ISSUE16 | FEB2010

www.gso.org.om

Page 02...President’s Message

Page 02...Note from the Editor

Page 03...A World-class Exposure

Page 08...Structural Evolution

Page 12...Fault Geometries in North Oman

Page 14...Sealing of Faults

Page 19...Neogene Compressional Structures

Page 22...Field Trip Report

Page 25...International News

Page 28...AGM Report

Page 29...Publications 2009

Page 33...Upcoming Events Page 2

President’s Message

Dear GSO Members,

On behalf of the GSO Executive proactive approach to geological 2010 season and I would like you to Committee I welcome you to the 2010 projects that serve preservation and come forward with your contributions GSO activity season. knowledge dissemination of our to GSO activities. The Society is This year is going to be very special geological heritage in Oman. For the best platform for discussion and as GSO will be celebrating its 10th this, the Society needs your input and sharing of your ideas and projects with Anniversary which will coincide with support. the wider geoscientist community. the 40th National Day for Oman. Geophysics and hydrogeology In summary, I would like to thank Thus, please join us to make it a very are two fields that we would like to all of you for your commitment and special geological year for the Society see more contribution from in our contribution, and to encourage you to and Oman. activities. I urge all geophysicists and stay connected to the Society though Since its inception, GSO has achieved hydrogeologists to contribute to GSO its activities and programs. much but many milestones are yet activities for the coming season and to be met. 2010 is going to be very share their knowledge and experience Regards, challenging, as we need to diversify with Society members. Dr. Mahmood Saif Al Mahrooqi our activities and have a more This al Hajar issue is the first for the GSO – President

Note from the Editor

Hi All,

Welcome to the 16th Edition contributed an International News Manager for the Middle East Learning of Al Hajar. This edition focuses on section and our upcoming events Hub for Shell Development Oman. the structural aspects of Oman’s section can be found on the last page. He brings an infectious enthusiasm geology with excellent contributions As the temperature starts to rise the for Omani geology to the role and an from GUTech, PDO and Shell. We field trip season draws to an end undeniable passion for life!! I’m sure would, as always, be delighted to but we will still continue with talks. you will join me in extending a warm hear your feedback on these articles. Upcoming talks include Measuring welcome to Ru as Editor. Drop a line to ‘The Ed.’ and we will Climate Change in the Arctic & in Just remains for me to say publish any thoughts you wish to April, one outlining EOR techniques thank you for all of your support – share. We also include a publications applicable in Oman. I look forward to I have thoroughly enjoyed the last two list detailing research in the Sultanate seeing you there. years as Editor and look forward to for 2009. I’m sure you will join me in This is my last edition as seeing the GSO go from strength to thanking John Aitken for diligently Editor as shortly Carlos & I will leave strength. providing this over the last few years. Oman. Ru Smith will now take over As always, IHS have generously this role. Ru is currently Programme Very best regards, Caroline

Front Page Al Hajar 16th edition Feb 2010 Page 3

A World-class Exposure of a Fossil High Pressure Cell on the Southern Flank of Jabal Shams in the Oman Mountains Max Arndt, Simon Virgo, Zoe Soebisch, Marc Holland, Christoph Hilgers, Janos L. Urai, Geological Institute, RWTH Aachen University and Department of Applied Geoscience, German University of Technology GUTech, Muscat, Oman.

Abstract The exhumed Cretaceous Our study area is located on the of which we find the vein density carbonates on the southern flank of Jabal southwest flank of Jabal Shams, throughout the entire field area to Shams in the Oman Mountains offers the highest peak of the Al Jabal al be very high (Holland et al., 2009). a world-class, ultra high resolution look Akhdar domal structure (Figure 1a, The detailed field into the inner workings of high pressure e.g. Glennie et al., 1974; Beurrier observations in excellent exposures cells which are common in sedimentary et al., 1986; Loosveld et al., 1996; provide the basis for a model of basins and contain large oil and gas Breton et al., 2004; Glennie, 2005; the multiphase evolution of the Jabal Shams high-pressure cell in deposits. This more than 2 km thick Al-Wardi, 2006; Hilgers et al., 2006a; Searle, 2007). accordance with the work of Hilgers sedimentary pile develops a complex Several deep wadis cut the et al. (2006a). This evolution is and rapidly changing set of continuously dip slope and offer impressive vertical illustrated by the schematic drawing forming and re-sealing fractures, leading profiles of which the tallest section shown in Figure 2. The earliest to a complex mechanical stratigraphy at Wadi Nakhr offers a continuous structures (V1) are a series of and producing several generations of vertical exposure of approximately 1 anticlockwise rotating veins (Figures pervasive regional fault and vein sets. km. The strata expose the Sahtan, 3, 4 and 5). Burial extension and the formation of Kahmah and Wasia groups of the The first of these formed overpressures led to the formation of Hajar Supergroup (Figure 7). in a north-south trending direction numerous fracture generations in an The emphasis of this study is (Figure 2b), followed by a set striking anticlockwise rotating stress field. This the characterization of the structural approximately 130º (Figure 2c), was followed by bedding-parallel shear evolution (Figure 2). These are 090º (Figure 2d) and 045º (Figure under lithostatic fluid-pressure conditions predominantly brittle deformation 2e). All vein sets are perpendicular at a minimum temperature of 134–221°C. fractures and faults (Figure 1b) to the bedding, have large apertures The high pressure cell was drained along dilatant normal faults that were also repeatedly cemented and reactivated.

Introduction The southern flank of Jabal Shams in the Oman Mountains offers a world-class outcrop of high pressure cells. The Structural Geology group of RWTH Aachen and the Department of Applied Geoscience of GUtech in Muscat has been studying these unique outcrops for the past 5 years, in projects funded by Shell International

and more recently by DGMK. Figure 1a: Landsat overlay on DEM showing the field area

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Figure 1b: Simplified map showing study area (rectangle) together with interpreted faults. The lithology of interest spans primarily the Wasia Group with the Nahr Umr and Natih formations as well as the Kahmah Group. After Holland et al., 2008

0 0 with blocky calcite cement. The geometry of the fracture shows no signs for interaction between the fracture sets in abutting or curving. Rapid sealing of the fractures and thereby a restored tensile strength is interpreted to be the major cause for the dense spacing of this pattern. The tensile effective stresses required for the formation of this regional vein system may have been formed in response to overpressure build-up during burial, perhaps in combination with outer- arc extension during emplacement of the Hawasina and Semail nappes. The joints in the ramp are normal to bedding, suggesting that the ramp postdates the jointing process. The south to southwest vergence of the ramp could indicate its relation to the emplacement of the Hawasina Figure 2: The evolution of the regional fracture network is interpreted to result from multiphase de- and Semail nappes. formation: (a) sets of veins with prominent apertures. (b, c, d, e) These fractures are formed perpen- The next stage is bedding dicular to the bedding probably as a response to high fluid pressures. The open-mode fractures are parallel shear (Figure 6), which cemented with white calcite. (f) An isolated ramp structure is interpreted to have formed next with a indicates a major change of the top-to-south-southwest movement. (g) Bedding parallel shear with a top-to-north and northeast move- effective stress tensor. Bedding- ment postdates the bedding-perpendicular veins forming layer-parallel veins and shear zones. Normal parallel veins indicate fluid faults (h) develop in the next stage, and nucleate partly along the anisotropy of the striking veins. (i) Exhumation, neotectonics and weathering lead to the opening of joints (simplified sketch, not to scale; pressures close to lithostatic. and arrow points north).

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Figure 3: Exposed carbonate bed with different sets of veins and joints. Cementation, spac- Figure 4: Complex vein network on polished surface with mul- ing and apertures differ between the different sets. tiple strike directions. system (Hilgers et al., 2006a). The faults nucleated as en-échelon vein sets or along the preexisting veins in the 090º and 130º strike direction. This means that these faults cannot be simply used to infer the principle stress directions, because of the anisotropy. A detailed geological map and profile of the SE-part of the area is shown in Figs. 9 and 10. The uncemented joints exposed in plane and profile views all strike into the directions of the first vein group perpendicular to

Figure 5: Example of an overprinting relationship: A thin vein striking approximately 045º offsets two the bedding (Figures 2i and 8). 130º striking veins. The uncemented joints generally cementation repeatedly restored the rock strength during deformation. The shear movement is top-to-north and top-to-east (Figure 2e). This direction – opposite to the nappes’ emplacement – suggests that these shear zones were formed after the nappe emplacement. An event like this is discussed in detail by Al- Wardi and Butler (2006). The next major change in effective stress, under continuously high fluid pressures, led to strongly dilatant normal faults (Figure 7) with strike-slip components that offset the bedding-parallel shear zones. These have a distinct isotopic signature indicating meteoric Figure 6: The bedding-perpendicular veins (d1) are cut and offset by layer-parallel veins. The latter are influence, draining the high pressure heavily cemented with bright calcite (pocket knife for scale; outcrop in Wadi Nakhr).

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Figure 8: Orthogonal joint set of only two strike directions. Photo width approximately 10 meters.

