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- Jacobs, Alan M., et al.
(författare)
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The Qualitative Transparency Deliberations : Insights and Implications
- 2021
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Ingår i: Perspectives on Politics. - 1537-5927 .- 1541-0986. ; 19:1, s. 171-208
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process-the Qualitative Transparency Deliberations (QTD)-involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups' final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net, the reports unpack transparency's promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports-the full versions of which can be found in the Supplementary Materials-offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate-as understood by relevant research communities-to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu.(1)
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| 4. |
- Israelson, C, et al.
(författare)
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Direct U-Th dating of organic- and carbonate-rich lake sediments from southern Scandinavia
- 1997
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Ingår i: EARTH AND PLANETARY SCIENCE LETTERS. - : ELSEVIER SCIENCE BV. ; 153:3-4, s. 251-263
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- U-Th ages of Holocene lacustrine sediments from southern Sweden have been determined to assess the reliability of this technique for dating climatic events from the last interglacial-glacial-interglacial cycle, and for calibration of the C-14 dating metho
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| 6. |
- Spencer, C.J., et al.
(författare)
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Generation and preservation of continental crust in the Grenville Orogeny
- 2015
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Ingår i: Geoscience Frontiers. - : Elsevier BV. - 1674-9871. ; 6, s. 357-372
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Tidskriftsartikel (refereegranskat)abstract
- Detrital zircons from modern sediments display an episodic temporal distribution of U-Pb crystallization ages forming a series of ‘peaks’ and ‘troughs’. The peaks are interpreted to represent either periods of enhanced generation of granitic magma perhaps associated with mantle overturn and superplume events, or preferential preservation of continental crust during global collisional orogenesis. The close association of those peaks with the assembly of supercontinents implies a causal relationship between collisional orogenesis and the presence of zircon age peaks. Here these two end-member models (episodic periodicity of increased magmatism versus selective preservation during collisional orogenesis) are assessed using U-Pb, Hf, and O analysis of detrital zircons from sedimentary successions deposited during the ∼1.3–1.1 Ga accretionary, ∼1.1–0.9 Ga collisional, and < 0.9 Ga extensional collapse phases of the Grenville orogenic cycle in Labrador and Scotland. The pre-collisional, accretionary stage provides a baseline of continental crust present prior to orogenesis and is dominated by Archean and Paleoproterozoic age peaks associated with pre-1300 Ma Laurentian geology. Strata deposited during the Grenville Orogeny display similar Archean and Paleoproterozoic detrital populations along with a series of broad muted peaks from ∼1500 to 1100 Ma. However, post-collisional sedimentary successions display a dominant age peak between 1085 and 985 Ma, similar to that observed in modern North American river sediments.Zircons within the post-orogenic sedimentary successions have progressively lower ɛHf and higher δ18O values from ∼1800 to ∼1200 Ma whereupon they have higher ɛHf and δ18O within the dominant 1085–985 Ma age peak. Furthermore, the Lu-Hf isotopic profile of the Grenville-related age peak is consistent with significant assimilation and contamination by older crustal material. The timing of this dominant age peak coincides with the peak of metamorphism and magmatism associated with the Grenville Orogeny, which is a typical collisional orogenic belt. The change from broad muted age peaks in the syn-orogenic strata to a single peak in the post-orogenic sedimentary successions and in the modern river sediments implies a significant shift in provenance following continental collision. This temporal change in provenance highlights that the source(s), from which detrital zircons within syn-orogenic strata were derived, was no longer available during the later stages of the accretionary and collisional stages of the orogenic cycle. This may reflect some combination of tectonic burial, erosion, or possibly recycling into the mantle by tectonic erosion of the source(s). During continental collision, the incorporated continental crust is isolated from crustal recycling processes operative at subduction margins. This tectonic isolation combined with sedimentary recycling likely controls the presence of the isotopic signature associated with the Grenville Orogeny in the modern Mississippi and Appalachian river sediments. These results imply that zircon age peaks, which developed in conjunction with supercontinents, are the product of selective crustal preservation resulting from collisional orogenesis.
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