Paleomagnetism of the Harp Lake Complex and associated rocks

1977 ◽  
Vol 14 (6) ◽  
pp. 1187-1201 ◽  
Author(s):  
E. Irving ◽  
R. F. Emslie ◽  
J. K. Park
Keyword(s):  
North America ◽  
Geomagnetic Field ◽  
Great Depth ◽  
Time Interval ◽  
Central Pacific ◽  
Remanent Magnetism ◽  
Low Latitudes ◽  
The World ◽  
The Mean ◽  
Harp Lake

The remanent magnetism of anorthositic rocks from the Harp Lake Complex consists of two antiparallel components, M and H, defined on the basis of their coercivities. M has remanent coercivities generally in the range 100–1000 Oe (7.96 × 103–7.96 × 103 A/m) but sometimes exceeding 2000 Oe (159 × 103 A/m), and is carried by magnetite and hematite, the former being the predominant contributor. H has remanent coercivities in excess of 2000 Oe (159 × 103 A/m), and is carried by hematite probably containing some ilmenite in solid-solution. The mean direction, irrespective of sign, based on 110 samples from 24 collecting sites is 270°, + 01° (α95 = 6°) with a pole 02°N, 154°W (A95 = 4°). This is considered to be the average direction of the geomagnetic field during initial cooling following intrusion of the complex at about 1450 Ma. At this time the complex was at great depth. The Harp dikes, which intrude the complex, have steeper inclinations, (263°, + 44°, α95 = 7°, pole 19°N, 132°W). The country rocks in the thermal aureole have directions roughly similar to those of the complex, but deflected towards the directions in the dikes (272°, + 29°,α95 = 10°, pole 14°N, 144°W). It is suggested that the country rocks were magnetized during final uplift of the area but prior to the intrusion of the Harp dikes. These and other paleomagnetic poles for the interval 1300–1500 Ma fall in the central Pacific indicating that Laurentia was in low latitudes. Previous reviewers have connected these poles by a simple polar loop, but these new observations indicate that the polar path may be more complicated, and a doubly looped path is suggested as a means of reconciling the results. There are about 20 accurately determined pole positions for the interval 1500–1200 Ma from North America, but only 4 from the rest of the world, and it is not yet possible to determine from such an unbalanced body of data the positions of other Precambrian shields relative to North America during this time interval.

scholarly journals Update on emissions and environmental impacts from the international fleet of ships. The contribution from major ship types and ports

2008 ◽  
Vol 8 (5) ◽  
pp. 18323-18384 ◽  
Author(s):  
S. B. Dalsøren ◽  
M. S. Eide ◽  
Ø. Endresen ◽  
A. Mjelde ◽  
G. Gravir ◽  
...  
Keyword(s):  
North America ◽  
Wet Deposition ◽  
Western Europe ◽  
Surface Ozone ◽  
Western North America ◽  
Ship Emissions ◽  
Low Latitudes ◽  
The World ◽  
Emission Modelling ◽  
The Impact

Abstract. A reliable and up-to-date ship emission inventory is essential for atmospheric scientists quantifying the impact of shipping and for policy makers implementing regulations and incentives for emission reduction. The emission modelling in this study takes into account ship type and size dependent input data for 15 ship types and 7 size categories. Global port arrival and departure data for more than 32 000 merchant ships are used to establish operational profiles for the ship segments. The modelled total fuel consumption amounts to 217 Mt in 2004 of which 11 Mt is consumed in in-port operations. This is in agreement with international sales statistics. The modelled fuel consumption is applied to develop global emission inventories for CO2, NO2, SO2, CO, CH4, VOC (Volatile Organic Compounds), N2O, BC (Black Carbon) and OC (Organic Carbon). The global emissions from ships at sea and in ports are distributed geographically, applying extended geographical data sets covering about 2 million global ship observations and global port data for 32 000 ships. In addition to inventories for the world fleet, inventories are produced separately for the three dominating ship types, using ship type specific emission modelling and traffic distributions. A global Chemical Transport Model (CTM) was used to calculate the environmental impacts of the emissions. We find that ship emissions is a dominant contributor over much of the world oceans to surface concentrations of NO2 and SO2. The contribution is also large over some coastal zones. For surface ozone the contribution is high over the oceans but clearly also of importance over western North America (contribution 15–25%) and western Europe (5–15%). The contribution to tropospheric column ozone is up to 5–6%. The overall impact of ship emissions on global methane lifetime is large due to the high NOx emissions. With regard to acidification we find that ships contribute 11% to nitrate wet deposition and 4.5% to sulphur wet deposition globally. In certain coastal regions the contributions may be in the range 15–50%. In general we find that ship emissions have a large impact on acidic deposition and surface ozone in western North America, Scandinavia, western Europe, western North Africa and Malaysia/Indonesia. For most of these regions container traffic, the largest emitter by ship type, has the largest impact. This is the case especially for the Pacific and the related container trade routes between Asia and North America. However, the contributions from bulk ships and tank vessels are also significant in the above mentioned impact regions. Though the total ship impact at low latitudes is lower, the tank vessels have a quite large contribution at low latitudes and near the Gulf of Mexico and Middle East. The bulk ships are characterized by large impact in Oceania compared to other ship types. In Scandinavia and north-western Europe, one of the major ship impact regions, the three largest ship types have rather small relative contributions. The impact in this region is probably dominated by smaller ships operating closer to the coast. For emissions in ports impacts on NO2 and SO2 seem to be of significance. For most ports the contribution to the two components is in the range 0.5–5%, for a few ports it exceeds 10%. The approach presented provides an improvement in characterizing fleet operational patterns, and thereby ship emissions and impacts. Furthermore, the study shows where emission reductions can be applied to most effectively minimize the impacts by different ship types.