Figure 7: Interpreted cliff exposure of the fault zones exposed at the western wall of Wadi Nakhr. The vertical exposure is 500 m and spans several formations. The fault system has straight segments where the thick stack of the Shu’aiba and Kharaib formations are offset against each other and splays towards the contact to the up- per Nahr Umr Formation, which deforms more like a monocline.

have higher densities and locally

much higher densities. In some cases, beds with open joints are on Figure 9: Synthetic perspective view of the QuickBird satellite image top of beds with cemented hairline warped on to a low-resolution ASTER DEM. The zoomed excerpt shows fractures with the same orientation. the mapping area with the distribution of mapping units. The white Line This indicates that some open joints shows the location of the profile shown in Figure 10 have formed as a result of dissolution and weathering. Another explanation could be that the joints were formed as relaxation fractures at exhumation, which would explain their ubiquitous presence. In the latter case, the denser spacing could reflect a change of the elastic properties of the rock as an effect of its P/T path. The influence of the neotectonic movements is a possible contributor to the joints as well. Fractures in cemented terraces inside Wadi Nakhr indicate recent tectonic movement that presumably guided erosion of the Wadi Nakhr canyon in the Pleistocene (Rodgers and Gunatilaka, 2003; Kusky et al., Figure 10: Profile through the Western part of the mapping area. Black lines are faults. Dashed black 2005). lines are faults inferred in depth. Recorded offset ranges from less than a meter to several hundred me- ters (northern fault).

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The high-pressure cell of Noorishad et al., 1996; Tsang, transport properties, as well as the Jabal Shams proves to be a natural 1999; Olsson and Barton, 2001). mechanical strength of the system, example of thermal, hydraulic, and The high fluid pressures and were constantly changing as the mechanical processes (Bradley, the repeated cementation of the calcite cement sealed the fractures. 1975; Zoback, 1978; Noorishad fracture system led to the formation et al., 1984; Bradley, 1994; of a complex fracture network. Its

Acknowledgements We thank Jean-Michel Larroque, Joachim Amthor, Jan Schreurs, Pascal Richard, Jean Paul Breton, Muhammad al-Wardi, and Manuela Gutberlet for support at various stages of this project, for providing data, scientific discussions and help with organizing the various field campaigns.

References (just a few ; Searle, 2007). Glennie, K.W., M.G.A. Boeuf, M.W. Hughes-Clarke, M. Moody-Stuart, W.F.H. Pilaar and B.M. Reinhardt 1974. Geology of the Oman Mountains (Parts 1, 2 and 3). The Hague, Martinus Nijhoff, Verhandelingen Koninklijk Nederlands Geologie en Mijnbouw Genootschap, v. 31. Beurrier, M., F. Bechennec, G. Hutin and D. Rabu 1986. Rustaq, Geological Map Oman, Scale 1:100,000,Sheet NF40-3D. Ministry of Petroleum and Minerals, Sultanate of Oman. Breton, J.-P., F. Béchennec, J. Le Métour, L. Moen-Maurel and P. Razin 2004. Eoalpine (Cretaceous) evolution of the Oman Tethyan continental margin: Insights from a structural field study in Jabal Akdhar (Oman Mountains). GeoArabia, v. 9, no. 2, p. 1-18. Holland, M., N. Saxena and J.L. Urai (in press). Evolution of fractures in a highly dynamic thermal, hydraulic, and mechanical system (II) – Interpretation of remote sensing data of Jabal Shams, Oman Mountains. GeoArabia (in press). Holland, M. and J. Urai (in prep.). The faults and fractures in the Mesozoic carbonates of Jabal Shams, Oman Mountains (II) fracture analysis based on satellite image interpretation. Hilgers, C., D.L. Kirschner, J.-P. Breton and J.L. Urai 2006a. Fracture sealing in a regional, high-pressure cell in Jabal Akhdar, Oman mountains - first results. Geofluids, v. 6, no. 2, p. 168-184. Hilgers, C., S. Nollet, J. Schoenherr and J.L. Urai 2006b. Paleo-overpressure formation and dissipation in reservoir rocks. Oil Gas European Magazine 2, p. 68-73. Loosveld, R.J.H., A. Bell and J.J.M. Terken 1996. The tectonic evolution of interior Oman. GeoArabia, v. 1, no. 1, p. 28-51. Glennie, K.W. 2005. The Geology of the Oman Mountains - An outline of their origin. Scientific Press Ltd. Al-Wardi, M. 2006. Structural evolution of the Jebel Akhdar culmination and its implications for exhumation processes in the northern Oman Mountains. University of Leeds. Al-Wardi, M. and R.W.H. Butler 2006. Constrictional extensional tectonics in the northern Oman Mountains, its role in culmination development and the exhumation of the subducted Arabian margin. In, A.C. Ries, R.W.H. Butler and R.H. Graham (Eds.), Deformation of the Continental Crust: The Legacy of Mike Coward. Geological Society of London, 272, p. 187-202. Rodgers, D.W. and A. Gunatilaka 2003. Bajada formation by monsoonal erosion of a subaerial forebulge, Sultanate of Oman. Sedimentary Geology, v. 154, nos. 3-4, 127. Kusky, T., C. Robinson and F. El-Baz 2005. Tertiary-Quaternary faulting and uplift in the northern Oman Hajar Mountains. Journal of the Geological Society, v. 162, no. 5, p. 871-888. Bradley, J.S. 1994. Pressure compartments in sedimentary basins; a review. In, D.E. Powley (Ed.), American Association of Petroleum Geologists Memoir 61. Zoback, M.D. and D.D. Pollard. Hydraulic fracture propagation and the interpretation of pressure- time records for in situ stress determinations. 19th U.S. Symposium on Rock Mechanics, Mackay School of Mines, University of Nevada, 1, p. 14-22. Noorishad, J., C.-F. Tsang and P.A. Witherspoon 1984. Coupled thermal-hydraulic-mechanical phenomena in saturated fractured porous rocks: Numerical approach. Journal of Geophysical Resources, v. 89, issue B12, p. 10,365-10,373. Tsang, C.-F. 1999. Linking thermal, hydrological, and mechanical processes in fractured rocks. Annual Review of Earth and Planetary Sciences, v. 27, no. 1, p. 359-384. Olsson, R. and N. Barton 2001. An improved model for hydromechanical coupling during shearing of rock joints. International Journal of Rock Mechanics and Mining Sciences, v. 38, p. 3, 317 p.

Front Page Al Hajar 16th edition Feb 2010 Page 8

Structural Evolution of Salakh Arch

Mohammed Al-Kindi, PDO

Having a strike-length of about Maradi Strike-Slip Fault, to form what hydrocarbon fields in the foreland 75km, Salakh Arch is the southern is known as the Adam foothills. The region, and recently, there has been gate for the North Oman Mountains, Arch is approximately 40 km from the more interest to re-explore the area (Figure 1). If you drive from south hydrocarbon-producing Natih and for hydrocarbon accumulations. to north Oman, the first high-flying Fahud fields and developed along The surface curvature of the feature is Jebel Salakh, standing the eastern edge of Fahud Salt Basin fold structures in Salakh Arch shows 1063m above sea level. Indeed, in a chain of anticlines that are from box-fold geometry (i.e. two hinges); everybody can feel their domal (turtle- E to W: Madmar, Hinaydil, Salakh, apart from Jebel Madmar which back) structures. That is what caused Nihaydah and Qusaibah. The Salakh has a gentle wide hinge. Surface Sir Wilfred Thesiger (so known in structure is divided to two parts: mapping of faults and fractures Arabia as Mubarak Bin London) to Salakh-E and Salakh-W. These indicate various trends and intensity write in his classic book “Arabian two parts differ significantly in their of deformation (Figure 3). Overall Sands” describing Jebels Madmar geometries and they are separated by the maximum shorting is roughly and Salakh in 1940s: “both of them a distinct gap. The area was explored oriented N-S. Normal faults and were dome-shaped, and I thought for hydrocarbon accumulation: extensional fractures that trend regretfully that their formation was Qusaibah-1 and Madmar-1 wells roughly perpendicular to the fold of the sort that geologists associate were drilled in the Arch in 1969 and structures occur mainly in Nihaydah, with oil”, read more in the newspaper in the late 1980s respectively. The the western part of Jebel Salakh- article, (Figure 2), provided by Alan drilling tests were disappointing. Heward. Nonetheless, the area has The Salakh Arch is concave remained an attraction for the towards the North. It occurs in hydrocarbon industry as it the central part of Oman, south of forms a good stratigraphical Hawasina nappes and NE of the and structural analogue to the

Figure 1: A Geological map of the study area (Salakh Arch). The inset illustrates the location of the Oman Mountains (Al-Kindi, 2006)

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Figure 2: Newspaper article recording the drilling of Madmar structure in 1989 (Courtesy of Alan Heward )

Figure 3: A summary of the orientations of fractures (rose diagrams) in the various Jebels. The figure also highlights the areas (red arrows) with arc parallel or oblique ex- tension. The black arrows show the orienta- tion of the maximum compression in various parts of the Arch as suggested by the fold-axis orientations and/or the paleostress analyses of σ-1 (red dots in the stereonets) from the kinematics of strike-slip faults. The numbers of measurements is shown next to each rose diagram. The green lines show the hinge areas in various Jebels in Salakh Arch as illlustrated below. Apart from Madmar, all Jebels in Salakh Arch have two hinges, illustrating box-fold geometry (Al-Kindi, 2006)

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West and in Madmar. Reverse faults form striking features and mostly underwent more or less pure compressional movement (vertical slickensides). They mainly occur in the flanks of the Jebels. The most important of them is the one in south Madmar, where Natih-E (deposited in Late Cretaceous) is overthrust on Barzman Formation (Late Tertiary) (Figure 4), which indicates that Salakh Arch was most likely formed during Late Tertiary or Early Quaternary. A number of fault-propagation folds Figure 4: Overthrusting of Natih-E on top of Barzman on this major bounding reverse fault in southern flank of Madmar indicates Late Tertiary or Early Quaternary formation of Salakh Arch. can be seen also, particularly in the northern flanks of Jebel Madmar, (Figure 5). These reverse faults are largely splays of the major blind reverse faults that bound the Jebels or they could also be reactivated Late Cretaceous NW-SE normal faults. Strike slip faults occur mainly in the areas of oblique or lateral ramps. Pre-existing faults have contributed in the segmentation of Salakh Arch folds. The gap between Madmar and Hinaydil, as well as the gap between Hinaydil and Salakh are controlled by Figure 5: A fault-propagation fold in the northern flank of Madmar. Note that the fold develops on the pre-existing Late Cretaceous faults as bend of the reverse fault. The fault is steeply dipping in the competent (more stiff) beds compared to designated by seismic data . the incompetent ones; all is Natih-B lithology. Seismic has not been acquired across the jebels themselves, but the seismic lines that were shot in the gaps between the Jebels are very useful. Seismic interpretation is highly uncertain particularly in the core of fold structures. Unfortunately, the fold cores are usually the most important areas to deduce the style of deformation. Various tests, restoration and balancing were done on the available seismic sections to understand the continuity and sense of movement on the bounding faults.

