scholarly journals Detrital zircons and sediment dispersal in the eastern Midcontinent of North America

Geosphere ◽  
2020 ◽  
Vol 16 (3) ◽  
pp. 817-843 ◽  
Author(s):  
William A. Thomas ◽  
George E. Gehrels ◽  
Kurt E. Sundell ◽  
Stephen F. Greb ◽  
Emily S. Finzel ◽  
...  
Keyword(s):  
Age Groups ◽  
Appalachian Basin ◽  
Detrital Zircons ◽  
Illinois Basin ◽  
Sediment Dispersal ◽  
Accreted Terranes ◽  
Appalachian Orogen ◽  
Northern Edge ◽  
Depositional Age ◽  
Age Range

Abstract Results of detrital-zircon analyses (U-Pb ages and initial Hf values, εHft) of Mississippian–Pennsylvanian sandstones in the Michigan, Illinois, and Forest City basins are remarkably similar to data for coeval sandstones in the Appalachian basin, indicating dispersal of sediment from the Appalachian orogen through the Appalachian basin to the eastern Midcontinent during the late Paleozoic. The similarities of results include matches of the two most prominent age groups (1300–950 Ma and 490–350 Ma), as well as matches of the less abundant age groups. Comparisons of the data are from observations of probability density plots and multidimensional scaling of U-Pb age data and of εHft values. Despite the dominance of an Appalachian signature in all samples, some samples contain grains with ages that suggest intermittent additional sources. Four samples (three ranging in depositional age from Morrowan to Atokan–Desmoinesian in the Illinois basin, and one of Desmoinesian age in the Forest City basin), in addition to typical Appalachian age distributions, have prominent age modes between 768 and 525 Ma, corresponding in age to Pan-African/Brasiliano rocks in Gondwanan accreted terranes in the Appalachian orogen, suggesting intermittent dispersal from the Moretown terrane of the northern Appalachians. Sandstones in the Appalachian basin and those in the Midcontinent basins have very few grains with ages that correspond to the Alleghanian orogeny in the Appalachian orogen. Nevertheless, three sandstones each in the Illinois basin and Forest City basin with depositional ages of 312–308 Ma have a few zircon grains in the age range of 321 ± 5 to 307 ± 4 Ma. The nearly identical crystallization and depositional ages suggest reworking at the depositional sites of air-fall volcanic ash from the Alleghanian orogen, rather than fluvial transport from the orogen. The basal Pennsylvanian sandstones lap onto a regional unconformity around the northern rims of the Illinois and Forest City basins, suggesting sources for recycled grains. Along the northern edge of the Illinois basin, Ordovician sandstones beneath the unconformity may have contributed minor concentrations of Superior-age zircons in the basal Pennsylvanian sandstones. Basal Pennsylvanian sandstones in the Forest City basin lap onto Mississippian strata, suggesting possible recycling of zircons from eroded Mississippian sandstones.

SHRIMP U–Pb geochronology of detrital zircons from the Treasure Lake Group — new evidence for Paleoproterozoic collisional tectonics in the southern Hottah terrane, northwestern Canadian Shield

2005 ◽  
Vol 42 (5) ◽  
pp. 833-845 ◽  
Author(s):  
S S Gandhi ◽  
O van Breemen
Keyword(s):  
Middle Part ◽  
Detrital Zircons ◽  
Slave Craton ◽  
The North ◽  
Quartz Arenite ◽  
Continental Arc ◽  
Wide Range ◽  
Depositional Age ◽  
Age Range ◽  
New Evidence