scholarly journals Update on emissions and environmental impacts from the international fleet of ships: the contribution from major ship types and ports

2009 ◽  
Vol 9 (6) ◽  
pp. 2171-2194 ◽  
Author(s):  
S. B. Dalsøren ◽  
M. S. Eide ◽  
Ø. Endresen ◽  
A. Mjelde ◽  
G. Gravir ◽  
...  
Keyword(s):  
North America ◽  
Wet Deposition ◽  
Western Europe ◽  
Surface Ozone ◽  
Western North America ◽  
Ship Emissions ◽  
Low Latitudes ◽  
The World ◽  
Emission Modelling ◽  
The Impact

Abstract. A reliable and up-to-date ship emission inventory is essential for atmospheric scientists quantifying the impact of shipping and for policy makers implementing regulations and incentives for emission reduction. The emission modelling in this study takes into account ship type and size dependent input data for 15 ship types and 7 size categories. Global port arrival and departure data for more than 32 000 merchant ships are used to establish operational profiles for the ship segments. The modelled total fuel consumption amounts to 217 Mt in 2004 of which 11 Mt is consumed in in-port operations. This is in agreement with international sales statistics. The modelled fuel consumption is applied to develop global emission inventories for CO2, NO2, SO2, CO, CH4, VOC (Volatile Organic Compounds), N2O, BC (Black Carbon) and OC (Organic Carbon). The global emissions from ships at sea and in ports are distributed geographically, applying extended geographical data sets covering about 2 million global ship observations and global port data for 32 000 ships. In addition to inventories for the world fleet, inventories are produced separately for the three dominating ship types, using ship type specific emission modelling and traffic distributions. A global Chemical Transport Model (CTM) was used to calculate the environmental impacts of the emissions. We find that ship emissions is a dominant contributor over much of the world oceans to surface concentrations of NO2 and SO2. The contribution is also large over some coastal zones. For surface ozone the contribution is high over the oceans but clearly also of importance over Western North America (contribution 15–25%) and Western Europe (5–15%). The contribution to tropospheric column ozone is up to 5–6%. The overall impact of ship emissions on global methane lifetime is large due to the high NOx emissions. With regard to acidification we find that ships contribute 11% to nitrate wet deposition and 4.5% to sulphur wet deposition globally. In certain coastal regions the contributions may be in the range 15–50%. In general we find that ship emissions have a large impact on acidic deposition and surface ozone in Western North America, Scandinavia, Western Europe, western North Africa and Malaysia/Indonesia. For most of these regions container traffic, the largest emitter by ship type, has the largest impact. This is the case especially for the Pacific and the related container trade routes between Asia and North America. However, the contributions from bulk ships and tank vessels are also significant in the above mentioned impact regions. Though the total ship impact at low latitudes is lower, the tank vessels have a quite large contribution at low latitudes and near the Gulf of Mexico and Middle East. The bulk ships are characterized by large impact in Oceania compared to other ship types. In Scandinavia and north-Western Europe, one of the major ship impact regions, the three largest ship types have rather small relative contributions. The impact in this region is probably dominated by smaller ships operating closer to the coast. For emissions in ports impacts on NO2 and SO2 seem to be of significance. For most ports the contribution to the two components is in the range 0.5–5%, for a few ports it exceeds 10%. The approach presented provides an improvement in characterizing fleet operational patterns, and thereby ship emissions and impacts. Furthermore, the study shows where emission reductions can be applied to most effectively minimize the impacts by different ship types.