Figure 6: A map-view restoration of the Salakh Arch using the shortening values (in km) measured di- These show that the most likely rectly from seismic sections or estimated from surface cross sections (yellow line is the present limit scenario is a thin-skinned deformation of the Arch and the blue is the restored original position). The yellow arrow shows the regional orien- with a sole thrust along the Ara tation of Tertiary compression, whereas the red arrows show the orientation of maximum horizontal Salt (Figure 7). The oblique ramp stresses at different areas in Salakh Arch. In the frontal ramp areas, the strain is mainly compressional of Nihaydah underwent significant (pure shear), whereas in oblique ramp areas the hanging wall materials get deflected and result in strike-slip deformation as manifested transpressional (reverse and strike slip deformation), Al-Kindi, 2006.

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Figure 7: Seismic line from Salakh Arch interpreted as thin-skinned structures with sole detachment along the salt, Location is shown above Al-Kindi, 2006.

by the surface strike-slip faults that trend parallel to the fold axis and by the steep geometry of the subsurface bounding faults (usually indicative of transpressional deformation). In summary, regional data and detailed evaluation of Salakh Arch evolution and hence the compression of the Late Tertiary system in Oman indicates a combination of both overthrust (thin-skinned) and upthrust (thick-skinned) tectonism. Many of the detaching thrusts are plausibly linked or breached from northern basement faults. In general five factors were identified as controls on the geometry and position of the Salakh Arch. These are: the thickness of deformed sediment, the variation of salt Figure 8: Group photos taken in the Geological Excursion to Salakh Arch, led by Mohammed Al-Kindi, thickness along the Arch, pre-existing Heiko Hillgartner and Redha Al-Lawati (thanks for Flora Kiss for taking the photo). basement faults, allochthonous units (namely the Hawasina nappes) and the margin slope.

Front Page Al Hajar 16th edition Feb 2010 Page 12 Fault Geometries in North Oman

Pascal Richard, PDO

fault length (or height), the vertical fault segments (see Filbrandt et al Faults are important elements and lateral continuity as well as the 2007 for more detailed reading and affecting most of the oil and gas fields impact of mechanical stratigraphy on more references on the subject). The of Oman. They tamage zones. On these the fault segmentation. The outcrops actual fault trace geometry is used to outcrops, geoscientists can observe the detailed fault geometries and elaborate (Figure 1) described in this paper are infer the original fault segments. An geometrical rules that helpi in the building on the southern flank of Jebel Shams, earlier stage of evolution of the similar of static models and interpreting faults on north of Tanuf and to the South-West fault growth and coalescence process seismic. The outcrops help to understand of Sinaw in Jebel Madar. These is also visible to the south of the large which simplifications are acceptable in outcrops can be visited in 2 days. fault (e.g. UTM 541477-2552034). At sub-surface modelling. In this paper, we this locality, one can look southeast- illustrate some of the best examples of Fault throw profile and relay wards towards a relay ramp between faults and discuss the concept of fault ramp example two smaller faults. segmentation. We also compare the These faults are linear, about natural examples to analogue models Along the track from Tanuf and seismic examples. up Jebel Shams excellent views are 2 km long with vertical offset in the afforded to the South over the Natih region of 30 to 40 m. With further dip-slope and across to the ophiolites deformation they would coalesce and Introduction form a single fault. The recognition of The southern flank and the in the distance (e.g. from UTM 543103 these relay ramp structures is important foothills of the Oman Mountains offers 2553456). A 4 km fault scarp can be for exploration and production alike. fantastic outcrops which, in PDO observed in the Natih formation For example, assuming a sealing (Petroleum Development Oman) we The fault is composed of fault plane, one might consider drilling have been using to train for decades approximately four segments now a well in a large fault dip closure if our petroleum engineers. One of the linked at bends in the fault trace. the fault mapped as a single plane. important subjects of these training The fault trends WNW-ESE and is However, in reality there is no closure sessions is about fault geometries and amongst the largest in the family of since the relay ramp is a location associated damage zones at different faults exposed on the dip-slope. The where hydrocarbons would leak. scales. The key geometrical elements fault is a result of progressive growth which can be investigated are the and coalescence of originally smaller

Figure 1. Location of the outcrops discussed in the paper. Vertical fault

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Figure 2. Fault escarpment on the structural slope of Jebel Shams. The lines are used as guide to mark the bedding surfaces.

Figure 3. Relay ramp between 2 segments of normal faults. segmentation The fault segmentation observed in map view exists as well in a vertical sense (Figure. 5). Steeply dipping faults cut through the Salil and Rayda formations (Jurassic – Cretaceous) and can be observed in a cliff some 100m high (UTM 52129- 2564145). The same fault zone can be followed across the entire cliff when standing at the top of the eastern edge of the wadi (Holland et al, 2009). Several fault segments can be traced (the major ones are indicated with dashed line on Figure 2.). A dense zone of calcite veins occurs in the relay between the 2 major fault segments. The development of the brecciated and cemented zone corresponds a squeezed block created in a compressional fault overlap (see to Zee et al 2005 for more background reading and references). The observed geometries can be

used to highlight the short coming and

Figure 4. Satellite picture and digital elevation model illustrating the fault geometries. simplification interpreters are facing Vertical fault segmentation. since seismic resolution can not capture such detailed geometries; hence simplification is required. However, it is critical to keep in

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Figure 5. Segmented fault zone (left) and close up on compressional overlap structure (right). The yellow represent typical seismic wavelets with 25 m spac- ing and illustrates the lines limited seismic resolution. Note the car for scale. mind the difference between the modelled faults and the geological reality in order to take the right decisions when it comes to drilling and field development. Another important example for Oman exploration and production is the example of vertical fault segmentation that can be observed in Jebel Madar (Figure 6). There, the outcrops offer spectacular examples of the impact of mechanical stratigraphy on fault propagation. The outcrops are made of competent massive carbonate of the Shuaiba and Natih formations separated by a less competent unit, the Nahr Umr Formation. It is possible to follow faults in the carbonates Figure 6. Vertical fault segmentation across the across the Nahr Umr formation. and observed whether or not the faults are continuous and visible in the Nahr Umr. The faults are in fact systematically interrupted in the Nahr Umr where it is not possible to trace them. This observation is critical for many seismic interpretations in Oman, where faults are developed in the Natih and the Shuaiba formation and they can easily be wrongly interpreted to cut the Nahr Umr in a similar way. Analogue models and seismic application Figure 7. Analogue model (A) and seismic (B) cross section of a vertically segmented fault. The blue Analogue models have and black lines on the seismic section represent two alternative ways of modelling the fault in a sub- been used since the early 1800’s to surface model. Front Page Al Hajar 16th edition Feb 2010 Page 15

help understand the development and the geometry of the faults in the Conclusions. of geological structure. Analogue overburden can be observed (see Zee Hopefully, these few lines on faults models are, in short, miniatures of et al, 2003 for more details). Note the in North Oman will have triggered an geological reality and are scaled difference between the faults below irresistible desire to go and visit these down for the mechanical properties, the OWE layer (Nahr Umr equivalent) outcrops. If so, please do so and enjoy deformation mechanism and time and the sand layers above. Oman geology. Every wadi and every (Hubbert, 1937). Fault segmentation The concept of fault segmentation can jebel contain hidden geological jewels has been intensively investigated be used to interpret fault on seismic which are waiting to be discovered. using this technique. In the example sections while the resolution does not Remember, however, to behave shown, the model was constructed reveal individual segments (Figure 5, safely in respect of the environment using horizontal layers of two distinct Figure 7). Depending on the level of & weather forecast and leave behind materials, a ductile Nahr Umr analogue detail of the sub-surface model, as a detailed journey management plan. (an oil water emulsion OWE on Figure well as the importance of the faults 7) and a brittle Carbonate analogue for the field development, one might (dry sand), overlying a basement fault decide to simplify the fault to a single dipping at 45 degrees. Movement plane (blue line on Figure 7B) or on the pre-existing basement fault to interpret the fault as a number of creates normal faulting in the multi- segments (black lines on Figure 7B). layered sedimentary overburden

References Filbrandt, J.B., S. Al-Dhahab, A. Al-Habsy, K. Harris, J. Keating, S. Al-Mahruqi, S.I. Ozkaya, P.D. Richard and T. Robertson 2006. Kinematics interpretation and structural evolution of North Oman, Block 6, since the Late Cretaceous and implications for timing of hydrocarbon migration into Cretaceous reser- voirs. GeoArabia v. 11, no. 1, p. 97-140. Filbrandt, J.B., Franssen, R.C. and Richard, P.D., 2007. Fault growth and coalescence: insights from numerical modelling and sandbox experiments. GeoArabia, Vol. 12, No. 1, p 17-32. Holland, M. Urai, J.L., Muchez, P. and Willemse, M. 2009. Evolution of fractures in a highly dynamic thermal, hydraulic, and mechanical system – (I) Field observations in Mesozoic Carbonates, Jabal Shams, Oman Mountains. GeoArabia, v. 14, no. 1, 2009, p. 57-110. Hubbert, M.K.. Theory of scale models as applied to the study of geologic structures, Geol. Soc. America Bull., 48, (1937) 1459-152O. Zee, vd W., Urai, J.L. and Richard, P.D., 2003. Lateral clay injection into normal faults. GeoArabia, Vol. 8, No. 3, p. 499-520.

