Subsurface Character Research Articles

A synergistic approach to morphotectonic evolution for watershed management in the Bearma River Basin, Central India

Abstract Environmental catastrophes on a global scale have prompted a thorough evaluation of river morphology for sustainable basin development methods. Geomorphological investigations of river basins can provide significant information regarding Quaternary tectonic deformations. The present investigation intends to reveal tectonic imprints in the Bearma River Basin (BRB). Bearma is a significant river in central India that flows through Vindhyan Supergroup, Lameta, and Deccan Trap and contributes to developing the architecture of the marginal Gangetic plain. The digital elevation data has been utilized to obtain the morphotectonic indices, tectonic activity classes, and topographic characteristics. Bearma is an elongated basin with uplifted topography, continuously migrating channels, high hypsometric integral, and several stream length-gradient anomalies, indicating tectonically controlled. According to the tectonic activity index, 15.33%, 38.99%, and 46.55% areas of the BRB have high, moderate, or low tectonic activity, respectively. In conjunction with field investigations, the topographic and lineament study of the BRB has revealed significant relief variations and the importance of tectonic activity over erosion and depositional processes in determining the landscape. Reactivation of basement faults and subsurface lineaments caused by Himalayan tectonics and the Narmada Son North Fault have resulted in the recent deformation and development of the hydrographic network.

Interpretation of aeromagnetic and remote sensing data of Auchi and Idah sheets of the Benin-arm Anambra basin: Implication of mineral resources

Abstract The need for mineral resources for economic development is key in both developing and developed countries. However, miners usually resort to random excavation of mineral deposits without proper investigation to identify structures of interest in target areas. This usually leads to land depletion and abandonment. The aim of this study is to assess the mineral potential in part of the Benin-arm of the Anambra basin by investigating the geophysical characteristics of the area using remote sensing and aeromagnetic data. Surface and subsurface regional structures, including faults and zones of mineralisation, were mapped by integrating aeromagnetic and remote sensing data. The mineral bearing zones that show high prospects of mineral deposits in the region were identified. The rose diagram revealed that the surface lineaments are aligned in the NW–SE, N–S, NE–SW, E–W, NNE–SSW, ENE–WSW, and ESE–WNW directions. The orientations of the subsurface lineaments are aligned mostly in the NE–SW, N–S, and E–W directions. The magnetic intensity ranged between −431.38 and 399.82 nT, while reduction-to-pole magnetic intensity ranged from –416 to 664.45 nT. The first vertical derivative showed magnetic intensity which ranged from –0.5863 to 0.9060 nT/km2. The total horizontal derivative magnetic intensity ranged from –0.00031 to 0.762691 nT/km2, while the analytic signal showed magnetic intensity ranging from 14.0664 to 394,607.3438 nT/cm2. The windowed Euler deconvolution depth to magnetic source showed depth range of <20 to 2,000 m. Many of the features delineated in the study area were characterised by shallow magnetic source depths (<500 m); this is a common characteristic of basement complex terrains. Deeper magnetic source depths (>1,000 m) were observed in the sedimentary terrain. Mineral exploration should be focused in areas with high lineament concentration, as lineaments are potential conduits for economic minerals deposition.

Morphotectonic Analysis of Wadi Al-Batin Alluvial Fan, South of Iraq, Using Remote Sensing and GIS Techniques

This research aimed to know the tectonic activity of the Wadi Al-Batin alluvial fan using hydrological and morphotectonic analyses. Wadi Al-Batin alluvial fan is deposited from Wadi Al-Rimah in Saudi Arabia, which extended to Iraqi and Kuwait international boundaries. The longitudinal and transverse faults that characterize this region were common. The Abu- Jir-Euphrates faults have a significant impact on the region. The faults zone consists of several NW- SE trending faults running from the Rutba in western Iraq to the south along the Euphrates through Kuwait and meeting the Al-Batin fault to the Jal Al-Zor fault. The Hydromorphometric analysis of the present fan shows five watersheds having asymmetry shapes, more elongated and activity from the elongation ratio and asymmetry factor values. In contrast, transverse topographic symmetry and mountain front sinuosity factor have moderate to low activity from the stream length gradient index. The morphotectonic analysis suggests that the Wadi Al-Batin alluvial fan has a moderate tectonic activity due to the tectonic activity of the subsurface lineaments and the oil field activities found in the region.

