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Melt Extraction and Crustal Thickness Variations at Segmented Mid-Ocean Ridges.

紀錄類型:	書目-語言資料,手稿 : Monograph/item
正題名/作者:	Melt Extraction and Crustal Thickness Variations at Segmented Mid-Ocean Ridges./
作者:	Bai, Hailong.
面頁冊數:	1 online resource (245 pages)
附註:	Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
標題:	Marine geology. -
電子資源:	click for full text (PQDT)
ISBN:	9780355301793

Melt Extraction and Crustal Thickness Variations at Segmented Mid-Ocean Ridges.
Bai, Hailong.

Melt Extraction and Crustal Thickness Variations at Segmented Mid-Ocean Ridges. - 1 online resource (245 pages)

Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.

Thesis (Ph.D.)--University of Maryland, College Park, 2017.

Includes bibliographical references

Mid-ocean ridges are underwater volcanic mountains extending more than 55,000 km in ocean basins worldwide, accounting for nearly 80% of the Earth's volcanism. They are the birthplace of new seafloor, resurfacing two thirds of the planet over about 100 million years. At mid-ocean ridges, tectonic plates move away from each other, a phenomenon known as seafloor spreading, at rates ranging from slow (&sim;10 cm/yr) to fast (&sim;100 cm/yr). Plate divergence induces the underlying mantle to rise and melt. Buoyant melts segregate from the mantle and collect toward axes of mid-ocean ridges, where they are extracted and solidify into new oceanic crust. The thickness of oceanic crust, the final product of ridge magmatism, contains integrated information about plate motion, mantle flow, mantle temperature, melt generation, melt extraction and crustal accretion. In this dissertation, I investigate three types of crustal thickness variations at mid-ocean ridges to provide insights into the Earth's deep, less accessible interior.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2018

Mode of access: World Wide Web

ISBN: 9780355301793Subjects--Topical Terms:

1178828
Marine geology.
Index Terms--Genre/Form:

554714
Electronic books.

Melt Extraction and Crustal Thickness Variations at Segmented Mid-Ocean Ridges.
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500 $a Source: Dissertation Abstracts International, Volume: 79-01(E), Section: B.
500 $a Adviser: Laurent G. J. Montesi.
502 $a Thesis (Ph.D.)--University of Maryland, College Park, 2017.
504 $a Includes bibliographical references
520 $a Mid-ocean ridges are underwater volcanic mountains extending more than 55,000 km in ocean basins worldwide, accounting for nearly 80% of the Earth's volcanism. They are the birthplace of new seafloor, resurfacing two thirds of the planet over about 100 million years. At mid-ocean ridges, tectonic plates move away from each other, a phenomenon known as seafloor spreading, at rates ranging from slow (&sim;10 cm/yr) to fast (&sim;100 cm/yr). Plate divergence induces the underlying mantle to rise and melt. Buoyant melts segregate from the mantle and collect toward axes of mid-ocean ridges, where they are extracted and solidify into new oceanic crust. The thickness of oceanic crust, the final product of ridge magmatism, contains integrated information about plate motion, mantle flow, mantle temperature, melt generation, melt extraction and crustal accretion. In this dissertation, I investigate three types of crustal thickness variations at mid-ocean ridges to provide insights into the Earth's deep, less accessible interior.
520 $a Mid-ocean ridges are broken into segments bounded by transform faults. At fast-spreading ridges, transform faults exhibit thicker crust than adjacent ridge segments, while the crust along transform faults at slow-spreading ridges is thinner. I show that these observations are compatible with melt being extracted along fast-slipping transform faults, but not at the slow-slipping ones.
520 $a The plates on either side of a ridge axis may move away from the ridge at different rates. I reveal a discrepancy between the expected and observed topography at such asymmetrically spreading ridges, and argue that the discrepancy is best explained by asymmetric crustal thickness, with thicker crust on the slower-moving plate and thinner crust on the faster-moving plate.
520 $a Crustal thickness may differ between ridge segments separated by a transform fault, in a way that correlates with the relative motion between the ridge and the underlying mantle. I study the three-dimensional effects of background mantle flow, and demonstrate that the pattern of along-axis crustal thickness variations is controlled by the relative angle between ridge and background mantle flow.
520 $a This dissertation systematically examines the origins of crustal thickness variations at mid-ocean ridges, and provides constraints on mantle and melt dynamics.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2018
538 $a Mode of access: World Wide Web
650 4 $a Marine geology. $3 1178828
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650 4 $a Plate tectonics. $3 782857
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710 2 $a University of Maryland, College Park. $b Geology. $3 1186021
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