Backswamp Research Articles

Analysis of coal facies and parting in The Balikpapan formation, Kutai Basin, East Kalimantan

The research area is located in RKBM coal mining area in East Kalimantan. One factor that influences the presence of parting in coal is the depositional environment. The existence of coal partings in this open pit area needs to be analyzed to determine the following steps in the exploration and further exploitation processes. The purpose of this study is a geological survey with the aim of knowing the coal facies and its parting characterization. The research was done by surface geological observation and drilling method. The results show that the facies association in this mining associated with delta systems such as channel, back swamp, flood plain, levee, crevasse splay, and inter distributary bay. The open pit area is composed of dominant lithology deposited in the upper delta plain environment. The presence of many and thin partings are often found in coal associated with the back swamp facies and deposited in the upper delta plain environment, which is mainly associated with fluvial systems. The distribution of parting in the study area is interpreted as not widespread because it is associated with back swamps that are affected by flood plains, and sometimes their distribution is cut off by channels.

Vegetation changes in 2014 and 2019 in back swamps disturbed in the tsunami and ground subsidence caused by the 2011 off the Pacific coast of Tohoku Earthquake

Vegetation changes in 2014 and 2019 in back swamps disturbed in the tsunami and ground subsidence caused by the 2011 off the Pacific coast of Tohoku Earthquake

Geomorphic controls on shallow groundwater arsenic contamination in Bengal basin, India.

The study was conducted to explore the influence of geomorphic features scattered throughout the area on the occurrence and distribution of arsenic in shallow groundwater. GIS techniques were frequently used to identify the geomorphic features and to correlate with arsenic distribution patterns. The study shows that the occurrence of geomorphic features and their distribution have a vital role in the heterogeneous distribution pattern of arsenic in shallow groundwater. The frequency distribution of geomorphic features is found similar to the arsenic distribution pattern. The moderate to highly contaminated zones are mostly consolidated to the central and southeastern part of the study area. Arsenic contamination levels are varying in different fluvial plains of the study area following the trend of Older Deltaic Plain (ODP) > Older Flood Plain (OFP) > Active Flood Plain (AFP). It has also been observed that arsenic contamination along the different geomorphic features follows the trend of abandoned channels > back swamps > other water bodies > swamps > cut-off meanders > meander scars > ponds > oxbow lakes > channel bar > point bars >channel islands. The present study indicates that the geomorphic features play a significant role in the mobilization of arsenic in shallow groundwater by supplying accumulated organic matter.

Facies Analysis, Markov Model and Linking of Sub-environments in the Early Permian Barakar Coal Measures of Godavari Gondwana Basin of Southeastern India

Abstract The early Permian Barakar coal measures Formation of Gondwana Supergroup in the Godavari basin comprise siliciclastic fluvial facies of passive continental margin. The lithofacies relationship and their sequences are analyzed quantitatively using embedded Markov Chain analysis along with improved binomial probability method. Summarized lithofacies sequence show the following order: (CGSD= Matrix supported conglomerate, gritty to pebbly / coarse-grained tabular and trough cross bedded sandstones) →(MGSD= Medium grained trough and planar cross bedded sandstones)→(FGSD= Fine-grained parallel and ripple drift cross-laminated sandstones)→ (SH= Shale/inter-bedded sandstone-shale and gray shale)→ (C=coal/shaly coal and carbonaceous shale)→ (CGSD= Matrix supported conglomerate, gritty to pebbly/coarse-grained planar and trough bedded sandstones). These repetitive cycles accumulated in a low sinuosity, high gradient braided streams which became moderately sinuous at places. The lithofacies relationships showing fining upward tendency suggest a progressive upward decline in current competency. The sequence is considered as the classical example of a sand dominated braided river. The lateral changes in lithofacies association indicate shifting of subenvironments from stream channel, overbank levee and peat forming back swamp to flood plains of fluvial system. It is suggested that the channel wandering along with differential intra-basinal tectonism and subsidence controlled cyclic repetition during early Permian sedimentation in the Godavari basin.

