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Age progressive volcanism in the New England seamounts and the opening of the Central Atlantic Ocean

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Title Age progressive volcanism in the New England seamounts and the opening of the Central Atlantic Ocean
Names Duncan, Robert A. (creator)
Date Issued 1984-11-10 (iso8601)
Note copyrighted by American Geophysical Union
Abstract Radiometric ages (K-Ar and ⁴⁰Ar-
³⁹Ar methods) have been determined on dredged
volcanic rocks from seven of the New England
Seamounts, a prominent northwest-southeast trending
volcanic lineament in the northwestern
Atlantic Ocean. The ⁴⁰Ar-³⁹Ar total fusion and
incremental heating ages show an increase in
seamount construction age from southeast to
northwest that is consistent with northwestward
motion of the North American plate over a New
England hot spot between 103 and 82 Ma. A linear
volcano migration rate of 4.7 cm/yr fits the
seamount age distribution. These ages fall
within a longer age progression from the Corner
Seamounts (70 to 75 Ma), at the eastern end of
the New England Seamounts, to the youngest phase
of volcanism in the White Mountain Igneous
Province, New England (100 to 124 Ma). The New
England hot spot, estimated from the new radiometric
ages and motion of North America in the
hot spot reference frame to be near 28°N, 33°W,
probably generated a short line of mid to late-Tertiary
age seamounts on the African plate but
appears to be presently inactive. The hot spot
reference frame is used to calculate the motion
of the North American plate away from the African
plate from early Cretaceous time to the present.
Prominent magnetic anomalies recorded in the
central Atlantic seafloor give the positions of
the spreading ridge for a range of known ages.
Hot spots that now underlie the African plate in
the eastern central Atlantic (New England,
Canary, Madeira, Cape Verde, Azores) could have
produced Cretaceous seamount and island chains on
the North American plate during the early opening
of the central Atlantic. Each of these hot spots
has been overridden by spreading ridges at predictable
times. Some of these hot spot crossings
are expressed as geochemical anomalies in the
oceanic crust now far removed from spreading
ridges.
Genre Article
Topic Volcanism
Identifier Duncan, R. A. (1984). Age progressive volcanism in the New England seamounts and the opening of the Central Atlantic Ocean. J. Geophys. Res., 89, B12.

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