China Block Research Articles

A new reliability evaluation method of injection/falloff testing interpretation in coal reservoir based on FAHP and cloud model

ABSTRACT Injection/falloff testing (IFT) is an important method for obtaining coalbed methane (CBM) reservoir permeability. It is necessary to evaluate IFT interpretation reliability for more accurate permeability values. To evaluate IFT interpretation reliability quantitatively, and efficiently, a new method is presented. Three first-level indexes, and 12 second-level indicators are chosen to establish an evaluation index system. The weightings of evaluation indexes are determined by the Fuzzy Analytic Hierarchy Process (FAHP). The cloud model is employed to establish the index’s judgment set, comprehensive standard cloud, and comprehensive evaluation matrix. Finally, four CBM reservoirs at Shilou North Block in China are evaluated. The evaluation results show that IFT interpretation reliability grades of coal reservoir No.8 and No.9 + 10 in well V01 C are good, and excellent respectively, while they are both poor in well V02 C. Although further improvement is needed on indicators selection, weighting determination and similarity acquisition, the method we proposed has the competitive ability for reliability evaluation on IFT interpretation. It can provide effective guidance for quality control of well testing, production and exploration of CBM, oil and gas.

Exploration of a magnetite deposit buried under thick and conductive sediments with multiple-source CSEM

The North China Craton (NCC) hosts abundant mineral resources, making it economically an important Precambrian block in China. The thick conductive loess strata in NCC presents a great challenge for successful application of controlled-source electromagnetic method (CSEM) by masking the deeper targets due to thick loess strata of conductive nature. In this work, we proposed a multiple-source CSEM method that addresses these weaknesses by using multiple-sources with inline and broadside configurations. The short offset was adopted to increase the S/N. Joint inversion of inline and broadside sources datasets enhance the detection accuracy. Based on an indirect detection strategy and the known ore-forming information, a deeply seated ore body at 1157 m was delineated.

Provenance and tectonic significance of the Zhongwunongshan Group from the Zhongwunongshan Structural Belt in China: insights from zircon geochronology

Abstract The Zhongwunongshan Structural Belt (ZWSB) locates between the Olongbruk Microblock of North Qaidam and the South Qilian Block in China, and it has important implication for understanding the tectonic significance of North Qaidam. Nowadays, there are few discussion on the Caledonian tectonothermal events of the Zhongwunongshan Structural Belt, and there exist different opinions on provenance and tectonic environment of the Zhongwunongshan Group in the ZWSB and its adjacent North Qaidam. In this study, a comprehensive analysis of the detrital zircon geochronological research was carried out on the Zhongwunongshan Group. The detrital zircon U-Pb dating results showed two major populations. The first was Neoproterozoic (966-725 Ma) with a ∈Hf(t) = −15.9 to 9.5, and the other was late Early Paleozoic (460-434Ma) with a ∈Hf(t) = −9.6 to −3.1. In combination with previous research, the dominated provenances were found to be the Neoproterozoic granitic gneiss of the Yuqia-Shaliuhe HP-UHP metamorphic belt and the late Early Paleozoic granite of the Tanjianshan ophiolite-volcanic arc belt in North Qaidam. The Zhongwunongshan Group was deposited in the back-arc sedimentary basin related to the Caledonian collisional orogeny during Middle Silurian-Early Devonian (434-407.9 Ma).

