scholarly journals Offshore bedrock geology of Eclipse Sound and Pond Inlet: connecting the structure and stratigraphy of Bylot and northern Baffin islands

2020 ◽  
Vol 57 (10) ◽  
pp. 1254-1267
Author(s):  
Lisel D. Currie ◽  
Tom A. Brent ◽  
Elizabeth C. Turner
Keyword(s):  
Fault Zone ◽  
Active Faults ◽  
Petroleum Exploration ◽  
Normal Faults ◽  
Sea Floor ◽  
Baffin Bay ◽  
Bay Area ◽  
History Of ◽  
Marine Seismic ◽  
Fault Displacement

Understanding the Mesoproterozoic and younger structural history of the Eclipse Sound/Pond Inlet area is essential for the interpretation of its Archean to Paleoproterozoic geological history and could have important implications for mineral and petroleum exploration models in the northern Baffin Bay area. The identification of potentially active faults is critical for understanding possible earthquake-related hazards in the area. The integrated interpretation of 1970s-vintage marine seismic data with hill-shaded bathymetry, aeromagnetic data, and onshore geology maps has facilitated the identification of probable Mesoproterozoic (Bylot Supergroup) to Holocene strata on and below the sea floor and a suite of episodically reactivated northwest-striking horst- and graben-bounding normal faults and fault zones. Fault displacement likely occurred during the development of the Mesoproterozoic Borden basin and the Cretaceous–Paleogene opening of Baffin Bay, and in some cases may continue today. Some faults become more west-trending toward the south, which requires parts of these faults to have intermittently accommodated transtensional and (or) transpressional motion, possibly explaining local folds and out-of-graben thrusting. Numerous previously unrecognised faults have been documented, with faults beneath Eclipse Sound (Eclipse Trough) spaced at 5 to 7 km intervals, and at least one fault zone (Cape Hay Fault Zone) that appears to be at least 250 km in length, suggesting faults of similar spacing and scale may be present under Baffin Bay. This study uses a multi-thematic office-based methodology that inexpensively, and with little environmental impact, facilitates the mapping of structures that intersect the sea floor in areas where glaciers have exposed bedrock.

Tectonic history of the Queen Charlotte Islands and adjacent areas—a model

1981 ◽  
Vol 18 (11) ◽  
pp. 1717-1739 ◽  
Author(s):  
C. J. Yorath ◽  
R. L. Chase
Keyword(s):  
Fault Zone ◽  
Upper Jurassic ◽  
Normal Faults ◽  
Queen Charlotte Islands ◽  
Tectonic History ◽  
History Of ◽  
Middle Component ◽  
High Level ◽  
Paleozoic Rocks ◽  
Alexander Terrane

The region including Queen Charlotte Islands, Hecate Strait, and Queen Charlotte Sound is underlain by two allochthonous terranes, Wrangellia and the Alexander terrane. The suture between them occurs in central Graham Island and central Hecate Strait and is coincident with the traces of the Sandspit and Rennell Sound fault zones, each of which developed in response to crustal rifting in Queen Charlotte Sound during mid-Tertiary time.The stratigraphic succession comprises four tectonic assemblages. (1) The allochthonous assemblages comprise Paleozoic rocks of the Alexander terrane and Upper Triassic and Jurassic rocks of Wrangellia, which on the basis of paleomagnetic and biogeographical data are clearly exotic. The distribution of these terranes beneath Queen Charlotte Sound and Hecate Strait is supported by geophysical information and subsurface data obtained from offshore wells. (2) The suture assemblage is represented by extremely coarse conglomerates, massive graywackes, and turbidites of Early Cretaceous age, and possibly by Upper Jurassic plutons. (3) The post-suture assemblage is expressed by the tripartite succession of the mid- to Upper Cretaceous Queen Charlotte Group whose middle component, the Honna Formation, comprises polymictic conglomerates that may have resulted from the final accretion of the amalgamated crustal fragments of the Alexander Terrane and Wrangellia to the continental margin. (4) The rift assemblage is expressed by mid- to upper Tertiary volcanics, epizonal plutons, and terrigenous clastics. Rifting is believed to have occurred in Queen Charlotte Sound above a mantle plume and resulted in crustal attenuation through development of listric, crustal-penetrative normal faults, and concurrent extrusion of subaerial volcanics and emplacement of high-level plutons. The attenuation caused northward motion of the Queen Charlotte Islands along the Louscoone Inlet – Sandspit fault zone and subsidence in Queen Charlotte Sound where Lower Miocene marine sediments were deposited within the rift zone. Later, additional rifting in southern Hecate Strait resulted in the reactivation of the old suture zone, manifest as the Rennell Sound fault zone. Concurrent with continued terrigenous deposition and volcanism, the Queen Charlotte Islands moved northwesterly along the Rennell Sound Fault, which disrupted the earlier fault trend. The final rotation of the islands to their modern position was accomplished through left-lateral motion along the Beresford Bay and Langara Faults.