New insights into the organic geochemistry of the Otway Basin

The Penola Trough of the Otway Basin in South Australia has enjoyed over 20 years of commercial hydrocarbon production from the sandstones of the Early Cretaceous Otway Group with 71.46 PJ sales gas and 65840 kL of condensate produced from five fields until production ceased in 2011. Recent success in Haselgrove 3, where a newly discovered deeper reservoir underlying depleted reservoirs of the Pretty Hill Formation flowed 25 MMscfd on test heralds a new phase of exploration and appraisal with a 2C Contingent Resource of 87 PJ assigned to the discovery. These hydrocarbons are considered to have been principally derived from lacustrine, floodplain and back swamp facies of the Pretty Hill Formation and lacustrine facies of the underlying Casterton Formation. The South Australia Department for Energy and Mining is currently investigating an unnamed Late Jurassic syn-rift sequence of interbedded metasediments, tuffaceous sediments and organically-rich shale, first identified as fractured basement in Sawpit 1, located on the northern flanks of the Penola Trough and which unconformably underlies the Casterton Formation. A low-sulfur medium-gravity paraffinic oil was recovered from drill stem tests from this well and subsequent total organic carbon and Rock-Eval analyses for the same unit in nearby Sawpit 2 identified a source rock containing algal organic matter and thought to be deposited in a deep anoxic lake setting. In this paper, we will present the preliminary results of detailed geochemical analyses of rocks and rock extracts from this previously unrecognised syn-rift sequence and discuss implications for hydrocarbon prospectivity in the deeper portions of the Penola Trough.

Wetland restoration by natural succession in abandoned pastures with a degraded soil seed bank

AbstractNatural restoration of historical wetland plant communities in fallow fields with a degraded seed bank has been assumed to be possible only if source populations of the target species are present adjacent to the abandoned fields and a high density of suitable microsites is available. However, few studies have monitored both factors simultaneously and verified this assumption. We hypothesized that plant communities that are similar to historical wetlands, including back marshes, back swamps, and bogs, will reestablish in abandoned pasturelands in cases when (1) gaps for new recruitment emerge, followed by the decline of pastures; and (2) seeds with longevity are supplied from the surrounding remnant plant communities of wetlands. We conducted a survey of vegetation and microsites in pastures, abandoned pastures, and reference wetlands followed by structural equation modeling to verify our hypothesis for the natural restoration of Phragmites australis–Phalaris arundinacea and Alnus japonica–Spiraea salicifolia communities. These communities represent historical back marshes and back swamps along a river. However, our hypothesis was not verified for the natural restoration of Vaccinium oxycoccos–Sphagnum spp. communities, which represent plant communities in historical bogs grown on acidic peat that are maintained by rainfall and fog. Our findings partly support our hypothesis that decline in pastures creates gaps and that cumulative seed dispersal from nearby remnant wetlands allows the original wetland plant communities to regenerate. Further case studies are needed to determine how the natural restoration of bog plant communities occurs.

Distribution and diversity of mangrove species in Gokana Local Government Area, Rivers State, Nigeria

Analysis of mangrove species distribution and diversity were carried out in Gokana Local Government Area, Rivers State, Nigeria. four transects (100 m x 10 m) with a distance of about 2 km from each other were set up at the mangrove back swamp starting from the waterfront towards upland. Each was divided into four equal plots of 25 m x 10 m. Data collection was based on identification and enumeration of the species. Distribution of the species as classified by Morisita’s index showed a uniform dispersion (id <1) in all plots. Simpson’s diversity index showed that species diversity was highest in Plots 4 (0.1272), followed by Plots 3 (0.2068). Plots 1 and 2 were dominated by Rhizophora racemosa (62.07% and 41.17% respectively). Plots 3 were dominated by R. mangle (4 1.67%) while Plots 4 had 26.56% of Acrostichum aureum and 26.56% of Phoenix reclinata. The overlapping mangrove species occurrence (Laguncularia racemosa and R. mangle) at the waterfronts should not alter the phenomenon of zonation for any form of reforestation project to be carried out in the area. Species for planting a specific mangrove area should be decided by environmental condition according to mangrove zonation principle so that reforestation and sustainable rehabilitation in the deteriorated ecosystem will be successfully achieved.Keywords: Nigerian mangroves, biodiversity, distribution, assemblage, Niger Delta