The study on exploitation potential of original low-oil-saturation reservoirs

It is preliminary estimated that the proved geological reserves of original low-oil-saturation reservoirs (OLOSRs) of 54 blocks in China are more than 820 million tons. As same as the high water-cut stage of a reservoir after water flooding, the initial water cut of OLOSRS is higher than 80%. The industrial application of EOR technology could efficiently enhance oil recovery rate from 8.4% to 20.1% of reservoirs after water flooding. The suitable measurements of EOR to the OLOSRs probably have a profound impact on achieving higher oilfield reserves and production. In this paper, the main characteristics and reserves potential of OLOSRs have been studied by investigations and laboratory experiments. The relationship between initial oil saturation and displacement efficiency is also analyzed. The feasibility of EOR technologies for different OLOSRs is discussed. The results show that the OLOSRs could be divided into two categories (primary and secondary) by origin of low oil saturation. The two categories contain abundant reserves in China’s major oilfields, but their occurrence states of crude oil are quite different. If the average oil saturation of the OLOSR is defined at 40%, there are 13.1%–54.2% crude oil that could be recovered by using the existing EOR technology, especially in the primary OLOSRs with low permeability and the secondary OLOSRs with high permeability.

The Lower Yangtze area: A next shale gas block for China? Preliminary potential assessment from some geology and organic geochemistry information

In the last several years, the massive success of the Fuling shale gas field in south‐western China has shown great potential in finding giant shale gas fields in the Upper Yangtze area, and it has also attracted the increasing attention from geologists to find more shale gas reservoirs around the world. However, there is still a great dispute as to whether the neighbouring Lower Yangtze area is a next potential shale gas block in China. In this study, we evaluate preliminarily the shale gas potentials of five important sets of marine shales based on systematic analyses for the sedimentary environment, thickness, total organic carbon (TOC), thermal maturity, and other organic geochemistry parameters of both geological records from outcrops and wells in the Lower Yangtze area. The first two sets of marine shales occur in the Lower Cambrian and the Ordovician, and they all are of over–high organic maturity due to strong effects from regional tectonic movements and thus have poor potential. Although the Lower Silurian shales are widely distributed in the Lower Yangtze region, a terrigenous delta, a low amount of organic matter (TOC < 1.2%), and late tectonic activity together created unfavourable conditions for the generation and accumulation of the Lower Silurian shale gas. The Permian black shales occur in the Middle and Upper Permian. Several proxies, such as the appropriate maturity (vitrinite reflectance Ro of approximately 2.0%), abundant organic matter (TOC of approximately 4 wt%), good total hydrocarbon potential (S1 + S2), and high level of hydrocarbon conversion have resulted in good conditions for shale gas generation. However, the relative thinness (only 30 m), severe tectonic modification, and regional cap rock are not favourable for shale gas preservation. The Lower Yangtze area therefore is not an excellent block for shale gas exploration compared to its neighbouring Upper Yangtze area. However, in some areas with less structural deformation, the possibility of finding shale gas reservoirs cannot be ruled out, especially for the Permian shales, which had a greater opportunity to generate and accumulate shale gas than the other marine shales. In addition, for new shale gas exploration breakthroughs in the future, structural studies are essential in offering better understanding of the preservation conditions in the Lower Yangtze area.

Characterization of unique natural gas flow in fracture-vuggy carbonate reservoir: A case study on Dengying carbonate reservoir in China

We investigate the natural gas flow behavior in the Dengying carbonate reservoir of Gaoshiti-Moxi Block in China. Outcrops observation, petrophysical properties measurement, and formation micro-resistivity image logging (FMI) all show that the vugs distribute in a stratified manner with characteristic length ranging from 0.2 to 4 cm. The horizontal permeability is significantly larger than the vertical permeability due to the stratified distribution of vugs and fractures. We build a representative conceptual reservoir model to describe this fracture-vuggy type carbonate reservoir. Both Darcy equation and Stokes-Brinkman equation are applied to simulate natural gas flow in this type of reservoir. Simulation results show that natural gas mainly flows along the free channel formed by low-dip fractures and flat ellipsoid vugs. Compared with the Darcy method, the Stokes-Brinkman method provides a more accurate prediction of gas flow behavior in the fracture-vug carbonate reservoir.