The recently defined Treasure Lake Group is a platformal sedimentary sequence more than 3 km thick that was deformed and metamorphosed prior to formation of the Great Bear continental arc during 1875–1845 Ma. The group is exposed as remnants in the southern part of the arc. Its basement is not exposed, but is interpreted to comprise the Paleoproterozoic Hottah terrane, which is exposed at Hottah Lake in the northern part of the arc. Studies in that region show that the Hottah terrane collided with the Archean Slave craton to the east ca. 1883 Ma following reversal of subduction polarity from west to east. Continued eastward subduction under the collision zone formed the Great Bear arc. The present study was undertaken to determine the age and provenance of the Treasure Lake Group. Thirty-nine detrital zircon grains from a sample of a quartz arenite unit in the middle part of the Treasure Lake Group were analyzed by SHRIMP (sensitive high-resolution ion microprobe). They show an age range from ca. 2729 to ca. 1880 Ma, with main modes at ca. 1895, 1985, 2090, and 2330 Ma. These data confirm a mainly Paleoproterozoic provenance for the group. The youngest group of five zircon analyses places the maximum depositional age at 1886 ± 8 Ma. The Treasure Lake Group is close to the north-trending Wopmay medial zone formed during collision of the Hottah terrane and the Slave craton. Deformation and metamorphism of the group can now be attributed to the collisional event. The group may in part be coeval with the Bell Island Bay and Akaitcho groups of the northern Hottah terrane, the lower parts of which were deposited ca. 1900 Ma. The wide range of detrital zircons ages found in this study is interpreted to reflect a complex Paleoproterozoic evolution of the Hottah terrane.

Detrital zircon ages from the islands of Inousses and Psara, Aegean Sea, Greece: constraints on depositional age and provenance

2008 ◽  
Vol 145 (6) ◽  
pp. 886-891 ◽  
Author(s):  
GUIDO MEINHOLD ◽  
DIRK FREI
Keyword(s):  
Age Groups ◽  
Aegean Sea ◽  
Detrital Zircons ◽  
Age Group ◽  
Icp Ms ◽  
Eastern Aegean ◽  
Depositional Age ◽  
Late Neoproterozoic ◽  
Early Palaeozoic ◽  
Detrital Zircon Ages

AbstractU–Pb LA–SF–ICP–MS analyses of detrital zircons from a metalitharenite on Inousses Island, Greece, gave major age groups of 310–350, 450–500, 550–700, 900–1050 and 1880–2040 Ma and minor peaks between 2600 and 2800 Ma. The youngest concordant zircon grains of 310–330 Ma indicate the maximum age of deposition to be Late Carboniferous, rather than Ordovician, as had been earlier assumed. The lack of zircon ages between 1.1 and 1.8 Ga, coupled with the occurrence ofc.2-Ga-old zircons, imply a northern Gondwana-derived source. Detrital zircons from a garnet–mica schist on Psara Island yielded a major age group ofc.295–325 Ma and only minor Early Palaeozoic and Late Neoproterozoic ages. The youngest grains around 270 Ma indicate the maximum age of deposition to be Late Permian. The Early Palaeozoic ages support a source from terranes at the southern margin of Laurussia during the Late Palaeozoic and hence clarify the palaeotectonic position of units from the eastern Aegean Sea within the Palaeotethyan realm.

scholarly journals Exploring Why Adult Mexican Males Do Not Get Vaccinated: Implications for COVID-19 Preventive Actions

2020 ◽  
Vol 42 (4) ◽  
pp. 515-527
Author(s):  
V. Nelly Salgado de Snyder ◽  
Deliana Garcia ◽  
Roxana Pineda ◽  
Jessica Calderon ◽  
Dania Diaz ◽  
...  
Keyword(s):  
Preventive Medicine ◽  
Age Groups ◽  
Adult Males ◽  
Cross Sectional ◽  
Administrative Services ◽  
Minority Males ◽  
Socially Disadvantaged ◽  
Preventive Actions ◽  
Socially Excluded ◽  
Age Range

