Show simple item record

dc.contributor.authorSliwinski, Maciej Grzegorz
dc.date.accessioned2018-08-07T18:44:03Z
dc.date.available2018-08-07T18:44:03Z
dc.date.issued2012
dc.identifier.urihttp://hdl.handle.net/11122/9137
dc.descriptionThesis (Ph.D.) University of Alaska Fairbanks, 2012
dc.description.abstractCarbonate deposits straddling the Early-Middle Frasnian (Late Devonian) transitional interval at the isolated Miette carbonate platform in the Western Canada Sedimentary Basin were studied geochemically to better understand the paleoceanographic changes that had taken place regionally during the global 'punctata Event' Earth-system perturbation, characterized by the short-term (<0.5 M.y.) yet wide-spread eutrophication of epeiric environments and the deposition of organic carbon-rich facies. This event occurred while the evolution of terrestrial forests entered a rapid, near exponential phase of diversification and expansion, thus altering nutrient-cycling between the terrestrial and marine realms through a transient increase in the intensity of pedogenic weathering. I've attempted a reconstruction of the chemostratigraphic variance of (1) bioproductivity, paleoredox and detrital elemental proxies, of (2) isotopic records (delta13C (carb & org); delta15Norg), and of (3) related parameters, including TOC, magnetic susceptibility (MS) and the abundance and mineralogy of acid-insoluble carbonate residues, and interpreted these within the context of regional sequence stratigraphy and paleogeography against the background of global geobiological events. Analytical methods and standards were developed for measuring low (<10 ppm) concentrations of crucial proxies in carbonates (down to 1-2 ppm) by WD-XRF, and were verified by a diversity of statistical tests and analyses. Evaluation of chemostatigraphic trends revealed that eutrophication and geochemical anomalies associate strongly with a 3rd-order transgression (IIc1) and increased detrital input in the lower punctata Zone. Factor analyses were thus applied to constrain the influence of 1) siliciclastic input vs. 2) the development of benthic anoxia (explaining 55 and 35% of total variance, respectively) on trace element excursions, but also to 3) assess the extent to which MS records within the stratigraphy track the clastic input. Mineralogical controls on MS variance were determined by XRD analyses of acid-insoluble limestone residues, and a multivariate linear regression model was found to account for 97.7 % of total variance as a function of variable admixing of illite, pyrite, quartz and feldspars, in turn variably diluted by the total carbonate content.
dc.subjectGeochemistry
dc.titleGeochemistry Of The Late Devonian 'Punctata' Event In The Western Canada Sedimentary Basin
dc.typeThesis
dc.type.degreephd
dc.identifier.departmentDepartment of Geology
dc.contributor.chairWhalen, Michael
dc.contributor.chairNewberry, Rainer J.
dc.contributor.committeeTrainor, Thomas P.
dc.contributor.committeeSeverin, Kenneth P.
refterms.dateFOA2020-03-05T17:28:34Z


Files in this item

Thumbnail
Name:
Sliwinski_M_2012.pdf
Size:
7.295Mb
Format:
PDF

This item appears in the following Collection(s)

Show simple item record