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Scaling of Faults and Fractures by Clay Sediment on Jebel Hafeet - Field Observations and Modeling

Heijn van Gent(1), *Erik Wanningen (1), and Marc Holland(1#), Janos L. Urai(1) (1) RWTH Aachen, , Germany and GUtech Muscat ([email protected]) (*) Now at Statoil-Hydro, Norway (#) Now at Geomechanics International

Introduction Carbonate reservoirs contain a large Oman Mountains (Noweir, 2000, see Faulting of brittle cohesive part of the world’s hydrocarbon also Figure 1).The young back-thrust- materials (such as carbonate reserves and there is a lot of interest in related anticline shows abundant reservoirs) often leads to the formation improving understanding of fractures normal fault systems parallel to the of open fault sections. The flow of in carbonate reservoirs. However, fold axis, which are interpreted to be formation water and hydrocarbons is good quality outcrops of massively related to outer-arc extension and uplift strongly influenced by these cavities dilatant fault zones in carbonates are (Figure 2). These normal fault zones (Holland et al., 2006). rare. Outcrops in Tertiary carbonates in the area can be massively dilatant. This project, funded by Shell on Jebel Hafeet, on the border Apertures of several decimetres are International, and run in cooperation between the United Arab Emirates common, predominantly filled with with RWTH Aachen and GUtech and Oman, expose some examples carbonate veins, crushed wall rock Muscat, was aimed at improving the in carbonates deformed at shallow or clay sediment (Figure 2a and understanding of fluid flow properties depths. Jebel Hafeet is one of a b). These sediments differ from the of faults and fractures in carbonates. series of foreland anticlines of the wall rock and often show a clear

Figure 2: (a) Normal fault zone in a competent carbonate (Ca), with approximately 3 m off- set, showing strongly variable internal structure, width of the fault cavities and clasitc infill. Material from a mechanically weaker, slightly more clayey carbonate layer (Cl) is included in the fault zone both between the up- and downthrown parts of the clastic deposits (a), as well as in cavities further down dip (b). Also note the empty cavity in the bottom of the picture (c). b) Opening mode fracture showing layered clastic infill. On the wall rock (A) a rim of precipi- tated calcite (B) covers the fracture walls. The centre of the fracture (C) is filled with strati- fied unconsolidated sediments. Stars indicate decimetre size clasts. c,d.) Tensile open mode fissures parallel to the fold crest of Jebel Hafeet. Within the massive fissures blocks of wall rock are rotated. (All images taken at Jebel Hafeet, U.A.E.) Figure 1: a) 0.7 m resolution Quickbird image of the Jebel Hafeet anticline. Faults are interpreted in red, fractures in the field in blue, yellow and green. Interpretation done in ArcGis

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in carbonates is observed in the field (Figure 2b). Sedimentation of clay from elsewhere in the sequence into open fractures is a process completely different from previously recognized mechanisms of clay- enrichment in fault zones. The mechanical background of open fault formation can be studied in analogue models using cohesive materials (Holland et al., 2006). Here we will briefly discuss the results of van Gent et al. (in press).

Analogue experiments Hemihydrate powder (CaSO4 · ½ H2O), a cohesive, fine grained powder was used for normal Figure 3: Analogue model results. Observed structures include: 1) tensile fractures, 2) dilational faulting experiments. faults, 3) antithetic faults, 4) cavities, 5) dip changes, 6) dilational jogs, 7) non-dilatant shear faults, 8) transitions from tensile fractures to dilational faults, 9) cliffs at the surface. stratification. This suggests episodic sedimentation within the fault zones by either gravitational or hydraulic transport. Wide surface fissures are common on the mountain crest. These open structures strike parallel to the fold axis of the anticline (Figure 2c and d), have opening magnitudes of more than a meter, and show angular blocks of carbonate, dislodged and rotated between the parallel walls (Figure 2c), but their depth is difficult to assess due both the material infill and the outcrop conditions. The dilatant structures of the fault zones must have a strong effect on hydraulic circulation, suggesting that the caves of the Jebel Hafeet region are fault-related. The development of clay smear has a pronounced effect on the sealing capacity of faults (Fulljames et al., 1997). The inclusion of even Figure 4: a) Rotating block formation (a1 and a2) and the disintegration of this block (a3) with increasing minor amounts of clay-rich material deformation. Fragments move down the fracture, forming a fault breccia, while at the surface a rubble in the dilatant fault segments (Figure zone and cliff are formed. b) Dilational jogs form on mechanical heterogeneities (black layers are a bit 2a), will decrease permeability stonger) (b1 and b2). Also shown is the gravitational collapse of the roof of the jog in b3. of the fault zone. An additional, powerful process of resealing faults

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Scaled model experiments to the dilational shear domain and the calculation of displacement- and Before the models can be from the dilational shear to the pure strain-fields in the experiments. properly scaled the model material shear domain correspond well with has to be carefully characterized. the material properties and inferred Discussion and conclusions Focusing on extensional stress states. Further observed Our field work on Jebel experiments with pure Hemihydrate structures include cliffs, rotating Hafeet has shown how massively and a buried master graben faults blocks and canyons at the surface, dilatant faults with large fractures with a dip of 60°, several structures dip changes in faults, fault linkage can be re-sealed by deposition of are observed (Figure 3). In the top and the formation of overstepping clay and calcite cement by moving 7 cm of the 20 cm model tensile fault arrays and antithetic faults. formation fluids. The follow-up model fractures are observed, that grade into Different models were created, and experiments have shown how such dilatant shear faults with asperities documented with high resolution dilatant fault zones form and how the and dilational jogs. These also show digital cameras. These images were 2D and 3D geometry of these fracture block rotation & gravity collapse. At used to make movies (see www.ged. networks evolves. the surface we observe the formation rwth-aachen.de) and allowed analysis Further work will concentrate of cliffs, canyons and rubble zones using Particle Image Velocimetry on 4D study, using CT-scanning of with progressive deformation (Figure (PIV) software (Adam et al., 2005; experiments in combination with 4). In the bottom 7cm of the model, Holland et al., 2006, van Gent et further field study. pure shear faults are observed. The al., in press). This high resolution, transitions from the tensile domain optical correlation technique allows

References Adam, J., Urai, J. L., Wieneke, B., Oncken, O., Pfeiffer, K., Kukowski, N., Lohrmann, J., Hoth, S., van der Zee, W., Schmatz, J.; 2005: Shear localization and strain distribution during tectonic faulting--new insights from granular-flow experiments and high-resolution optical image correlation techniques. Journal of Structural Geology 27(2), 283-301. Fulljames, J.R., Zijerveld, L.J.J., Franssen, R.C.M.W.; 1997: Fault seal processes: Systematic analysis of fault seals over geological and production time scales. In: Moeller-Pedersen & Koester, A.G. (Eds.), Hydrocarbon Seals, NPF special publication 7, 51-59. Holland, M., Urai, J. L., Martel, S.; 2006: The internal structure of fault zones in basaltic sequences. Earth and Planetary Science Letters 248(1-2), 286-300. Noweir, M.A.; 2000: Back-thrust origin of the Hafit structure, northern Oman Mountain Front, United Arab Emirates. GeoArabia Manama 5, 215 - 228. van Gent, H. W., Holland, M., Urai, J. L., Loosveld, R.; in press. Evolution of fault zones in carbonates with mechanical stratigraphy - insights from scale models using layered cohesive powder. Journal of Structural Geology: Special publication. doi:10.1016/j.jsg.2009.05.006

Front Page Al Hajar 16th edition Feb 2010 Page 19 Neogene Compressional Structures in the Muscat Area: New 3D Models

Ru Smith, PDO

Paleogene carbonates principles of multiscale 3D modelling recently demonstrated on the GSO and clastics in the Muscat area are developed for subsurface applications field excursion of December 10th deformed into a set of open folds (see summary in Smith & Ecclestone 2009. with axes orientated N-S to NNW- 2006) and recently applied to the The major open folds in the SSE, at a very high angle to the major Khuff Formation in Oman (see Kohrer, Darsayt to Qurum area are here obduction/exhumation fault (Wadi Aigner & Poppelreiter in Al Hajar issue named the Darsayt Syncline and Mina Kabir Fault of Searle et al. 2004 and 15). The resultant suite of models is Al Fahal Anticline. Further west, in the its curved extension westward) that used by the Middle East Learning Rusayl Embayment, the Paleogene bounds them to the South. Smaller- and Development Hub (Shell/PDO) is folded into the Ghala Anticline and scale folds (some with tighter interlimb to teach geoscience and multiscale Misfah Syncline. The dominant fold angles) together with thrust, normal approaches to interpretation and axis trend is North-South (not parallel and strike-slip faults are associated description of subsurface geology. with major folds in the Saih Hatat with the major folds. This small area contains an culmination to the South as has been Capture of both the structural outstandingly rich set of analogues suggested in the literature). However, and sedimentological architectures of for subsurface reservoirs deposited local fold limb steepening occurs in the this area in quantitative 3D models has in Aeolian, fluvial, coastal and shallow Ras Al Hamra area in association with recently been initiated, following the marine carbonate environments, as a change in orientation of fold axes

Figure 1. 3D view (from N) of the larger (19 km wide) region of interest, stretching from Ghala in the West to Muttrah in the East, and showing the nested local (4 km wide) region of interest around

Ras Al Hamra and Mina Al Fahal. Higher resolution sedimentary architecture and effective property models are constructed within the local volume.

