16 research outputs found

    Present-day stress orientations and tectonic provinces of the NW Borneo collisional margin

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    Extent: 15p.Borehole failure observed on image and dipmeter logs from 55 petroleum wells across the NW Borneo collisional margin were used to determine maximum horizontal stress (σH) orientations; combined with seismic and outcrop data, they define seven tectonic provinces. The Baram Delta–Deepwater Fold-Thrust Belt exhibits three tectonic provinces: its inner shelf inverted province (σH is NW-SE, margin-normal), its outer shelf extension province (σH is NE-SW, margin-parallel), and its slope to basin floor compression province (σH is NW-SE, margin-normal). In the inverted province, σH reflects inversion of deltaic normal faults. The σH orientations in the extension and compression provinces reflect deltaic gravitational tectonics. The shale and minibasin provinces have been recognized in offshore Sabah. In the shale province, σH is N010°E, which aligns around the boundary of a massif of mobile shale. Currently, no data are available to determine σH in the minibasin province. In the Balingian province, σH is ESE-WNW, reflecting ESE absolute Sunda plate motions due to the absence of a thick detachment seen elsewhere in NW Borneo. The Central Luconia province demonstrates poorly constrained and variable σH orientations. These seven provinces result from the heterogeneous structural and stratigraphic development of the NW Borneo margin and formed due to complex collisional tectonics and the varied distribution and thicknesses of stratigraphic packages.Rosalind C. King, Mark R. P. Tingay, Richard R. Hillis, Christopher K. Morley, and James Clar

    Relationship between structural style, overpressures, and modern stress, Baram Delta Province, northwest Borneo

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    The Baram Delta differs from most large (passive margin) deltas because of its location on an active postcollisional margin. Structural style and evolution is influenced both by gravity-driven deformation and regional stress. Key structural features of the delta include (1) late development of the toe fold and thrust belt (latest Miocene-Recent) with respect to 17 Ma recent development of growth faults on the shelf; (2) a narrow active region of extension on the outer shelf upper slope; (3) absence of well-developed shale diapirs; and (4) inner shelf onshore folding, thrusting, and growth fault inversion. Overpressure magnitude, type, distribution, and principal stress orientation and magnitude for the shelfal area were determined from well data. The inner shelf onshore area of inversion displays decreasing vertical stress gradient offshore and pronounced transfer of disequilibrium compaction overpressure from the Setap (shale) Formation into the overlying Belait Formation. This loss of overpressure permitted partial recoupling of once detached deltaic sediments with basement. Evidence for partial recoupling includes decreasing minimum horizontal stress gradient from NE (area of maximum inversion) to SW across the shelf and coast-perpendicular inner shelf Shmax directions appropriate for inversion, but with stress magnitudes insufficient to cause deformation. These observations constrain models to explain why toe fold-thrust belt activity occurred relatively late, while inner shelf folding developed early and is inactive today. During delta progradation disequilibrium compaction overpressures developed in the outer shelf slope area and helped decouple the section from basement late in the delta history, hence compressional deformation shifted further offshore. Conversely onshore inner shelf inversion caused late overpressure loss, resulting in partial recoupling of the deltaic section with basement.Christopher K. Morley, Mark Tingay and Richard Hillis Australian School of Petroleum, University of Adelaide, Adelaide, Australia Rosalind Kin

    Recognition of COVID-19 with occupational origin: a comparison between European countries

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    Objectives: This study aims to present an overview of the formal recognition of COVID-19 as occupational disease (OD) or injury (OI) across Europe. Methods: A COVID-19 questionnaire was designed by a task group within COST-funded OMEGA-NET and sent to occupational health experts of 37 countries in WHO European region, with a last update in April 2022. Results: The questionnaire was filled out by experts from 35 countries. There are large differences between national systems regarding the recognition of OD and OI: 40% of countries have a list system, 57% a mixed system and one country an open system. In most countries, COVID-19 can be recognised as an OD (57%). In four countries, COVID-19 can be recognised as OI (11%) and in seven countries as either OD or OI (20%). In two countries, there is no recognition possible to date. Thirty-two countries (91%) recognise COVID-19 as OD/OI among healthcare workers. Working in certain jobs is considered proof of occupational exposure in 25 countries, contact with a colleague with confirmed infection in 19 countries, and contact with clients with confirmed infection in 21 countries. In most countries (57%), a positive PCR test is considered proof of disease. The three most common compensation benefits for COVID-19 as OI/OD are disability pension, treatment and rehabilitation. Long COVID is included in 26 countries. Conclusions: COVID-19 can be recognised as OD or OI in 94% of the European countries completing this survey, across different social security and embedded occupational health systems
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