S. Back

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Hemin Koyi

Uppsala University

Gabriel Gutierrez-Alonso

University of Salamanca

Peter B Golden

Rutgers, The State University of New Jersey

Marlene Laruelle

The George Washington University

Paulo Emanuel T F Fonseca

Universidade de Lisboa

Sergey Abashin

European University at St. Petersburg

Gaurav Srivastava

BSIP

Rashmi P Joshi (Sawalkar)

Sant Gadge Baba ,Amravati , University

Ali Eisawi

AL-Neelain University

Jana Javornik

University of East London

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Papers by S. Back

3D depositional architecture of a non-tropical carbonate shelf, Eocene-Oligocene, Browse Basin (NW Australia)

Seismic Expression of Sedimentary Processes on a Carbonate Shelf and Slope System, Browse Basin, Australia – Part II – Tropical Carbonates

71st EAGE Conference and Exhibition incorporating SPE EUROPEC 2009, 2009

Tectonic and sedimentation of the northern part of the Livingstone basin, lake Nyasa, Tanzania

Three-dimensional seismic analysis of sediment waves and related geomorphological features on a carbonate shelf exposed to large amplitude internal waves, Browse Basin region, Australia

Sedimentology, 2014

ABSTRACT This study analyses the three-dimensional geometry of sedimentary features recorded on t... more ABSTRACT This study analyses the three-dimensional geometry of sedimentary features recorded on the modern sea floor and in the shallow subsurface of a shelf to upper slope region offshore Australia that is characterized by a pronounced internal wave regime. The data interpreted comprise an extensive, &gt;12,500 km² industrial three-dimensional seismic-reflection survey that images the northern part of the Browse Basin, Australian North West Shelf. The most prominent seismic–morphological features on the modern sea floor are submarine terrace escarpments, fault-scarps and incised channels, as well as restricted areas of seismic distortion interpreted as mass wasting deposits. Besides these kilometre-scale sea floor irregularities, smaller bedforms were discovered also, including a multitude of sediment waves with a lateral extent of several kilometres and heights up to 10 m. These sedimentological features generally occur in extensive fields in water depths below 250 m mostly at the foot of submerged terraces, along the scarps of modern faults and along the shelf break between the outer shelf and the upper continental rise. Additional bedforms that characterize the more planar regions of the outer shelf are elongate, north-west/south-east oriented furrows and ridges. The formation of both sediment waves and furrow-ridge systems requires flow velocities between 0.3 m s-1 and 1.5 m s-1, which could be generated by oceanic currents, gravity currents or internal waves. In the studied setting, these velocities can be best explained as being generated by bottom currents induced by internal waves, an interpretation that is discussed against oceanographic background data and modelling results. In addition to the documentation of three-dimensional seismic–geomorphological features of the modern sea floor it was also possible to map kilometre-scale buried sediment wave fields in the seismic volume down to ca 500 ms two-way-time below the present sea floor, indicating the general potential for the preservation of such bedforms in the sedimentary record.This article is protected by copyright. All rights reserved.

A combined 3D surface-subsurface model of the middle Miocene Belait Delta, onshore Brunei Darussalam, NW Borneo

Analysis of the Cretaceous and Cenozoic successions offshore Namibias

ABSTRACT Multiple phases of volcanism, uplift and subsidence are recorded after the breakup of th... more ABSTRACT Multiple phases of volcanism, uplift and subsidence are recorded after the breakup of the Namibian South Atlantic margin segment - features which are regarded as atypical when compared to published examples of other post-breakup continental margin successions. It is currently not understood whether these geodynamic processes are only of regional or a broader, South Atlantic intercontinental importance. On the basis of 5000km of high resolution 2D wireline seismic data from offshore northern and central Namibia, regional differences in uplift, subsidence and sedimentation rates of one selected southern South Atlantic margin segment are analysed. The study area is parallel to the Namibian coastline, covering about 45.000 km2. Integrated analysis and calibration of seismic data with well-logs and biostratigraphic data of 3 industry wells enables the subdivision of late Cretaceous and Cenozoic strata in seismic stratigraphic units that can be traced over the entire study area. Thicknesses of each seismic subunit are analysed using isopach maps, aiding the identification of variable subsidence and sedimentation trends. A more detailed sequence stratigraphic analysis of selected subbasins is then used to discuss the controls for the observed regional variation of subsidence and sedimentation pattern offshore Namibia.

