Implications of a nonlinear 40Ar/39Ar age progression along the Louisville seamount trail for models of fixed and moving hot spots

被引:80
作者
Koppers, AAP [1 ]
Duncan, RA
Steinberger, B
机构
[1] Univ Calif San Diego, Scripps Inst Oceanog, Inst Geophys & Planetary Phys, La Jolla, CA 92093 USA
[2] Oregon State Univ, Coll Ocean & Atmospher Sci, Corvallis, OR 97331 USA
[3] Japan Agcy Marine earth Sci & Technol JAMSTEC, IFREE, Yokosuka, Kanagawa 2370061, Japan
关键词
40Ar/39Ar geochronology; seamounts; guyots; submarine alteration; Pacific plate; hot spots; geochemistry : geochronology; marine geology and geophysics : plate tectonics; tectonophysics; dynamics; convection currents and mantle plumes;
D O I
10.1029/2003GC000671
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
[1] The Louisville seamount trail has been recognized as one of the key examples of hot spot volcanism, comparable to the classic volcanic Hawaiian-Emperor lineaments. The published total fusion 40Ar/39Ar data of Watts et al. [ 1988] showed an astonishing linear age progression, firmly establishing Louisville as a fixed hot spot in the South Pacific mantle. We report new 40Ar/39Ar ages based on high-resolution incremental heating 40Ar/39Ar dating for the same group of samples, showing a marked increase in both precision and accuracy. One of the key findings in our reexamination is that the age progression is not linear after all. The new data show a significantly decreased "apparent'' plate velocity for the Louisville seamount trail older than 62 Ma but confirm the linear trend between 47 Ma and the present day ( although based on only three samples over 2150 km). The most recent volcanic activity in the Louisville seamount trail has now been dated at 1.11 +/- 0.04 Ma for the most southeastern seamount located at 50degrees 26'S and 139degrees 09'W. These results indicate that the Louisville age progression should be interpreted on the basis of both plate and hot spot motion. In this paper we examine our new results in conjunction with the numerical mantle flow models of Steinberger et al. [ 2004] that also predict marked deviations from simple linear age progressions. With these models we can achieve a good fit to the geometry of both the Hawaiian and Louisville seamount trails and their age progressions as well as the similar to15degrees paleolatitudinal shift observed by Tarduno et al. [ 2003] for the Hawaiian hot spot between 80 and 47 Ma. If the model is restricted to Pacific hot spots only, we can improve the fit to the nonlinear age trend for the Louisville seamount trail by allowing an additional rotation change of the Pacific plate around 62 Ma and by decreasing the initiation age of the Louisville plume from 120 to 90 Ma. This improved model features a significant eastward hot spot motion of similar to5degrees between 80 and 30 Ma for the Louisville hot spot, which is quite dissimilar to the southward motion of the Hawaiian hot spot during the same time interval, followed by a minor similar to2degrees latitudinal shift over the last 30 Myr. If hot spot tracks are considered globally, the age trend observed for the oldest part of the Louisville seamount trail does not entirely follow the numerical model predictions. This may indicate some remaining inaccuracies in the global plate circuit, but it may also indicate that the Louisville hot spot experienced a motion somewhat different than in the numerical model: faster in the interval between 62 and 47 Ma but slower before that.
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页数:22
相关论文
共 43 条
[1]  
ANTRETTER M, 2004, IN PRESS GEOL SOC SP
[2]   GEOPHYSICS OF THE PITMAN FRACTURE-ZONE AND PACIFIC-ANTARCTIC PLATE MOTIONS DURING THE CENOZOIC [J].
CANDE, SC ;
RAYMOND, CA ;
STOCK, J ;
HAXBY, WF .
SCIENCE, 1995, 270 (5238) :947-953
[3]   REVISED CALIBRATION OF THE GEOMAGNETIC POLARITY TIMESCALE FOR THE LATE CRETACEOUS AND CENOZOIC [J].
CANDE, SC ;
KENT, DV .
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, 1995, 100 (B4) :6093-6095
[4]   Three distinct types of hotspots in the Earth's mantle [J].
Courtillot, V ;
Davaille, A ;
Besse, J ;
Stock, J .
EARTH AND PLANETARY SCIENCE LETTERS, 2003, 205 (3-4) :295-308
[5]  
Dalrymple G. B., 1981, 1176 US GEOL SURV
[6]   Are the Pacific and Indo-Atlantic hotspots fixed? Testing the plate circuit through Antarctica [J].
DiVenere, V ;
Kent, DV .
EARTH AND PLANETARY SCIENCE LETTERS, 1999, 170 (1-2) :105-117
[7]   HOTSPOTS, MANTLE PLUMES, FLOOD BASALTS, AND TRUE POLAR WANDER [J].
DUNCAN, RA ;
RICHARDS, MA .
REVIEWS OF GEOPHYSICS, 1991, 29 (01) :31-50
[8]  
DUNCAN RA, 1985, OCEAN BASIN MARGIN, V7, P89
[9]   INTERPRETATION OF DISCORDANT AR-40-AR39 AGE-SPECTRA OF MESOZOIC THOLEIITES FROM ANTARCTICA [J].
FLECK, RJ ;
SUTTER, JF ;
ELLIOT, DH .
GEOCHIMICA ET COSMOCHIMICA ACTA, 1977, 41 (01) :15-32
[10]   Is "hotspot" volcanism a consequence of plate tectonics? [J].
Foulger, GR ;
Natland, JH .
SCIENCE, 2003, 300 (5621) :921-922