Верхнепермские рифы Южного Китая – последние рифы палеозоя

Subject of research . The upper Permian reefs of the Yangtze block of southern China are considered. Among them there are two species which differ in location in the basin and the nature of the internal structure. Methods and results. On the basis of geological and lithological methods of research it is shown that the main rift builders were a variety of sponges, whith a lesser extent bryozoans and wide development of non-carcass organisms. Along with relatively simple buildings (biostromes), the reefs in the strict sense of this term are also established. The beginning of reef formation is fixed by the accumulation of detritus of echinoderms with micro-grain cemented material. Reef formation ended until the end of Permian, before bulk biota extinction on the border of Permian and Triassic although potentially reef-building organisms still existed. Conclusion. The events that led to the great mass extinction were preceded by certain changes, which primarily destroyed the system of reef biocenosis, which led to the cessation of the formation of reefs with the continued existence of individual groups of organisms.

Empirical Study on the Boundary Space Form of Residential Blocks Oriented Toward Low-Carbon Travel

As one of the three major carbon sources in cities, urban mobility has posed severe challenges to the social environment. Promoting low-carbon travel for residents is an important measure for building a low-carbon city and mitigating climate change. However, to date, previous research on residents’ low-carbon travel has been more oriented toward urban planning, while quantitative research on the influence of the boundary space form of residential blocks on residents’ travel modes, which takes residential blocks as the research objects at the meso- and micro-level, is relatively rare. Residential blocks in China, which were built in the late 1990s, mostly have a large and gated spatial form. Individual residential blocks are often gated by fences, commercial buildings, and other forms of interfaces, forming an independent residential group. Long and closed boundary forms will have a certain impact on residents’ choice of low-carbon travel modes, such as walking, riding bikes, and so on. Taking Nanjing as an example, this paper explores the essential factors that impact residents’ travel behaviors from the perspective of the boundary space of residential blocks, combining the socio-economic attributes of residents, land use, and transit facilities, and there are four dimensions to the study, including the boundary block scale, types of boundary interface, density and distribution of accesses, and the slow-travel environment, proposing recommended values of the relevant indicators in a targeted manner. This paper selects 21 residential blocks in the main districts in Nanjing, conducting a related survey on the residents’ socio-economic attributes and travel characteristics, boundary space form, land use, and transit facilities. The data obtained from the survey are analyzed by correlation analysis and multiple logistic regression analysis, so as to screen out the key variables of the boundary space forms of the blocks that affect residents’ low-carbon travel. Meanwhile, on the basis of the appropriate share of low-carbon travel, the unary linear regression model is used to propose ideal recommended values of the key variables of the boundary space forms of the residential blocks. For instance, the block boundary density is recommended to be above 34.38 km/km², the permeability coefficient of the block interface should be above 0.43, the commercial interface ratio should be above 18.16 km/km², the density of accesses of the blocks is recommended to be above 246.71 km/km², and the cross-sectional ratio of the slow-travel roads should be above 0.5.