Sedimentology of the Jalan Selaiman and Bukit Melinsung outcrops, western Sabah: is the West Crocker Formation an analogue for Neogene turbidites offshore

Tectonic vs. eustatic control on the 3D sedimentary architecture of a carbonate succession from the Browse Basin, NW-Australia: An integration of well logs, 2D-and 3D-seismic data

ABSTRACT An extensive and multivariate dataset from the Browse Basin on the Australian NW-shelf p... more ABSTRACT An extensive and multivariate dataset from the Browse Basin on the Australian NW-shelf provides the opportunity to gain a comprehensive picture of the area by combining the benefits of several data types. From the Early to Middle Miocene onward, the carbonate sediment system of the Browse Basin is characterized by tropical reef growth. Reef growth terminates during the earliest Late Miocene by stepwise drowning, preceded by a subaerial exposure event. 3D-seismic data from two adjacent multichannel seismic dataset covering more than 1000 km2 provide valuable insights on the geometries and timely development of the reef system, thus contributing to a better spatial understanding of such systems. The analysis of seismic attributes and facies allows further constraints on the distribution of rock fabrics. The regional context of the sedimentary system is provided by a large -scale network of 2D-seismic lines, documenting the tectonic framework for the evolution of the sedimentary succession. This allows to determine the influence of subsidence, respectively uplift caused by the approach of the NW-shelf to the Sunda-Banda arc subduction zone. Additionally, wireline logs, isotopic records and core material from two wells provide stratigraphic control and additional paleoenvironmental information from microfossils and isotope data. The integration of these data allows a correlation of features of the Browse Basin carbonate shelf to global events and thereby an estimation of the proportional influence of tectonics and eustasy on the evolution of the tropical reef system. Generally the succession of the depositional features in the Browse Basin conforms to a pattern recognised in several other carbonate sediment systems from the Indo-pacific region, both tropical and non-tropical, implying a strong impact of eustatic changes, despite the active tectonic setting.

3D depositional architecture of a non-tropical carbonate shelf, Eocene-Oligocene, Browse Basin (NW Australia)

Calciclastic gravity-flow deposits accumulated on continental margins can form potentially very i... more Calciclastic gravity-flow deposits accumulated on continental margins can form potentially very important and attractive targets for hydrocarbon exploration. A correct reservoir characterization of calciclastic slope deposits needs a robust understanding of their sedimentary facies and three-dimensional depositional architecture. Conventional 2D grids often lead to a spatial aliasing whenever the size of submarine gullies and canyons is less than the spacing of the grid. In contrast, high-resolution 3D seismic data are ultimately comparable in resolution to those achieved by multi-beam bathymetry of the present seafloor. Seismic data from the western part of the Browse Basin, North West Shelf, Australia, reveal the internal geometry and depositional history of a progradational Eocene-Oligocene non-tropical carbonate shelf. The prograding slope system is superbly imaged by two adjacent, three-dimensional multichannel seismic volumes embedded in a two-dimensional multichannel seismic ...

Deformation style and basin-fill architecture of the offshore Limón back-arc basin (Costa Rica)

Marine and Petroleum Geology, 2007

The Limo´n back-arc basin, located at the eastern coast of Costa Rica, is part of the southern Ce... more The Limo´n back-arc basin, located at the eastern coast of Costa Rica, is part of the southern Central American arc-trench system. Basin evolution started in Late Cretaceous times as response to the onset of the subduction of the Farallo´n Plate below the Caribbean Plate. The Limo´n Basin can be subdivided into a northern and a southern sub-basin separated by the E-W trending Trans Isthmic Fault System. A regional grid of offshore seismic lines allows the comparative analysis of the basin-fill architecture and the deformation style in both sub-basins. The northern sub-basin shows exclusively normal faults. The basin-fill architecture resembles a passive continental margin setting showing a distinct wedge-shaped geometry and seaward propagating depositional units. The area of the Rio San Juan Delta is characterized by gravity-driven, deltaic deformation exhibiting a series of listric growth faults both on the shelf and in slope areas. In contrast to the northern basin, the southern sub-basin is characterized by the development of thinskinned fold-and-thrust belt tectonics best recorded in concentric or asymmetric hangingwall anticlines separated by listric or planar southwestward dipping thrust faults. Due to the pronounced NE-propagating of folding the shelf is broader and the slopes are steeper in the southern sub-basin, compared with the northern sub-basin. Thus both sub-basins show a very different tectonic style. In the North Limo´n Basin an extensional regime established, whereas in the South Limo´n Basin compression dominated. However, in both sub-basins the basal detachment is probably controlled by a lithological change from limestone to shale.

