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Lyle, Mitchell W.

Works: 11 works in 52 publications in 1 language and 95 library holdings
Roles: Author
Classifications: QE39, 551.46083
Publication Timeline
Publications about Mitchell W Lyle
Publications by Mitchell W Lyle
Most widely held works by Mitchell W Lyle
Proceedings of the Ocean Drilling Program. B : Scientific results ( Book )
in English and held by 82 libraries worldwide
The formation and growth of ferromanganese oxides on the Naxca Plate by Mitchell Lyle( Archival Material )
1 edition published in 1978 in English and held by 2 libraries worldwide
Proceedings of the Ocean Drilling Program. B : Sites 1033-1034 : Scientific results ( Book )
in English and held by 2 libraries worldwide
Sedimentation rates and geochemistry of three cores from eastern tropical Pacific, supplementary data to: Lyle, Mitchell W; Murray, David W; Finney, Bruce P; Dymond, Jack R; Robbins, James M; Brooksforce, Kathryn (1988): The record of Late Pleistocene biogenic sedimentation in the eastern tropical Pacific Ocean. Paleoceanography, 3(1), 39-59 by Mitchell W Lyle( Computer File )
in English and held by 1 library worldwide
We have generated approx. 300 Kyr records of biogenic opal, calcite, and organic carbon (Corg) for three cores in the eastern and central equatorial Pacific Ocean and have compared the records to determine whether common periods of biogenic sedimentation have occurred throughout the region. We find that Corg has been deposited in common pulses throughout the area, while opal has a much more local pattern of variation. Calcite varies regionally, but the record is shaped by superimposed dissolution and productivity processes. The most intense Corg peak occurs at 18 ka and can have greater than 2 times the Holocene Corg content. Other major Corg peaks occur 150 ka and perhaps at 280 ka. We have compared the Corg record in one of the cores, V19-28, to a model deepwater oxygen record developed from d13C data in the nearby V19-30 to test whether the Corg record has been mostly shaped by degradation or by the rain of organic matter from the euphotic zone. We found no coherence between the two records, implying that the Corg record is primarily a measure of productivity. By comparing the opal, calcite, and Corg records in V19-28, a core which is at or above the lysocline, we found that both increased calcite and opal deposition matches high Corg accumulation. We also found, however, that the calcite and opal records were uncorrelated, so that episodes of high opal deposition do not necessarily accumulate calcite rapidly. We hypothesize that at least two different plankton communities have been dominant in the waters above this site, one rich in opal-secreting plankton and one more dominated by calcite producers. The opal-rich plankton community was dominant during the intervals 10-15 ka and 35-60 ka
Sedimentology and stable isotope ratios of the northwest Pacific, supplementary data to: Lyle, Mitchell W; Zahn, Rainer; Prahl, Frederick G; Dymond, Jack R; Collier, Robert W; Pisias, Nicklas G; Suess, Erwin (1992): Paleoproductivity and carbon burial across the California current: the multitracer transect 42?N. Paleoceanography, 7(3), 251-272 by Mitchell W Lyle( Computer File )
in English and held by 1 library worldwide
The Multitracers Experiment studied a transect of water column, sediment trap, and sediment data taken across the California Current to develop quantitative methods for hindcasting paleoproductivity. The experiment used three sediment trap moorings located 120 km, 270 km, and 630 km from shore at the Oregon/California border in North America. We report here about the sedimentation and burial of particulate organic carbon (Corg) and CaCO3. In order to observe how the integrated CaCO3 and Corg burial across the transect has changed since the last glacial maximum, we have correlated core from the three sites using time scales constrained by both radiocarbon and oxygen isotopes. By comparing surface sediments to a two-and-a-half year sediment trap record, we have also defined the modern preservation rates for many of the labile sedimentary materials. Our analysis of the Corg data indicates that significant amounts (20-40%) of the total Corg being buried today in surface sediments is terrestrial. At the last glacial maximum, the terrestrial Corg fraction within 300 km of the coast was about twice as large. Such large fluxes of terrestrial Corg obscure the marine Corg record, which can be interpreted as productivity. When we corrected for the terrestrial organic matter, we found that the mass accumulation rate of marine Corg roughly doubled from the glacial maximum to the present. Because preservation rates of organic carbon are high in the high sedimentation rate cores, corrections for degradation are straightforward and we can be confident that organic carbon rain rate (new productivity) also doubled. As confirmation, the highest burial fluxes of other biogenic components (opal and Ba) also occur in the Holocene. Productivity off Oregon has thus increased dramatically since the last glacial maximum. CaCO3 fluxes also changed radically through the deglaciation; however, they are linked not to CaCO3 production but rather to changes in deepwater carbonate chemistry between 18 Ka and now
