A reassessment of the timing of early Archaean crustal evolution in West Greenland

1998 ◽  
pp. 88-93 ◽  
Author(s):  
Stephen Moorbath ◽  
Balz Samuel Kamber
Keyword(s):  
Grain Structure ◽  
Crustal Evolution ◽  
Pb Isotope ◽  
West Greenland ◽  
Ion Probe ◽  
Combined Use ◽  
Wide Range ◽  
History Of ◽  
Single Zircon ◽  
Precambrian Terrain

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Moorbath, S., & Kamber, B. S. (1998). A reassessment of the timing of early Archaean crustal evolution in West Greenland. Geology of Greenland Survey Bulletin, 180, 88-93. https://doi.org/10.34194/ggub.v180.5091 _______________ In last year’s Review of Greenland activities, Kalsbeek (1997) divided the recent history of geochronology into three successive periods: 1. single-sample K-Ar and Rb-Sr mineral or whole-rock age determinations; 2. Rb-Sr and Pb/Pb whole-rock isochrons and multigrain zircon U-Pb isotope data; 3. the present, where ‘single’ zircon U-Pb data are predominantly used. To these three, we would propose adding a fourth, namely a combination of all three, in order to achieve the maximum age information within complex terrains. For an early Precambrian terrain like that of West Greenland, we consider that the combined use of at least the last two approaches is essential (to which should be added the Sm-Nd method). In recent years, study of the geochronological evolution of the Godthåbsfjord and Isua regions has been dominated by rapid and precise ion-probe U-Pb dating of complex-structured zircons, and it has become fashionable to regard the wide range of zircon dates, and particularly the oldest, as giving the age of rock formation. Dates obtained from whole-rock Rb-Sr, Sm-Nd and Pb/Pb regressions have been regarded as too imprecise for adequate age resolution, whilst constraints on crustal evolution imposed by initial Sr, Nd and Pb isotope ratios have been summarily dismissed or totally ignored. We consider that this sole dependence on ion-probe dating of zircon can lead (as, indeed, in the early Archaean of West Greenland) to a potential misinterpretation of the timing of crustal evolution, especially in those cases where little or no information regarding the relationship between measured date and internal grain structure is available. Figure 1 shows the localities mentioned in the text.

scholarly journals Continental crust in the Davis Strait: new evidence from seabed sampling

2006 ◽  
Vol 10 ◽  
pp. 33-36 ◽  
Author(s):  
Finn Dalhoff ◽  
Lotte M. Larsen ◽  
Jon R. Ineson ◽  
Svend Stouge ◽  
Jørgen A. Bojesen-Koefoed ◽  
...  
Keyword(s):  
Seismic Analysis ◽  
Gravity Corer ◽  
Preliminary Screening ◽  
Side Scan Sonar ◽  
West Greenland ◽  
Petroleum Systems ◽  
Structural Framework ◽  
Wide Range ◽  
History Of ◽  
New Evidence

Although the structural framework of the subsurface offshore West Greenland has been well documented based on comprehensive seismic analysis (cf. Dalhoff et al. 2003), the stratigraphy of the region is less well known. The oldest documented sedimentary rocks drilled offshore West Greenland are Santonian sandstones reached at TD in the 6354/4-1 well (Fig. 1) although reworked palynomorphs of Carboniferous, Triassic and Jurassic (Kimmeridgian) age have been reported from a number of wells in the region. In order to obtain better constraints on the pre-Upper Cretaceous stratigraphy, a preliminary screening was undertaken to identify inversion structures and erosional canyons where such deeper stratigraphic levels crop out at the seabed (Nielsen et al. 2001). Sea-floor sampling at selected sites between 62° and 67°N (Fig. 1) was undertaken during the summers of 2003 and 2004. Other objectives of these cruises were to seek direct evidence of active petroleum systems, to establish further constraints on tectonic and stratigraphic models, and to obtain a better understanding of the Neogene and Pleistocene history of the region (Dalhoff et al. 2005). The most promising seabed features identified by Nielsen etal.(2001) were investigated in more detail using a wide range of techniques in order to optimise sampling positions. In 2003, these techniques included echo sounder, side-scan sonar, singlechannel seismic and video inspection before sampling either by dredge, gravity corer, or by video-controlled grab. In 2004, comprehensive data acquisition with a deep-water sparker system was undertaken before sampling by dredge or gravity corer, supplemented by grab samples at selected stations.

