Page 10 - i1052-5173-31-10+AR

United States: Geology, v. 28, p. 735–738, https:// 2016, Synchronous opening of the Rio Grande establishment of northwest- and north-trending
doi .org/10.1130/0091-7613(2000)28 <735 :IOPEFA> rift along its entire length at 25–10 Ma supported tectonic grains in the southwestern United
2.0.CO;2. by apatite (U-Th)/He and fission-track thermo- States: Geological Society of America Bulletin,
McIntosh, W.C., and Bryan, C., 2000, Chronology chronology, and evaluation of possible driving v. 113, p. 163–181, https://doi.org/10.1130/0016
and geochemistry of the Boot Heel volcanic mechanisms: Geological Society of America -7606 (2001)113<0163:PMCAGE>2.0.CO;2.
field, New Mexico, in Lawton, T.F., McMillan, Bulletin, v. 128, p. 397–424, https://doi.org/ van Wijk, J., Koning, D., Axen, G., Coblenz, D.,
N.J., and McLemore, V.T., eds., Southwest Pas- 10.1130/ B31223.1. Gragg, E., and Sion, B., 2018, Tectonic subsi-
sage—A Trip through the Phanerozoic: New Ricketts, J.W., Roiz, J., Karlstrom, K.E., Heizler, dence, geoid analysis, and the Miocene-Pliocene
Mexico Geological Society Field Conference M.T., Guenthner, W.R., and Timmons, M.J., unconformity in the Rio Grande rift, southwest-
Guidebook, v. 51, p. 157–174. 2021, Tectonic controls on basement exhumation ern United States: Implications for mantle up-
Murray, K.D., Murray, M.H., and Sheehan, A.F., in the southern Rocky Mountains: The power of welling as a driving force for rift opening: Geo-
2019, Active deformation near the Rio Grande combined zircon (U-Th)/He and K-feldspar sphere, v. 14, p. 684–709, https://doi.org/10.1130/
rift and Colorado Plateau as inferred from con- 40 Ar/ Ar thermochronology: Geology, https:// GES01522.1.
39
tinuous global positioning system measure- doi.org/10.1130/G49141.1. West, M., Ni, J., Baldridge, W.S., Wilson, D., Aster,
ments: Journal of Geophysical Research. Solid Seager, W.R., and Morgan, P., 1979, Rio Grande rift R., Gao, W., and Grand, S., 2004, Crust and upper
Earth, v. 124, p. 2166–2183, https://doi.org/ in southern New Mexico, west Texas, and north- mantle shear wave structure of the southwest
10.1029/ 2018JB016626. ern Chihuahua, in Rieker, R.E., ed., Rio Grande
Reade, N.Z., Biddle, J.M., Ricketts, J.W., and Amato, Rift: Tectonics and Magmatism: Washington, United States: Implications for rifting and sup-
J.M., 2020, Zircon (U-Th)/He thermochronologic D.C., American Geophysical Union, p. 87–106, port for high elevation: Journal of Geophysical
constraints on the long-term thermal evolution https://doi.org/10.1029/SP014p0087. Research, v. 109, B03309, https://doi.org/10.1029/
of southern New Mexico and western Texas: Soreghan, G.S., Keller, G.R., Gilbert, M.C., Chase, 2003JB002575.
Lithosphere, v. 2020, 8881315, https://doi.org/ C.G., and Sweet, D.E., 2012, Load-induced sub- Wilson, D., Aster, R., West, M., Ni, J., Grand, S.,
10.2113/2020/8881315. sidence of the Ancestral Rocky Mountains re- Gao, W., Baldridge, W.S., Semken, S., and Patel,
Reiter, M.R., Chamberlain, R.M., and Love, D.L., corded by preservation of Permian landscapes: P., 2005, Lithospheric structure of the Rio
2010, New data reflect on the thermal antiquity Geosphere, v. 8, p. 654–668, https://doi.org/ Grande rift: Nature, v. 433, p. 851–855, https://
of the Socorro magma body locale, Rio Grande 10.1130/ GES00681.1. doi.org/10.1038/nature03297.
rift, New Mexico: Lithosphere, v. 2, no. 6, Timmons, J.M., Karlstrom, K.E., Dehler, C.M.,
p. 447–453, https://doi.org/10.1130/L115.1. Geissman, J.W., and Heizler, M.T., 2001, Pro- Manuscript received 20 Mar. 2021
Ricketts, J.W., Kelley, S.A., Karlstrom, K.E., terozoic multistage (ca. 1.1 and 0.8 Ga) extension Revised manuscript received 1 June 2021
Schmandt, B., Donahue, M.S., and van Wijk, J., recorded in the Grand Canyon Supergroup and Manuscript accepted 11 June 2021

SPECIAL PAPER 551

Biostratigraphy, Age, and Paleoenvironment of the
Special Paper 551
By Pliocene Beaufort Formation on Meighen Island,
R.W. Barendregt,
R.W. Barendregt,
J.V. Matthews Jr., Canadian Arctic Archipelago
J.V. Matthews Jr.,
V. Behan-Pelletier,
V. Behan-Pelletier,
J. Brigham-Grette,
J. Brigham-Grette, Biostratigraphy, Age, and
J.G. Fyles,
L.E. Ovenden,
D.H. McNeil,
E. Brouwers, Paleoenvironment of the By R.W. Barendregt, J.V. Matthews Jr., V. Behan-Pelletier,
L. Marincovich,
N. Rybczynski, J. Brigham-Grette, J.G. Fyles, L.E. Ovenden, D.H. McNeil,
and
T.L. Fletcher Pliocene Beaufort Formation E. Brouwers, L. Marincovich, N. Rybczynski, and T.L. Fletcher
on Meighen Island,
Canadian Arctic Archipelago M The Beaufort Formation records extraordinary details of Arctic environ-
M
M

ments and ampli ed temperatures at approximately modern levels of
atmospheric CO . It was deposited during the Neogene on the west-
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Island is a key locality for studying this formation because marine
$ $ $ $ $ $ $ $ $ $ $ 18 ern side of what is now the Canadian Arctic Archipelago. Meighen
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sediments there are interbedded with terrestrial fossiliferous sands.
The biostratigraphic succession, fossils from the marine beds, and
paleo magnetic data from the Bjaere Bay region of the island suggest
two potential ages for the studied exposures: either continuous depo-
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sition at ca. 3.0 Ma, or a sequence of deposits at ca. 4.5 Ma and 3.4 Ma.
The sediments appear to encompass at least two eustatic highstands of
sea level and a particularly warm climate interval of the Pliocene Arctic.
SPE551, 39 p., ISBN 9780813725512
list price $26.00 | member price $18.00
By R.W. Barendregt, J.V. Matthews Jr., V. Behan-Pelletier, J. Brigham-Grette, J.G. Fyles,
L.E. Ovenden, D.H. McNeil, E. Brouwers, L. Marincovich, N. Rybczynski, and T.L. Fletcher
Biostratigraphy, Age, and Paleoenvironment of the Pliocene Beaufort Formation on Meighen Island, Canadian Arctic Archipelago
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551
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