The formation of Congo River and the origin of bonobos: A new hypothesis

2018 ◽  
Author(s):  
Hiroyuki Takemoto ◽  
Yoshi Kawamoto ◽  
Takeshi Furuichi
Keyword(s):  
Nous Avons ◽  
Pan Paniscus ◽  
Congo Basin ◽  
Sea Floor ◽  
Terrestrial Mammals ◽  
Congo River ◽  
Il Y A ◽  
History Of ◽  
Area North ◽  
New Hypothesis

The Congo River functions as a strong geographical barrier for many terrestrial mammals in the Congo Basin, separating forest habitat into right and left banks of the river. However, there has been little discussion on the biogeography of the Congo Basin because the history of the river has been obscured. Based on the recent information of the sea-floor sediments near the mouth of the river and the geophysical survey on the continent, this chapter proposes a plausible hypothesis on the Congo River formation and presents a consequent hypothesis on the divergence of bonobos (Pan paniscus) from other Pan populations. The present hypothesis is also helpful for understanding the distribution of other primates and other mammals in the basin. Furthermore, this hypothesis suggests that all hominid clades, including human, chimpanzee and gorilla, except bonobo, evolved in the area north or east of the Congo River. La rivière du Congo a la fonction d’une barrière géographique forte pour plusieurs mammifères dans le bassin du Congo, séparant l’habitat forêt dans les banques gauches et droites de la rivière. Cependant, il y a eu peu de discussions sur la biogégraphie du bassin du Congo, parce que l’histoire de la rivière a été voilée. Récemment, quelque données importantes qui peuvent avoir des liens avec la formation de la rivière du Congo ont été acquise, surtout par la recherche des sédiments du fond marin près de la bouche de la rivière et par l’enquête géographique du continent. À partir de cette nouvelle information, nous avons proposé une hypothèse plausible sur la formation de la rivière du Congo. Nous avons aussi présenté une hypothèse conséquente sur la divergence des bonobos (Pan paniscus) des autres populations Pan (voire Takemoto et al., 2015 pour la publication originale de cette étude). L’hypothèse présente nous aide aussi à comprendre la distribution des autre primates et des autres mammifères dans le bassin. De plus, cette hypothèse suggère que tous les hominidés clades, humains inclus, chimpanzés et gorilla à l’exception du bonobo, ont évolué dans la régions du nord ou de l’est de la rivière du Congo.

scholarly journals Holocene polynya dynamics and their interaction with oceanic heat transport in northernmost Baffin Bay

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rebecca Jackson ◽  
Anna Bang Kvorning ◽  
Audrey Limoges ◽  
Eleanor Georgiadis ◽  
Steffen M. Olsen ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Active Role ◽  
Atlantic Water ◽  
The Arctic ◽  
Negative Consequences ◽  
Baffin Bay ◽  
The North ◽  
North Water ◽  
History Of ◽  
Ocean Conditions

