Md. Sakawat Hossain

Abstract

The process of vein growth is generally associated with circulation of mineral nutrients or fluids in the rock for transport, propagation and opening of vein space, and finally precipitation. Mass transport occurs through diffusional mass transfer, advective fluid flow and mobile hydrofractures, whereas nucleation and growth of minerals in vein occurs by epitaxial overgrowth, homogeneous or heterogeneous nucleation. The relative tensile strength of the wall rock matrix, vein and vein wall interface may influence where successive increments of vein growth occur and thus control the development of syntaxial, antitaxial, ataxial and composite vein growth types. It is found that the types of internal textures in veins and their tracking capability, depend on six important factors and these are: vein opening velocity, wall roughness, growth anisotropy of the mineral phase, location of material accretion site, fluid transport mechanisms and the relative tensile strength of the vein interior and the vein/wall rock interface.

Shock-fragmentation of the Ries impact crater forms characteristic and complex fracture patterns from micro- to kilometre-scale. Outside the crater rim, prominent fractures are mainly vertical to sub-vertical, either in radial or tangential orientation to the crater. The traces of radial fractures from various outcrops around the Ries consistently point towards to impact centre and, consequently, represent an excellent tool for locating the crater centre. The presence of prominent fractures in numerous outcrops outside the Ries crater indicates that impact-induced brittle deformation reaches as far as 70 km away from the crater centre. Time series analyses of fracture frequency reveals regularly spaced, ca. 3-4 m interval elongate vertical to sub-vertical zones of high deformation. This periodicity of increased fragmentation appears typical of impact fragmentation. The cyclic repetition of intensely fractured zones and their variations with distance are most likely the results of the interaction of rapidly evolving impact-induced shock waves.

Shock-induced fragmentation structures of basement rocks and their limestone cover in and around the Ries impact crater (Germany) were recorded on outcrop, sample and thin section scale and quantified mainly by fractal-geometry methods. Quantification was performed by automated procedures and in areas of square-centimetres to square-decametres with maximum resolution of micrometre scale. In 2D and on all scales, the fragmentation structures form complex, statistically self-similar patterns (fractals) with specific characteristics: (i) The pattern fractality is scale dependent. (ii) Three different power-law relationships exist, which reflect the effect of three fragmentation processes. (iii) The fracture patterns are anisotropic and inhomogeneous over larger areas. (iv) Complexity and anisotropy of the fracture patterns vary systematically. Such systematic variation appears typical for impact-related fragmentation.

The process of vein growth and vein internal textures in the magmatic-hydrothermal system are controlled by multiple factors. Detailed studies of the veins from a number of magmatic-hydrothermal systems situated in different geological settings have been carried out to understand the process of vein growth and vein internal textures. Three factors have been recognized from this study and these are: fracture or crack localization and their recurrence, vein sealing processes, and roughness of the vein/wall rock interface. These factors may influence where successive increments of vein growth occur and thus control the development of syntaxial, antitaxial, ataxial and composite vein growth types. Finally, a new classification of the vein has been proposed here for better understanding, based on successive growth surface position, number of growth vectors and their directions during vein formation.

Existing studies on the magmatic-hydrothermal veins emphasize two factors on the vein localization, vein width, spacing and orientation. These two factors are: (a) relative tensile strength of wall rock, vein/wall rock interface and vein, and (b) spatial distribution of heterogeneity of the material properties within the system. Veins from diverse array of magmatic-hydrothermal systems from different geological provinces have been studied to understand these factors as well as their relationship with the vein forming processes. Detail study on these veins reveals a third factor; orientation of the imposed principal stresses relative to any pre-existing plane of weakness has been considered to be of significant importance in vein growth processes. Moreover, it is also observed that tensile strength of vein/wall rock interface is mostly controlled by two parameters: (i) nucleation and growth of vein minerals, and (ii) wall rock roughness. These observations regarding the vein growth processes of magmatic-hydrothermal systems will provide important insights on the microtectonics, vein microstructures and ore mineralization.