Holocene sea-surface reconstructions for the Californian margin, supplementary data to: Herbert, Timothy D; Schuffert, J; Andreasen, Dyke; Heusser, Linda E; Lyle, Mitchell W; Mix, Alan C; Ravelo, Ana Christina; Stott, Lowell D; Herguera, Juan Carlos (2001): Collapse of the California current during glacial maxima linked to climate change on land. Science, 293, 71-76 by Timothy D Herbert( Computer File )
in English and held by 1 library worldwide
Time series of alkenone unsaturation indices gathered along the California margin reveal large (4? to 8?C) glacial-interglacial changes in sea surface temperature (SST) over the past 550,000 years. Interglacial times with SSTs equal to or exceeding that of the Holocene contain peak abundances in the pollen of redwood, the distinctive component of the temperate rainforest of the northwest coast of California. In the region now dominated by the California Current, SSTs warmed 10,000 to 15,000 years in advance of deglaciation at each of the past five glacial maxima. SSTs did not rise in advance of deglaciation south of the modern California Current front. Glacial warming along the California margin therefore is a regional signal of the weakening of the California Current during times when large ice sheets reorganized wind systems over the North Pacific. Both the timing and magnitude of the SST estimates suggest that the Devils Hole (Nevada) calcite record represents regional but not global paleotemperatures, and hence does not pose a fundamental challenge to the orbital ("Milankovitch") theory of the Ice Ages
Bulk geochemical and lipid biomarker data for sediment core W8402A-14, supplementary data to: Prahl, Frederick G; Muehlhausen, LA; Lyle, Mitchell W (1989): An organic Geochemical Assessment of Oceanographic conditions at manop site C over the Past 26,000 Years. Paleoceanography, 4(5), 495-510 by Frederick G Prahl( Computer File )
in English and held by 1 library worldwide
Eleven sediment samples taken downcore and representing the past 26 kyr of deposition at MANOP site C (0?57.2?N, 138?57.3?W) were analyzed for lipid biomarker composition. Biomarkers of both terrestrial and marine sources of organic carbon were identified. In general, concentration profiles for these biomarkers and for total organic carbon (TOC) displayed three common stratigraphic features in the time series: (1) a maximum within the surface sediment mixed layer (<=4 ka); (2) a broad minimum extending throughout the interglacial deposit; and (3) a deep, pronounced maximum within the glacial deposit. Using the biomarker records, a simple binary mixing model is described that assesses the proportion of terrestrial to marine TOC in these sediments. Best estimates from this model suggest that 20% of the TOC is land-derived, introduced by long-range eolian transport, and the remainder is derived from marine productivity. The direct correlation between the records for terrestrial and marine TOC with depth in this core fits an interpretation that primary productivity at site C has been controlled by wind-driven upwelling at least over the last glacial/interglacial cycle. The biomarker records place the greatest wind strength and highest primary productivity within the time frame of 18 to 22 kyr B.P. Diagenetic effects limit our ability to ascertain directly from the biomarker records the absolute magnitude that different types of primary productivity have changed at this ocean location over the past 26 kyr
Sedimentation at Manop Site H in the eastern equatorial Pacific, supplementary data to: Finney, Bruce P; Lyle, Mitchell W; Heath, G Ross (1988): Sedimentation at Manop site H (eastern equatorial Pacific) over the past 400,000 years: climatically induced redox variations and their effects on transition metal cycling. Paleoceanography, 3(2), 169-189 by Bruce P Finney( Computer File )
in English and held by 1 library worldwide
Gravity cores recovered from Manganese Nodule Project site H (6?33'N, 92?49'W) show marked downcore variations in the abundance of calcium carbonate, organic carbon, opal, manganese, and other components deposited over the past 400,000 years. Variations in the downcore abundance of organic carbon, which ranges from 0.2 to 1.0%, can be used to hindcast redox conditions in the surface sediments over this time. The results indicate that the depth to the manganese redox boundary varied from about 5 to 25 cm below the seafloor during four major cycles. Downcore variations in solid phase Mn, Ni, and Cu can be produced by such changes in redox conditions. A model which predicts that solid phase Mn can be trapped and buried when the Mn redox boundary migrates rapidly upward is consistent with the observed organic carbon and Mn records and supports the reconstructed redox variations. The history of redox variations at site H can be explained by changes with time in surface water productivity. Major productivity variations at the site occur over 100-kyr cycles, with relatively higher productivity occurring during glacial stages. Thus Quaternary climate changes influence surface water productivity, redox conditions in sediments, and the cycling of transition metals
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