Heavy Oil Potentials in Central Sumatra Basin, Indonesia Using Remote Sensing, Gravity, and Petrophysics Data: From Literature Review to Interpretations and Analyses

Central Sumatra basin is located on Sumatra Island, Indonesia, and is considered an oil prolific basin that produces heavy oil. The basin is believed to have unexplored heavy oil potential. Therefore, this study aims to map the heavy oil potential distribution in the basin using surface and subsurface lineaments analyses interpreted from satellite imagery and gravity data, and assisted by well log/petrophysics analysis. A thorough basin analysis was conducted based on surface/subsurface structures’ control and source rock location settings to map all potential heavy oil traps. The gravity anomaly data interpretation identified the low areas and lineaments in NW – SE, and N – S directions. The interpretation of satellite imageries showed very similar lineament patterns with the same general direction. It was observed that there is continuity between subsurface and surface lineament features, which provide contact between reservoirs and surface water sources, thereby facilitating heavy oil generation. Overlapping the lineament interpretation of gravity and satellite imagery data, supported by petroleum system understanding and verification from wells data have confirmed 7 heavy oil trap potential areas within the sedimentary basin.

Lineaments Tracing of Magnetic Sources Depending on the Aeromagnetic Data: Case Study in Salman Basin and Surrounding Areas, Southern Desert of Iraq

This study deals with the processing and analysis of aeromagnetic data for an area covering the region of Salman Basin within AL- Muthanna, Iraq. The objective of this study is to use the available satellite images and aeromagnetic data to investigate the boundaries of geological structures. For further understanding of the tectonic of the study area, the Centre for Exploration Targeting Grid Analysis extension which is available in Oasis montaj software was applied to the data. It is proposed that it provides unbiased results, but to check the results Tilt Derivative or local phase derivative is used where the zero-contour line of the tilt derivative strongly delineates the edges of structures. Also, the drainage pattern for the basin is done using Geographic Information System and Digital Elevation Model raster to see if the drainage is affected by the subsurface lineaments that are determined using the Centre for Exploration Targeting technique. As a result, the deep main linear features follow the general trend of the main faults that formed the Salman Basin. The new lineaments were discovered using the Exploration Targeting grid analysis, zero contour of. There are two systems of lineaments in the present study area. The first set is taken the NW-NE direction perpendicular to the extensional structures, while the second set has the NS-EW direction.

Establishing an integrated workflow identifying and linking surface and subsurface lineaments for mineral exploration under cover: example from the Gawler Craton, South Australia

Abstract. Mineral exploration in areas comprising thick and complex cover represents an intrinsic challenge. Cost- and time-efficient methods that help to narrow down exploration areas are therefore of particular interest to the Australian mining industry and for mineral exploration worldwide. Based on a case study around the Tarcoola gold mine in the regolith-dominated South Australian central Gawler Craton, we suggest an exploration targeting workflow based on the joint analysis of surface and subsurface lineaments. The datasets utilised in this study are a digital elevation model and radiometric data that represent surface signals and total magnetic intensity and gravity attributed to subsurface signals. We compare automatically and manually mapped lineament sets derived from remotely sensed data. In order to establish an integrated concept for exploration through cover based on the best-suited lineament data, we will point out the most striking differences between the automatically and manually detected lineaments and compare the datasets that represent surficial in contrast to subsurface structures. We further show how lineaments derived from surface and subsurface datasets can be combined to obtain targeting maps that help to narrow down areas for mineral exploration. We propose that target areas are represented by high lineament densities which are adjacent to regions comprising high density of lineament intersections.

Determination of subsurface lineaments in the Hoang Sa islands using enhanced methods of gravity total horizontal gradient

The Hoang Sa islands, located in the northern part of the East Vietnam Sea, lack information on geological structural boundaries. The gravity data from the global marine gravity model were analyzed using the enhanced total horizontal gradient methods to delineate geological structures that appear as lineaments on the transformed gravity anomaly maps of the area. Before applying the techniques to gravity data of the Hoang Sa islands, their effectiveness was demonstrated by comparing them with the results from the total horizontal gradient method for a synthetic model. Applying the enhanced horizontal gradient methods shows that most of the lineaments identified in the Hoang Sa islands are trending in the WSW-ENE, NE-SW, E-W, WNW-ESE and NNW-SSE directions. These results provide a better understanding of the subsurface structural features of the islands.