Abstract
Eight mechanisms that explain intraplate earthquakes so far recorded in different parts of the Earth has been reviewed in this study. Among these, zone of weakness, stress concentration and localized shear deformation are the most suitable for explaining of the origin of intraplate earthquakes. Although the zone of weakness model is most probable mechanism for the explanation of the origin of intraplate earthquakes, a sequential combination of these three models can explain the occurrence as well as the most plausible future locations of intraplate earthquakes.

Abstract

Bengal Basin is one of the largest basin of the world in which most of the reservoir trap is structural especially anticlinal type and strong water drive mechanism are reported in some of the gas filed. Habiganj Gas Field (HGF) is one of them where overestimation of original gas in place (OGIP) is mainly due to strong water drive mechanism. This reservoir has already been identified as a strong bottom water drive. Without considering a water influx, the conventional material balance (p/z vs. Gp method) for OGIP of upper sand can be determined as 16 Tcf that is actually overestimation of real volume, and cannot match with the present flow and pressure data. Considering bottom water drive, the Havlena-Odeh interpretation for materials balance has been applied, as the total underground withdrawal is equal to summations of water influx and gas-water expansion. The calculation of water influx (We) by Allard-Chen and Carter-Tracy methods for Havlena-Odeh interpretation indicates that the average OGIP of that sand is 4.52 Tcf which is acceptable and seems more reliable with respect to the present production data.

Abstract

Bangladesh constitutes the major part of the Bengal Basin, which is located at the head of the Bay of Bengal. The eastern margin of the Bengal Basin coincides with the Frontal Fold Belt of the Indo-Burman Ranges, which comprises two tectonic belts, the Mizo Fold Belt in the east and the Chittagong-Tripura Fold Belt in the west. This western zone is characterized by subparallel, arcuate, elongated folds of meridional and submeridional trends. The area has gone through complex tectonic, geologic and geomorphic processes to attain its present configuration. The Burmese plate being overridden by the Indian plate has served as the main pushing force for the compression of the Tertiary sediments to develop folds. The tectonic forces thus generated from the east caused intensive deformation in the east and become progressively weak towards the west to give rise to the formation of folds in Chittagong and Chittagong Hill Tracts.

The Inani-Dakhin Nhila structures are situated in the southern part of the Chittagong fold zone, which runs along the coastline of the Bay of Bengal. The development of the Bengal Foredeep is directly related to the development of the Himalayan Mountains in the north and the Indo-Burman Ranges in the east, and so the development of the Inani-Dakhin Nhila structures is contemporaneous to the formation of the Bengal Foredeep.

The regional trend of both the Inani-Dakhin Nhila anticlinal structures strikes between N17-19W and S17-19E. The anticlines are asymmetrical with the axial planes inclined to the east and have gentle dips in the eastern flank relative to the western flank. In the western flank there are evidences of tectonic disturbance with sharp escarpment and sudden omission of strata. The greater portion of western flank containing the younger formations has been eroded away by the sea. The Dakhin Nhila structure is separated from south-plunging Inani structure by a saddle at Mona Khali khal, whereas, in the south the separation of Dakhin Nhila structure and St. Martin’s Island is not apparent due to complexity in dip variations in the southern pitch of the Dakhin Nhila structure and wide erosional gap up to the St. Martin’s Island.

The Eastern Fold Belt of the Bengal Basin exposes mainly geosynclinal molasse sediments of Neogene age, comprising alternating shale, mudstone, siltstone and sandstone in varying proportions. The succession has been lithostratigraphically subdivided into Surma, Tipam and Dupi Tila Groups. Shales, siltstones, sandstones, occasionally, intraformational conglomerates, tabular and spheroidal calcareous concretions of these groups developed in the Inani-Dakhin Nhila structures. The sediments were most likely deposited in fluviatile-deltaic environmental conditions. The deposits of the Inani structure have been divided into Boka Bil, Tipam Sandstone, Girujan Clay and Dupi Tila Formations, whereas, those of the Dakhin Nhila structure into Bhuban (Upper), Boka Bil and Tipam Formations. The more argillaceous rocks, generally exposed in the cores of the anticlinal fold, are believed to be equivalent to the Surma Group of Miocene age. The younger arenaceous rocks in the flanks are considered as the Tipam Group of Pliocene age.

