Comparing onshore and offshore volumes of large igneous provinces associated with passive continental margins 

2021 ◽  
Author(s):  
Seth Stein ◽  
Molly Gallahue ◽  
Carol Stein ◽  
Tyrone Rooney ◽  
Andie Gomez-Patron
Keyword(s):  
Passive Margin ◽  
Igneous Rocks ◽  
Continental Rifting ◽  
Large Igneous Provinces ◽  
Passive Margins ◽  
Igneous Provinces ◽  
Euler Pole ◽  
Seismic Reflection Profiles ◽  
The Relationship ◽  
Insight Into

<p>The rifting of continents can lead to the initiation of seafloor spreading and the formation of passive margins. Magma-rich passive margins, which are defined as being underlain by enormous volumes of igneous rocks, are often associated with large igneous provinces (LIPs). However, the relationship between the igneous units found along these magma-rich passive margins, rifting processes, and LIPs is poorly understood.</p><p>We have developed the VOLMIR (VOLcanic passive Margin Igneous Rocks) dataset to investigate these relationships. VOLMIR is based on seismic reflection profiles in which the volumes and geometries of both shallow seaward dipping reflector (SDR) and deeper high velocity lower crustal (HVLC) units can be measured. We find a relatively consistent ratio of SDR to HVLC volumes, with SDR volumes about one third that of HVLC. This consistency suggests that the units are related during formation and may be used to provide insight into how such units form during continental rifting and breakup. Presumably, as magmas rise and erupt to the surface to form SDRs, the remaining high-density residuum or cumulate becomes the HVLC. The volumes of SDR units are moderately positively correlated with distance from the Euler pole, and weakly negatively correlated with distance from the nearest hotspot, suggesting that lithospheric processes play more of a role in late-stage continental rifting and breakup than hotspot/mantle plume processes.</p><p>The Mid- and South Atlantic Ocean breakups, and the resulting offshore volcanic passive margins, are temporally and spatially associated with the Central Atlantic Magmatic Province (CAMP) and Paraná-Etendeka LIP. Using VOLMIR, we estimate the amount of igneous material in the offshore volcanic passive and compare it to estimates for the adjacent on-land LIPs. The results indicate that a significant volume of volcanics exist in the offshore passive margins, increasing the inferred amount of volcanic output associated with the LIPs. Further studies will provide insight into the relationship between offshore passive margins and on-land LIPs, and perhaps provide further understanding on the role of magmatism in rifting processes.</p>

EXPLORING THE RELATIONSHIP BETWEEN VOLCANIC PASSIVE MARGINS AND ADJACENT LARGE IGNEOUS PROVINCES

2020 ◽  
Author(s):  
Molly M. Gallahue ◽  
◽  
Seth Stein ◽  
Carol A. Stein ◽  
Donna M. Jurdy ◽  
...  
Keyword(s):  
Large Igneous Provinces ◽  
Passive Margins ◽  
Igneous Provinces ◽  
The Relationship

scholarly journals Kinematic Boundary Conditions Favouring Subduction Initiation at Passive Margins Over Subduction at Mid-oceanic Ridges

2021 ◽  
Vol 9 ◽  
Author(s):  
A. Auzemery ◽  
E. Willingshofer ◽  
P. Yamato ◽  
T. Duretz ◽  
F. Beekman
Keyword(s):  
Convergence Rate ◽  
Oceanic Lithosphere ◽  
Passive Margin ◽  
Continental Margins ◽  
Subduction Initiation ◽  
Passive Margins ◽  
Geodynamic Processes ◽  
The Alps ◽  
The Relationship

We perform numerical modelling to simulate the shortening of an oceanic basin and the adjacent continental margins in order to discuss the relationship between compressional stresses acting on the lithosphere and the time dependent strength of the mid-oceanic ridges within the frame of subduction initiation. We focus on the role of stress regulating mechanisms by testing the stress–strain-rate response to convergence rate, and the thermo-tectonic age of oceanic and continental lithospheres. We find that, upon compression, subduction initiation at passive margin is favoured for thermally thin (Palaeozoic or younger) continental lithospheres (<160 km) over cratons (>180 km), and for oceanic basins younger than 60 Myr (after rifting). The results also highlight the importance of convergence rate that controls stress distribution and magnitudes in the oceanic lithosphere. Slow convergence (<0.9 cm/yr) favours strengthening of the ridge and build-up of stress at the ocean-continent transition allowing for subduction initiation at passive margins over subduction at mid-oceanic ridges. The results allow for identifying geodynamic processes that fit conditions for subduction nucleation at passive margins, which is relevant for the unique case of the Alps. We speculate that the slow Africa–Europe convergence between 130 and 85 Ma contributes to the strengthening of the mid-oceanic ridge, leading to subduction initiation at passive margin 60–70 Myr after rifting and passive margin formation.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