High precision structural mapping using edge filters of potential field and remote sensing data: A case study from Wadi Umm Ghalqa area, South Eastern Desert, Egypt

Recently, detecting the edges and geologic structures (deep and shallow) from potential field sources provides a fundamental tool for interpreting geological structures. Therefore, the high precision computation of the edges of potential sources is becoming an essential requirement for studying subsurface structures. In this study, nine common detectors like tilte angle (TA), Theta-map (TM), Horizontal tilt angle (TDX), hyperbolic tilt angle (HTA), Improved tilt angle (ITA), Tilt angle of the total horizontal gradient (TTHG), Tilt angle of the total gradient (TTG), improved Theta-map (ITM), and improved logistic (IL) were applied. These filters have been tested on theoretical models and real data (aeromagnetic) from the Wadi Umm Ghalqa area, South Eastern Desert of Egypt. The obtained results have shown that the improved logistic (IL) filter could detect edges more successfully than the other eight filters. The results of the IL method were used to generate new accurate structural maps for local and deep components of the investigated area. Moreover, surface structures obtained from remote sensing data were considered to control the interpretation of the mapped subsurface lineaments. Hence, the IL method can be utilized as a sharp tool for the high precision structural imaging of the potential data.

Applications of the Kuwahara and Gaussian filters on potential field data

Edge detection methods based on derivatives of potential fields have been commonly utilizing to interpret the potential field data. Although these techniques are very useful tools for determining subsurface lineaments, they have some limitations such as sensitivity to noise, thick or diffuse detected boundaries and blurred edges. In this study, the Kuwahara filter, an edge enhancement operator which has smoothing, edge preserving and edge sharpening effects, is proposed to enhance the boundaries in the potential field data without above-mentioned limitations. Three synthetic model applications are made to demonstrate the mentioned advantages of the Kuwahara filter. The effect of the window size on the filter response has been studied and demonstrated in detail. After that, the total horizontal derivative, analytic signal and vertical gradient of the Kuwahara filter responses of the noisy synthetic gravity dataset have been calculated and compared with those calculated from the original data. In addition, it has been shown that the results can be further improved by applying the Gaussian smoothing to the Kuwahara filter responses. Finally, the Bouguer gravity dataset compiled from Konya-Beyşehir region in Turkey have been utilized to show the performance of the Kuwahara filter on real data. Both synthetic and real data applications have shown that more clearly edges and detailed results can be obtained from the datasets filtered by using the Kuwahara and Gaussian filters.

Mapping geologic structures from Gravity and Digital Elevation Models in the Ziway-Shala Lakes basin; central Main Ethiopian rift

This study attempts to delineate subsurface lineaments for the tectonically and volcanically active region of the Ziway-Shala Lakes basin, central Main Ethiopian rift. Most of the previously mapped subsurface structures in the region under consideration focus on delineating crustal structures thicknesses and Moho depths undulations. Moreover, surface structures in the same region were mapped using analysis of Digital Elevation Model image data. On the other hand, there are few studies that have targeted in mapping geologic structures lying at depth levels between the shallower and deeper subsurface. The objective of this research is thus to map the subsurface geologic structures/lineaments to an average depth of 3 km (crystalline basement layer depth) from surface using gravity data. These investigation results are validated by Digital Elevation Model extracted lineaments. Filtering techniques including derivative filters, upward-continuation and line module algorithm of PCI Geomatica are used to extract the gravity and topographic lineaments of the region. Orientation analyses of these subsurface and surface lineaments are made using line direction histogram of the QGIS software. Accordingly, the gravity subsurface lineaments mapped in this study are found to be dominantly oriented in the NNW-SSE to NW-SE and E-W direction on average. These results appear to be contrary to the NNE-SSW to NE-SW trending surface geologic structure mapped on the bases of actual field observation carried out by previous researchers and automatically extracted lineaments based on Digital Elevation Models data considered in this research. The subsurface lineaments mapped using gravity data are believed to govern groundwater dynamics within the basin and the adjacent basins in the area. These structural lineaments which are considered to be masked in the subsurface coincide with the orientation of the Mesozoic Ogaden rift as compared to the overlying surface structures which appear to coincide with the orientation of the Cenozoic Main Ethiopian rift.

