Muhammad Mudasar Saqab

Geological and geophysical evidence for a mafic igneous origin of the Porcupine Arch, offshore Ireland

Sedimentary basins west of Ireland contain a number of deep seismic structures that have been variously interpreted as fault blocks, serpentinite extrusions or igneous complexes. The Porcupine Arch (PA) is a deep-level (>11 km) domal 50 km wide seismic feature associated with a prominent free-air gravity anomaly high and high P-wave velocities. Detailed seismic mapping of igneous sill complexes in the Porcupine Basin suggests a possible connection with the PA. The sills form a thick (>5 km) interconnected network extending from the PA into the flanking post-rift Cretaceous stratigraphy, suggesting that the PA may be the top of a large (ultra)mafic intrusion that fed the sills. An intrusive origin for the PA is in agreement with geophysical modelling (gravity and Vp), the seismic character of the Porcupine Arch structure and the primitive bulk composition of the Porcupine sills, and is consistent with documented regional Cenozoic uplift in the basin with the development of shallow water and the occurrence of Paleocene–Eocene deltaic depositional systems. Similar mafic–ultramafic intrusive complexes have been documented elsewhere on the northeastern Atlantic margin, including the Rockall Trough. These findings emphasize that higher heat flow in the early Cenozoic may have prevailed over the northern part of the Porcupine Basin.

Re-thinking the unimpeded tube-well growth under the depleting groundwater resources in the Punjab, Pakistan

Groundwater resources are crucial in sustaining agro-ecosystems and ensuring food security in many parts of the world, including Pakistan. However, the sustainability of groundwater resources is subject to a number of challenges, including over-extraction, deterioration in quality, and vulnerability to the impacts of climate change and population growth. Given the current state of groundwater resources in Pakistan, policymakers seek to manage groundwater resources by limiting groundwater extraction. To achieve this goal on a national scale, it is important to understand the determinants of the decisions made by local farmers in respect of tube-well adoption. This study investigates smallholder farmers’ decisions to adopt tube-well technology in the face of dwindling groundwater resources and falling water tables. Analysis is based on a cross-sectional survey of 200 rural households from the arid to semi-arid predominantly groundwater-irrigated plains of the Punjab province, Pakistan. It is found that farmers will adopt tube-well technology in pursuit of reliable irrigation water supplies to hedge against production risks but not against the risk associated with unfavourable extreme events (downside risk) such as total crop failure. This suggests that the adoption decision is influenced by the expected long-term rather than the short-term benefits. This paper draws attention to the need to regulate groundwater resource exploitation by requiring the use of tube-well technology to be accompanied by irrigation water-efficient techniques and technologies.RésuméLes ressources en eau souterraine sont cruciales pour l’alimentation des agro-ecosystèmes et assurer la sécurité alimentaire dans de nombreuses régions du monde, notamment au Pakistan. Cependant, la durabilité des ressources en eau souterraine est. soumise à de nombreux enjeux, tels que la surexploitation, la dégradation de leur qualité et la vulnérabilité aux impacts du changement climatique et de la croissance de la population. Compte-tenu de l’état actuel des ressources en eau souterraine au Pakistan, les décideurs cherchent à gérer les ressources en eau souterraine en en limitant les prélèvements. Pour atteindre cet objectif à l’échelle nationale, il est. important de comprendre les déterminismes des décisions prises par les agriculteurs locaux en ce qui concerne l’adoption des forages d’eau. Cette recherche étudie les décisions des petits exploitants agricoles qui adoptent la technologie des forages d’eau dans un contexte de diminution des ressources en eau souterraine et de chute des niveaux piézométriques. L’analyse est. basée sur une enquête transversale au sein de 200 foyers ruraux des plaines arides à semi-arides principalement irriguées au moyen d’eau souterraine, de la province du Punjab, Pakistan. Il est. montré que les agriculteurs adopteront la technologie du forage d’eau à la quête d’une alimentation en eau d’irrigation fiable afin de couvrir les risques de production, mais pas contre le risque associé aux évènements extrêmes défavorables (risque de perte), tel. que l’échec total de la récolte. Cela suggère que la décision d’adoption est. influencée par le long terme prévu plutôt que par les bénéfices à court terme. Cet article attire l’attention sur le besoin de réguler l’exploitation de la ressource en eau souterraine en imposant que l’utilisation de la technologie du forage d’eau soit accompagnée par des techniques et technologies d’irrigation efficientes en eau.ResumenLos recursos de agua subterránea son cruciales para mantener los agroecosistemas y garantizar la seguridad alimentaria en muchas partes del mundo, incluido Pakistán. Sin embargo, la sostenibilidad de los recursos de agua subterránea está sujeta a una serie de desafíos, que incluyen la extracción excesiva, el deterioro de la calidad y la vulnerabilidad a los impactos del cambio climático y el crecimiento de la población. Dado el estado actual de los recursos de aguas subterráneas en Pakistán, los responsables de las políticas buscan gestionarlos limitando la extracción de aguas subterráneas. Para lograr este objetivo a escala nacional, es importante comprender los determinantes de las decisiones tomadas por los agricultores locales con respecto a la adopción de pozos entubados. Este estudio investiga las decisiones de los pequeños agricultores de adoptar tecnología de pozos entubados frente a la disminución de los recursos de agua subterránea y la profundización de la capa freática. El análisis se basa en un relevamiento transversal de 200 hogares rurales de las llanuras áridas a semiáridas predominantemente con riego con agua subterránea en la provincia de Punjab, Pakistán. Se encuentra que los agricultores adoptaron la tecnología de los pozos entubados en busca de suministros confiables de agua de riego para protegerse contra los riesgos de producción, pero no contra el riesgo asociado con eventos extremos desfavorables (riesgo de pérdida) como el fracaso total de la cosecha. Esto sugiere que la decisión de adopción está influenciada por los beneficios esperados a largo plazo en lugar de los beneficios a corto plazo. Este documento llama la atención sobre la necesidad de regular la explotación de los recursos de agua subterránea al requerir que el uso de la tecnología de los pozos entubados vaya acompañado de técnicas y tecnologías de riego eficiente.摘要在世界很多地区包括巴基斯坦,地下水资在源维持农业生态系统和确保粮食安全上至关重要。然而,地下水资源的可持续性受到很多挑战,包括超采、水质恶化、对气候变化和人口增长影响的脆弱性。考虑到巴基斯坦目前地下水资源的现状,政策制定者寻求通过限制地下水开采管理地下水资源。,为了在全国范围内完成这个目标,了解当地农民针对管井的选择做出决定的主要因素非常重要。本研究项目调查了 农民在面临地下水资源减少以及地下水位下降的情况下选择管井技术的决定。根据巴基斯坦Punjab省干旱到半干旱的地下水主要灌溉平原200个农户代表性调查结果进行了分析。发现,农民选择管井技术以寻找可靠的灌溉水源,应对生产风险,但应对不了与极端不利事件(负面风险)诸如整个作物歉收。这表明选择决定受到预期的长期收益而不是短期收益的影响。本文强调了应该通过把管井技术与灌溉节水技术结合一起来管理地下水资源。ResumoOs recursos hídricos subterrâneos são cruciais em sustentar os agroecossistemas e garantir a segurança alimentar em várias partes do mundo, incluindo o Paquistão. Entretanto, a sustentabilidade dos recursos hídricos subterrâneos é submetida a um grande número de desafios, incluindo a superexploração, deterioração em qualidade e vulnerabilidade aos impactos das mudanças climáticas e crescimento populacional. Dado o estado atual de recursos hídricos subterrâneos no Paquistão, os legisladores procuram gerenciar água subterrânea por limitação de extração. Para atingir este objetivo em escala nacional, se torna importante entender as razões determinantes das decisões tomadas por agricultores locais em respeito à adoção de poços tubulares. Este estudo investiga as decisões de pequenos agricultores de adotar poços tubulares frente à contínua redução de recursos hídricos subterrâneos e níveis de carga hidráulica. A análise é baseada em uma revisão transversal de 200 domicílios rurais nas planícies áridas ou semiáridas da província de Punjab, Paquistão, que são predominantemente irrigadas por águas subterrâneas. Foi descoberto que agricultores irão adotar poços tubulares em busca de fornecimento confiável de água para se protegerem contra riscos de produção, mas não para se protegerem dos riscos associados com eventos extremos desfavoráveis (riscos negativos) como falha total na produção. Isto sugere que a decisão de adoção é influenciada pela previsão de longo prazo, ao invés de se pautar no curto prazo. Este artigo chama atenção à necessidade de regular a exploração de recursos hídricos subterrâneos, exigindo que o uso de poços tubulares seja acompanhado por técnicas e tecnologias eficientes no consumo de água na irrigação.