Comparative analysis of mangrove species and seedlings in a Riverine Region of Ogoniland, Nigeria

The comparative study of mangrove species and seedlings with respect to their density and relative abundance were carried out in the mangrove back swamp in Gokana Local Government Area, Rivers State, Nigeria. Four transects each with length and width of 100 m and 10 m respectively were set up with more than 1 km from each other. Each station was subdivided into four subplots of 2 5 m x 1.0 m. Data collection was based on identification, enumeration and recording. Density of species and seedlings were analysis using number of stem wood per hectare while relative abundance was expressed in percentage. Mangrove species density was highest in Plots 4 and lowest in Plot 1. Rhizophora racemosa had highest relative abundance in Plots 1 (62.07%) and 2 (4 1.08%). R. mangle had highest relative abundance (4 1.67%) in Plots 3, while in Plots 4, R. mangle, A. aureum and P. reclinata recorded 26.56% each. Mangrove seedlings were: Plot 1(1.35%), (Plot 2) 2.02%, Plot 3 (93.67%) and Plot 4 (2.96%). The bulk density of seedlings in Plots 3 was attributed to high population of matured stand which enhanced constant production of propagates. Critical attention and artificial regeneration should therefore be given to waterfronts to facilitate sustainable growth and development of species and seedlings at the water front and the entire ecosystem.Keywords: Nigerian mangroves, composition, abundance, Rhizophora racemosa, Niger Delta

Habitat Selection by Large Mammals in South Luangwa National Park, Zambia

An assessment to determine habitat selection by large mammals was carried out in South Luangwa National Park, eastern Zambia. We divided Habitat types into five groups based on physiognomic classification as: savannah wood-land, back swamp, Combretum thicket, Mopane woodland, and Terminalia-Erythrophleum. Road count method was used to sight animals across the four identified habitat types. Results showed that puku, impala, elephant, and zebra were highly selective of habitat types. Puku occurred mainly in back swamp habitat (86.6%) followed by water buck (75.0%), elephant (72.3%) and zebra (65.7%). Impala were more abundant in Terminalia-Erythrophleum woodland (69.50%) while buffalo was mainly sighted in Mopane-woodland (45.07%). Other species were more cosmopolitan. It was suggested that foraging behaviour, season and security with respect to predation were the factors singularly or collectively that influenced the observed pattern of habitat selection by large mammals.

Predominant period and amplification factor estimation with respect to geomorphology - a case study of Sylhet city corporation area, Bangladesh

Predominant period and amplification factor of the subsurface soils of Sylhet city corporation area have been estimated using microtremor. Their relation to the geomorphological units of the city has been determined. The estimated predominant periods of alluvial fan, back swamp, flood plain, isolated hills, level hills, piedmont plain, point bar and ridge of the city are 0.60, 0.75, 0.73, 0.23, 0.62, 0.45, 0.73 and 0.66 sec., respectively. With maximum (± 0.88) and minimum (± 0.38) standard deviation amplification factor of alluvial fan, back swamp, flood plain, isolated hills, level hills, piedmont plain, point bar and ridge are 3.1, 4.1, 4.6, 3.75, 2.22, 4.12, 4.18 and 4.42, respectively. According to amplification seismic hazard of different geomorphological units of the city has been ranked from very low to relatively high hazard zone whereas level hill falls under very low, alluvial fan under low, flood plain under relatively high and back swamp, isolated hills, piedmont plain, point bar and ridge falls under moderate hazard zone.Bangladesh J. Sci. Res. 27(1): 1-10, June-2014

津波浸水域の土地利用履歴にもとづく土地活用の方向性

This study focuses on land use in the tsunami inundation area caused by the Great East Japan Earthquake, particularly land use history in the tsunami-affected area. Hanagama District, Yamamoto City, Miyagi prefecture, was selected as the study area. Land use were examined using aerial photographs taken in 1975, 2010 and 2013. Relationships between land use change and the disaster hazard areas, natural land conditions were analyzed with GIS. As a result of land use analysis, in 1975, land use base on natural land conditions (Residences, Dry fields and Forests- Beach ridge, Paddy fields- Back swamp) were consisted. These land uses were greatly changed by urbanization and tsunami damage.