Age determination of Precambrian rocks from Greenland: past and present

1997 ◽  
pp. 55-59 ◽  
Author(s):  
Feiko Kalsbeek
Keyword(s):  
Age Determination ◽  
Isotopic Analysis ◽  
Radiometric Dating ◽  
Pb Isotope ◽  
Precambrian Rocks ◽  
Igneous Intrusions ◽  
Dating Methods ◽  
History Of ◽  
Single Zircon

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Kalsbeek, F. (1997). Age determination of Precambrian rocks from Greenland: past and present. Geology of Greenland Survey Bulletin, 176, 55-59. https://doi.org/10.34194/ggub.v176.5062 _______________ Age determination is an essential part of many geological investigations. The ages of Phanerozoic sedimentary rocks are typically determined by palaeontological studies (often with high precision), but for Precambrian rocks as well as for younger igneous intrusions, precise ages can only be obtained by isotopic analysis of minerals or rocks. Isotopic (radiometric) age determination of Greenland rocks began in the early 1960s and has continued since with gradually improving methods. In this contribution, the development of geochronological knowledge of the Precambrian of Greenland is described in historical perspective, and an outline of new results is given. The history of geochronology can be roughly divided into three periods: 1) a period of single-sample K-Ar and Rb-Sr mineral or whole-rock age determinations; 2) a time when most ages were determined with the help of Rb-Sr and Pb-Pb whole-rock isochrons and multi-grain zircon U-Pb isotope data; 3) the present, where ‘single’ zircon U-Pb data are the preferred method to obtain rock ages. These stages in the development of radiometric dating methods partly overlap in time, and each has yielded very significant contributions to the knowledge of Precambrian evolution in Greenland.

High-resolution cathodoluminescence combined with SHRIMP ion probe measurements of detrital zircons

1999 ◽  
Vol 63 (2) ◽  
pp. 179-187 ◽  
Author(s):  
J. Götze ◽  
U. Kempe ◽  
D. Habermann ◽  
L. Nasdala ◽  
R. D. Neuser ◽  
...  
Keyword(s):  
High Resolution ◽  
Quartz Sand ◽  
Emission Band ◽  
Detrital Zircons ◽  
Minor Importance ◽  
Ion Probe ◽  
Wide Range ◽  
Single Zircon ◽  
Probe Measurements

AbstractCathodoluminescence (CL) microscopy and spectroscopy combined with SHRIMP ion probe measurements were carried out on detrital zircons from the Cretaceous Weferlingen quartz sand (Germany) to distinguish and characterize different zircon populations.Investigations by CL microscopy, SEM-CL and BSE imaging show that there are three main types of zircons (general grain sizes of 100–200 µm): (1) apparently weakly zoned, rounded grains with relict cores, (2) well rounded fragments of optically more or less homogeneous zircon grains showing CL zoning predominantly parallel to the z-axis, and (3) idiomorphic to slightly rounded zircon grains typically showing oscillatory euhedral CL zoning. A fourth type of low abundance is characterized by well-rounded grain fragments with an irregular internal structure showing bright yellow CL.High-resolution CL spectroscopic analyses reveal that blue CL is mainly caused by an intrinsic emission band centered near 430 nm. Dy3+ is the dominant activator element in all zircons, whereas Sm3+, Tb3+, Nd3+ have minor importance. Yellow CL (emission band between 500 and 700 nm) is probably caused by electron defects localized on the [SiO4] groups (e.g. related to oxygen vacancies) or activation by Yb2+ generated by radiation. Variations of the integral SEM-CL intensity are mainly controlled by the intensity of the broad bands and the Dy3+ peaks.SHRIMP analysis provides in situ high-resolution U-Pb dating of single zircon grains and confirms different ages for the evaluated different zircon types. The measurements show that the U-Pb ages of the zircons from Weferlingen scatter over a wide range (340 to 1750 Ma), backing up earlier conclusions that the quartz sand from Weferlingen is quite heterogeneous in terms of provenance.