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Fig.2. 3D view of the Ras Al Hamra Anticline-Darsayt-Syncline showing the restored base-sediment surface where it projects above the present land sur- face. The Ophiolite core of the S-plunging anticline has been preferentially eroded to yield the present day bay. W-E field of view is approximately 4 km and there is no vertical exaggeration. Shorter-wavelength folds, with tighter interlimb angles occur locally in the western limb of the Ras Al Hamra Anticline.

Figure 2. 3D view (from N) showing the main tectonic elements in the region of interest.

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towards NNW-SSE and development folds, including normal and strike-slip further north. of typical fault-propagation fold faults (commonly NE-SW, but locally The approach of mapping geometry (Figure 2). Given evidence N-S) and bed-scale thrusts. outcrop geology by fitting surfaces for Late Cretaceous-Early Paleogene Although the timing of through the intersections between extensional faulting in the area (e.g. compression corresponds with important geological surfaces and Fournier et al. 2006) a tempting Zagros continent-continent collision the present day land surface forces explanation for this geometry is that (Late Oligocene to Early Miocene) internally consistent interpretations an early normal fault was reactivated the WSW-ENE to E-W compression and is far less forgiving than as a reverse fault during Neogene direction implied by the observed traditional techniques of geological compressional deformation, forcing folds does not correspond with the map making. Geological observations a fold in the cover (e.g. Smith 1987). convergence vector between the at different scales can be recorded in The implied orientation of such an Arabian and Eurasian plates and a common 3D context, a property of early extensional fault is consistent interaction between the Arabian and this approach that has yielded strong with the average Late Cretaceous- Indian plates has been postulated economic benefits when applied to the Early Paleogene extension direction (Fournier et al. 2006). Approximately subsurface (see Smith & Ecclestone (N72oE) computed by Fournier et al. N-S compression is recorded at the 2006). (2006). Small-displacement faults are southern front of the Oman Mountains common in association with the larger and in late structures (Pliocene)

References Fournier, M., Lepvrier C., Razin, P. & Jolivet, L. 2006. Late Cretaceous to Paleogene post-obduction extension and subsequent Neogene compression in the Oman Mountains. GeoArabia, Vol. 11, 17-40. Searle, M.P., Warren, C.J., Waters, D.J. & Parrish, R.R. 2004. Structural evolution, metamorphism and restoration of the Arabian continental margin, Saih Hatat region, Oman Mountains. Journal of Structural Geology, 26, 451-473. Smith, R.D.A. 1987a. Structure and deformation history of the Central Wales Synclinorium, NE Dyfed: evidence for a long-lived basement structure. Geological Journal, 22, 183-198. Smith, R.D.A. & Ecclestone, M. 2006. Multiscale 3D Interpretation and modelling for exploration and on down the lifecycle stream. GCSSEPM, Houston. Reservoir Characterization: Integrating Technology and Business Practices. pp. 875-892.

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From Snowball Earth to Hothouse A Journey into Oman’s Distant Past-7th January 2010

John Aitken,PDO

Excursion Leader : Joachim E. Amthor (PDO)

The fourth field trip ever briefly discussed the formation of sandstones are interpreted to be organised by GSO, in February the Al Hajar mountains including the result of sediment gravity flows. 2003, was led by Joachim Amthor the emplacement of the Semail Joachim described the overall and visited the Precambrian section, Ophiolite. All this was done over depositional setting, expounded on particularly focusing on the glacigenic the constant rumble of lorries on the ‘Snowball Earth’ hypothesis that deposits of the Fiq Formation and the nearby track leading to the new these and similar deposits on all overlying cap carbonate (Hadash opencast site. the continents have been attributed formation), in Wadi Bani Kharus and Then into Wadi Bani Kharus to. Joachim also explained and Wadi Hajir. The trip was run again and through to Wadi Hajir all the described geochronological dating in January 2004 and, after Joachim time traveling back in time to about techniques that allow us to assign had returned to Oman, again on 7th 650 Million years ago and the ages to such old rocks. January 2010, with an updated field massive diamictites interbedded Lunch was held in a more guide. with sandstones that outcrop near secluded side wadi, some way from The trip began with a stop the village of Halhal. The diamictites the village, but still surrounded by at the abandoned chromite mine were deposited in a marine setting by the Fiq glaciation diamictites. After near Nakhal. With the back drop of rain-out of material from floating ice lunch a short climb up the Wadi wall the mountains, Joachim described and probably also by remobilization to see a granite boulder of 1-2m the stratigraphy of Oman and processes (debris flows) whilst the diameter within the Fiq diamictites.

The majority of the participants

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The Hadash Formation (‘cap carbonate’) directly overlying a diamictite of the Fiq Formation Next a short drive around the corner described their characteristics Khuff Formation (Saiq Formation and up a short access road, followed and their possible implications for in the outcrop), c.250 million years by a short climb to stand above our ‘Snowball Earth’. Discussion was old. This gives a marked angular lunch spot and on the top of the Fiq held regarding ‘Snowball Earth’ vs. unconformity with about 300 million Formation (Abu Mahara Group) at ‘Slushball Earth’ vs. standard style years of stratigraphy missing. Around the base of the Nafun Group. Here glaciation with extent being related the corner of the wadi the Buah the Hadash Formation, a dolomitic to the distribution of the continents in Formation can be inspected in detail carbonate moderately depleted in one single landmass. No conclusion and its constituent stromatolites and 13C, directly overlies diamictite was drawn!! thrombolites seen. and is known as a ‘cap carbonate’, Back into Wadi Bani Kharus On the way back to Muscat, bcause, globally, such carbonates with the sun beginning to sink and one final stop was made near the overlie (cap) Neoproterozoic glacial casting the deep wadi into shade, new road across the mountains to deposits. This implies that carbonate bringing the temperature down to Fanja. Here pillow lavas of the semail sedimentation occurred worldwide at almost glacial levels and a well- ophiolite and a nearby outcrop of the the onset of transgressions related known Omani outcrop where Permian ‘Oman Exotics’ were briefly to the melting of large volumes of the steeply dipping Precambrian examined with some discussion ice. The Hadash Formation is one carbonates of the Buah Formation on the origin of the ‘Oman Exotics’ of the most prominent, from a global (Kharus Formation in the outcrop), and the different models for their perspective, of these cap carbonates. c.550 million years old, are existence. The origin of these cap carbonates is unconformably overlain by the slightly For me this was a field trip still heatedly debated and Joachim dipping Permian carbonates of the down memory lane, as the first

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350Ma of missing stratigraphy at the angular unconformity between the Buah (Kharus) Formation and the Khuff (Saiq) Formation. outcrops I visited in Oman were however, to go with someone who third time for GSO. It was greatly in Wadi Bani Kharus and Wadi knew the outcrops and the stories appreciated and enjoyed by all who Hajir, including some of the ones behind them. Thanks is extended to participated. visited on this trip. It was better, Joachim for running this trip for the