Identification of Micro-Earthquake Hypocenters using Geiger and Coupled Velocity-Hypocenters Methods

The accuracy location of hypocenter is needed to determine the subsurface character beneath a geothermal area. The study used 73 micro-earthquake events; each micro-earthquake event was classified based on the time difference between the P and S waves (ts-tp) that had values ≤ 3seconds, the magnitude of micro-earthquake ≤ 3SR and each micro-earthquake event was recorded at least by 3 observer stations. We inverted selected P and S travel times from 11-unit seismic stations on X geothermal area. The initial hypocenter location was determined using Geiger method. The result of the Geiger method's initial hypocenter location was then used as the input to determine the accurate hypocenter location in the following method, Coupled Velocity-Hypocenters method. Other parameters were also used on this second method, including hypocenter location, 1-D velocity model, origin time, vp/vs ratio, zshift and the station correction. The distribution of hypocenter locations of micro-earthquakes obtained using the second method was better than the results from Geiger method. This result is supported by the Coupled Velocity-Hypocenters average RMS error value, which was smaller, only 0.19 seconds, compared to the Geiger method, which had an average RMS error of 0.74 seconds. The hypocenter location of the relocation was more clustered in the reservoir area, precisely in the production well, and in the heat source area. The hypocenter location in the production well area indicates fluid flow through the fracture from the permeable zone.

Structural interpretation of magnetic and satellite remotely sensed data of Osun State, Southwestern, Nigeria

ABSTRACT This study delineates surface and subsurface structural features in the hard rock terrain of Osun State using magnetic data and satellite remote sensing imageries. To achieve this aim, several image enhancement methods were applied to the magnetic data and satellite remotely sensed imageries to improve visualization and interpretation. The subsurface lineaments were detected and traced out from the maxima of Horizontal Gradient Magnitude, peaks of Analytical Signal Magnitude, and an Euler solution of Osun state. The magnetic lineament map reveals that the structural trend in the area is dominant by NE-SW and NNE-SSW. These structural trends were found to be consistent with the regional tectonics of the Southwest Basement of Nigeria. The NE-SW is the most conspicuous structural trend in the study area. The satellite imageries depict a characteristics feature of the occurrence of underlying structures in the basement complex of Osun State. The major lineament trends delineated in the composite surface lineament map are the NE-SW, NNE-SSW, and ENE-WSW directions. The 2.5 D model across the unmapped lineaments confirmed the existence of a thin dyke’s characteristic of fracture/fault in a typical basement complex terrain. The derived lineaments may serve as a reference for future geological and structural mapping.

A geomagnetic analysis for lineament detection and lithologic characterization impacting groundwater prospecting; a case study of Buffalo catchment, Eastern Cape, South Africa

A lithostratigraphy analysis commonly adopted for subsurface structures exploration in oil prospecting is deployed for groundwater prognosis, due to the need to address the prevailing water shortage. In this study, the lithology characterization was based on a clustered approach of geomagnetic analysis, geomorphometric analysis, and sequence stratigraphy correlation across the Buffalo catchment, Eastern Cape, South Africa. The result showed the existence of a spatial correlation between the tectonic stress field and the surficial lineaments. Similarly, a significant azimuthal correlation (WNW-ESE) was found between surficial lineaments (203 m–6249 m), subsurface lineaments, and the neotectonic structures. The depth-slicing analysis enables the estimation of the depth of the tectonic stress field, at 382 m, 577 m, 913 m, 1.49 km, and 10.7 km in the subsurface. The sequence stratigraphy correlation based on borehole lithology data enables the identification of the fault system at the contact zones, heterolithic bedding, and the characterization of the hydrostratigraphic domain of the catchment. The study shows that Buffalo hydrostratigraphic structures are dominated by fracture networks, whereby the shallow groundwater resources are possibly hosted by the dolerite-host rock contact zones in the north of the Buffalo catchment. Specific recommendations concerning groundwater management are made to water and environment stakeholders considering the vulnerability of the shallow groundwater system to pollution in the permeable contact zones of dolerite-host rock. The study also recommends the adaptation of surficial lineaments as a morpho-tectonic aid and a hydrostratigraphic analysis tool. The clustered approach demonstrated in this study has important prospects for groundwater exploration in environments with similar geology.