Neogene oblique extensional system in the north-western Bonaparte Basin, Australia

The North-western Bonaparte Basin offers a very good opportunity to understand the nature of oblique extension system, where Neogene flexure-induced extension was superimposed obliquely to the Mesozoic rift-related structures. The Mesozoic trends strongly control the distribution and style of the younger Neogene structures, both at regional and local scale. The younger Neogene activity produced a new set of NE trending, right-stepping en echelon faults and reactivated the older faults. In addition, episodes of stratigraphic growth provide critical evidence regarding the timing of fault activity. Results demonstrate that, in the study area, main fault activity occurred in several pulses during the latest Miocene to Late Pleistocene. These episodes of fault activity correspond to recently constrained regional tectonic events i.e., the initial collision of the Australian Plate with the Banda Arc, the episodes of uplift of the Timor Island and the timing of lithospheric flexure.

Quaternary isolated carbonate build-ups in the Timor Sea (NW Australia) - Understandings and Implications

Distribution and growth history of isolated carbonate build-ups (ICBs) is controlled by complex interplay between various tectonic, eustatic, and oceanographic parameters. Quaternary ICBs in the Timor Sea (NW Australia) are located in tropical waters, and at present they form clusters of ~150 build-ups, developing 2 to 85 km from the edge of a wide continental shelf. The tectonic evolution of the Timor Sea lead to regional changes in the oceanography and flexural deformation of the NW Bonaparte Basin, which in turn had a major impact on the evolution of ICBs. Flexure-induced fault activity produced structural topography for the growth of ICBs over ‘highs’, while oceanic current through Timor Trough provided warm and nutrient-rich water. Our results demonstrate that, despite potentially good conditions for carbonate production, ICBs did not form until the Mid Pleistocene (ca. 0.582-0.8 Ma BP). This age corresponds to the onset of repeated, high-amplitude (+120 m) sea level fluctuations with rapid deglacial rises and slow falls. Thus, we infer that the NW Australia ICBs formed due to: (1) structural shaping of the margin; (2) oceanographic changes, and; most importantly, (3) onset of repeated short-term transgressions reactivating the carbonate production along isolated highs. The distribution and growth of ICBs could be useful to understand the evolution of ancient ICBs that formed along very wide shelves and epeiric seas.