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International News

Kindly supplied by

INDIA IRAN has been increased to a gross 1.9 (P90) to 7.4 (P10) billion barrels of Gas flowed at the rate of Perhaps mindful of the global oil, with a mean of 4.2 billion barrels. 5.4 MMcf/d, with 7.5 bc/d, at an interest currently being shown towards Previous estimates were 1.0 (P90) onshore wildcat drilled by ONGC its neighbor Iraq, and holding the and 5.0 (P10) billion barrels. There in the Krishna Godavari Basin. The world’s second largest gas reserves are also prospective resources below Pennugonda 1A well on the Block after Russia, Iran has reminded it 2,950m (lower Triassic and Permian) 1B PEL was tested on a 6mm choke seeks US$ 85 billion in investments for which the evaluation has assigned in the Cretaceous Raghavapuram within a decade to bolster gas exports. potential reserves of 1 to 5 billion Formation sandstones perforated at According to Reza Kasaizadeh, barrels and 6 to 14 Tcf gas. The 3,062-3,071.5m, 3,080-3,086m and managing director of the National report concludes that Shaikan 1 has 3,092-3,099m intervals (Object I). In Iranian Gas Exports Company, the discovered a significant resource of oil addition, the well yielded 500 Mcf/d oil ministry plans to attract the money and gas in the Cretaceous Sarmord, through a 6mm choke from intervals from both foreign and private sector Jurassic Barsarin, Sargelu, Alan, in the Object II at 3,253-3,261m, investors. The development of Iran’s Mus, Butmah, Baluti and Triassic 3,271-3,276m and 3,278-3,280m. gas sector is hampered by a lack of Kurre Chine formations. Spudded in November 2007, the well productive investment and the growth Targeting prospective was drilled to a total depth of 5,259m. of domestic consumption such that intervals in the Cretaceous and the ONGC is also reporting it has made an Iranians have faced gas shortages Jurassic, Kalegran, a subsidiary of oil discovery on the Sibsagar District due to high consumption, especially MOL, has spudded Bijeel 1, its first (Assam Shelf) PEL. Few details have in winter. The high demand has well in the Akri Bijeel block that will been released on the onshore Geleki led Iran to cut gas supply to Turkey be drilled to a total depth of 4,300m. North 1 well, which reached a total several times in the past. Having Kalegran holds an 80% interest in depth of 3,545m in September 2009. signed agreements with China and the permit, the remaining 20% is held ONGC has made a gas discovery Malaysia, the Islamic republic has by Gulf Keystone and the latter’s in the Kutch Basin offshore north- been seeking to compensate for the success with the Shaikan 1 well in western India. The GK-28-1 (GK- absence of Western companies in its adjoining acreage has de-risked this 28-A) exploration well within the energy sector. and a number of other prospects Kutch Offshore Block 1 Extension nearby. Located in the Kurdistan shallow water concession flowed IRAQ region of northern Iraq, the 889 sq 4.5 MMcf/d through a 12mm choke. km onshore Akre-Bijeel Block was The closure has been interpreted as Gulf Keystone has published awarded in November 2007 for an a fault influenced structure. The well an independent evaluation of its initial exploration period of three years. was spudded in October 2009 by the Shaikan 1 new field wildcat in the The work obligation includes the Transocean’s “F. G McClintock” J/U Shaikan Block, which has confirmed acquisition of approximately 200km of and drilled to a total depth of 1,550m. the well as the largest industry 2D seismic data, with an option to drill The original prognosed total depth discovery of 2009. Reviewing the one exploration well within the first was 3,500m. data from the Cretaceous, Jurassic exploration phase. Under the PSC, and Triassic formations, the range of the Kurdistan Regional Government oil in-place for the Shaikan structure has the right to a participation interest

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of between 20% and 25%, and it has bc/d and 105 MMcf/d of associated production of seven oil areas in retained the right to assign third party sour gas to be processed at the Syria under the basis of Production participation interests of between Khursaniyah gas plant, the project Sharing Contracts (PSCs). The 15% and 25% to qualified Iraqi and is the last of a series of large oil field seven oil areas have been divided international companies. development projects scheduled by into two groups; Group I comprises the company that in 2009 took its the Turaib West, Halimeh and Al PAKISTAN total capacity to 12.5 MMb/d. Saudi Dahl oil field areas and Group II Aramco slowed work on the project comprises the Jaideen, Tel Asfar, Pakistan Petroleum Ltd as it looked to cut costs on oil service Zinati and El Halul oil field areas. (PPL) has been awarded two contracts at the field and across its All of the fields are currently located onshore exploration licenses in energy industry while simultaneously, in the ‘Central’ block in the Palmyra the Lower Indus Basin that were a slump in global energy demand Zone and operated by Syrian offered in the 2009 Licensing Round. made further oil field development Petroleum Company. All companies Gambat South 2568-18 EL comprises less urgent. Manifa has six reservoirs wishing to qualify for the round are 2,435.95 sq km in the Sindh province. containing heavy, sour oil that is expected to submit qualification Five dry holes have been drilled on being developed to compensate for documents to MOPMR no later than the tract, including most recently declining capacity at other fields rather 18 February 2010. The international Tullow’s Shahpur Chakar 1 which was than to add to total capacity. It was bid round will close at 14:00 on 19 abandoned at a total depth of 3,392. brought onstream in February 1966 May 2010. PPL was declared the successful from the Manifa Zone and produced Gulfsands Petroleum has received bidder after the closing of the licensing an average of 60,000 bo/d during the confirmation from Syria’s General round on 30 September 2009. Rival year. The Lower Ratawi reservoir Petroleum Corporation that it has bids were submitted by PEL, OGDC, started producing in 1974 and by been granted a 25-year production Hycarbex and NHEPL. In addition, 1990 there were 12 flowing wells. license to develop the Yousefieh oil PPL was awarded the Jungshahi Further development of Manifa was field in Block 26 North East Syria, 2467-12 EL. Also located in the Sindh planned in May 1990, but the project which it operates with a 50% interest. province, it encompasses 2,459.26 was deferred. In his address, Khalid The license may be extended for a sq km. It also includes five dry holes, al-Falih also let it be known that his further 10 years. The Yousefieh field the most recent of which was drilled company plans to further explore for was assessed at the end of 2008 -- again by Tullow -- in 1995. OGDC oil and gas in the deep waters of the as containing gross proved plus made a rival bid for this block. The Red Sea off its eastern coast and probable reserves of 11 MMbo and 2009 Licensing Round was launched will launch an extensive 3D seismic first oil is anticipated early in April shortly after the approval of new survey. It was implied that further 2010. Production will commence Petroleum Exploration & Production emphasis would be given to non- from two wells, Yousefieh 1 and Policy 2009 and Model Petroleum conventional oil and gas resources Yousefieh 3, at an expected initial Concession Agreement (PCA)/ given advances in technology. He combined rate of up to 1,000 bo/d. Pakistan Petroleum (Exploration & had earlier commented that Aramco The current expectation is that the Production) Rules. planned to drill in deeper offshore Yousefieh field has lower reservoir frontiers in 2012. energy than the nearby Khurbet SAUDI ARABIA East field and planning is underway SYRIA to install permanent down-hole Speaking in Bangalore, Saudi artificial lift equipment in both Aramco chief executive officer Khalid The Syrian Ministry of Petroleum Yousefieh wells later in the year. In al-Falih said output from Manifa, a and Mineral Resources (MOPMR) addition, a further development well supergiant field, will begin in 2013 and General Petroleum Company on Yousefieh is planned for 2010. It with full development completed in are inviting successfully qualified is anticipated that production from 2015, but that costs have risen US$ international petroleum companies the Yousefieh field will reach a rate 7 billion and now stand at nearly US$ to participate in an International of approximately 6,000 bo/d by 16 billion. With a capacity to produce Bid Round. The round involves 2012. 900,000 b/d of heavy crude, 65,000 the exploration, development and

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TPAO has stated that it hopes to find exploration phase and will earn 50% TURKEY a minimum of 5 billion barrels of oil in interest in the 8,500 sq km Samsun the Black Sea region jointly held with Block and the eastern part of Block Issuing a joint statement, Petrobras. The rig is now in Turkish 3921 (21,000 sq km). ExxonMobil ExxonMobil is joining Black Sea waters and is expected to spud the and TPAO will invest between US$ exploration acreage covering over Sinop 1 well for Petrobras in February 400 to US$ 450 million in this first 30,000 sq km that is currently held 2010. Petrobras’ International Director, stage of exploration. by TPAO and Petrobras. Subject to Jorge Zelada, had previously stated With thanks to IHS Energy regulatory approval, the deal covers the company was planning to invest For further information please contact the Sinop, Ayancik and Carsamba US$ 300 million to drill two exploration Ken White or Stuart Lewis sub-blocks of Block 3922. New wells in the Black Sea in 2010. Block e-mail : [email protected] equities will be TPAO (operator, 50%), 3922 has an average water depth of e-mail : [email protected] ExxonMobil (25%) and Petrobras 2,200m and is undrilled. Note that web site : www.ihs.com (25%). In March 2009, Petrobras since June 2008, ExxonMobil has contracted the Ocean Rig “Leiv had a 50% interest in the Samsun Eiriksson” S/S for a seven-well, three- sub-block of 3922 and the eastern year period of drilling in the Black Sea part of Block 3921. ExxonMobil will in a deal valued at US$ 630 million. become the operator during the initial

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AGM Report - GSO grows to grab larger projects

Kaushalendra S Singh, Oman Observer

The following article is selected people under different Defender and drives off to wander taken from the Oman Observer, categories. The honours were over some piece of outcrop, his reporting on the GSO Annual given in the categories of ‘Active recent work on the Fara outcrops of General Meeting. role in making of Oman Geology Wadi Bani Awf. The chief speaker MUSCAT - The Geological Documentary’, ‘Active role in Dr Fu’ad spoke at length and Survey of Oman (GSO) honoured GSO-Al Watan news group’ and covered areas like international members and non-members ‘Supporting GSO and facilitating and domestic economy and their for their active participation in link at SQU Geo-group’. Those who overall impact on Omani economy. geological activities of Oman got trophies and shields included, He also touched topics like Omani at its annual meeting held at Ali al Jardani for Financial Support employment and expatriates Crowne Plaza Hotel on Sunday. and personal commitment for remittances. The meeting was held under the GSO cause, Juma al Balushi for auspices of Nasser bin Khamis participation in the making of the al Jashmi, Under-Secretary of geology documentary, Mohammed Ministry of Oil and Gas. The guest al Kindy for continuous contribution speaker on the occasion was Dr to the GSO and also for his Fu’ad Jafer Sajwani, Chairman participation in the making of the of Economic Council at Shura geology documentary. Council and former vice-president Yousuf al Sinani was of Central Bank of Oman. honoured for improving the GSO Addressing the gathering, website and Ken Glennie for Dr Mahmood Saif al Mahrooqi, providing valuable contribution to GSO President, termed year 2009 the Oman Geology documentary. as a very good year for the GSO. The highlight of the meeting “We stepped out of GSO’s normal was the honour extended to Dr activities of talks and field trips Jan Schreurs for his interest into projects that have a significant and commitment in the Omani impact on awareness of Oman’s geology. Dr Jan arrived in Oman geology.” “On the membership in 2001 to take up the position front, the GSO members have risen of Head Geological Services in steadily reflecting the increasing the exploration Directorate of interest in GSO and the geology Petroleum Development Oman of Oman. The budget of the GSO (PDO). also saw an increase that made Jan’s passion for field possible for us to accommodate geology is second to none and larger projects and activities.” weather permitting, most weekends The chief guest distributed he gets into his Land Rover certificates and gifts among the