A review of niobium and tantalum metallogenic regularity in China

Niobium and tantalum are critical mineral resources in the world. Although they have coherent geochemical behavior, they can be separated to some degree during ore-forming processes. The alkaline property of the host rock is one main factor to control the separation of Nb-Ta. As a result, niobium and tantalum resources can be divided into tantalum-dominated deposits in a peraluminous granitic magma system, including granite-type and granitic pegmatite-type deposits, and into niobium-dominated deposits in alkaline and carbonate magmatic systems, including carbonate-type, carbonate-weathering crust-type and alkaline rock-type deposits. In China, tantalum and niobium resources are mainly present in granite (e.g., the Yichun deposit in Jiangxi), granitic pegmatite (e.g., the Renli deposit in Hunan), alkaline rock (e.g., the Ba’erzhe deposit in Inner Mongolia), and carbonate (e.g., Miaoya in Hubei); however, currently, there are no occurrences of carbonate-weathering crust niobium resources. In China, tantalum deposits of the peraluminous granitic magma system are primarily located in the tantalum-metallogenic belts of Altay, Songpan-Ganze, Jiangnan paleocontinent, Nanling, southern Tibet-western Yunnan with mineralizations in the Caledonian, Indosinian and Yanshanian, and few cases in the Himalayas. The niobium deposits of alkaline and carbonate magma systems are primarily located in the niobium-metalogenic belts of Talimu-Northern China, Qinling, and western Yangtze block with mineralizations from Hercynian to Indianian with a few cases from the Proterozoic. Deposits of the peraluminous granitic magma system are primarily located in flysch sedimentary formations with a huge thickness that can be melted into rare metal-rich granitic magma during the orogenic process in a compressional tectonic environment. However, deposits of the alkaline and carbonate magma systems are primarily distributed along deep fractures or rift regions, bearing features of ore-forming material sourced from the mantle. These features show niobium and tantalum mineralization separation and alternation with spatial and temporal distributions, which can be controlled via compression-extension histories of different blocks in China. Although the reserves of niobium and tantalum in China are huge, most niobium and tantalum deposits in China usually bear low grades of Ta5O2 and Nb2O5 and are difficult to utilize. Therefore, in the exploration of niobium and tantalum resources in China, we should pay attention to high-grade granitic pegmatite-type tantalum deposits in the Songpan-Ganze, Jiangnan, Qinling, southern Tibet, and western Yunnan regions. Additionally, we can explore carbonate-type niobium deposits in Talimu-Northern China. The associated niobium and tantalum resources in tungsten and tin deposits may have great potential for exploration in the Nanling, western Yunnan, and Qinling regions.

Newly discovered early Neoproterozoic (ca. 900 Ma) andesitic rocks in the northwestern Tarim Craton: Implications for the reconstruction of the Rodinia supercontinent

The Tarim Craton, one of the largest continental blocks in China, has been considered as a constituent block of the Rodinia supercontinent. However, the early Neoproterozoic tectonic evolution and the role of the Tarim Craton in the reconstruction of Rodinia remain controversial. Here, we present zircon U-Pb and Lu-Hf isotopic and whole-rock geochemical data for the newly discovered andesitic rocks in the Aksu area of northwestern Tarim Craton. LA-ICP-MS zircon dating results show that they were formed at ca. 908–903 Ma. These andesites have arc-type geochemical features such as enrichment in LREEs with (La/Yb)N ratio of 4.4–6.9 and obviously negative Nb, Ta, Ti anomalies. The high positive zircon εHf (t) (+7.5 to +11.9) values, integrated with trace element signatures, indicate that the magma source of the andesitic rocks were derived from partial melting of mantle wedge that was metasomatized by the sediment/slab-derived fluids through subduction, with possibly insignificant contributions from crustal materials. These geochronological and geochemical data suggest that subduction-related arc magmatism occurred in the northwestern Tarim Craton as early as ca. 900 Ma. Combined with a compilation of previous published data, these results therefore indicate that active continental margin probably widely occurred along the northwestern and southeastern margins of the Tarim Craton and adjacent microcontinents during the early Neoproterozoic, which may be linked to the Neoproterozoic circum-Rodinia subduction-accretion system.

Phototropism of Petrified Wood and Its Relation with the Rotation of Different Blocks in China and the Possibility of Application in the World

Normally, trees on the side directly exposed to sunlight will grow faster than the opposing side. This phenomenon is termed plant phototropism. Moreover, palaeomagnetists have revealed that the Junnar Block has never rotated since the Mesozoic. The petrified woods in the Jiangjunmiao area of Qitai County show the positive phototropism direction of SSW220. By compared with the modern normal growth stumps in plain area, which have positive phototropism direction of SSW 219 ± 5, this observation supports the conclusion of palaeomagnetic researchers: the Junggar basin has never rotated since the Late Jurassic.