Delineation of hydrocarbon potential zones in Masila oil field, Yemen

Hydrocarbon is a powerful contributor to development. The present study makes an attempt to use remote sensing data coupled with geophysical and geological data that has been integrated into Arc GIS to delineate favorable zones for hydrocarbon potential in the Masila oil field. Lineaments have been extracted using satellite data and geological data by their surface spectral signatures, whereas the subsurface lineaments have been inferred using geophysical data. Digital image processing of satellite image using ERDAS IMAGINE-14 have been carried out, sequentially using various techniques (Sobal, Laplacian filters and band composite), lineament digitized as layers, layers were converted to raster (grid) format, classified, analyzed, integrated and visualized using Arc GIS. The resulting lineaments obtained from each data, suggests that most of the lineaments are trended in NW–SE which coincides and are in conformity with the existing trend of the study area. The output potential map was classified into five zones of hydrocarbon potentiality, namely very high, high, moderate, low and very low potential zones. The hydrocarbon evaluation results of the present study reveal that 6.9% of the total area falls under very high potential, 14.2% highly potential, 21.3% moderately potential, 25.7% low potential and 31.9% falls under very low potential zones. The zones were verified with oil fields and existing wells in the area which shows a positive correlation. Such studies are significant for hydrocarbon potential resource planning and management. Further, the methodology used for this study can be, replicated in another similar geological setup elsewhere for mapping hydrocarbon potential zones.

Evolution of high-Arctic glacial landforms during deglaciation

Glacial landsystems in the high-Arctic have been reported to undergo geomorphological transformation during deglaciation. This research evaluates moraine evolution over a decadal timescale at Midtre Lovénbreen, Svalbard. This work is of interest because glacial landforms developed in Svalbard have been used as an analogue for landforms developed during Pleistocene mid-latitude glaciation. Ground penetrating radar was used to investigate the subsurface characteristics of moraines. To determine surface change, a LiDAR topographic data set (obtained 2003) and a UAV-derived (obtained 2014) digital surface model processed using structure-from-motion (SfM) are also compared. Evaluation of these data sets together enables subsurface character and landform response to climatic amelioration to be linked. Ground penetrating radar evidence shows that the moraine substrate at Midtre Lovénbreen includes ice-rich (radar velocities of 0.17 m ns−1) and debris-rich (radar velocities of 0.1–0.13 m ns−1) zones. The ice-rich zones are demonstrated to exhibit relatively high rates of surface change (mean thresholded rate of −4.39 m over the 11-year observation period). However, the debris-rich zones show a relatively low rate of surface change (mean thresholded rate of −0.98 m over the 11-year observation period), and the morphology of the debris-rich landforms appear stable over the observation period. A complex response of proglacial landforms to climatic warming is shown to occur within and between glacier forelands as indicated by spatially variable surface lowering rates. Landform response is controlled by the ice-debris balance of the moraine substrate, along with the topographic context (such as the influence of meltwater). Site-specific characteristics such as surface debris thickness and glaciofluvial drainage are, therefore, argued to be a highly important control on surface evolution in ice-cored terrain, resulting in a diverse response of high-Arctic glacial landsystems to climatic amelioration. These results highlight that care is needed when assessing the long-term preservation potential of contemporary landforms at high-Arctic glaciers. A better understanding of ice-cored terrain facilitates the development of appropriate age and climatic interpretations that can be obtained from palaeo ice-marginal landsystems.