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The structural evolution of folds in a deepwater fold and thrust belt – a case study from the Sabah continental margin offshore NW Borneo, SE Asia

Marine and Petroleum Geology, 2010

The deepwater fold and thrust belt offshore Sabah, NW Borneo, is located on a continental margin ... more The deepwater fold and thrust belt offshore Sabah, NW Borneo, is located on a continental margin that hosts a number of proven hydrocarbon accumulations. Reprocessed and depth-migrated regional 2D seismic data reveal the occurrence of a wide range of compressional, syn-depositional deformation features including large-scale thrust faults and prominent thrust-hangingwall anticlines. This paper focuses on the documentation and detailed description of the style of deepwater folds and the associated stratal patterns within a study area of ca. 3000 km 2 offshore Sabah, NW Borneo. This region exhibits a variety of fold systems including (1) anticlines with large interlimb angles that exhibit no seafloor expression; (2) anticlines with medium interlimb angles, seafloor relief and a faulted anticline crest; (3) anticlines with small to medium interlimb angles, a seafloor expression and flanks associated with slides and slumps, and finally; (4) anticlines with small interlimb angles that are commonly buried by a thick sedimentary overburden and, in places, modified by superimposed syn-sedimentary, deltaic normal faults. If analysed section per section perpendicular to the strike of the fold and thrust belt, the widest anticlines occur in the most seaward parts of the fold belt near the present-day thrust front, whereas the narrower anticlines are located further landward. However, if viewed along the strike of the deepwater fold belt, there are significant variations in the geometry of laterally corresponding, contemporaneously developing fold systems. To explain these differences, factors such as rock inhomogeneities in the deformation wedge, variable surface slope, irregular basement topography, differential sediment input or the presence or absence of subsurface gas hydrates need to be taken into account. These factors vary significantly within the studied system, and are therefore difficult to generalise and transfer to other submarine fold and thrust belts.

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Stratigraphic development of synkinematic deposits in a large growth-fault system, onshore Brunei Darussalam

Journal of the Geological Society, 2005

... Back, S. &amp;amp; Lambiase, JJ 2001. Deep-water reservoirs of NW Borneo: evaluating pote... more

Estimating hinterland exhumation from late orogenic basin volume, NW Borneo

Journal of the Geological Society, 2008

ABSTRACT A new approach for restoring sediment volumes onto the sediment source area to estimate ... more ABSTRACT A new approach for restoring sediment volumes onto the sediment source area to estimate uplift timing and magnitude is discussed and used in the context of late Tertiary basin and topographic development in NW Borneo. Sediment volumes for the Baram Deltaic Province were estimated for four time periods (latest Early, Middle and Late Miocene, and Pliocene-Recent), using 2D and 3D seismic horizons, wells and outcrops. Volume restoration onto the palaeo-sediment source area determined exhumation amount at the drainage divide (c. 5 km from 17 Ma to Recent) and provided a reasonable match with other denudation estimation methods (cooling ages and an older, regional sediment restoration study using 1979 vintage sediment isopach maps). Restoration took into account: (1) changing sediment densities during the erosion-deposition cycle; (2) changing area of the sediment source province with time (e.g. changing shoreline location as a result of eustacy, uplift and delta progradation, tectonic shortening); (3) uplift and partial erosion of Baram Deltaic Province sediment. Denudation at the drainage divide for the Middle Miocene, Late Miocene and Pliocene-Recent has proceeded at a similar rate for each period. Initial uplift of central Borneo has been attributed to buoyancy of thinned continental crust that jammed the subduction zone under NW Borneo in the Early Miocene. However, the absence of decay in the erosion rates with time from the Middle Miocene to Recent suggests operation of an additional uplift mechanism that may be related to delamination of mantle lithosphere; slab detachment is the favoured explanation.