Research on Countermeasures of Local Culture-based Sustainability of Urban Block Patterns

Under the influence of the idea of globalization and modernism planning, in the process of urban development, inefficient use of land, supremacy of functionalism and traffic congestion have become important problems in Chinese cities because of the expansion of land scale, the transformation of urban functions and the leading of maneuverable traffic. As the component unit of the city, urban block is also faced with the problems of unordered environment and the loss of culture. To realize the comprehensive and sustainable development of economy, society and ecological environment in the city, it is of great significance to study the corresponding urban block patterns suitable for the city. This paper starts from the perspective of local culture and conducts in-depth discussion on the internal causes of the current problems of urban blocks in China. On this basis, the paper puts forward the countermeasures of the sustainability of urban block patterns from three aspects of society, technology and management and attempts to explore the construction path of sustainable development for urban blocks in the future.

On Adaptability Evaluation and Strategy Research of Historical Block

The concept of adaptability was originated from the “theory of evolution” of biology. Based on the concept of adaptability, there are some literature achievements in the relevant research of historical blocks in China, which are worth summarizing and carding certain existing literature. The adaptability evaluation of historical block is a method for evaluating the integrating degree between the existing environmental condition and the current production and living demand, used for comprehending the actual condition of objective environment. The research on adaptive renewal strategy of historical blocks often uses field research to summarize the renewal optimization strategy for specific regions, specific block types and specific building functions. Therefore, this paper summarizes and classifies the development direction of adaptability evaluation and protection and renewal strategies of historical blocks, summarizes the conventional research methods and steps, in order to help the future research related to the adaptability of historical blocks. The paper is composed of four parts, the first part introduces the concept of adaptability; the second part focuses on figuring out systematically the development direction of adaptability evaluation of historical block, and summarizing the research procedures and research methods of historical block’s adaptability evaluation；the third part focuses on summarizing and classifying the adaptability protection renewal strategy of historical block and introducing the common research methods; the last part describes the author's thoughts and suggestions.

Geochronology and geochemistry of Mesozoic igneous rocks of the Hunjiang basin, Jilin Province, NE China: Constraints on regional tectonic processes and lithospheric delamination of the eastern North China block

The Hunjiang basin in Jilin Province, China, is host to a NE-trending sequence of sedimentary rocks located along the northeastern margin of the North China block in the Paleoproterozoic Jiao-Liao-Ji belt. The North China block is the largest and oldest cratonic block in China, but unlike other Precambrian cratons, its eastern part has been decratonized by multiple Phanerozoic orogenic events. No comprehensive geochronology study has been conducted on the rocks of the Hunjiang basin, and both the mechanisms and timing of lithospheric delamination beneath the eastern part of the North China block are largely unconstrained. In the Hunjiang basin, Proterozoic to Paleozoic sedimentary rocks are intruded by Mesozoic granitoids and are overlain unconformably by sedimentary and volcaniclastic rocks. Twenty igneous rocks (granites, porphyritic rocks, and volcaniclastic rocks) from the basin were analyzed for whole-rock geochemistry and dated by U-Pb laser ablation-inductively coupled plasma-mass spectrometry of magmatic zircons. The samples collected are felsic to intermediate in composition and of calc-alkaline affinity, and the granitic and porphyritic rocks show an adakite-like geochemistry. With the exception of one Neoarchean granite dike with a 207Pb/206Pb age of 2524 ± 9 Ma that intrudes the basement along the northeastern margin of the basin, all igneous rocks dated in the present study have Mesozoic crystallization ages between 180 ± 1 Ma and 90 ± 2 Ma. The Precambrian inherited zircons show age peaks at ~2700 Ma, ~2650 Ma, and ~2500 Ma. The presence of inherited zircons with ages as old as 3387 ± 38 Ma (207Pb/206Pb ages) shows that Paleoarchean crust exists beneath the Proterozoic to Paleozoic sedimentary rocks of the basin. The geochronological results suggest that magmatic activity and associated formation of hydrothermal ore deposits in the Hunjiang basin were prevalent from the Middle Jurassic to the early Late Cretaceous. Furthermore, structural constraints on the cessation of major tilting in the basin are provided, as an Early Cretaceous (127 ± 1 Ma) flat-lying volcaniclastic rock unit unconformably overlies steeply dipping sedimentary rocks. The adakite-like geochemistry of most granitic and porphyritic rocks suggests partial melting of a delaminated eclogitic lower crust, whereas the higher MgO, Ni, and Cr content of the Early Cretaceous porphyritic rocks indicates reaction between adakitic melts and mantle peridotite. Many of the volcaniclastic rocks have more evolved, less adakitic signatures and show negative Eu anomalies, indicating these formed from more evolved melts at shallower crustal depths, accompanied by assimilation-fractional crystallization processes. The results of this study indicate that major delamination was completed in the Hunjiang basin by the Middle Jurassic, while delamination was ongoing into the Early Cretaceous in many other parts of eastern China.