Paleomagnetic study of the Ordovician Table Head Group, Port au Port Peninsula, Newfoundland

1988 ◽  
Vol 25 (9) ◽  
pp. 1407-1419 ◽  
Author(s):  
Stuart A. Hall ◽  
Ian Evans
Keyword(s):  
North America ◽  
Geomagnetic Field ◽  
Head Group ◽  
Time Interval ◽  
Reverse Polarity ◽  
Middle Ordovician ◽  
Early Ordovician ◽  
Stable Component ◽  
Paleomagnetic Study ◽  
Two Component

A paleomagnetic study of the Ordovician Table Head Group in the Port au Port Peninsula of western Newfoundland reveals a simple two-component magnetization history comprising a reversely magnetized, stable southeasterly remanence with a, shallow to moderate inclination, and an unstable present-day overprint. Pole positions for the stable component, both with and without tectonic tilt correction, correspond with the Early to middle Ordovician pole positions for North America, suggesting this remanence is early. Although the nature of the geomagnetic field in the Ordovician is not well known, the polarity observed is consistent with that reported from other mid-Ordovician studies and appears to reflect a predominance of reverse polarity for this time interval. Evidence of significant rotation of any of the sites studied is absent, indicating that the continental margin in this region acted in an integral rather than a fragmented fashion during deformation.Previously published and new, but preliminary, results from the Early Ordovician St. George Group indicate the presence of two stable components of remanence. These components have similar south-southeasterly declinations but differ in inclination. The shallow to intermediate positive inclination component has a direction that is broadly compatible with Early Ordovician poles from North America. The shallow negative inclination component observed in rocks of similar age from other parts of western Newfoundland appears to be consistent with a later remagnetization of this unit.

Effect of particulate iron on tracking indoor PM2.5 of outdoor origin: A case study in Nanjing, China

2020 ◽  
pp. 1420326X1989914
Author(s):  
Zhitong Wang ◽  
Cong Liu ◽  
Qian Hua ◽  
Xiaohong Zheng ◽  
Wenjing Ji ◽  
...  
Keyword(s):  
North America ◽  
South America ◽  
Spatial Scales ◽  
The World ◽  
Particulate Iron ◽  
The Mean ◽  
Temporal And Spatial ◽  
Indoor Pm2.5 ◽  
Indoor And Outdoor

A tracer element can help distinguish between indoor PM2.5 of outdoor origin and that of indoor origin. PM2.5-associated iron has been proposed as a tracer element of PM2.5 in Beijing. This study aims to examine the effect of particulate iron on tracking indoor PM2.5 of outdoor origin in temporal and spatial scales. From July 2018 to March 2019, we collected 24 pairs of indoor and outdoor PM2.5 samples in Nanjing, China. We calculated a normalized ratio (ratio of indoor/outdoor (I/O) ratio of iron to that of PM2.5). Results show a mean ± SD of the normalized ratio of 1.0 ± 0.38. It suggests that particulate iron tracks PM2.5 well during outdoor-to-indoor transport on average. This tracking performance varies temporally. The mean ± SD of the normalized ratio is 0.79 ± 0.17 from July to December 2018 and 1.2 ± 0.41 in March. The results from studies published in different regions of the world over recent years show a mean normalized ratio of 0.88, 0.67, 1.3 and 0.8 in Asia, Europe, North America and South America, respectively, indicating the spatial heterogeneity of iron’s tracking effect. In comparison, sulphate appears to exhibit a less stable tracking effect than iron.

IODIDE METABOLISM IN ONTARIO

1967 ◽  
Vol 54 (4) ◽  
pp. 604-608 ◽  
Author(s):  
Fred Rosen ◽  
Calvin Ezrin ◽  
Robert Volpé
Keyword(s):  
United States ◽  
North America ◽  
Renal Clearance ◽  
Young Women ◽  
The United States ◽  
Iodized Salt ◽  
Endemic Goitre ◽  
Iodide Uptake ◽  
The World ◽  
The Mean

ABSTRACT Various parameters of inorganic iodide metabolism have been measured in a group of 22 healthy young women in a previous endemic goitre region of Ontario. The mean plasma inorganic iodide (PII) was comparable to values obtained in North America and Iceland, but higher than those in Scotland. The increased utilization of iodized salt in North America is thought to be responsible for this difference, and for the reduced incidence of endemic goitre. The thyroidal radioiodine clearance tended to be low (10.1 ml/min), but the absolute iodide uptake (AIU) was comparable to values obtained in the United States. The renal clearance of radioiodine was 30.0 ml/min. This compares well with values reported from around the world.

