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Gee, JS, Cande SC, Hildebrand JA, Donnelly K, Parker RL.  2000.  Geomagnetic intensity variations over the past 780 kyr obtained from near-seafloor magnetic anomalies. Nature. 408:827-832.   10.1038/35048513   AbstractWebsite

Knowledge of past variations in the intensity of the Earth's magnetic field provides an important constraint on models of the geodynamo. A record of absolute palaeointensity for the past 50 kyr has been compiled from archaeomagnetic and volcanic materials, and relative palaeointensities over the past 800 kyr have been obtained from sedimentary sequences. But a long-term record of geomagnetic intensity should also be carried by the thermoremanence of the oceanic crust. Here we show that near-seafloor magnetic anomalies recorded over the southern East Pacific Rise are well correlated with independent estimates of geomagnetic intensity during the past 780 kyr. Moreover, the pattern of absolute palaeointensity of seafloor glass samples from the same area agrees with the well-documented dipole intensity pattern for the past 50 kyr. A comparison of palaeointensities derived from seafloor glass samples with global intensity variations thus allows us to estimate the ages of surficial lava flows in this region. The record of geomagnetic intensity preserved in the oceanic crust should provide a higher-time-resolution record of crustal accretion processes at mid-ocean ridges than has previously been obtainable.

Gaina, C, Muller RD, Cande SC.  2000.  Absolute plate motion, mantle flow, and volcanism at the boundary between the Pacific and Indian Ocean mantle domains since 90 Ma. The history and dynamics of global plate motions. ( Richards MA, Gordon RG, Van der Hilst RD, Eds.).:189-210., Washington, D.C.: American Geophysical Union Abstract
Raymond, CA, Stock JM, Cande SC.  2000.  Fast Paleogene motion of the Pacific hotspots from revised global plate circuit constraints. The history and dynamics of global plate motions. ( Richards MA, Gordon RG, Van der Hilst RD, Eds.).:359-376., Washington, D.C.: American Geophysical Union Abstract
Muller, RD, Gaina C, Tikku A, Mihut D, Cande SC, Stock JM.  2000.  Mesozoic/Cenozoic tectonic events around Australia. The history and dynamics of global plate motions. ( Richards MA, Gordon RG, Van der Hilst RD, Eds.).:161-188., Washington, D.C.: American Geophysical Union Abstract
Heinemann, J, Stock J, Clayton R, Hafner K, Cande S, Raymond C.  1999.  Constraints on the proposed Marie Byrd Land-Bellingshausen plate boundary from seismic reflection data. Journal of Geophysical Research-Solid Earth. 104:25321-25330.   10.1029/1998jb900079   AbstractWebsite

Single-channel and multichannel marine seismic data off the coast of West Antarctica collected during two Nathaniel B. Palmer cruises (NP92-8 and NP96-2) in the vicinity of 65 degrees S to 71 degrees S, 220 degrees E to 250 degrees E, reveal a NNW trending graben. We interpret this graben to be part of the paleodivergent plate boundary between the Marie Byrd Land and Bellingshausen plates. This graben coincides with a -520 nT magnetic anomaly to the NNW and a -720 nT anomaly to the SSE, as well as a 20 mGal negative gravity anomaly. Seismic profiles subparallel to the graben (22 km/Ma half-spreading rate) reveal greater seafloor roughness to the NE, where seafloor spreading was slower, than to the SW (27 km/Ma half-spreading rate). These data allow the position of the Marie Byrd Land-Bellingshausen plate boundary to be constrained more precisely than has previously been possible, with a trend of N17 degrees W from 68.52 degrees S, 233.65 degrees E to 68.41 degrees S, 233.56 degrees E. The sediment-filled graben has normal separation of sedimentary layers varying from 740 +/- 30 m to 580 +/- 20 m imaged in seafloor of age A33y (74 Ma).

Tikku, AA, Cande SC.  1999.  The oldest magnetic anomalies in the Australian-Antarctic Basin: Are they isochrons? Journal of Geophysical Research-Solid Earth. 104:661-677.   10.1029/1998jb900034   AbstractWebsite

We present a revised tectonic interpretation of Australia and Antarctica incorporating new magnetic data off of Wilkes Land, Antarctica, for the earliest period of seafloor spreading on the Southeast Indian Ridge, from the Late Cretaceous to Early Tertiary. Reconstructions based on our revised anomaly identifications are characterized by a surprisingly large amount of continental overlap, involving the South Tasman Rise, Tasmania, and the Victoria Land region of Antarctica. The overlap is due to continental extension and/or deformation of oceanic crust in the Australian-Antarctic Basin. The second hypothesis would imply that the magnetic anomalies older than chron 31 in the Australian-Antarctic Basin are not isochrons. We also fmd evidence for a previously unrecognized period of extremely slow spreading on the Southeast Indian Ridge from chron 31 (68.7 Ma) to chron 24 (53.3 Ma) in the Australian-Antarctic Basin. In the western end of the basin we have tentatively identified a hiatus in the generation of crustal accretion associated with a minimum sustainable threshold half spreading rate of 1.5 mm/yr. In addition, we recognize a new fracture zone on the Antarctic plate, the Vincennes fracture zone, as the conjugate to the Perth fracture zone on the Australian plate, in the western Australian-Antarctic Basin. These fracture zones record the initial NW-SE opening direction between Australia and Antarctica.