On Metaphysics and the Political: A Polemics of Reading Baudelaire in the 1930s

2019 ◽  
Vol 58 (2) ◽  
pp. 249-259
Author(s):  
Joseph Acquisto
Keyword(s):  
Twentieth Century ◽  
Political Crisis ◽  
The Political ◽  
Modern Poetry ◽  
Progressive Politics ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

This essay examines a polemic between two Baudelaire critics of the 1930s, Jean Cassou and Benjamin Fondane, which centered on the relationship of poetry to progressive politics and metaphysics. I argue that a return to Baudelaire's poetry can yield insight into what seems like an impasse in Cassou and Fondane. Baudelaire provides the possibility of realigning metaphysics and politics so that poetry has the potential to become the space in which we can begin to think the two of them together, as opposed to seeing them in unresolvable tension. Or rather, the tension that Baudelaire animates between the two allows us a new way of thinking about the role of esthetics in moments of political crisis. We can in some ways see Baudelaire as responding, avant la lettre, to two of his early twentieth-century readers who correctly perceived his work as the space that breathes a new urgency into the questions of how modern poetry relates to the world from which it springs and in which it intervenes.

The Annual Reports of the Prison Commissioners for Scotland and Religion, 1903–1931

2019 ◽  
Vol 48 (1) ◽  
pp. 83-101
Author(s):  
Cameron McKay
Keyword(s):  
Annual Report ◽  
Annual Reports ◽  
Individual Choice ◽  
Drinking Habits ◽  
Parental Neglect ◽  
Late Nineteenth ◽  
Causes Of Crime ◽  
Criminological Theories ◽  
The Relationship ◽  
Insight Into

During the late nineteenth and early twentieth century penologists began to explore the possibility that environment and upbringing, as opposed to individual choice, were the causes criminality. The Prison Commissioners for Scotland, the devolved body who administered prisons north of the border, were not immune to this wider trend. Smith has argued that from the 1890s onwards the Commissioners began to accept that criminality was caused by social problems, namely alcoholism, but also parental neglect, poor education and poverty. In their efforts to test these new criminological theories, the Commissioners began to make more careful enquiries into the backgrounds of their charges. From 1896 to 1931 the Commissioners interviewed a sample of prisoners each year and included the findings in their annual report. Although the main focus of these interviews was on the upbringing and drinking habits of prisoners; by the 1900s the Commissioners seem to have added irreligion to the growing list of etiological causes of crime, and from 1903 onwards prisoners were asked to give details on their religious habits. Although it is debateable how much the Prison Commissioners revealed about the relationship between religion and crime, they did however provide a useful insight into the religiosity of the average prisoner.

The Relationship between Seeker and Spiritual Guide as portrayed in contemporary Western Sufi Autobiographies

2011 ◽  
Vol 5 (2) ◽  
pp. 297-332
Author(s):  
Kate Zebiri
Keyword(s):  
Life Writing ◽  
New Age ◽  
The Self ◽  
Individual Autonomy ◽  
Religious Authority ◽  
The Face ◽  
The Relationship ◽  
Insight Into ◽  
Continuity And Discontinuity

This article aims to explore the Shaykh-mur?d (disciple) or teacher-pupil relationship as portrayed in Western Sufi life writing in recent decades, observing elements of continuity and discontinuity with classical Sufism. Additionally, it traces the influence on the texts of certain developments in religiosity in contemporary Western societies, especially New Age understandings of religious authority. Studying these works will provide an insight into the diversity of expressions of contemporary Sufism, while shedding light on a phenomenon which seems to fly in the face of contemporary social and religious trends which deemphasize external authority and promote the authority of the self or individual autonomy.

Empathy as moderator of gender differences in Chinese insurance agents' business ethical sensitivity

2017 ◽  
Vol 45 (6) ◽  
pp. 1029-1042 ◽  
Author(s):  
Na Zhang ◽  
Jian Zhang ◽  
Jing Wang
Keyword(s):  
Gender Differences ◽  
Business Ethics ◽  
Research Field ◽  
Ethical Sensitivity ◽  
Men And Women ◽  
Insurance Agents ◽  
Factors Associated ◽  
Ethics Research ◽  
The Relationship ◽  
Insight Into

To expand the business ethics research field, and to increase society's understanding of Chinese insurance agents' business ethics, we investigated how gender differences are related to agents' business ethical sensitivity and whether or not these relationships are moderated by empathy. Through a regression analysis of the factors associated with the business ethical sensitivity of 417 Chinese insurance agents, we found that gender played an important role in affecting business ethical sensitivity, and empathy significantly affected business ethical sensitivity. Furthermore, empathy had a moderating effect on the relationship between gender and business ethical sensitivity. Both men and women with strong empathy scored high on business ethical sensitivity; however, men with strong empathy had higher levels of business ethical sensitivity than did women with little empathy. The findings add to the literature by providing insight into the mechanisms responsible for the benefits of empathy in increasing business ethical sensitivity.

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