Vaccination is the single most important preventive medicine action worldwide. However, there are inequalities in the procurement of vaccines particularly among US ethnic and racial minority males when compared to the rest of the US population. This study explored the reasons given by adult Mexican-origin males residing in Texas, for obtaining or not, immunizations. This was a cross-sectional, exploratory study with a sample of convenience of 401 adult males (age range 18–79) who were invited to participate in the study while waiting their turn to receive administrative services at the Mexican Consulate in Austin Texas. Data was collected in Spanish with a seven-item multiple choice questionnaire, using electronic tablets. The majority of respondents received their last vaccination longer than 5 years earlier. A higher percentage of individuals in the older age groups received a vaccine in the last year, as opposed to their younger counterparts who obtained their last immunization 3 to 5 years earlier. Among the reasons given for not getting vaccinated were lack of time or money, feared injections and side effects, insufficient information, interest or motivation. Others did not get vaccines because they perceived themselves to be healthy and did not feel sick. Findings from this study have important implications for future preventive medicine and vaccination practices that reach socially excluded groups in times of COVID-19. Recommendations are made to facilitate access to vaccines to the target group of this study and other socially disadvantaged populations in the global health context.

scholarly journals Characteristics of Osteoporosis & Osteoporotic Fractures in Korea Based on Health Insurance Review and Assessment (HIRA) Database: 2009–2017

Healthcare ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 324
Author(s):  
Ho-Seok Oh ◽  
Sung-Kyu Kim ◽  
Hyoung-Yeon Seo
Keyword(s):  
Health Insurance ◽  
Age Groups ◽  
Osteoporotic Fractures ◽  
Prescription Data ◽  
Diagnostic Codes ◽  
Number Of Patients ◽  
Upper And Lower Extremities ◽  
Fractures Of The Spine ◽  
And Gender ◽  
Age Range

To investigate the incidence and characteristics of osteoporosis and osteoporotic fractures in Korea, we used the Health Insurance Review and Assessment Service (HIRA) database. Patients over 50 years old, who were diagnosed or treated for osteoporosis and osteoporotic fractures in all hospitals and clinics, were analyzed between 1 January 2009 and 31 December 2017 by using the HIRA database that contains prescription data and diagnostic codes. These data were retrospectively analyzed by decade and age-specific and gender-specific incidents in each year. We also evaluated other characteristics of patients including medication state of osteoporosis, primary used medical institution, regional-specific incidence of osteoporosis, and incidence of site-specific osteoporotic fractures. The number of osteoporosis patients over 50 years old, as diagnosed by a doctor, steadily increased from 2009 to 2017. The number of osteoporosis patients was notably greatest in the 60′s and 70′s age groups in every study period. Patients undergoing treatment for osteoporosis increased significantly (96%) from 2009 to 2017. Among the patients diagnosed with osteoporosis, the proportion who experienced osteoporotic fracture increased gradually (60%) from 2009 to 2017. The number of patients with osteoporotic fractures of the spine and hip was highest in the 70 to 90 age range, and the number of patients with osteoporotic fractures in the upper and lower extremities was highest in the 50 to 70 age range. Understanding the trends of osteoporosis in Korea will contribute to manage the increased number of patients with osteoporosis and osteoporotic fractures.

scholarly journals Older Adults and Technology Use: A Systematic Literature Review

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 823-823
Author(s):  
Hyung Wook Choi ◽  
Rose Ann DiMaria-Ghalili ◽  
Mat Kelly ◽  
Alexander Poole ◽  
Erjia Yan ◽  
...  
Keyword(s):  
Older Adults ◽  
Technology Use ◽  
Age Groups ◽  
Well Being ◽  
Sample Population ◽  
Age Cohorts ◽  
Fine Grained ◽  
Nuanced Understanding ◽  
Smart Technologies ◽  
Age Range

Abstract Researchers are increasingly interested in leveraging technology to support the physical and mental well-being of older adults. We systematically reviewed previous scholars’ criteria for sampling older adult populations, focusing on age cohorts (namely adults over 65) and their use of internet and smart technologies. We iteratively developed keyword combinations that represent older adults and technology from the retrieved literature. Between 2011 and 2020, 70 systematic reviews were identified, 26 of which met our inclusion criteria for full review. Most important, not one of the 26 papers used a sample population classification more fine-grained than “65 and older.” A knowledge gap thus exists; researchers lack a nuanced understanding of differences within this extraordinarily broad age-range. Demographics that we propose to analyze empirically include not only finer measures of age (e.g., 65-70 or 71-75, as opposed to “65 and older”), but also those age groups’ attitudes toward and capacity for technology use.