Abstract

The Bengal Basin, located in the northeastern part of the Indian subcontinent, comprises three geo-tectonic provinces, e.g. 1) The Stable Shelf, in the northeast, 2) The Foredeep in the east and southeast, and 3) The Fold Belt in the east. In the Stable Shelf, relatively thin and limited sedimentary sequence of Permian to Recent age overlies the crystalline basement. On the other hand, the Foredeep as well as the Fold Belt areas represents huge sedimentary sequence predominantly of Tertiary to Recent age. The Surma Group of Neogene age, with a thickness up to 4,500 m and increasing further east to Mizoram, is composed of monotonous alternating shales, siltstones, sandstones and some conglomerates. The Surma Group with its two formations Bhuban and Bokabil is the most significant stratigraphic unit since it contains all the natural gas reservoirs of the country.

It is believed that the natural gas in the Bengal Basin was generated at depths between 5,000 and 8,000 m in the Jenum Shale of the Barail Group. Subsequently the gas migrated upward through the fractures within multi layer sand-shale sequence into the Neogene sandstone reservoir rocks at depths between 1,000 and 3,000 m. So far 24 natural gas fields have been discovered in Bangladesh, where 20 fields are located in the western part of the Fold Belt. It was expected that in the areas of the eastern part of the Fold Belt accumulated huge amount of natural gas. But due to subsequent thrusting and faulting associated with intense tectonic deformation the prospect for natural gas in most of these structures has been extensively diminished.

The Bengal Foredeep, stretching from the Surma Basin up to the Bay of Bengal (water depth of <200 m) is proved to be the second most important petroleum province with 4 natural gas fields so far discovered. The Stable Shelf area along with the Palaeo-Continental Slope (Hinge Zone) has not yet proved to contain any hydrocarbon.

Abstract

Dhaka, the capital of Bangladesh is one of the densely populated cities in the world. The population of the city was rising rapidly since 1980s but the scope of urban expansion was not linear with its population increment. The estimation of water demand for 2025 was evaluated based on the existing population growth and required water demand. The study revealed that the total amount of groundwater abstraction in 2004 was 700 Mm3 that was 17 times higher than that of 1964. But during the last 40 years, the scenario change drastically due to employment opportunities, unplanned urbanization, population migration etc. In 2005, total number of deep tube wells was 435 that was one and half time higher than that of 2001. The lower Dupi Tila aquifer (third aquifer) ranges from surface to 353.28 m explored depth that lies within 35% of the sediment column while the Top aquifer (first) and Intermediate (second) Aquifer system lies within 32% of the sediment column. Water table in the shallow aquifer dropping rapidly in all over the city and the maximum declination of the groundwater level at present was found at -60.40 m at Tejgaon Industrial area. The average declining rate of water table in the Upper Dupi Tila aquifer is 2-2.5 m/year. This declining trend of groundwater level might be due to groundwater mining in the aquifer system; on the contrary, the deeper aquifer system has piezometric elevation of -10 m. From the long term aquifer test in the deeper aquifer system, the current study reveals that the average transmissivity of the system is 1805.61 m2/day, the storage coefficient is 0.00239 and the hydraulic conductivity is 27.09 m/day. Therefore, it is found that the deeper aquifer system might be only satisfy the future groundwater demand for the next 25 years with the high increasing trend of urbanization of Dhaka city.