Group Experiences and Individual Differences in Stuttering

2019 ◽  
Vol 62 (12) ◽  
pp. 4335-4350 ◽  
Author(s):  
Seth E. Tichenor ◽  
J. Scott Yaruss
Keyword(s):  
Individual Differences ◽  
Support Groups ◽  
Support Group ◽  
Affective States ◽  
Life Outcomes ◽  
Self Help ◽  
Wide Range ◽  
Group Experiences ◽  
History Of ◽  
Adults Who Stutter

Purpose This study explored group experiences and individual differences in the behaviors, thoughts, and feelings perceived by adults who stutter. Respondents' goals when speaking and prior participation in self-help/support groups were used to predict individual differences in reported behaviors, thoughts, and feelings. Method In this study, 502 adults who stutter completed a survey examining their behaviors, thoughts, and feelings in and around moments of stuttering. Data were analyzed to determine distributions of group and individual experiences. Results Speakers reported experiencing a wide range of both overt behaviors (e.g., repetitions) and covert behaviors (e.g., remaining silent, choosing not to speak). Having the goal of not stuttering when speaking was significantly associated with more covert behaviors and more negative cognitive and affective states, whereas a history of self-help/support group participation was significantly associated with a decreased probability of these behaviors and states. Conclusion Data from this survey suggest that participating in self-help/support groups and having a goal of communicating freely (as opposed to trying not to stutter) are associated with less negative life outcomes due to stuttering. Results further indicate that the behaviors, thoughts, and experiences most commonly reported by speakers may not be those that are most readily observed by listeners.

Introduction: Emotion, History and the Arts

2018 ◽  
Vol 7 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Erin Sullivan ◽  
Marie Louise Herzfeld-Schild
Keyword(s):  
Historical Change ◽  
Carson Mccullers ◽  
Emotional Life ◽  
Review Section ◽  
The Arts ◽  
Wide Range ◽  
War Correspondents ◽  
History Of ◽  
Johan Huizinga

This introduction surveys the rise of the history of emotions as a field and the role of the arts in such developments. Reflecting on the foundational role of the arts in the early emotion-oriented histories of Johan Huizinga and Jacob Burkhardt, as well as the concerns about methodological impressionism that have sometimes arisen in response to such studies, the introduction considers how intensive engagements with the arts can open up new insights into past emotions while still being historically and theoretically rigorous. Drawing on a wide range of emotionally charged art works from different times and places—including the novels of Carson McCullers and Harriet Beecher-Stowe, the private poetry of neo-Confucian Chinese civil servants, the photojournalism of twentieth-century war correspondents, and music from Igor Stravinsky to the Beatles—the introduction proposes five ways in which art in all its forms contributes to emotional life and consequently to emotional histories: first, by incubating deep emotional experiences that contribute to formations of identity; second, by acting as a place for the expression of private or deviant emotions; third, by functioning as a barometer of wider cultural and attitudinal change; fourth, by serving as an engine of momentous historical change; and fifth, by working as a tool for emotional connection across communities, both within specific time periods but also across them. The introduction finishes by outlining how the special issue's five articles and review section address each of these categories, while also illustrating new methodological possibilities for the field.

History of the Study of Apocrypha in Early Medieval England

2020 ◽  
Vol 48 (3-4) ◽  
pp. 13-26
Author(s):  
Brandon W. Hawk
Keyword(s):  
Old Testament ◽  
Medieval England ◽  
Medieval Period ◽  
Early Medieval ◽  
Future Directions ◽  
Early Judaism ◽  
Wide Range ◽  
History Of ◽  
The Subject ◽  
Early English

Literature written in England between about 500 and 1100 CE attests to a wide range of traditions, although it is clear that Christian sources were the most influential. Biblical apocrypha feature prominently across this corpus of literature, as early English authors clearly relied on a range of extra-biblical texts and traditions related to works under the umbrella of what have been called “Old Testament Pseudepigrapha” and “New Testament/Christian Apocrypha." While scholars of pseudepigrapha and apocrypha have long trained their eyes upon literature from the first few centuries of early Judaism and early Christianity, the medieval period has much to offer. This article presents a survey of significant developments and key threads in the history of scholarship on apocrypha in early medieval England. My purpose is not to offer a comprehensive bibliography, but to highlight major studies that have focused on the transmission of specific apocrypha, contributed to knowledge about medieval uses of apocrypha, and shaped the field from the nineteenth century up to the present. Bringing together major publications on the subject presents a striking picture of the state of the field as well as future directions.