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Sultanate of Oman Geoscience Publications 2009 John F. Aitken,PDO

A list of peer reviewed, geoscience publications, concerning the Sultanate of Oman, issued in 2009, is provided below. As with previous listings it covers geology, palaeontology, petrology, geophysics, hydrogeology, geomorphology and archaeology (that includes a geoscience component). Papers dealing with neighbouring countries that have relevance to Oman, particularly the extension of the Oman Mountains into the UAE, have also been included. As usual, omitted are annual reviews, papers dealing with the entire Arabian Peninsula, or large parts thereof, regional summaries and items from trade publications, except one that is specifically technical. Also excluded are conference abstracts and papers that have not undergone peer review, although these may contain significant contributions to the understanding of the Sultanate’s geosciences. These references have been compiled through the use of internet search engines, browsing publisher’s websites and from browsing the Journals available to the compiler. It is as complete as possible within these limitations. In this respect, additional 2007 and 2008 publications on the geology of Oman have been encountered since the publication of the listings for these years in the 12th and 14th editions of Al Hajar, respectively. These additional references are included here ¬(below the 2009 publications). If any reader notices any omissions, please contact the editor ([email protected]) or compiler and these will be published in a future edition of Al Hajar, with an acknowledgment.

2009

Adams, E.W., Bellian, J.A. & Reyes, R. 2009. Digital outcrop models reduce uncertainty and improve reservoir characterization. World Oil, September 2009.

Alagarsamy, R. 2009. Geochemical variability of copper and iron in Oman Margin sediments. Microchemical Journal 91, 111-117.

Al-Barram, I. 2009. Carboniferous-Permian spore assemblages from Oman. PhD Thesis, University of Sheffield.

Ali, M.Y., Sirat, M. & Small, J. 2009. Integrated gravity and seismic investigation over the Jabel Hafit structure: implications for basement configuration of the frontal fold-and-thrust belt of the northern Oman Mountains. Journal of Petroleum Geology 32, 21-38.

Anan, H.S. 2009. Paleontology and stratigraphic distribution of suborder Lagenina (benthic foraminifera) from the Middle-Late Eocene Mazyad Member of the Dammam Formation in Jabal Hafit, Al Ain area, United Arab Emirates, Northern Oman Mountains. Revue de Paléobiologie, Genève 29, 1-18.

Basile, C. & Chauvet, F. 2009. Hydromagmatic eruption during the buildup of a Triassic carbonate platform (Oman Exotics): Eruptive style and associated deformations. Journal of Volcanology and Geothermal Research 183, 84-96.

Blechschmidt, I., Matter, A., Preusser, F. & Rieke-Zapp, D. 2009. Monsoon triggered formation of Quaternary alluvial megafans in the interior of Oman. Geomorphology 110, 128-139.

Böning, P. & Bard, E. 2009. Millenial/centennial-scale thermocilne ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments. Geochimica & Cosmochimica Acta 73, 6771-6788.

Bowring, S.A., Grotzinger, J.P., Condon, D.J., Ramezani, J. & Newall, M.J. 2009. Reply to comment: Oman Chronostratigraphy: (Reply to comment by Erwan Le Guerroué, Ruben Rieu and Andrea Cozzi on “Geochronologic Constraints on the Chronostratigraphic Framework of the Neoproterozoic Huqf Supergroup, Sultanate of Oman”, American Journal of Science 307, 1097-1145). American Journal of Science 309, 91-96.

Breesch, L., Swennen, R. & Vincent, B. 2009. Fluid flow reconstruction in hanging and footwall carbonates: compartmentalization by Cenozoic reverse faulting in the Northern Oman Mountains (UAE). Marine and Petroleum Geology 26, 113-128.

Chauvet, F., Dumont, T. & Basile, C. 2009. Structures and timing of Permian rifting in the central Oman Mountains (Saih Hatat). Tectonophysics 475, 563- 574.

Cheng, H., Fleitmann, D., Edwards, R.L., Wang, X., Cruz, F.W. Auler, A.S., Mangini, A., Wang, Y., Kong, X., Burns, S.J. & Matter, A. 2009. Timing and structure of the 8.2 kyr B.P. event inferred from δ18O records of stalagmites from China, Oman, and Brazil. Geology 37, 1007-1010.

Coogan, L.A. 2009. Altered oceanic crust as an inorganic record of paleoseawater Sr concentration. Geochemistry, Geophysics, Geosystems G3 10. Online Journal (http://g-cubed.org/).

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Dare, S.A.S., Pearce, J.A., McDonald, I. & Styles, M.T. 2009. Tectonic discrimination of peridotites using ƒO2-Cr# and Ga-Ti-FeIII systematics in chrome- spinel. Chemical Geology 261, 199-216.

Dilek, Y. & Furnes, H. 2009. Structure and geochemistry of Tethyan ophiolites and their petrogenesis in subduction rollback systems. Lithos 113, 1-20.

Donato, S.V., Reinhardt, E.G., Boyce, J.I. Pilarczyk, J.E. & Jupp, B.P. 2009. Particle-size distribution of inferred tsunami deposits in Sur Lagoon, Sultanate of Oman. Marine Geology 257, 54-64.

Fleitmann, D. & Matter, A. 2009. The speleothem record of climate variability in Southern Arabia. Comptes Rendu Geoscience 341, 633-642.

Fookes, P.G. & Lee, M. 2009. Desert environments of inland Oman. Geology Today 25, 226-231.

France, L., Ildefonse, B. & Koepke, J. 2009. Interactions between magma and hydrothermal system in Oman ophiolite and in IODP Hole 1256D: Fossilization of a dynamic melt lens at fast spreading ridges. Geochemistry, Geophysics, Geosystems 10. Online Journal (http://g-cubed.org).

Giraud, J. 2009. The evolution of settlement patterns in the eastern Oman from the Neolithic to the early Bronze Age (600-2000 BC). Comptes Rendus Geosciences 341, 739-749.

Grégoire, M., Langlade, J.A., Delpech, G., Dantas, C. & Ceuleneer, G. 2009. Nature and evolution of the lithospheric mantle beneath the passive margin of East Oman: evidence from mantle xenoliths sampled by Cenozoic alkaline lavas. Lithos 112, 203-216.

Grosjean, E., Love, G.D., Stalvies, C., Fike, D.A. & Summons, R.E. 2009. Origin of petroleum in the Neoproterozoic-Cambrian South Oman Salt Basin. Organic Geochemistry 40, 87-110.

Holland, M., Saxena, N. & Urai, J.L. 2009. Evolution of fractures in a highly dynamic thermal, hydraulic, and mechanical system – (II) remote sensing fracture analysis, Jabal Shams, Oman Mountains. GeoArabia 14(3), 163-194.

Holland, M., Urai, J.L., Muchez, P. & Willemse, E.J.M. 2009. Evolution of fractures in a highly dynamic thermal, hydraulic, and mechanical system – (I) field observations in Mesozoic carbonates, Jabal Shams, Oman Mountains. GeoArabia 14(1), 57-110.

Immenhauser, A. 2009. Phreatic cave calcites: archives of two realms. Geology Today 25, 29-33.

Kacimov, A.R., Sherif, M.M., Perret, J.S. & Al-Mushikhi, A. 2009. Control of sea-water intrusion by salt-water pumping: coast of Oman. Hydrogeology Journal 17, 541-558.

Kowalewski, I., Carpentier, B., Huc, A.-Y., Adam, P., Hanin, S., Albrecht, P., Wojciak, P., Frewin, N. & Al-Ruwehy, N. 2009. An unconventional Neoproterozoic- early Cambrian source rock interval in southern Oman: implications for oil and gas generation. GeoArabia 14(4), 53-86.

Knaust, D. 2009. Complex behavioural pattern as an aid to identify the producer of Zoophycos from the Middle Permian of Oman. Lethaia 42, 146-154.

Le Guerroué, E., Rieu, R. & Cozzi, A. 2009. Comment: Oman Chronostratigraphy: (Comment on “Geochronologic constraints on the chronostratigraphic framework of the Neoproterozoic Huqf Supergroup, Sultanate of Oman” by Samuel A. Bowring, John P. Grotzinger, Daniel J. Condon, Jahandar Ramezani, Mark J. Newall and Philip A. Allen, American Journal of Science 307, 1097–1145.). American Journal of Science 309, 85-90.

Lézine, A.-M. 2009. Timing of vegetation changes at the end of the Holocene Humid Period in desert areas at the northern edge of the Atlantic and Indian monsoon systems. Comptes Rendu Geoscience 341, 750-759.

Lorand, J.-P., Alard, O. & Godard, M. 2009. Platinum-group element signature of the primitive mantle rejuvenated by melt-rock reactions: evidence from Sumail peridotites (Oman Ophiolite). Terra Nova 21, 35-40.

Love, G.D., Grosjean, E., Stalvies, C., Fike, D.A., Grotzinger, J.P., Bradley, A.S., Kelly, A.E., Bhatia, M., Meredith, W., Snape, C.E., Bowring, S.A., Condon, D.J. & Summons, R.E. 2009. Fossil steroids record the appearance of Demospongiae during the Cryogenian period. Nature 457, 718-721.