scholarly journals Provenance of sediments from Barra del Tordo and Tesoro beaches, Tamaulipas State, northwestern Gulf of Mexico

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Mayla A. Ramos-Vázquez ◽  
John S. Armstrong-Altrin
Keyword(s):  
Gulf Of Mexico ◽  
Age Groups ◽  
Source Area ◽  
Detrital Zircons ◽  
Sediment Provenance ◽  
Geochemical Composition ◽  
Chemical Index ◽  
Beach Sediments ◽  
Chemical Index Of Alteration ◽  
Ree Patterns

AbstractThe mineralogy, bulk sediment geochemical composition, and U–Pb ages of detrital zircons retrieved from the Barra del Tordo (Tordo) and Tesoro beach sediments in the northwestern Gulf of Mexico were analyzed to determine their provenance. The beach sediments are mainly composed of quartz, ilmenite, magnetite, titanite, zircon, and anorthite. The weathering proxies such as the Chemical Index of Alteration (CIA), Chemical Index of Weathering (CIW), and Plagioclase Index of Alteration (PIA), reveal a moderate-to-high intensity of weathering in the source area. The chondrite-normalized rare earth element (REE) patterns are similar to felsic igneous rocks, with large negative europium anomaly (Eu/Eu* = ~ 0.47–0.80 and ~ 0.57–0.67 in the Tordo and Tesoro beach sediments, respectively).Three major zircon U–Pb age groups are identified in the Tordo and Tesoro beach sediments, i.e., Proterozoic (~ 2039–595 Ma), Mesozoic (~ 244–70.3 Ma), and Cenozoic (~ 65.9–1.2 Ma). The differences of the zircon age spectrum between the Tordo and Tesoro beach sediments are not significant. The comparison of zircon U–Pb ages in this study with ages of potential source terranes suggests that the Mesozoic and Cenozoic zircons of the studied Tordo and Tesoro beach sediments were derived from the Eastern Alkaline Province (EAP) and Mesa Central Province (MCP). Similarly, the likely sources for the Proterozoic zircons were the Sierra Madre Oriental (SMOr) and Oaxaquia in the northwestern Gulf of Mexico. The results of this study further indicate that the sediments delivered to the beaches by rivers and redistributed by longshore currents were crucial in determining the sediment provenance.

scholarly journals An evaluation of the factor structure of the Self-Assessed Wisdom Scale (SAWS) and the creation of the SAWS-15 as a short measure for personal wisdom

2021 ◽  
pp. 1-11
Author(s):  
Trilas M. Leeman ◽  
Bob G. Knight ◽  
Erich C. Fein ◽  
Sonya Winterbotham ◽  
Jeffrey Dean Webster
Keyword(s):  
Factor Analysis ◽  
Factor Structure ◽  
Latent Variables ◽  
Emotional Regulation ◽  
Short Form ◽  
Age Groups ◽  
Total Sample ◽  
Future Research ◽  
Personal Wisdom ◽  
Age Range

ABSTRACT Objectives: Although wisdom is a desirable life span developmental goal, researchers have often lacked brief and reliable construct measures. We examined whether an abbreviated set of items could be empirically derived from the popular 40-item five-factor Self-Assessed Wisdom Scale (SAWS). Design: Survey data from 709 respondents were randomly split into two and analyzed using confirmatory factor analysis (CFA). Setting: The survey was conducted online in Australia. Participants: The total sample consisted of 709 participants (M age = 35.67 years; age range = 15–92 years) of whom 22% were male, and 78% female. Measurement: The study analyzed the 40-item SAWS. Results: Sample 1 showed the traditional five-factor structure for the 40-item SAWS did not fit the data. Exploratory factor analysis (EFA) on Sample 2 offered an alternative model based on a 15-item, five-factor solution with the latent variables Reminiscence/Reflection, Humor, Emotional Regulation, Experience, and Openness. This model, which replicates the factor structure of the original 40-item SAWS with a short form of 15 items, was then confirmed on Sample 1 using a CFA that produced acceptable fit and measurement invariance across age groups. Conclusions: We suggest the abbreviated SAWS-15 can be useful as a measure of individual differences in wisdom, and we highlight areas for future research.