Abstract

Wetlands around Dhaka city are its vital life line for its groundwater recharge; safe passage of incoming huge amount of flood water that rush from the upstream catchment areas; for survival of the Buriganga River, which related to the very beginning and the sustainability of the city; for recreational purpose of the city dwellers; and for its overall environmental conservation. Geomorphologically, these are drainage valleys, bounded by “less eroded” remnant terrace parts of the Pleistocene Modhupur Tract, and faults. This study was carried out on the lowlands located on the western margin on the Dhaka city, in the Ashulia and Jadurchar areas. Presently, giant housing projects are being implemented by filling of lowlands of Ashulia and Jadurchar (LAJ). This may threaten in the long run, the very existence of the Dhaka city. The LAJ generally has a concave-up, basin like morphology. The drainage pattern within the basin is dominantly dendrites. The LAJ clearly shows the form partially-filled basins. The sediment character of the LAJ is overwhelmingly dominated by clay and peats. Up to the depth of 3-4 meter from the surface, more than 60% is clay layers and 30-35% peat bands. Very fine grade sand is only found along the channel belts, as isolated thin beds. The geomorphic and sedimentary characters of LAJ clearly indicate basin-filling processes and products. Vertical accretion has been the dominant basin-filling process. Area continued to be a low-lying swampy region for last few thousand years. All signs indicate that this is likely to continue in the fore-seeable future, if the natural “wish” is not interrupted by all human interference.

Abstract

The study focused on the scope of sustainable water management and facing the challenges to accomplish the water demand for the next 25 years. The population of the city area is rapidly increasing due to centralization of all activities, migration of rural people due to the occurrence of disaster and creating employment opportunities for the last 40 years. Most of the supply-water in Dhaka city comes from groundwater and it covers 81% of the total supply. The water demand for the predicted population was analyzed up to 2025. The study obtained that groundwater table is dropping rapidly all over the city and recently the maximum lowering has been identified at Tejgaon industrial area. The groundwater elevation of shallow and intermediate aquifer at Tejgaon area has been calculated as – 62.4.m and – 13.14 m respectively. However, the average rate of water table declination is 2.5 meter/year. The over exploitation of this resource may occur land subsidence and moreover the concentration of trace elements are becoming higher in groundwater. Hereby considering all aspects, the study is innovated to apply some new and effective tools for the sustainable management of groundwater for the city dwellers. More attention may draw on the preservation of wetlands around the Dhaka city, artificial recharge of the shallow & intermediate aquifers from the peripheral channels, development of injection wells and rain water harvesting may play significant role for the fulfilment of water demand.

Abstract

This paper deals with the groundwater quality of Maddhapara Granite mine areas. There are two aquifers at Maddhapara Granite mine area. The upper aquifer comprises fine to coarse-grained sands with occasional clays and is of unconfined nature. The upper aquifer belongs to Eocene Tura Formation and Plio-Pleistocene Dupi Tila Formation. The lower aquifer constitutes interconnected fractures and fissures of weathered and fresh Precambrian igneous and metamorphic rocks and is of leaky confined nature. The aquifers are separated by 2 to 12m thick kaolinitic clay aquitard. The concentration of major ions, minor ions and some trace elements were measured in the laboratory to determine the usability of water for domestic and irrigational purposes. The water of the upper aquifer is fresh, soft, potable and suitable for irrigation. The water of the basement aquifer is of high-temperature, -TDS, -pH, –alkalinity. The water of the basement aquifer is not potable and unsuitable for irrigation because of high concentration of some trace elements (Ni, Cd, Cr and Pb) exceeding the WHO (1993) guidelines and medium to high sodium hazard, respectively.

Abstract

Three aquifers have been determined in the study area up to a depth of about 300m. The upper aquifer is composed of fine to very fine sand. Intermediate and lower aquifers are composed of grey fine sand and grey medium to coarse sand, respectively. Maximum groundwater elevation is 4.3m and the minimum groundwater elevation is 1.6m in the study area. In the upper aquifer high concentration of sodium is probably due to recharge of tidal saline water. Higher concentration of calcium in lower aquifer may be due to calcium dissolution. The higher concentration of chloride in lower aquifer indicates mixing of seawater with the groundwater. Nitrate concentration in upper and lower aquifer of the study area is generally low. Average manganese concentration in upper aquifer exceeds the WHO (1993) guideline values. In the upper aquifer barium concentration is very low, but in some lower aquifer samples the barium concentration exceeds the acceptable limit of 1.0 mg/L. Water type of lower aquifer are mainly Mg-Na-HCO3-Cl, Mg-Na-Cl-HCO3 Mg-Na-Cl, Na-Mg-Cl and Na-Cl type. In the upper aquifer the water is mainly Mg-Ca-Na-HCO3 and Na-HCO3 type. Upper aquifer of the study area is highly contaminated with the arsenic but free from salinity. The water of the lower aquifer is generally free from arsenic and suitable for drinking purposes. With few exception most of the water in the study area is good for irrigation.