Evaluation of Flooding Risk in Greater Dhaka District Using Satellite Data and Geomorphological Land Classification Map

Flood is a common feature in rapidly urbanizing Dhaka city and its surrounding areas. In this research, evaluation of flood risk of Greater Dhaka in Bangladesh has been developed by using an integrated approach of GIS and remote sensing. The objective of the study is to measure the flooding risk based on the satellite data and geomorphological land classification map under the land use/land cover change from 1995 to 2015 related with the urbanization of Dhaka city. Comparing with each landform, land cover unit and historical rainfall data the flooding return period has been calculated. Terrace, natural levee and back swamp has been divided into three sub categories. Especially the built-up zone which is closer to the river channel, former river course and the back swamps are mostly vulnerable to flood inundation. This study revealed that, 70% of Greater Dhaka district within moderate to very high hazard zone, especially surrounding city like Manikganj Sadar Upazila areas. It is expected that, this study could contribute to effective flood forecasting, relief and emergency management for future flood event.

Megaspores from the Upper Cretaceous (Campanian) Horseshoe Canyon Formation of south-central Alberta, Canada, with a review of the genera Costatheca and Spermatites

Eighty-nine samples from three boreholes penetrating the Horseshoe Canyon Formation (Late Campanian) in south-central Alberta (Canada) were investigated for megaspore content. The samples were found to contain 49 species belonging to the genera Azolla, Bacutriletes, Costatheca, Dictyothylakos, Echitriletes, Erlansonisporites, Ghoshispora, Glomerisporites, Minerisporites, Molaspora, Monophyllosporites, Paxillitriletes, Spermatites, Striatriletes and Trileites, including one new species of Spermatites (S. reticulatus). Deposits representing low-lying coastal plains with widespread peat swamps, meandering channels and back swamp environments yielded the highest numbers of megaspores. An analysis of characteristics of the 22 species of Costatheca and 18 species and one subspecies of Spermatites leads to the proposal of a system of shape classes. Dichotomous keys to species were prepared. The geographical and stratigraphical distributions of the genera were also reviewed to elucidate their potential use in biostratigraphic and palaeoecological studies.

Sequence stratigraphy and paleogeography of the Middle Jurassic coal measures in the Yuqia coalfield, northern Qaidam Basin, northwestern China

Detailed stratigraphic and paleogeographic analyses of data from 72 boreholes for the Middle Jurassic intermontane fluvial-lacustrine coal-bearing sequences were conducted in the Yuqia coalfield of the northern Qaidam Basin, northwestern China. Three third-order sequences lasting in total ca. 10.6 m.y., and an internal lowstand systems tract (LST), transgressive systems tract (TST), highstand systems tract (HST), and falling-stage systems tract (FSST) have been identified. A series of sequence-specific paleogeographic maps have been constructed based on the contours of lithological parameters. The paleogeographic units include alluvial fan-braided (meandering) fluvial plain, upper delta plain, lower delta plain, subaqueous delta, shore-shallow lake, and deep lake. The preferred sites of coal accumulation are interdelta bays, upper delta plains, lower delta plains, and fluvial back swamps. The sequence stratigraphic and sedimentological analysis of the Middle Jurassic coal-bearing measures of the Yuqia coalfield provides a basis for a comprehensive coal accumulation model that involves a six-period evolution from the LST, early TST, late TST, early HST, late HST to FSST. The major coal seams were accumulated in the early and late TST of the sequences S1 and S2. These results are of practical significance for coal resources exploration and enhance geological effects of prospecting engineering in the northern Qaidam Basin.