FROM THE HISTORY OF THE FORMATION AND DEVELOPMENT OF PERIODICALS IN NAMANGAN

2019 ◽  
Vol 20 (2) ◽  
pp. 49-54
Author(s):  
Dildora Alinazarova ◽  
Keyword(s):  
The Past ◽  
Wide Range ◽  
History Of ◽  
Printing House

In this article, based on an analysis of a wide range of sources, discusses the emergence and development of periodicals and printing house in Namangan. The activities of Ibrat- as the founder of the first printing house in Namangan are considered. In addition, it describes the functioning and development of "Matbaai Ishokia" in the past and present

Young Scholars Conference “Slavic World: Commonality and Diversity”. 21–22 May 2019. Session “Linguistics”

2019 ◽  
Vol 14 (1-2) ◽  
pp. 295-297
Author(s):  
Sergej A. Borisov
Keyword(s):  
Czech Republic ◽  
Middle Ages ◽  
The Czech Republic ◽  
International Context ◽  
Slavic Languages ◽  
Russian Academy Of Sciences ◽  
Current State ◽  
Wide Range ◽  
History Of ◽  
Academy Of Sciences

For more than twenty years, the Institute of Slavic Studies of the Russian Academy of Sciences celebrates the Day of Slavic Writing and Culture with a traditional scholarly conference.”. Since 2014, it has been held in the young scholars’ format. In 2019, participants from Moscow, St. Petersburg, Kazan, Togliatti, Tyumen, Yekaterinburg, and Rostov-on-Don, as well as Slovakia, the Czech Republic, Hungary, and Romania continued this tradition. A wide range of problems related to the history of the Slavic peoples from the Middle Ages to the present time in the national, regional and international context were discussed again. Participants talked about the typology of Slavic languages and dialects, linguo-geography, socio- and ethnolinguistics, analyzed formation, development, current state, and prospects of Slavic literatures, etc.

From the history of the development of electronic dictionaries: foreign and domestic experience

2020 ◽  
Vol 11 (1) ◽  
pp. 6-12
Author(s):  
O. Y. Balalaieva ◽  
Keyword(s):  
Human Activity ◽  
Current Level ◽  
Ease Of Use ◽  
Advanced Search ◽  
Wide Range ◽  
Promising Area ◽  
History Of ◽  
Machine Readable ◽  
Everyday Communication ◽  
Educational Professional

The purpose of the article is to study the dynamics of electronic dictionaries development abroad and in Ukraine using methods of analysis of scientific sources, comparison, generalization and systematization. Electronic dictionaries have been found to be a relatively new phenomenon in the lexicographic market, evolving from machine-readable dictionaries, exact copies of paper editions to complex digital lexicographic systems with a powerful arsenal of functions over the decades. The stages of development of autonomous and online dictionaries are described. Electronic dictionaries due to the advanced search capabilities, speed, simplicity, ease of use, accessibility and compactness have gained popularity among a wide range of users. Today they are used in many spheres of human activity – scientific, educational, professional, everyday communication. However, the analysis of the current level of development of Ukrainian electronic resources indicates a shortage of electronic dictionaries both common and terminological vocabulary. The lack of electronic dictionaries is due to a number of objective problems, both practical and theoretical, that is why research in the field of domestic computer lexicography is a promising area of further research.

Network Organizational Structure (a Scientific and Practical Review)

2020 ◽  
Vol 26 (6) ◽  
pp. 613-618
Author(s):  
A. V. Altukhov ◽  
S. A. Tishchenko
Keyword(s):  
Organizational Structure ◽  
Network Structure ◽  
Business Models ◽  
Scientific Development ◽  
Network Structures ◽  
Scientific Publications ◽  
Wide Range ◽  
Modern Business ◽  
History Of ◽  
Business Structures

The presented study reviews practically relevant research papers in the field of network structures, modern network business models and platforms.Aim. The study aims to elaborate and explain the concept of network structure and platform and to show the reasons for the progressiveness and potential of network organizational structure at the current stage of socio-economic and scientific development.Tasks. The authors highlight the main scientific ideas about network structures in business, including significant studies in this area; provide and explain the main terms and definitions and examine the key characteristics of network business structures; characterize “platforms” as an important concept for modern business and show the relationship between platforms and network structures.Methods. This study uses analysis of information and subsequent synthesis of new knowledge in the form of the authors’ conclusions and a wide range of relevant scientific publications of Russian and foreign authors, including original publications in English and French.Results. The history of network structures is briefly provided. Definitions and characteristics of such concepts as “network structure” and “platform” in relation to business are provided and explained by the authors.

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