Social Integration Measurement of Inhabitants in Historic Blocks: The Case of Harbin, China

The inhabitants of historic blocks require more social and planning consideration. A basic means to achieve inclusive planning and social sustainability in such areas is to quantitatively study the social integration of their inhabitants. Based on social survey data for the inhabitants of Harbin’s Central Street and DaoWai historic block in China, this paper establishes the measurement factors that affect inhabitant social integration to construct a measurement model. Statistical analysis is performed using exploratory factor analysis (EFA) and confirmatory factor analysis (CFA). The analysis results reveal five dimensions of inhabitant social integration: behavioral integration, cultural integration, industrial integration, spatial integration, and management integration. Subsequently, the statistical scores for social integration and related factors are calculated. The empirical results indicate that the level of the inhabitant social integration has an impact on the vitality and sustainable development of the blocks. The social integration score of the inhabitants of Central Street is higher than that of the inhabitants of the DaoWai historic block. Among the five dimensions, the industrial integration level of Central Street is the highest, whereas the spatial integration level of DaoWai historic block is the highest. The level of management integration is the lowest for both blocks. The difference in the levels of industrial integration between the two blocks is the highest, and cultural integration is the lowest. Comparing the status quo of the two blocks, the paper concludes that the promotion of inhabitant social integration requires enhancing the dimensions with lower measurement scores according to the specific conditions of the block. In this manner, a fundamental theory for a socially inclusive revitalization of historic blocks is established, thus to enhance social sustainability.

A new production decline model for horizontal wells in low-permeability reservoirs

Predicting well performance in low-permeability reservoirs has attracted attentions in the last decades. Decline curve analysis is treated as the most convenient and efficient approach to forecast production. However, each single decline model has its own limitations due to the low permeability and porosity. Hence, we cannot directly apply these models in the low-permeability reservoirs, especially the dramatically drop in the early period. In this study, based on the analysis of conventional production decline models and the development characteristics of low-permeability reservoirs, a new production decline model was proposed, which can quickly and accurately predict the future performance of horizontal wells. Three fitting parameters were employed representing the production performance in early, middle and late-life period respectively. A decline exponent parameter of n was also included in the proposed model. Subsequently, the proposed model was validated, and good agreement was obtained with the production data of a low-permeability block in China. The comparison between new method and other models are analyzed in detail, which illustrates that this proposed approach is more flexible and confident. This work can give a useful insight into accurately and efficiently predicting well performance in low-permeability reservoirs.