Abstract

Hydrogeological zonation along with hydrological & hydrogeological assessment of the aquifer system and determination of surface & groundwater source has been carried out in the coastal part of Chittagong city based on geological, geomorphological and hydrogeological information. The study area has been divided into two distinctive zones of hydrogeological characters and these are i) Zone 1 is the Southern Coastal Plane Land Zone and ii) Zone 2 is the Northern Tertiary Hills & Valley Zone. In the Southern Coastal Plane Land Zone (Zone 1) ground elevation varied from 5-10m above sea level. Quaternary sediments are exposed at the surface. Three or four aquifers mainly observed separated by variable thick clay layers. Shallow aquifer composed of loose medium to fine sand of Quaternary age and deep aquifers mainly composed of medium sand. Low transmissivity (290 m2/day) and conductivity (5.44 m/day) value is mainly for the sand and clay intercalation in the Quaternary sediments of the coastal part. Minimum elevation of groundwater in shallow wells varies between -1.58m to -6.39m, for deep wells -10m to -25m. Pumping water level in different production wells varies between -25m to -58m, which might result centrifugal groundwater flow towards the central part and make the deeper aquifer more vulnerable for the sea water intrusion especially in the south-western part. Horizontal inflow and upward vertical movement are two principal mechanisms of sea water intrusion in the shallow and deep aquifer respectively.

In the Northern Tertiary Hills & Valley Zone (Zone 2) ground elevation varied from 49-12m above sea level. Tertiary sediments exposed in the hill range and weathered tertiary sediments found in the valley & slopes of the Tertiary hill and plane land. Two or three aquifers mainly identified are comprised of sands or sandstone of Tertiary age. Aquicludes dividing the aquifers are comprised of clay, silty shale or shale. Aquifer thickness and depth is highly variable probably due to part of an anticline. Most of the CWASA production wells belong in this zone. High transmissivity (1327 m2/day) and conductivity (27.93 m/day) value is probably due to the continuous aquifer of well sorted sand free of clay or silt intercalations that make this zone more suitable for groundwater development than Zone 1. In the deep aquifer average groundwater elevation is -10m and major water gradient observed from north to south. The maximum part of this zone is free from sea water intrusion as the average groundwater elevation is low; ground surface level is high, high pressure water gradient from north east to south west.

Shock-fragmentation of the Ries impact crater forms characteristic and complex fracture patterns from micro- to kilometre-scale. Outside the crater rim, prominent fractures are mainly vertical to sub-vertical, either in radial or tangential orientation to the crater. The traces of radial fractures from various outcrops around the Ries consistently point towards to impact centre and, consequently, represent an excellent tool for locating the crater centre. The presence of prominent fractures in numerous outcrops outside the Ries crater indicates that impact-induced brittle deformation reaches as far as 70 km away from the crater centre. Time series analyses of fracture frequency reveals regularly spaced, ca. 3-4 m interval elongate vertical to sub-vertical zones of high deformation. This periodicity of increased fragmentation appears typical of impact fragmentation. The cyclic repetition of intensely fractured zones and their variations with distance are most likely the results of the interaction of rapidly evolving impact-induced shock waves.

Numerous quarries in and around the Ries me-teorite crater provide an excellent opportunity to study impact-related deformation features and structures in the basement rocks and their thin sedimentary cover. In this investigation, impact-induced brittle deformation features from Malm Limestone exposures outside the inner crater ring are studied. Shock waves cau-se deformation of the target rocks far beyond the range and style typical for regional deformation. The resulting fractures form com-plex patterns from micro- to kilometre scale. In horizontal and vertical directions, fracture patterns vary systemically with increasing distance from the impact centre (Hossain & Kruhl 2014).