AbstractBaffin Bay hosts the largest and most productive of the Arctic polynyas: the North Water (NOW). Despite its significance and active role in water mass formation, the history of the NOW beyond the observational era remains poorly known. We reconcile the previously unassessed relationship between long-term NOW dynamics and ocean conditions by applying a multiproxy approach to two marine sediment cores from the region that, together, span the Holocene. Declining influence of Atlantic Water in the NOW is coeval with regional records that indicate the inception of a strong and recurrent polynya from ~ 4400 yrs BP, in line with Neoglacial cooling. During warmer Holocene intervals such as the Roman Warm Period, a weaker NOW is evident, and its reduced capacity to influence bottom ocean conditions facilitated northward penetration of Atlantic Water. Future warming in the Arctic may have negative consequences for this vital biological oasis, with the potential knock-on effect of warm water penetration further north and intensified melt of the marine-terminating glaciers that flank the coast of northwest Greenland.

scholarly journals High food insecurity in Latinx families and associated COVID-19 infection in the Greater Bay Area, California

BMC Nutrition ◽  
2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Milagro Escobar ◽  
Andrea DeCastro Mendez ◽  
Maria Romero Encinas ◽  
Sofia Villagomez ◽  
Janet M. Wojcicki
Keyword(s):  
Food Security ◽  
Food Insecurity ◽  
San Francisco ◽  
Employment Status ◽  
The United States ◽  
Household Food Security ◽  
Bay Area ◽  
Household Food ◽  
History Of ◽  
The Impact

Abstract Background Food insecurity impacts nearly one-in-four Latinx households in the United States and has been exacerbated by the novel coronavirus or COVID-19 pandemic. Methods We examined the impact of COVID-19 on household and child food security in three preexisting, longitudinal, Latinx urban cohorts in the San Francisco Bay Area (N = 375 households, 1875 individuals). Households were initially recruited during pregnancy and postpartum at Zuckerberg San Francisco General Hospital (ZSFG) and UCSF Benioff prior to the COVID-19 pandemic. For this COVID-19 sub-study, participants responded to a 15-min telephonic interview. Participants answered 18 questions from the US Food Security Food Module (US HFSSM) and questions on types of food consumption, housing and employment status, and history of COVID-19 infection as per community or hospital-based testing. Food security and insecurity levels were compared with prior year metrics. Results We found low levels of household food security in Latinx families (by cohort: 29.2%; 34.2%; 60.0%) and child food security (56.9%, 54.1%, 78.0%) with differences between cohorts explained by self-reported levels of education and employment status. Food security levels were much lower than those reported previously in two cohorts where data had been recorded from prior years. Reported history of COVID-19 infection in households was 4.8% (95% Confidence Interval (CI); 1.5–14.3%); 7.2% (95%CI, 3.6–13.9%) and 3.5% (95%CI, 1.7–7.2%) by cohort and was associated with food insecurity in the two larger cohorts (p = 0.03; p = 0.01 respectively). Conclusions Latinx families in the Bay Area with children are experiencing a sharp rise in food insecurity levels during the COVID-19 epidemic. Food insecurity, similar to other indices of poverty, is associated with increased risk for COVID-19 infection. Comprehensive interventions are needed to address food insecurity in Latinx populations and further studies are needed to better assess independent associations between household food insecurity, poor nutritional health and risk of COVID-19 infection.

Fault displacement gradients on normal faults and associated deformation

AAPG Bulletin ◽  
2014 ◽  
Vol 98 (6) ◽  
pp. 1161-1184 ◽  
Author(s):  
Alan P. Morris ◽  
Ronald N. McGinnis ◽  
David A. Ferrill
Keyword(s):  
Normal Faults ◽  
Fault Displacement
Sign in / Sign up

Export Citation Format

Share Document