400年を越えて続いた日本史上最大最長の土木事業

River improvement works in the Kanto Plain have long history of over 400 years. Rice-paddy development in the Kanto Plain was significantly delayed compared to that in other plains including the Osaka Plain and the Nobi Plain. This was because of the difficulty in constructing an irrigation and drainage network, and protecting rice paddies from inundation. Therefore, the Tokugawa government started river improvement works in the Kanto Plain just after Tokugawa settled in Edo in 1590, and the works continue now. The flow of the Tone River into Tokyo Bay was originally blocked by uplands, but was finally rerouted to Choshi, 90 km east to the original mouth. The Ara River was also rerouted to the south. The purpose of rerouting was not only to reduce the risk of flooding in Edo city, but also to develop a waterway network for rice paddies to expand in the central Plain. Moreover, rerouting and connecting the Tone River with the Edo River enhanced the inland waterway transportation network of the Kanto Plain. Accordingly, a number of riverside towns, or Kashi, grew as nodes of the network. Small sailing ships and flatboats were the major conveyors of products. During the Meiji era, which followed the Edo period, canals were constructed and steamboats were introduced to replace sailing ships, at a time when water transportation was peaking. The inland waterway soon began to be replaced by present-day economic transportation systems such as rail and road. The central Kanto Plain was featured consistently by a subsiding basin through the Quaternary. Although the entire Plain was uplifted, Tokyo Bay, at the center of the Kanto Plain, sank over 1000 m. In contrast, the outer margin of the plain was uplifted 50 to 1000 m. Choshi, at the mouth of the present Tone River, is in the uplifted area. In contrast, the lower reaches of the River are at the northern extent of the subsiding basin. This is the reason why back swamp lakes or an estuary such as Kasumiga-ura and the ancient Katori-no-umi were formed in the area. Such crustal movements in the Kanto Plain continued throughout the Quaternary. Hydration and dehydration of two plates lying beneath this region were the driving force. Hydration of mantle peridotite underneath the Kanto Plain due to dehydration of the underlying Philippine Sea Plate (PHS plate), subducting from south to north 30-60 km deep (2 cm/year), causes volumetric expansion particularly at the marginal zone of the overlying plate (North American (NA) Plate). Serpentinized peridotite, produced above the Pacific Plate (PAC plate), which subducts from east to west under the PHS and NA plates, expands like popcorn and results in uplifting of the Boso Peninsular (non-volcanic outer arc) . In contrast, the sinking of the Tokyo Bay area is explained by the overlapping of the fore arc basin towards the PHS and PAC plates. From the viewpoint of tectonics, the sinking belt including Tokyo Bay is in a physical field where a sedimentary basin formed under tensile stress in the NE-SW direction. Small mantle convection caused by serpentinization of the uppermost mantle beneath the fore arc is the key to understanding the tectonic setting of the Kanto Plain.

Coal petrology and coal facies interpretations of bark liptobiolith

A detailed analytical study of Leping bark liptobiolith in Jiangxi was conducted to determine its petrographic characteristics and depositional environment based on coal petrography and geochemistry. Results indicate that barkinite mainly occurs in the middle and lower coal sea4ms, whereas less barkinite and more vitrinite occur in the middle and upper coal seams. Coal facies analysis of bark liptobiolith was performed to determine its characteristics under various depositional conditions, such as the presence of a water table and gelification during coal formation. Results indicate that the environmental evolution of bark liptobiolith begins from brackish-marine swamp facies (barkinite-rich coal seam) and ends in back barrier swamp facies (barkinite-poor coal seam).

Seismic Damage Investigation of Residential Fill Ground in the Eastern Part of Kyoto Basin

Several earthquakes record that the residential fills always suffer severe damages. In order to know the seismic damage mechanism and evaluate the damage extent of residential fill ground, research is carried out on two fill grounds in the eastern part of Kyoto basin. The research includes field survey about terrain condition, geological condition, development history, disaster condition during 1995 Kobe earthquake and surface wave explorations. Some remarkable conclusions are summarized as follows: In Jyodo-ji area, it is a residential fill on soft alluvium ground. The geological condition is back swamp. The thickness of surface fill soil is about 1~4 meters. In Kiyomizu-dera area, it is a valley filled ground. The geological condition is hilly platform.