Lucazeau, F., Leroy, S., Autin, J., Bonneville, A., Goutorbe, B., Watremez, L., d’Acremont, E., Düsünur, D., Rolandone, F., Huchon, P., Bellahsen, N. & Tuchais, P. 2009. Post-rift volcanism and high heat-flow at the ocean-continent transition of the eastern Gulf of Aden. Terra Nova 21, 285-292.

Maurer, F., Martini, R., Rettori, R., Hillgärtner, H. & Cirilli, S. 2009. The geology of Khuff outcrop analogues in the Musandam Peninsula, United Arab Emirates and Oman. GeoArabia 14(3), 125-158.

Mohapatra, R.K., Schwenzer, S.P., Herrmann, S., Murty, S.V.S., Ott, U. & Gilmour, J.D. 2009. Noble gases and nitrogen in Martian meteorites Dar al Gani 476, Sayh al Uhaymir 005 and Lewis Cliff 88516: EFA and extra neon. Geochimica et Cosmochimica Acta 73, 1505–1522.

Musson, R.M.W. 2009. Subduction in the Western Makran: the historian’s contribution. Journal of the Geological Society 166, 387-391.

Nicolas, A., Boudier, F. & France, L. 2009. Subsidence in magma chamber and the development of magmatic foliation in Oman ophiolite gabbros. Earth and Planetary Science Letters 284, 76-87.

Preusser, F. 2009. Chronology of the impact of Quaternary climate change on continental environments in the Arabian Peninsula. Comptes Rendu Geoscience 341, 621-632.

Rajmohan, N., Al-Futaisi, A. & Al-Touqi, S. 2009. Geochemical process regulating groundwater quality in a coastal region with complex contamination sources: Barka, Sultanate of Oman. Environmental Earth Sciences 59, 385-389.

Remeysen, K. & Swennen, R. 2009. Application of microfocus computed tomography in carbonate reservoir characterization: possibilities and limitations.

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Marine and Petroleum Geology 25, 486-499.

Reuning, L., Schoenherr, J., Heimann, A., Urai, J.L., Littke, R., Kukla, P.A. & Rawahi, Z. 2009. Constraints on the diagenesis, stratigraphy and internal dynamics of the surface-piercing salt domes in the Ghaba Salt Basin (Oman): a comparison to the Ara Group in the South Oman Salt Basin. GeoArabia 14(3), 83-120.

Rollinson, H. 2009. New models for the genesis of plagiogranites in the Oman Ophiolite. Lithos 112, 603-614.

Rowan, C.J., Roberts, A.P. & Broadbent, T. 2009. Reductive diagenesis, magnetite dissolution, greigite growth and paleomagnetic smoothing in marine sediments: a new view. Earth and Planetary Science Letters 277, 223-235.

Roy, R., Launeau, P., Carrere, V., Pinet, P., Ceuleneer, G., Clenet, H., Daydou, Y., Giradeau, J. & Amri, I. 2009. Geological mapping strategy using visible near- infrared-shortwave infrared hyperspectral remote sensing: application to the Oman ophiolite (Sumail Massif). Geochemistry, Geophysics, Geosystems G3 10. Online Journal (http://g-cubed.org/).

Sansom, I.J., Miller, C.G., Heward, A., Davies, N.S., Booth, G.A., Fortey, R.A. & Paris, F. 2009. Ordovician fish from the Arabian Peninsula. Palaeontology 52, 337-342.

Schneider, C. 2009. Facies, Sequence Stratigraphy and 3D modelling of the Sudair Formation Saiq Plateau, Jebel Akhdar, Oman Mountains. MSc. Thesis, Universität Tübingen.

Schoenherr, J., Schléder, Z., Urai, J.L., Littke, R. & Kukla, P.A. 2009. Deformation mechanisms of deeply buried and surface-piercing Late Pre-Cambrian to Early Cambrian Ara Salt from interior Oman. International Journal of Earth Sciences (Geologisches Rundschau). Online First, Springer Berlin.

Schoenherr, J., Reuning, L., Kukla, P.A., Littke, R., Urai, J., Siemann, M. & Rawahi, Z. 2009. Halite cementation and carbonate diagenesis of intra-salt reservoirs from the Late Neoproterozoic to Early Cambrian Ara Group (South Oman Salt Basin). Sedimentology 56, 567-589.

Searle, M.P. & Ali, M.Y. 2009. Structural and tectonic evolution of the Jabal Sumeini – Al Ain-Buraimi region, northern Oman and eastern United Arab Emirates. GeoArabia 14(1), 115-142.

Thiele, S., Heinson, G., Gray, D.R. & Gregory, R.T. 2009. Ophiolite emplacement in NE Oman: constraints from magnetotelluric sounding. Geophysical Journal International 176, 753-766.

Urban, B. & Buerkert, A. 2009. Palaeoecological analysis of a Late Quaternary sediment profile in northern Oman. Journal of Arid Environments 73, 296- 305.

Urban, B. & Buerkert, A. 2009. Corrigendum to ‘‘Palaeoecological analysis of a Late Quaternary sediment profile in northern Oman’’ [Journal of Arid Environments 73 (2009) 296–305]. Journal of Arid Environments 73, 694.

van der Neut, J. & Bakulin, A. 2009. Estimating and correcting the amplitude radiation pattern of a virtual source. Geophysics 74, S127-S136.

Vizán, H., Turner, P., Millson, J.A. & Ixer, R.A. 2009. Palaeomagnetism of the Mahatta Humaid Group (Cambrian-Early Ordovician, Oman), including a re- interpretation of previous Neoproterozoic palaeomagnetic data. GeoArabia 14(2), 71-96.

Webster, G.D., Angiolini, L. & Tintori, A. 2009. Permian crinoids from the Saiwan and Khuff Formations, southeastern Oman. Rivista Italiana di Paleontologia e Stratigrafia 115, 27-48.

Wetzel, A., Uchman, A., Blechschmidt, I & Matter, A. 2009. Omanichnus and Vitichnus – two new Graphoglyptid ichnogenera from Upper Triassic deep-sea fan deposits in Oman. Ichnos 16, 179-185.

Yoshitake, N., Arai, S., Ishida, Y. & Tamura, A. 2009. Geochemical characteristics of chloritization of mafic crust from the northern Oman ophiolite: implications for estimating the chemical budget of hydrothermal alteration of the oceanic lithosphere. Journal of Mineralogical and Petrological Sciences 104, 156-163.

2008 Cheng, H., Fleitmann, D., Edwards, R.L., Burns, S.J. & Matter, A. 2008. Timing of the 8.2-kyr event in a stalagmite from Northern Oman. PAGES News 16, 29-30.

Love, G.D., Stalvies, C., Grosjean, E., Meredith, E. & Snape, E. 2008. Analysis of molecular biomarkers covalently bound within Neoproterozoic sedimentary kerogen. In: Kelley, P.H & Bambach, R.K. (eds.) From evolution to geobiology: research questions driving paleontology at the start of a new century, Paleontological Society Short Course, October 4, 2008. Paleontological Society Papers 14. pp.67-83.

2007 Agematsu, S., Orchard, M.J. & Sashida, K. 2008. Reconstruction of an apparatus of Neostrachanognathus tahoensis from Oritate, Japan and species of Nesotrachanognathus from Oman. Palaeontology 51, 1201-1211.

Demidova, S., Nazarov, M., Lorenz, C., Kurat, G., Brandstätter, F. & Ntaflos, Th. 2007. Chemical composition of lunar meteorites and the lunar crust.

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Petrology 15, 386-407.

Fike, D.A. 2007. Carbon and Sulfur Isotopic Constraints on Ediacaran Biogeochemical Processes, Huqf, Supergroup, Sultanate of Oman. PhD Thesis, Massachusetts Institute of Technology.

Harzhauser, M., 2007. Oligocene and Aquitanian gastropod faunas from the Sultanate of Oman and their biogeographic implications for the early western Indo-Pacific. Palaeontographica 280, 75-121.

Homewood, P., Vahrenkamp, V., Mettraux, M., Mattner, J., Vlaswinkel, B., Droste, H. & Kwarteng, A. 2007. Bar Al Hikman: a modern carbonate and outcrop analogue in Oman for Middle East Cretaceous fields. First Break 25, 55-61.

Naidu, P.D. 2007. Influence of monsoon upwelling on the planktonic foraminifera off Oman during Late Quaternary. Indian Journal of Marine Science 36, 322-331.

Schoenherr, J., Schléder, Z., Urai, J.L., Fokker, P.A. & Schulze, O. 2007. Deformation mechanisms and rheology of Pre-cambrian rocksalt from the South Oman Salt Basin. In: Wallner, M., Lux, K., Minkley, W. & Hardy, H. (eds.) The Mechanical Behavior of Salt – Understanding of THMC Processes in Salt: Proceedings of the 6th Conference (SaltMech6), Hanover, Germany, 22-25 May 2007. Taylor & Francis, Abingdon. pp.167-173.

Webster, G.D. & Sevastopulo, G.D. 2007. Paleogeographic significance of Early Permian crinoids and blastoids from Oman. Palæontologische Zeitschrift 81, 399-405.

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Upcoming Events . Talks 13 March Measuring Climate Change in the Arctic Val Brock

tbc April Enhanced Oil Recovery in Oman Bert-Rik DeZwart

Field Trips 4 March Fara Formation of Wadi Bani Awf Carlos Fonseca & Jan Schreurs

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Front Page Al Hajar 16th edition Feb 2010