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| Titel |
Crustal models for the Melville Bay and Northern Baffin Bay |
| VerfasserIn |
Tabea Altenbernd, Wilfried Jokat, Ingo Heyde |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250091037
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| Publikation (Nr.) |
 EGU/EGU2014-5303.pdf |
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| Zusammenfassung |
| The Baffin Bay between Greenland and Baffin Island (Canada) opened during the separation
of Greenland and Canada in the Palaeocene and Eocene. The Melville Bay is situated in its
northeastern part. The crustal composition of Northern and Southern Baffin Bay
has been studied in detail: Southern Baffin Bay is underlain by oceanic crust with
volcanic margins, while the margins of northern Baffin Bay are characterized by
serpentinized mantle material. In contrast, the nature of crust in the deep, central Baffin
Bay and the Melville Bay was still unclear due to a lack of deep seismic sounding
lines.
In 2010 a joint geophysical experiment in the Greenlandic part of Baffin Bay acquired
seismic, magnetic and gravity data. We present three velocity and density models derived
from seismic refraction and gravity data. Two of the three profiles are located within the
Melville Bay and extend in a SW - NE direction from the deep sea area of central Baffin
Bay to the shelf area of the Melville Bay. The third profile crosses the northern
profile in the Melville Bay and extends in a N - S direction into the Northern Baffin
Bay.
The profiles in the Melville Bay can be divided in three crustal sections. The deep-sea
area reveals a 3.5 - 7 km thick, 2-layered oceanic crust with increasing thickness towards the
shelf and up to 6 km thick sediments. The crust is underlain by serpentinized upper
mantle with velocities of 7.6 - 7.8 kms-1. A transition zone, which is affected by
volcanism, connects the oceanic crust with stretched continental crust underneath the
Melville Bay. Basement highs and deep sediment basins characterize the stretched
and rifted continental crust. The Melville Bay Graben, the deepest rift basin in the
Melville Bay, contains up to 10 km thick, possibly metamorphosed sediments with
unusually high velocities of up to 4.9 kms1. Well-constrained reflections of the
crust-mantle boundary can be found in many seismic sections indicating a maximum
crustal thickness of ~ 26 km in the northern profile and ~ 32 km in the southern
profile.
In the southern part of the third, N-S extending profile, a 2-layered oceanic crust is
covered by up to 5 km thick sediments. Underneath the shelf edge, the crust thickens towards
the north in several steps and reaches a maximum thickness of ~ 40 km. The northern part of
the profile is characterized by faulted end eroded basement, which crops out at the seafloor. |
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