. A slightly enrichment of CH3 group is observed in maturity range 0.9- 2.1% vitrinite reflectance. Secondly, during coalification the content of protonated aromatic carbons increases until R0 ~ 1.6%, then decreases with further maturation.