30 research outputs found
Cenozoic contourite drifts and palaeoceanographic development of the Faeroe Shetland Basin
This thesis investigated the palaeoceanographic history of the Faeroe Shetland Basin, NE Atlantic, via identification and analysis of contourite drift deposits using petroleum industry seismic and well data. Integration of regional 2D seismic lines, 3D seismic volumes and high resolution seismic profiles w ith industrial well data permitted full spatial and temporal characterisation of the contourites within the basin, including identification of small scale architectural elements and subtle stratigraphic relationships. In turn, it was possible to make interpretations regarding the palaeoceanographic regime within the basin from the onset and evolution of thermohaline current flow through the basin to correlation with the present day oceanographic situation. Overall, the study serves to highlight the efficacy of industrial seismic and well data for contourite and palaeoceanographic research. A variety of contourite drift types were identified during seismic-chronostratigraphic division of the Cenozoic succession. Identification of an early middle Eocene contourite drift within the southern Faeroe Shetland Basin dates the onset of southerly flowing deep waters from the Norwegian Greenland Sea into the North Atlantic as part of a North Atlantic Conveyor Belt-style circulation system at approximately 49 million years, predating previous estimates by more than 15 million years. The presence of Oligocene, Miocene and Pliocene contourite drifts within the basin reveals that following initiation in the middle Eocene, southerly flowing deep water circulation through the basin was continuous throughout the late Palaeocene and Neogene to the present day. A gradual increase in deep water flux through the basin throughout this time is hypothesised based on contourite distribution, and is thought to relate to the global greenhouse to icehouse climatic transition that occurred during the Cenozoic. Pulses of increased deep water current velocity related to a combination of climatic and tectonic factors are thought to be responsible for the formation of major deep w ater erosional unconformities which are associated with the contourite drift successions. A link between contourite deposition and the climatic fluctuations that characterised the late Neogene northern hemisphere is also proposed based on the identification of direct indicators of significant glaciation including iceberg plough marks within the contourite drift units. Contourite drift deposition is interpreted to occur predominantly during climatically warmer episodes, while periods of glaciation are characterised by apparent disruption of ocean current circulation within the basin
Antarctic climate, Southern Ocean circulation patterns, and deep water formation during the Eocene
We assess early-to-middle Eocene seawater neodymium (Nd) isotope records from seven Southern Ocean deep-sea drill sites to evaluate the role of Southern Ocean circulation in long-term Cenozoic climate change. Our study sites are strategically located on either side of the Tasman Gateway and are positioned at a range of shallow (Nd(t) = −9.3 ± 1.5). IODP Site U1356 off the coast of Adélie Land, a locus of modern-day Antarctic Bottom Water production, is identified as a site of persistent deep water formation from the early Eocene to the Oligocene. East of the Tasman Gateway an additional local source of intermediate/deep water formation is inferred at ODP Site 277 in the SW Pacific Ocean (εNd(t) = −8.7 ± 1.5). Antarctic-proximal shelf sites (ODP Site 1171 and Site U1356) reveal a pronounced erosional event between 49 and 48 Ma, manifested by ~2 εNd unit negative excursions in seawater chemistry toward the composition of bulk sediments at these sites. This erosional event coincides with the termination of peak global warmth following the Early Eocene Climatic Optimum and is associated with documented cooling across the study region and increased export of Antarctic deep waters, highlighting the complexity and importance of Southern Ocean circulation in the greenhouse climate of the Eocene
Quaternary evolution of the northern North Sea margin through glacigenic debris-flow and contourite deposition
The Norwegian Channel Ice Stream of the Scandinavian Ice Sheet extended across the northern North Sea margin during the mid- to late Quaternary, eroding older sediment from the continental shelf. Consequently, little is known about early Quaternary sedimentation on this margin. We use two- and three-dimensional seismic-reflection data to investigate changing sediment volumes and sources in the northern North Sea through the Quaternary. The northern North Sea Basin was infilled during the early Quaternary by intercalated glacigenic debris-flows and contourites, which provide a record of the delivery of glacigenic sediment to the slope and the intensity of North Atlantic thermohaline circulation during early Quaternary glacial-interglacial cycles. The infilling of the basin reduced accommodation and led to the deflection of mid- to late Quaternary sediments into the Norwegian Sea, forming the North Sea Fan. Close to the onset of the mid-Quaternary, the south-western Scandinavian Ice Sheet margin was drained by an ice stream located beneath Måløy Plateau, 60 km east of the Last Glacial Maximum Norwegian Channel Ice Stream. The southward-flowing Norwegian Sea Bottom Water current was directed into the partially filled northern North Sea Basin during the early Quaternary, and deflected progressively northwards as the basin became infilled.During this work, C. L. Batchelor was in receipt of a Junior Research Fellowship at Newnham College, Cambridge