Gabor Deconvolution as Preliminary Method to Reduce Pitfall in Deeper Target Seismic Data

Anelastic attenuation process during seismic wave propagation is the trigger of seismic non-stationary characteristic. An absorption and a scattering of energy are causing the seismic energy loss as the depth increasing. A series of thin reservoir layers found in the study area is located within Talang Akar Fm. Level, showing an indication of interpretation pitfall due to attenuation effect commonly occurred in deeper level seismic data. Attenuation effect greatly influences the seismic images of deeper target level, creating pitfalls in several aspect. Seismic amplitude in deeper target level often could not represent its real subsurface character due to a low amplitude value or a chaotic event nearing the Basement. Frequency wise, the decaying could be seen as the frequency content diminishing in deeper target. Meanwhile, seismic amplitude is the simple tool to point out Direct Hydrocarbon Indicator (DHI) in preliminary Geophysical study before a further advanced interpretation method applied. A quick-look of Post-Stack Seismic Data shows the reservoir associated with a bright spot DHI while another bigger bright spot body detected in the North East area near the field edge. A horizon slice confirms a possibility that the other bright spot zone has smaller delineation; an interpretation pitfall commonly occurs in deeper level of seismic. We evaluates this pitfall by applying Gabor Deconvolution to address the attenuation problem. Gabor Deconvolution forms a Partition of Unity to factorize the trace into smaller convolution window that could be processed as stationary packets. Gabor Deconvolution estimates both the magnitudes of source signature alongside its attenuation function. The enhanced seismic shows a better imaging in the pitfall area that previously detected as a vast bright spot zone. When the enhanced seismic is used for further advanced reprocessing process, the Seismic Impedance and Vp/Vs Ratio slices show a better reservoir delineation, in which the pitfall area is reduced and some morphed as background lithology. Gabor Deconvolution removes the attenuation by performing Gabor Domain spectral division, which in extension also reduces interpretation pitfall in deeper target seismic.

Three deep resource plays in the San Joaquin Valley compared with the Bakken Formation

A continuous oil accumulation is one that is pervasive throughout a large area and is not affected by natural hydrodynamic influences. Three source rocks in the San Joaquin Valley of California are actively producing hydrocarbons and represent potential continuous oil accumulations: the Monterey, Kreyenhagen, and Moreno Formations. The Energy Information Administration announced in 2014 that there are potentially 15 billion bbl of recoverable oil in the Monterey Formation in California, spiking huge interest. Such a resource would make the Monterey by far the largest continuous oil accumulation in North America. This number has since been reduced dramatically to 600 million bbl of oil for the state and 21 million bbl of oil within the San Joaquin Valley. In this study, the subsurface character of the Bakken Formation of North Dakota is compared with the three source rocks in the San Joaquin Valley at oil window depths. To characterize these reservoirs, hundreds of well logs, core descriptions, and mud logs were studied. A technique to rank character of oil show data was developed in which interesting, possibly interesting, or not interesting wells were located on thermal maturity maps. Interesting wells have significant oil shows, whereas not interesting wells have minor or no shows. In the Bakken Formation, the character of the oil show correlates with well productivity. Applying this same classification to the San Joaquin Valley source rocks leads to a more disappointing conclusion. Although there are oil shows in the source rocks of the San Joaquin Valley at oil window depths suggesting the presence of a continuous oil accumulation, the distribution of shows is both laterally and vertically heterogeneous and not predictable. Moreover, recent attempts to produce from source rocks at these depths have not been economically successful. We conclude that the three source rocks in the San Joaquin Valley represent heterogeneous and discontinuous oil accumulations at oil window depths in the subsurface. Likely there are billions of barrels of oil in these discontinuous oil accumulations. Source rocks in the Bakken are rated as world class; source rocks in the San Joaquin Valley are good to excellent quality. However, the quality of the oil shows in the San Joaquin Valley appears poorer than the Bakken Formation. It is possible that effective drainage between the source rocks and the up-dip reservoirs has left large volumes of the source rocks at oil window depths with only residual oil saturation. Complex structural and stratigraphic architecture, heterogeneity, and continuity create issues of predictability for optimal areas to target. Rapid rates of subsidence over the past few million years and accompanying thrusting and folding resulted in a complex subsurface pressure regime. The lack of clear hydraulic fracture targets, analogous to the middle Bakken, further complicates drilling decisions and likely deliverability. In addition, the oil windows in the San Joaquin Valley are significantly deeper than the Bakken Formation, which would result in substantially higher well cost. Recent drilling results support this study and suggest that heterogeneous and discontinuous oil accumulations in the San Joaquin are unlikely to become economic without dramatic changes in technology.