Palaeomagnetic comparisons between Europe and North America

1965 ◽  
Vol 258 (1088) ◽  
pp. 1-11 ◽  
Keyword(s):  
North America ◽  
Continental Drift ◽  
Western United States ◽  
Core System ◽  
Quantitative Evidence ◽  
Separate Branch ◽  
Palaeomagnetic Data ◽  
Low Latitudes ◽  
The Mean ◽  
Almost All

Much of the current interest in continental drift arose from the discovery of large divergences between the polar wandering curves determined from the palaeomagnetic directions in different continents. The geological lines of evidence for continental drift, each indecisive yet as a whole striking, were thus supported in a remarkable way by quantitative evidence from an entirely separate branch of geophysics. The palaeomagnetic evidence from Europe and North America is of particular interest as almost all geological periods have been sampled in these continents back to 1200 My. A systematic westward displacement, of the order of 20° to 30°, of the polar wandering path from American rocks from that determined from European rocks has been demonstrated. That the mean geomagnetic field is axially symmetrical seems a secure deduction from the mechanics of the mantle-core system. The possibility that the discrepancy could be due to the field having had an axial but non-dipole character during these periods can be dismissed on palaeoclimatic grounds. The palaeomagnetic data can therefore be used to reconstruct the northern hemisphere in pre-Triassic times: Europe and North America were closer together and in low latitudes. Comparison between the Precambrian of the western United States and the Keweenawan system appears to provide evidence of displacements within North America before the world-wide orogenic epoch of 1000 My ago.

Perbedaan Pengetahuan Siswa Tentang Penyakit Hepatitis A Sebelum Dan Sesudah Penyuluhan Di MTsN 02 Bondowoso Tahun 2015

2017 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Putri Megasari
Keyword(s):  
Hepatitis A ◽  
Hepatitis Virus ◽  
Sampling Technique ◽  
Mean Value ◽  
Test Design ◽  
The World ◽  
Before And After ◽  
Post Test ◽  
The Mean ◽  
Paired T Test

Hepatitis has become a health problem in the world. The hepatitis virus infected many people. According to the teacher of MTsN 02 Bondowoso more than 20 students have hepatitis A viral infection. The purpose of this research was to know the differences of students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study used pre-experimental (pre-post test design). This study used stratified random sampling technique, 127 students from 270 sample involved this research,and 143 students was excluded. We used questionnaires to collect data. The results showed that the mean value of the students 'knowledge about hepatitis A before counseling in MTsN 02 Bondowoso 2015 was 83.96 with the lowest value of 37.5 and the highest value was 100. The mean value of the students' knowledge about hepatitis A after counseling in MTsN 02 Bondowoso 2015 was 93.21 with the lowest value waf 62.5 and the highest value was 100. Paired t test showed that t (-9.07) > t table (1.98), the null hypothesis (H0) was rejected. There was a difference between students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study showed that routine counseling by healthcare provider was important to prevent hepatitis A infection.; Keywords: counseling, knowledge of students, hepatitis

Modern Office Technology Competencies Expected of Office Technology and Management (OTM) Graduate Workers in Delta State.

2019 ◽  
pp. 81-88
Author(s):  
Ozoem Martha ◽  
Chibuike Victoria C. ◽  
Ugwunwoti Emeka P.
Keyword(s):  
Information Processing ◽  
Technology Competencies ◽  
Male And Female ◽  
The World ◽  
Alpha Reliability ◽  
Communication Competencies ◽  
The Mean ◽  
Research Questions ◽  
Level Of Significance ◽  
Descriptive Survey

This study was carried out to determine the modern office technology competencies expected of office technology and management (OTM) graduate workers by supervisors in Delta State. The study was guided by two research questions and two hypotheses tested at 0.05 level of significance. The respondents consisted of 142 supervisors, made up of 74 heads of department and directors of government establishments, and 68 managers and directors of private establishments in the study area. Descriptive survey research design was used to conduct the study and 28 – items questionnaire were used to collect data from respondents. The instrument was validated by three experts and had a Cronbach Alpha reliability coefficient of 0.77. Means with standard deviations were used to answer the research questions, while t-test was used to test the null hypotheses. The extent of supervisor‟s expectations of information processing competencies did not differ significantly based on the mean ratings of male and female supervisors of OTM graduates in government and private establishments. The findings also revealed that supervisors expect much information processing and communication competencies from the OTM graduate workers. Based on the findings and the implications, it was recommended among others that, curriculum planners, business and OTM education lecturers should ensure that the competencies required for modern office technologies are entrenched and taught in the institutions to prepare the OTM graduates for the world of work.

Sign in / Sign up

Export Citation Format

Share Document