scholarly journals Examining Play Counts and Measurements of Injury Incidence in Youth Football

2017 ◽  
Vol 52 (10) ◽  
pp. 955-965 ◽  
Author(s):  
Zachary Y. Kerr ◽  
Susan W. Yeargin ◽  
Aristarque Djoko ◽  
Sara L. Dalton ◽  
Melissa M. Baker ◽  
...  
Keyword(s):  
Outcome Measure ◽  
Age Groups ◽  
Injury Rate ◽  
Football Players ◽  
Injury Incidence ◽  
Injury Rates ◽  
Head Impacts ◽  
Youth Football ◽  
Rate Ratios ◽  
Age Range

Context: Whereas researchers have provided estimates for the number of head impacts sustained within a youth football season, less is known about the number of plays across which such impact exposure occurs.Objective: To estimate the number of plays in which youth football players participated during the 2013 season and to estimate injury incidence through play-based injury rates.Design: Descriptive epidemiology study.Setting: Youth football.Patients or Other Participants: Youth football players (N = 2098; age range, 5−15 years) from 105 teams in 12 recreational leagues across 6 states.Main Outcome Measure(s): We calculated the average number of athlete-plays per season and per game using independent-samples t tests to compare age groups (5–10 years old versus 11–15 years old) and squad sizes (<20 versus ≥20 players); game injury rates per 1000 athlete-exposures (AEs) and per 10 000 athlete-plays; and injury rate ratios (IRRs) with 95% confidence intervals (CIs) to compare age groups.Results: On average, youth football players participated in 333.9 ± 178.5 plays per season and 43.9 ± 24.0 plays per game. Age groups (5- to 10-year-olds versus 11- to 15-year-olds) did not differ in the average number of plays per season (335.8 versus 332.3, respectively; t2086.4 = 0.45, P = .65) or per game (44.1 versus 43.7, respectively; t2092.3 = 0.38, P = .71). However, players from smaller teams participated in more plays per season (373.7 versus 308.0; t1611.4 = 8.15, P < .001) and per game (47.7 versus 41.4; t1523.5 = 5.67, P < .001). Older players had a greater game injury rate than younger players when injury rates were calculated per 1000 AEs (23.03 versus 17.86/1000 AEs; IRR = 1.29; 95% CI = 1.04, 1.60) or per 10 000 athlete-plays (5.30 versus 4.18/10 000 athlete-plays; IRR = 1.27; 95% CI = 1.02, 1.57).Conclusions: A larger squad size was associated with a lower average number of plays per season and per game. Increasing youth football squad sizes may help reduce head-impact exposure for individual players. The AE-based injury rates yielded effect estimates similar to those of play-based injury rates.

Jurassic–Cretaceous arc magmatism along the Shyok–Bangong Suture from NW Himalaya: Formation of the peri-Gondwana basement to the Ladakh Arc

2021 ◽  
pp. jgs2021-035
Author(s):  
Wanchese M. Saktura ◽  
Solomon Buckman ◽  
Allen P. Nutman ◽  
Renjie Zhou
Keyword(s):  
Late Cretaceous ◽  
Nw Himalaya ◽  
Content Type ◽  
Magmatic Arc ◽  
Basement Rocks ◽  
Ladakh Himalaya ◽  
Accreted Terranes ◽  
Volcaniclastic Rocks ◽  
Supplementary Material ◽  
Depositional Age