REMOTE SENSING DETECTION OF DYNAMIC VARIATION OF THE SALINE LAND IN THE YELLOW RIVER DELTA

Land salinization is a dynamic phenomenon or process. With the annual and seasonal variation of the groundwater table, the nature, extension, magnitude and spatial distribution of the saline land are changing from time to time. The grasp of the up-to-date and reliable information on the saline land is a prerequisite for land reclamation and regional sustainable development. For the purpose of providing a generalized view of a fairly large area, remote sensing is widely used in saline land survey and dynamic study. Three groups of Landsat data were selected for the study of saline land dynamics during the past 15 years in the Yellow River Delta. Based on repeated field survey and soil sample analysis, an integrated classification method was developed for the extraction of information about saline lands. The study shows that, from 1987 to 2000, the trend of land salinization was rapidly accelerated: light saline land greatly increased; strong saline land gradually decreased; barren saline land increased from 1987 to 1996 and then decreased. The spatial structure of saline land distribution in such 6 types of landforms as terrace uplands, present flood plain, abandoned river courses, embanked former back swamps, isolated depressions and salt marshes tidal flats in 2000 was almost the same as that in 1987.

Multivariate statistical analysis of geochemical data of groundwater in Veeranam catchment area, Tamil Nadu

The study of hydrogeochemistry of the Mio-Pliocene sedimentary rock aquifer system in Veeranam catchment area produced a large geochemical dataset. Groundwater samples were collected at 52 sites over 963.86 km2 area and analyzed for major ions. The large number of data can lead to difficulties in the integration, interpretation and representation of the results. Two multivariate statistical methods, Hierarchical cluster analysis (HCA) and Factor analysis (FA), were applied to a subgroup of the dataset to evaluate their usefulness to classify the groundwater samples, and to identify geochemical processes controlling groundwater geochemistry. Hydrochemical data for 52 groundwater samples were subjected to Q- and R- mode factor and cluster analysis. R-mode analysis reveals the inter-relations among the variables studied and the Q-mode analysis reveals the inter-relations among the samples studied. The R-mode factor analysis shows that Ca, Mg and Cl with HCO3 account for most of the electrical conductivity, total dissolved solids and total hardness of groundwater. The ‘single dominance’ nature of the majority of the factors in the R-mode analysis indicates non-mixing or partial mixing of different types of groundwater. Both Q-mode factor and Q-mode cluster analyses indicate an exchange between the river water and the groundwater in the vicinity. The rock water interaction like flood basin back swamp deposits of silty clayey formation is the major cause for the cluster II classification. Cluster classification map reveals that 58% of the study area comes under cluster II classification.

Comparison of pollen distribution patterns in surface sediments of a Colombian Caribbean mangrove with geomorphology and vegetation

Distribution patterns of mangrove pollen taxa in recent surface sediments of the lagoon system of Cispatá are compared with geomorphological and vegetational patterns. The pollen spectra of 51 samples show the floral composition and structure of mangrove stands in three main geomorphic units in the study area. The oldest mangrove stands, with the highest tree mean diameter at breast height and total height, are represented in the pollen spectra by the highest mean percentages (> 65%) mainly Rhizophora mangle. The area with estuarine conditions shows, mean mangrove pollen percentages between 35 and 50% reflecting the mangrove colonization process since 1930, as well as current anthropogenic disturbance. Lowest proportions of mangrove pollen (< 25%) are found in the foothills, reflecting high disturbance of mangroves and the transition from mangroves to terra firme forest. Distribution patterns of the pollen and spores indicate that water transport is more important than wind transport over short distance and reflect local vegetation. Fern spores and pollen grains of secondary forest taxa and grasslands are widely distributed and reflect regional vegetation. Rhizophora pollen proportions reflect its relative abundance in the forest stands. Even low proportions of Avicennia pollen indicate this species’ dominance in sparse stands and saline back swamp conditions. Conocarpus presence provides evidence of supratidal location of stands. An inverse relationship between proportions of Laguncularia pollen and Acrostichum spores demonstrates successional processes triggered by anthropogenic disturbance. This is the first report on pollen in surface sediments in the Colombian Caribbean. As such, the data should prove valuable in efforts to apply interpretations of marine records to reconstruct past environmental and climate changes in the Caribbean.