MARC 主機 00000nam a2200469K 4500
001 AAI10190360
005 20170724102535.5
006 m o u
007 cr mn||||a|a||
008 170724s2016 xx sbm 000 0 eng d
020 9781369412420
035 (MiAaPQ)AAI10190360
040 MiAaPQ|cMiAaPQ
100 1 Dunlea, Ann Genevieve
245 10 Biogeochemistry and geochemical paleoceanography of the
South Pacific Gyre|h[electronic resource]
260 |c2016
300 1 on line resource (366 pages)
500 Source: Dissertation Abstracts International, Volume: 78-
04(E), Section: B
500 Adviser: Richard W. Murray
502 Thesis (Ph.D.)--Boston University, 2016
504 Includes bibliographical references
520 Pelagic clays cover nearly one half of the ocean floor,
but are rarely used for paleoceanographic research because
of their extremely slow sedimentation rates, post-
depositional alteration(s), and the lack of biogenic
material available to provide ages. My dissertation
develops and applies approaches to study pelagic clays by
targeting the largest marine sediment province in the
world: the South Pacific Gyre (SPG). I present an
unprecedented spatially and temporally extensive
paleoceanographic history of the SPG and discuss
authigenic processes in pelagic clays that are linked to
changes in global seawater composition through the
Cenozoic
520 My research was based on an extensive inorganic
geochemical dataset I developed from samples gathered
during Integrated Ocean Drilling Program Expedition 329. I
applied multivariate statistical techniques (e.g., Q-mode
factor analysis and constrained least squares multiple
linear regression (CLS)) to the dataset in order to (a)
identify the existence of six end-members in pelagic clay
(namely, eolian dust, Fe/Mn-oxyhydroxides, apatite, excess
Si, and two types of volcanic ash), (b) quantify their
abundances, (c) determine their mass accumulation rates,
and (d) infer major features in the paleoceanographic
evolution of the SPG. Key parts of my research also
developed improved MATLAB codes to facilitate and speed
the search for best fitting end-member combinations in CLS
modeling. Additionally, I expanded the natural gamma
radiation instrumental capabilities on the D/V JOIDES
Resolution to quantify concentrations of uranium, thorium,
and potassium
520 I dated the pelagic clay at four of the IODP sites with a
cobalt-based age model that I developed, and documented
that the seawater behavior of cobalt determines the extent
to which this method can be applied. Collectively, the
results track the spatial extent of dust deposition in the
SPG during the aridification of Australia, dispersed ash
accumulation from episodes of Southern Hemisphere
volcanism, and other features of Earth's evolution during
the Cenozoic. I further quantified two geochemically
distinct types of authigenic ash alterations within the
pelagic clay, indicating that altered ashes may be a
significant and variable sink of magnesium in seawater
over geologic timescales
533 Electronic reproduction.|bAnn Arbor, Mich. :|cProQuest,
|d2017
538 Mode of access: World Wide Web
590 School code: 0017
650 4 Marine geology
650 4 Paleoclimate science
650 4 Biogeochemistry
655 7 Electronic books.|2local
690 0556
690 0653
690 0425
710 2 ProQuest Information and Learning Co
710 2 Boston University.|bEarth and Environment
773 0 |tDissertation Abstracts International|g78-04B(E)
856 40 |uhttps://pqdd.sinica.edu.tw/twdaoapp/servlet/
advanced?query=10190360|zclick for full text (PQDT)
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