Fission Track Dating of Apatite and Sphene from Paleogene Sediments of Deep Sea Drilling Project Leg 81, Site 555

Duddy, Ian R.; Gleadow, Ajw; Keene, J.B.

doi:10.2973/dsdp.proc.81.127.1984

Cited by 4 publications

(4 citation statements)

References 8 publications

(12 reference statements)

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“…The fission track age provides constraints on the time elapsed since the source rocks cooled through about 110°C, and the track-length distributions can be used to determine the thermal history which can be used to study the history of uplift and erosion (e.g., Agar et al, 1989;Kampetal., 1989;Corrigan and Crowley, 1990;Arne, 1992). Furthermore, fission track ages may help define the source terrain(s) from which the sediments were eroded (e.g., Gleadow et al, 1983;Duddy et al, 1984;Hurford and Carter, 1991).…”

Section: Apatite Fission Track Analysis Backgroundmentioning

confidence: 99%

Fission Track Analysis of Detrital Apatites from Sites 859, 860, and 862, Chile Triple Junction

George¹,

Hegarty²

1995

Proceedings of the Ocean Drilling Program, 141 Scientific Results

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Fission track analysis of detrital apatite grains recovered from sediment samples of upper Pliocene to Quaternary age from the Chile Triple Junction (Sites 859, 860, and 862), shows that the apparent ages of individual grains are older than the stratigraphic ages. The apatite fission track data indicate that there has been no significant postdepositional heating (i.e., maximum paleotemperatures have never exceeded ~60°C). The apatite grains, therefore, derive their fission track characteristics from the source area. The mineral assemblages are similar in all samples and indicate that this source area was dominated by crystalline basement and a volcanic terrain. The track-length distributions characterized by relatively long means (13-14 µm) are a significant feature of the fission track data, given that the apatite grains were eroded from mixed sources of a known broad age range. These data record moderately rapid cooling through ~ 110°C, which we attribute to moderately rapid uplift and erosion of the source area, followed by transportation and deposition of the sediment.Two distinct age populations are recognized in the combined samples from each of the three sites. The younger population is represented by a fission track age of -7 ± 2 Ma, whereas the older population gives an age of -25 ± 5 Ma. The younger age group is interpreted as revealing the time of moderately rapid cooling, produced by uplift and erosion of the source area. Recognition of this late Miocene (~7 Ma) event in the fission track data coincides with several major processes, including magmatism and tectonism, which have been documented already in the area. Erosion of the source (arc-forearc) region at this time is most likely a direct result of tectonic uplift caused by collision and subduction of one or two segments of the Chile Ridge. The older age (-25 Ma) identified in the fission track data records a discrete cooling event which we interpret as denudation and/or deformation of the forearc-arc region as a consequence of oblique convergence at the Chile margin.

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Section: Apatite Fission Track Analysis Backgroundmentioning

confidence: 99%

Fission Track Analysis of Detrital Apatites from Sites 859, 860, and 862, Chile Triple Junction

George¹,

Hegarty²

1995

Proceedings of the Ocean Drilling Program, 141 Scientific Results

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“…The dipping reflectors consist of subaerial, reversely magnetized, depleted tholeiitic flow basalt of MORB affinity, and minor interbedded sediments. K-Ar dating of the lavas at Site 555 east of the dipping wedge gave ages of 53.5 ±1.9 Ma for the basalts (Maclntyre and Hamilton, 1984), and fission track analysis of detrital apatite from the lower Tertiary sediments yields 56 ± 3 Ma (Duddy et al, 1984). We note that Maclntyre and Hamilton (1984) categorically state that there is no evidence of significant continental contamination, while Pb isotope studies of MORB-like magmas at Site 553 within the dipping wedge (Morton and Taylor, 1987) show contamination, probably from an ancient subcontinental lithospheric mantle (Merriman et al, 1988).…”

Section: West Rockall Marginmentioning

confidence: 99%

Evolution of the Vøring Volcanic Margin

Eldholm¹,

Thiede²,

Taylor³

1989

Proceedings of the Ocean Drilling Program

135

107

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ODP Sites 642 and 643 recovered a succession of rocks which have greatly improved the understanding of how the Cenozoic volcanic Wring Margin evolved, particularly by providing important constraints on the series of events that occurred during the initial opening of the Norwegian-Greenland Sea. The more than 900 m of igneous rocks and interbedded sediments drilled at Site 642 constitute two distinct, strikingly different volcanic series. The upper series, composed of transitional mid-oceanic tholeiitic lava flows and thin interbedded volcaniclastic sediments confirmed the seaward-dipping reflectors to be a terrestrially constructed extrusive complex. The lower series, probably extending for several hundred meters below the bottom of the hole, consists of another flow complex of dacitic composition, some dikes and thicker interbedded sediments, partially continentally derived. We suggest that the margin evolved by crustal extension in the Paleocene accompanied by uplift and a progressively more intense invasion of dikes and sills in the rift zone. Just prior to breakup, magma from shallow crustal melts produced the lower series. The upper series was constructed during an intense, rapidly waning, volcanic surge of subaerial accretion of oceanic magma following breakup in middle of Chron 24.2R. The surge is characterized by a much increased rate of magma production and high spreading rate. The upper series cover both newly formed oceanic crust and large areas of the adjacent thinned continental crust. The dipping wedge was formed by subsidence due to loading and thermal contraction, possibly amplified by a tectonic force. When the surge had abated, the injection center quickly subsided and normal oceanic crust was formed. Our interpretation is that the continent/ocean boundary occurs at the seaward termination of reflector K, which separates the two volcanic series. However, a region of strongly intruded transitional crust is inferred in 30-to 50-km wide zones on either side of the Vdring Plateau Escarpment.The Wring Margin experienced crustal uplift and extension prior to breakup, restricted to a Tertiary marginal basin west of the present shelf edge. The initial volcanic surge and shallow extrusion level are related to a higher than normal temperature at the base of the lithosphere, inducing partial melting combined with opening in previously thinned crust. The commonly described non-extensional nature of this margin is only an apparent phenomenon. Except for the outer basin, extension by dike injection coupled with high strength of the thin, pre-opening crust in the Vdring Basin precluded the formation of a faulted rift unconformity. We believe these observations have relevance for volcanic margins elsewhere, but infer that seaward-dipping reflectors can form in many environments.The Wring Plateau marginal high and other similar features in the North Atlantic are an integrated part of the North Atlantic Volcanic Province, which extends 2000 km longitudinally. Compared to the central, transverse, part of ...

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“…Apatite, sphene and zircon are among the possible candidates for this treatment. Three apatite groups are present in Palaeogene sandstones of DSDP site 555 (Rockall Plateau), at about 56 Ma, 100 Ma and 200 Ma; sphenes group at 62 Ma and 1380 Ma (81). Fissiontrack dating of zircon populations from Wealden sandstones of southern England confirms that sediment was supplied from at least two distinct source areas (82).…”

Section: Ness Fm ( Uppermentioning

confidence: 77%