Analysis of prominent fracture orientations reveals two main sets of sub-vertical to vertical fractures. One set is tangential and the other one radial to the crater centre. Based on the orientation of the radial fracture set in different outcrops around the crater, the crater centre can be determined (Fig. 1). The fracture sets are observed as far as 70 km away from the crater centre.

Prominent fracture orientation is an important shock deformation feature, which can be used to locate crater centre whose original mor-phology is often barely visible or strongly modified due to erosion. One example is the recently reported 1.2 billion years old impact ejecta near Ullapool (Stac Fada Member of the Stoer Group, NW Scotland). The impact is mainly indicated by the presence of shocked quartz and high 53Cr content (Amor et al. 2008). Our study reveals additional impact-induced brittle deformation features, such as zones of high fragmentation and a systematic orientation of prominent fractures.

Shock waves of the Ries meteorite impact (Fig. 1) caused fragmentation of the target rock far beyond the range and style typical for regional brittle deformation. In horizontal and vertical directions fracture patterns vary systemically with increasing distance from the impact centre. Quantification of fracture patterns with different fractal-geometry methods shows that impact fragmentation largely follows power laws, but to variable extent on different scales and at different locations. Box counting of limestone fracture patterns in a ca. 114 m long and 9 m high vertical section at the crater margin shows two different power-law relationships. They are interpreted as resulting from two different pattern-forming processes: pre-impact compaction of the sediment and impact-induced deformation. The strong pattern anisotropy and its spatial variation are quantified by the Mapping of Rock Fabric Anisotropy (MORFA) method [1]. The pattern’s local systematic variation is interpreted as resulting from shatter-cone style fractures on the dm- to m-scale [2]. The regular variation of complexity and orientation of the fracture patterns seems to be typical for impact-related fragmentation [3].

Fragment size distributions (FSD) and fracture patterns of boulders collected inside the crater show power-law relationships over one order of magnitude, most likely resulting from material excavation through non-ballistic ejection during the impact. The two different power-law relationships for the FSD and fracture patterns of the Ries drill cores, however, demonstrate two subsequent pattern-forming processes. Probably, the first one is related to shock-wave fragmentation, the second one to elastic rebound of the transient crater floor from a depth of ca. 4.5-5 km. Whereas the box-counting dimension (D) of the fragmentation patterns do not vary with depth, the D-values of the two different power-law relationships for FSD of the drill cores decrease. Only at greatest depth of ca. 1200 m the higher D-value is clearly increased. This can be related to stress localization with enhanced comminution [4]. In general, fractal geometry - specifically when based on automated procedures - proves a powerful tool for quantifying and analysing complex rock structures.

Fracture patterns and fragment size distributions (FSD) are parameters frequently used to describe and quantify brittle fabrics of rocks. The Ries meteorite crater represents an excellent example for studying impact fragmentation of thin sedimentary cover and basement rocks. Shock-related brittle deformation is characterized. It includes analyses of large-scale fracture orientations from Malm limestone exposures and quantification of fracture patterns and FSD from boulders and the drill core of the 1973 Ries Research Bore Hole. Fracture orientation analysis leads to two main sets of fractures. Both sets are approximately vertical. One is tangential and the other one radial to the crater centre. Based on the radial fracture set in different outcrops around the crater, the impact centre can be located (Fig.1). Impact-related brittle deformation is observed as far as ca. 71.8 km away from crater centre.

Fractal-geometry-based quantification of fracture patterns in Malm limestone from a vertical N-S section of the Eireiner quarry (Fig.1) suggests impact-related brittle deformation together with pre-impact, possibly compaction-induced fracturing. These two fragmentation processes are indicated by two different fractal dimensions on two different scales. Map Counting and Mapping of Rock Fabric Anisotropy (Peternell et al., 2011) reveal inhomogeneity and anisotropy of the fracture patterns respectively. Fracture patterns and FSD from boulders, again, follow power laws. This is interpreted as resulting from nappe formation during crater growth (Chao et al., 1978). Fracture patterns and FSD from core samples show two different fractal dimensions, interpreted as resulting from, first, fragmentation during impact and, second, from shearing and comminution during elastic rebound of the transient crater basement.

