Petrology, Structure, and Correlation of the Upper Precambrian Ely's Peak Basalts

A Thesis submitted to the faculty of the Graduate School of the University of Minnesota by James A. Kilburg in partial fulfillment of the requirements for the degree of Master of Science, May 1972. Plate 1 referenced in the thesis is also attached to this record.The Upper Precambrian Ely's Peak basalts crop out in a north-south trending, wedge-shaped belt in the area around Nopeming, southwest of Duluth, Minnesota. These Lower Keweenawan flows overlie the basal Upper Precambrian quartzite in the southwestern portion of the Lake Superior basin. There are at least 20 individual flows with a total thickness of about 1,200 feet. The thickest flow is about 125 feet thick while the thinnest is less than 10 feet thick. Many of the flows show considerable lateral continuity; for example, one flow is traceable for about three miles along strike. Chemically, there are two main types of flows as classified by MacDonald and Katsura (1964); these are alkali basalts and tholeiite basalts. The alkali basalts, which have a low silica content, are fine- to medium-grained and form flows which vary in thickness from about 15 to just over 100 feet. Plagioclase, small, anhedral olivine pseudomorphs, and actinolite after augite form a subophitic to poikilitic texture. The opaque minerals ilmenite and magnetite form phenocrysts up to 1.5 mm in diameter in some rocks but are usually found as interstitial microlites in the groundmass. Textures and structures within the flows suggest a low viscosity. Structures within these flows include level, ropy surfaces, bent and straight pipe vesicles, straight vesicle cylinders and vesicular tops. Crude columnar joints were observed in one flow. The tholeiitic basalts are usually fine- to medium-grained, but some thicker flows are coarse-grained. These flows are usually from 30 to 90 feet thick. They include porphyritic, subophitic, and poikilitic types. Augite occurs as phenocrysts in the porphyritic flows and as poikilitic oikocrysts and as intergranular grains in the others. Olivine pseudomorphs are occasionally present, and magnetite and ilmenite generally occur as evenly distributed microlites in the groundmass. Structures within the flows include pillows (only in the basal flow), stretched amygdules, and vesicular tops. The augite-porphyritic basalts which lie at the base of the sequence are distinctive and very rare in the North Shore Volcanic Group. The whole sequence of lavas has undergone hydrothermal metamorphism to the high zeolite-low greenschist facies. Minerals present which demonstrate this are actinolite, chlorite, and epidote. The only zeolite present is wairakite which has been discovered here apparently for the first time in the Lake Superior region. It is the highest-temperature zeolite. Intrusion of the Duluth Complex is thought to be responsible for elevating the geothermal gradient and thus, permitting the formation of wairakite. The gabbro intrusion also contact-metamorphosed the lavas to a medium-grained pyroxene hornfels for a distance of up to one-fifth of a mile from the contact. Pressures of metamorphism are thought to have been between 2,000 and 2,500 bars. This pressure was produced by the weight of up to 30,000 feet of overlying Upper Precambrian lavas and Duluth Complex which underlie the North Shore of Lake Superior. Temperatures are estimated to have been between 290° C and 370° C during the hydrothermal metamorphism. Based on their distinctive petrology and reversed magnetic polarity (Green and Books, 1972), the Ely's Peak basalts appear to correlate with the basal flows at Grand Portage, Minnesota. This implies that the time of deposition at these localities was approximately the same, and the source from which these lavas were derived and the physical conditions of magma generation were the same

Scavenger Receptor BI Attenuates IL-17A–Dependent Neutrophilic Inflammation in Asthma

Asthma is a common respiratory disease currently affecting more than 300 million worldwide and is characterized by airway inflammation, hyperreactivity, and remodeling. It is a heterogeneous disease consisting of corticosteroid-sensitive T-helper cell type 2–driven eosinophilic and corticosteroid-resistant, T-helper cell type 17-driven neutrophilic phenotypes. One pathway recently described to regulate asthma pathogenesis is cholesterol trafficking. Scavenger receptors, in particular SR-BI (scavenger receptor class B type I), are known to direct cellular cholesterol uptake and efflux. We recently defined SR-BI functions in pulmonary host defense; however, the function of SR-BI in asthma pathogenesis is unknown. To elucidate the role of SR-BI in allergic asthma, SR-BI–sufficient (SR-BI(+/+)) and SR-BI–deficient (SR-BI(−/−)) mice were sensitized (Days 0 and 7) and then challenged (Days 14, 15, and 16) with a house dust mite (HDM) preparation administered through oropharyngeal aspiration. Airway inflammation and cytokine production were quantified on Day 17. When compared with SR-BI(+/+) mice, the HDM-challenged SR-BI(−/−) mice had increased neutrophils and pulmonary IL-17A production in BAL fluid. This augmented IL-17A production in SR-BI(−/−) mice originated from a non–T-cell source that included neutrophils and alveolar macrophages. Given that SR-BI regulates adrenal steroid hormone production, we tested whether the changes in SR-BI(−/−) mice were glucocorticoid dependent. Indeed, SR-BI(−/−) mice were adrenally insufficient during the HDM challenge, and corticosterone replacement decreased pulmonary neutrophilia and IL-17A production in SR-BI(−/−) mice. Taken together, these data indicate that SR-BI dampens pulmonary neutrophilic inflammation and IL-17A production in allergic asthma at least in part by maintaining adrenal function

Experiences of clinical psychologists working in palliative care:A qualitative study

Background Compassion fatigue refers to the emotional and physical exhaustion felt by professionals in caring roles, whereas compassion satisfaction encompasses the positive aspects of helping others. Levels of compassion satisfaction and fatigue have been found to be inconsistent in palliative care professionals, which could have serious implications for patients, professionals and organisations. Objectives This study explored the experiences of clinical psychologists working in palliative care, all worked with adults with cancer, to gain an understanding of the impact this work has on their self and how they manage this. Methods A qualitative approach was taken, using semi‐structured interviews and interpretative phenomenological analysis. Results Three superordinate themes were identified: commitment, existential impact on the self and the oracle. The participants' experiences were characterised by the relationship between themselves and their patients, the influence of working in palliative services on their world view and the impact of organisational changes. Differences between working as a clinical psychologist in palliative care versus non‐palliative settings were considered. Conclusions Professionals working in palliative care should be supported to reflect on their experiences of compassion and resilience, and services should provide resources that facilitate staff to practice positive self‐care to maintain their well‐being