ChemInform Abstract: STUDIES OF THE TRIPHENYLPHOSPHINEGOLD(I)/SULFATE SYSTEM. SYNTHESIS AND CRYSTAL STRUCTURE OF (PH3PAU)2SO4.MEOH
Cooperative Extension Agents as Key Informants in Assessing Wildlife Damage Trends in Georgia
To manage emerging human-wildlife conflicts, wildlife managers will require more information regarding trends in wildlife damage and public perceptions of control measures. In 2017, we administered an online survey to Georgia Agriculture and Natural Resource County Cooperative Extension Agents (ANR Agents) to assess the types of inquiries or complaints about nuisance wildlife they had received during the previous year. We asked questions about the common species creating problems, the nature of the damage reported, and perceptions of client preferences regarding different types of nuisance wildlife control. We compared the results of our 2017 survey to a similar survey conducted in Georgia in 2002 to determine how human-wildlife conflict issues may have changed over time and how ANR Agents could serve as information sources regarding these changing trends. In 2017, ANR Agents received more inquiries about deer (Odocoileus virginianus) than any other species. Other species frequently identified included armadillos (Dasypus novemcinctus), wild pigs (Sus scrofa), moles (Scalopus spp.), squirrels (Sciurus spp.), and voles (Microtus spp.). Complaints about voles had increased since the previous survey (P = 0.019), as well as complaints about unknown sources of damage (P = 0.041) and requests for more general information on wildlife damage (P = 0.041). Fewer complaints about bats (Order: Chiroptera) (P = 0.0007), woodpeckers (Family: Picidae) (P = 0.021), squirrels (P = 0.047), and moles (P = 0.026) were reported during this survey than were reported in the 2002 survey. More ANR Agents in Georgia received complaints about wild pigs (P = 0.00004). Most complaints about nuisance wildlife referred to damage to yards/landscapes, followed by gardens, and then row crops. Complaints about damage to row crops had increased since the 2002 survey, (P = 0.046) while complaints about damage to houses/barns had decreased (P = 0.01). Lastly, ANR Agents believed their clients were not opposed to lethal control of nuisance wildlife. We believe these findings highlight the many benefits of targeting ANR Agents as key informants and recommend that other managers implement similar techniques to acquire information on nuisance wildlife trends within their own states
Onset of North Atlantic Deep Water production coincident with inception of the Cenozoic global cooling trend: Reply
We are grateful for the opportunity to reply to the Comment by Stoker et al. (2013), who raise questions of interpretation regarding our paper (Hohbein et al., 2012). The main focus of the paper is the interpretation of the Eocene basinal succession of the Faerøe-Shetland Basin as a contourite drift body, using two-dimensional seismic and borehole data. This interpretation is exactly that: an interpretation, and as is the case with regional seismic stratigraphic interpretation in general, alternative views are often forthcoming, and to be encouraged
ENGO Iconic Species Content Analysis
Data are collected from six organizations' press releases from 2015-2018 that contain the phrase "icon" or "iconic" in reference to iconic species
Recommended from our members
Superficial Thrombosis of Pelvic Congestion Syndrome Mimicking Pelvic Abscess
Pelvic congestion syndrome (PCS) is an uncommon illness that is typically diagnosed after chronic pelvic pain. We present a case of superficial thrombosis of pelvic veins from PCS that presented to the emergency department (ED) as a previous diagnosis of pelvic abscess with cellulitis. PCS was diagnosed in the ED by computed tomography after an abnormal point-of-care ultrasound. Here we describe this unusual presentation and our approach to the diagnosis
Recommended from our members
Spontaneously Conceived Ruptured Heterotopic Pregnancy Presenting with Chest Pain and Dyspnea: A Case Report
Introduction: Heterotopic pregnancy, defined as simultaneous intrauterine and ectopic pregnancy, is a rare and potentially life-threatening condition. The incidence of heterotopic pregnancy has significantly increased in the modern era, primarily due to use of assisted reproductive technology. Heterotopic pregnancy in the absence of risk factors is uncommon. The symptoms of heterotopic pregnancy are similar to those of ectopic pregnancy, primarily abdominal pain and vaginal bleeding.Case Report: We report a case of heterotopic pregnancy occurring in the absence of risk factors and presenting with primary symptoms of chest pain and shortness of breath.Conclusion: While uncommon, heterotopic pregnancy may occur in patients without risk factors and may present with atypical symptoms such as chest pain and shortness of breath