The Jurassic–Cretaceous Tsoltak Formation from the eastern borderlands of Ladakh Himalaya consists of conglomerates, sandstones and shales, and is intruded by norite sills. It is the oldest sequence of continent-derived sedimentary rocks within the Shyok Suture. It also represents a rare outcrop of the basement rocks to the voluminous Late Cretaceous–Eocene Ladakh Batholith. The Shyok Formation is a younger sequence of volcaniclastic rocks that overlie the Tsoltak Formation and record the Late Cretaceous closure of the Mesotethys Ocean. The petrogenesis of these formations, ophiolite-related harzburgites and norite sill is investigated through petrography, whole-rock geochemistry and U–Pb zircon geochronology. The youngest detrital zircon grains from the Tsoltak Formation indicate Early Cretaceous maximum depositional age and distinctly Gondwanan, Lhasa microcontinent-related provenance with no Eurasian input. The Shyok Formation has Late Cretaceous maximum depositional age and displays a distinct change in provenance to igneous detritus characteristic of the Jurassic–Cretaceous magmatic arc along the southern margin of Eurasia. This is interpreted as a sign of collision of the Lhasa microcontinent and the Shyok ophiolite with Eurasia along the once continuous Shyok–Bangong Suture. The accreted terranes became the new southernmost margin of Eurasia and the basement to the Trans-Himalayan Batholith associated with the India-Eurasia convergence.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5633162

ELECTROCARDIOGRAPHIC PATTERNS OF NORMAL CHILDREN FROM BIRTH TO FIVE YEARS OF AGE

PEDIATRICS ◽  
1951 ◽  
Vol 8 (3) ◽  
pp. 349-361
Author(s):  
GERARD GROS ◽  
ARMOND GORDON ◽  
ROBERT MILLER
Keyword(s):  
Left Ventricle ◽  
Transition Zone ◽  
Age Groups ◽  
Later Life ◽  
Distinct Pattern ◽  
Age Group ◽  
S Wave ◽  
Normal Children ◽  
Age Range ◽  
Q Wave

The ECGs of 104 normal children from a few hours old to 5 years of age were studied. These ECGs consisted of the standard limb leads, the aV limb leads and six precordial leads: V4R, V1, V2, V4, V5 and V6. While the number of cases in each group are small, the following conclusions are suggested by this study: 1. ECGs of the newborn infant present important variations from those seen in later life. This is especially true during the first week of life. Thereafter the contour evolves [SEE FIG. 2 IN SOURCE PDF] in a definite manner until the adult-like pattern is reached. 2. The vertical and semivertical "electric" positions were the most frequently encountered in this age group. 3. P-waves present a rather permanent pattern in this age range: a. is usually upright in lead 1 and 2, aVF, V4, V5 and V6. b. is usually inverted in lead 2 and aVR. c. is either upright, inverted or diphasic in lead 3, aVL, V4R, V1 and V2. 4. The P-R interval varies from 0.10 sec. minimum to 0.16 sec. maximum with the average being 0.12 sec. in this age range. It tends to become greater in the older age groups. 5. QRS duration is shorter in the younger age groups and increases slowly with age. 6. Polyphasic, M-shaped or slurred QRS complexes are not uncommon in the ECGs of normal children in this age range. 7. A Q wave is frequently absent in lead 1 and in all chest leads during the first week of life. Thereafter up to 5 years of age the pattern of the Q wave is as follows: a. Q is generally absent in lead 1, V4R, V1, V2 and V4. b. Q is generally present in lead 3, V4R, aVF, V5 and V6. 8. There is a distinct pattern of right ventricular dominance in leads from the sternum and to its right at birth. This pattern gradually undergoes involution, probably related to normal physiologic development, until the left ventricle becomes dominant. Thus the evolution of the S-wave parallels a gradual involution of the R-wave in right precordial leads and probably also in aVR. This dominance of the left ventricle over the entire precordium is usual by about 3 years, but may be delayed normally until 5 years of age. 9. The T-wave is upright or diphasic in V4R, V1, and V2 and inverted in V5 and V6 for the first 24 hours of life; it gradually alters so that by the fourth day it is inverted in V4R, V1 and V2 and upright in V5 and V6 and thereafter. 10. The transition zone of QRS varies from one age group to another and tends in some ages to be broad. In some instances no real transition zone can be determined.

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