The Ries crater with a diameter of approximately 25 km is a well-preserved meteorite crater, located in Germany at the western border of Bavaria. The crater was formed by a 1.1 to 1.5 km large meteorite, probably of achondritic composition, by an oblique impact 14.6 ± 0.1 (0.2) years ago (Schwarz & Lippolt, 2013) in a two layered target terrain that consisted of approximately 620-750 m sub-horizontally layered water saturated sediments of Triassic to Jurassic age, resting on basement rocks which received their last deformational and metamorphic overprint ca. 320 million years ago (Meyer, 2011). The Ries impact with three distinct parts, centre, inner crater ring, and outer crater rim (Stöffler, 1977; Meyer, 2011), is one of the most extensively studied impact craters from various geological and geophysical perspectives. Fracture networks in outcrops in and around the impact pose new questions regarding impact-related brittle deformation. Based on various fractal-geometry methods, this study presents new data on (i) fragment size distributions (FSD), (ii) density and orientation of fractures, and (iii) inhomogeneity and anisotropy of fracture patterns. The patterns are compared with patterns from different natural and artificial settings and pattern-forming processes are discussed.

The Ries impact crater is a well-preserved complex crater of approximately 25 km in diameter, located in western Bavaria (Germany). The Ries impact crater has been intensively studied from different geological and geophysical perspective to answer the question regarding crater formation mechanics. It has three distinct parts: centre, inner crater ring, and outer crater rim (Stöffler, 1977). Fractures resulting from the meteoritic impact pose questions regarding crater formation mechanics in earth as well as other terrestrial planets and satellites. This study presents new data on impact fracture patterns ranging from tens of meter to centimetre-scale, as scale-dependent variations of fracture patterns provide significant information about fracture-forming processes. Four sets of primary data have been collected from the Eireiner and Gosheim quarries located in the eastern margin of the outer rim of the Ries crater: (i) fracture orientation data in conjunction with the section orientation, (ii) outcrop images of fractured wall rock, (iii) oriented samples (contain cm to mm scale fractures), and (iv) core samples from the Ries research borehole. Stereographic analysis of fracture geometries orientation reveal three sets of fractures in the Eireiner and Gosheim quarries. Vertical to sub-vertical fractures have WNW-ESE strike. The second set of fractures strike approximately NNW-SSE and dip mostly towards the centre of the crater. The third set of fractures are almost similar in orientation to the second set but have opposite dip-direction, i.e. roughly away from the crater centre. These three sets of fractures are in good agreement with the radial, concentric and conical fractures, reported as typical fracture patterns from numerous impact experiments (Polanskey & Ahrens, 1990; Buhl, et al., 2013) as well as from naturally formed impact craters (Kumar & Kring, 2008).

The binary fracture images generated from the digital photographs have been analysed by two individual methods: (i) 2D Box Counting (Kaye, 1989; Turcotte, 1989), and (ii) 1D Cantor Set (Manning, 1994; Merceron & Velde, 1991) to check the fractality of the fracture pattern. It is found that images with a high fractal dimension contain a large number of fractures whereas images with a small fractal dimension contain a small number of fractures and the variation of fractal dimension follows the 5th order polynomial distribution. To understand this spatial variation of fractal dimension, inhomogeneity and anisotropy of fracture distribution patterns have been quantified using two methods originally based on fractal geometry: (i) Map Counting (Peternell et al., 2011) based on 2D Box Counting illustrates an inhomogeneity on the centimetre to meter scale, which corresponds to the regularity of alignment and fracture packing density, and (ii) mapping of rock fabric anisotropy (MORFA) (Gerik & Kruhl, 2009; Peternell et al., 2011) based on 1D Cantor Dust shows correlation between high fractal dimension with less anisotropy which in turn corresponds to more a regular alignment of fractures and a high packing density.