Characteristics of repeated, detached, Miocene–Pliocene tectonic inversion events, in a large delta province on an active margin, Brunei Darussalam, Borneo

Journal of Structural Geology, 2003

The Baram Delta province evolved during the Middle Miocene to present day from a foreland basin t... more The Baram Delta province evolved during the Middle Miocene to present day from a foreland basin to a shelf margin. Episodic folding events affected the region, causing uplift of the hinterland, delta progradation, and inversion of gravity-related faults. Existing models place the N-Sand NE-SW-trending folds in a strike-slip transpressional setting. New geological mapping and re-interpretation of existing data suggest the region is better understood as the development of a west-verging thrust belt in a Middle Miocene foreland basin (filled by sandstones and shales of the Belait and Setap Formations), with key major folds (Jerudong and Belait anticlines, Belait syncline) forming during the Middle Miocene as fault bend and fault propagation folds. The deformation style is complicated by the predominantly shaley Middle Miocene-Pliocene Setap Formation becoming thicker and more overpressured from south to north. Onshore where the Setap Formation is thin or absent, the Belait formation is attached to the underlying Lower Miocene and older sequences. Offshore and in a narrow onshore strip the overpressured Setap Formation causes deformation in the Beltait Formation to be detached from the underlying Cretaceous-Tertiary accretionary prism 'basement'. The detached style exhibits considerable structural complexity, including lift-off folds, growth faults, shale diapirs and pipes. Onshore thrust and inversion features are dominantly N-S-trending and began activity in the Middle Miocene; deformation is probably associated with an E-W maximum horizontal stress direction. In the Late Miocene (around 7.5 Ma; Watters et al., 1999) NE-SW striking inversion folds developed, located mostly over early counter-regional faults and associated reactive diapirs. Folds verge towards the NW when underlain by counter regional faults, and towards the S or SE when underlain by regional faults. Folds and diapirs along N-S trends were also reactivated. Continuation of this deformation into the Pliocene is largely confined to the offshore area. Onshore the N-S structures (no detachment) were not reactivated during the Pliocene.

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Fault Controls on Sediment Distribution Patterns, Lim�n Basin, Costa Rica

Journal of Petroleum Geology, 2007

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Autotracking of faults on 3D seismic data

GEOPHYSICS, 2006

Manual fault mapping in 3D seismic interpretation is labor-intensive and time-consuming. Complex ... more Manual fault mapping in 3D seismic interpretation is labor-intensive and time-consuming. Complex fault geometries and the distortion of the seismic signal close to faults complicate full automation of the fault-mapping process. We present a semiautomatic fault-tracking method for 3D seismic data that consists of fault highlighting followed by model-based fault tracking. Fault highlighting uses log-Gabor filters for emphasizing oriented amplitude discontinuities at faults in the presence of noise. Subsequent fault tracking fits an active contour to the highlighted fault voxels. The active contour searches for a connected, smooth curve which fits the data and disambiguates misleading or missing information. The fault tracker requires the interpreter to place the active contour close to a fault on one initial seismic inline (2D pick). The active contour deforms to the closest amplitude dis-continuity highlighted. This tracking result is then projected forward to the next inline, provid...

The deep-water fold-and-thrust belt offshore NW Borneo: Gravity-driven versus basement-driven shortening

Geological Society of America Bulletin, 2009

The deep-water region offshore NW Borneo is an active fold-and-thrust belt that hosts a signifi c... more The deep-water region offshore NW Borneo is an active fold-and-thrust belt that hosts a signifi cant number of proven hydrocarbon accumulations. In the past, two mechanisms have been discussed as pri- mary control for Neogene to Holocene fold- ing and thrusting in this deep-water prov- ince: (1) basement-driven crustal shortening and (2) gravity-related delta tectonics. In this study, new, balanced

Reviewers for Basin Research 2011

Basin Research, 2012

We would like to thank all people listed below for their expert reviews of submitted manuscripts ... more

Three-dimensional restoration of original sedimentary geometries in deformed basin fill, onshore Brunei Darussalam, NW Borneo

Basin Research, 2008

The western £ank of the Jerudong Anticline, onshore Brunei Darussalam, provides a rare opportunit... more The western £ank of the Jerudong Anticline, onshore Brunei Darussalam, provides a rare opportunity to analyse the base of a major Miocene mud-rich delta in outcrop, including kilometre-scale prograding clinoforms, delta-front turbidites and large-scale syndepositional faults.The lateral continuation of this system in the subsurface of the Belait Syncline is documented on twodimensional (2D) re£ection seismic data and wireline logs. In order to link geological observations at surface with corresponding geophysical subsurface signatures, we constructed a combined, quantitative 3D surface^subsurface model of onshore Brunei Darussalam.This 3D model is used to analyse and discuss the relation between ¢eld geology and geophysical subsurface interpretation, and provides the base for a quantitative kinematic restoration of the Miocene Belait delta to its original shape before folding. Final decompaction of the balanced rockvolume allows the reconstruction of the palaeo-relief of a series of Miocene clinoforms, indicating a close relation between delta-lobe activity, clinoform morphology and the generation of delta-front turbidites.

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