CURVGRAV-GUI: a graphical user interface to interpret gravity data using curvature technique

CURVGRAV-GUI is an open source software that was developed to interpret gridded gravity data by using curvature technique. It was developed using C# language with Microsoft.NET Framework 4.0. This program calculates the critical and extreme points, and estimates the depths of source bodies at this points. Besides, CURVGRAV-GUI processes gravity data by using minimum curvature, one of the attributes of curvature, and detects the subsurface lineaments. It is a user-friendly application that can display obtained solutions and gravity data thanks to image and scatter maps. CURVGRAV-GUI was designed to develop both synthetic and field applications. Additionally, the β constant, a parameter related to the source geometry, was examined for different source types such as sphere, horizontal and vertical cylinder and thin vertical fault. This program was tested by using two synthetic model applications. In the first synthetic model application, it was used a complex synthetic model consisting of three sphere and a horizontal cylinder located at the different depths. In the second synthetic model application, a graben model consisting of two thin vertical fault was used. Finally, the performance of the CURVGRAV-GUI was tested with using a real gravity data belonging to Kozakli-Central Anatolia region, Turkey. Very successful results were obtained for both synthetic and field data. Earth scientist can use CURVGRAV-GUI for educational experiments.

Integrating millennial and interdecadal shoreline changes: Morpho-sedimentary investigation of two prograded barriers in southeastern Australia

Prograded barriers are distinctive coastal landforms preserving the position of past shorelines as low relief, shore-parallel ridges composed of beach sediments and commonly adorned with variable amounts of dune sand. Prograded barriers have been valued as coastal archives which contain palaeoenvironmental information, however integrating the millennial timescale geological history of barriers with observed inter-decadal modern beach processes has proved difficult. Technologies such as airborne LiDAR, ground penetrating radar (GPR) and optically stimulated luminescence dating (OSL) were utilised at Boydtown and Wonboyn, in southeastern Australia, and combined with previously reported radiocarbon dates and offshore seismic and sedimentological data to reconstruct the morpho-sedimentary history of prograded barrier systems. These technologies enabled reconstruction of geological timescale processes integrated with an inter-decadal model of ridge formation explaining the GPR-imaged subsurface character of the barriers. Both the Boydtown and Wonboyn barriers began prograding ~7500–8000years ago when sea level attained at or near present height along this coastline and continued prograding until the present-day with an initially slower rate of shoreline advancement. Sources of sediment for progradation appear to be the inner shelf and shoreface with a large shelf sand body likely contributing to progradation at Wonboyn. The Towamba River seems to have delivered sediment to Twofold Bay during flood events after transitioning to a mature estuarine system sometime after ~4000cal. yr BP. Some of this material appears to have been reworked onto the Boydtown barrier, increasing the rate of progradation in the seaward 50% of the barrier deposited over the past ~1500years. The GPR imaged beachfaces are shown to have similar geometry to beach profiles following recent storm events and a model of ridge formation involving cut and fill of the beachface, and dune building in the backshore, explains the character of the preserved beachface record and the morphology of the ridges. This model is applicable to future management of individual beaches where such beaches are subject to ongoing cut and fill, dune building processes and inherited sediment budget conditions.

Renewed Archaeological Investigations at the Bowles Creek (41CE475), Cornfield (41CE476), and Peach Orchard (41CE477) Sites in the Bowles Creek Valley, Cherokee County, Texas

There are a number of Allen phase Historic Caddo sites on Bowles Creek (Figure 1), a southwardflowing tributary to the Neches River in the East Texas Pineywoods, including the Bowles Creek (41CE475), Cornfield (41CE476), and Peach Orchard (41CE477) sites (Perttula and Stingley 2016a, 2016b; Perttula et al. 2016). In conjunction with remote sensing investigations conducted by Dr. Duncan P. McKinnon (University of Central Arkansas), renewed archaeological investigations have been completed in January 2016 at these three sites to better understand the subsurface character of their archaeological deposits.