Investigation of the Yellow River buried fault in the Wuhai basin, northwestern Ordos Block, China, using deep/shallow seismic reflection and drilling techniques

Studying the faults in Wuhai Basin, which is located in the northwestern corner of the Ordos Block in China, can not only guide earthquake-safe construction in the region, but also provide a greater understanding of the structure of the Wuhai Basin and the dynamic environment of Northwestern Ordos Block. In this study, we effectively detected the Yellow River buried Fault (YRF), which we believe currently presents a risk to human life in the area. First, we laid out a deep seismic reflection profile (DSRP) in the north of the Wuhai Basin and found that the YRF is composed of two subparallel faults, the east branch of the Yellow River buried Fault (EYF) and the west branch of the Yellow River buried Fault (WYF), which formed a Y-type graben in the section. We then used 25 shallow seismic exploration profiles to find out how the faults are distributed. Finally, we used drillings and Quaternary dating methods to certify their existence and obtain their activity parameters. We used the sequence stratigraphy method to compare sediment strata and identified paleo-earthquake events by finding the unequal thickness layers (UTLs) on both sides of the fault. The drillings revealed that four earthquakes occurred on the YRF around 25.6 ± 0.11 ka BP, 39.5 ± 0.45–41.7 ± 0.57 ka BP, 58.25 ± 7.13 ka BP, and 111 ± 1.21 ka BP. Since the last activity on the YRF occurred much longer ago than its estimated recurrence cycle, we believe that the fault YRF currently presents a dangerous risk. Our study confirms that the YRF is a normal fault graben and that the Wuhai Bain is an extensional basin formed by the relative movement of the Tibetan Plateau, the Alashan Block, and the Ordos Block.

Intention to move in renovated historical blocks in China

Using data from 8 renovated historical blocks in China, the influence of social-demographic characteristics and residential satisfaction on the intention to move is analysed using multinomial logit models. To explore the observed and unobserved heterogeneity among individuals, a mixed logit model was adopted. The model results indicate that older residents and residents who live in blocks during the middle renovation stage are less interested in relocating. Higher residential satisfaction will lead to a lower intention to move house, and housing satisfaction and satisfaction with the living environment have a higher impact compared with satisfaction related to other residential dimensions. Moreover, the interaction between neighbourhood satisfaction and renovation stages was found influential, while the unobserved taste variation between residents was not identified.

The transformation of traditional commercial blocks in China: Characteristics and mechanisms of youthification

Abstract To understand the diversities and complexities of the gentrification of commercial blocks, this study investigated the relationship between young people and China's commercial blocks through the lens of ‘youthification’. The significance of this research lies in utilizing first-hand data to decode the characteristics and mechanisms of the youthification of commercial blocks in China. Through analyzing retail activities in the Guilin Road Commercial Block, the characteristics and mechanisms of youthification are identified. The youthification of this commercial block is characterized by a large-scale influx of young people, clubbing and nightlife, popular cultural and creative activities, and the distinctive culture of roadside stands. The emergence and development of youthification in traditional commercial blocks can be closely linked with globalization and cultural identity, local factors, the youthification of the population composition of surrounding areas, and an inclusive commercial atmosphere. The key differences of the youthification of commercial blocks between China and Western countries mainly concern three aspects: the developmental background, the role undertaken by the government and the participation of young people.

Comparative Life Cycle Assessment of Autoclaved Concrete Blocks and Fired Blocks in China

In this paper, a variety of blocks were grouped into the autoclaved blocks and fired blocks as far as the productive technology is concerned. In order to compare the life cycle impacts of the two kinds of the blocks, a life cycle assessment of two products on the functional unit 1m3 was carried out through the exploitation of mineral stage, transportation stage and the production of the blocks stage on the considering of the resource and energy consumption and the pollutant discharges. The results demonstrated that the fired blocks appeared to have less impact than autoclaved concrete blocks on human health, marine ecotoxicity toxicity and terrestrial ecotoxicity toxicity nearly 30%. The raw coal led to the serious impacts on the fossil depletion through the cement production stage of the autoclaved concrete blocks accounting for 45.86% and the gangue exploitation stage of the fired blocks accounting for 42.5%. Assessment of the data quality that the data was of pretty high or within the permission. The sensitivity analysis and contribution analysis assessment showed that the conclusion were robust.