Muller, RD, Royer JY, Cande SC, Roest WR, Maschenkov S.  1999.  New constraints on the Late Cretaceous/Early Tertiary plate tectonic evolution of the Caribbean. Caribbean Basins. ( Mann P, Ed.).:33-59., Amsterdam ; Oxford: Elsevier Abstract
Tebbens, SF, Cande SC, Kovacs L, Parra JC, Labrecque JL, Vergara H.  1997.  The Chile ridge: A tectonic framework. Journal of Geophysical Research-Solid Earth. 102:12035-12059.   10.1029/96jb02581   AbstractWebsite

A new Chile ridge tectonic framework is developed based on satellite altimetry data, shipboard geophysical data and, primarily, 38,500 km of magnetic data gathered on a joint U.S.-Chilean aeromagnetic survey. Eighteen active transforms with fossil fracture zones (FZs), including two complex systems (the Chile FZ and Valdivia FZ systems), have been mapped between the northern end of the Antarctic-Nazca plate boundary (Chile ridge) at 35 degrees S and the Chile margin triple junction at 47 degrees S. Chile ridge spreading rates from 23 Ma to Present have been determined and show slowdowns in spreading rates that correspond to times of ridge-trench collisions. The Valdivia FZ system, previously mapped as two FZs with an uncharted seismically active region between them, is now recognized to be a multiple-offset FZ system composed of six FZs separated by short ridge segments 22 to 27 km long. At chron 5A (similar to 12 Ma), the Chile ridge propagated from the Valdivia FZ system northward into the Nazca plate through crust formed 5 Myr earlier at the Pacific-Nazca ridge. Evidence for this propagation event includes the Friday and Crusoe troughs, located at discontinuities in the magnetic anomaly sequence and interpreted as pseudofaults. This propagation event led to the formation of the Friday microplate, which resulted in the transferal of crust from the Nazca plate to the Antarctic plate, and in a 500-km northward stepwise migration of the Pacific-Antarctic-Nazca triple junction. Rift propagation, microplate formation, microplate extinction, and stepwise triple junction migration are found to occur during large-scale plate motion changes and plate boundary changes in the southeast Pacific.

Bangs, NL, Cande SC.  1997.  Episodic development of a convergent margin inferred from structures and processes along the southern Chile margin. Tectonics. 16:489-503.   10.1029/97tc00494   AbstractWebsite

Seismic reflection data acquired in the vicinity of Isla Mocha across the southern coast of Chile image structures formed along the continental margin and reveal an episodic history of accretion, nonaccretion, and possibly erosion. Structures formed at the toe of the continental slope suggest frontal accretion of 3/4 to 1 3/4 km of trench fill. Seismic images also reveal that a small accretionary wedge, 20-30 km wide, abuts the truncated continental metamorphic basement that extends seaward from beneath the shelf. The small size of the accretionary wedge on three profiles examined here is not consistent with a long history of accretion with the current deformational style, as current rates of frontal accretion could have accumulated all of the existing accretionary wedge in less than 1-2 m.y. This is a small fraction of convergence history along this margin, and the current accretionary mode has not been consistently maintained in the past. The Isla Mocha region is located between the temperate climate of central Chile and the glacial climate of southern Chile, and climatic conditions in this region have likely fluctuated sufficiently to cause significant variation in trench sediment supply. Accretionary and nonaccretionary or erosional episodes are probably linked to temporal variations in trench sediment thickness, as suggested by observations along the Chile margin. Currently, thick trench sediment correlates with accretion along the southern Chile margin, and thin trench sediment correlates with nonaccretion/tectonic erosion as near the Chile Ridge and from the Juan Fernandez Ridge to northern Chile. The Isla Mocha region also lies 900-1000 km north of the Chile triple junction, and the Chile Ridge lies approximately 2000 km to the west and has not yet collided and affected the margin near Isla Mocha. This part of the precollision zone provides an excellent reference to examine the effects of Chile Ridge collision in the development of the Chile margin. The most apparent effect of subduction of the buoyant, young crust of the Chile Ridge is a shallow trench that is nearly devoid of sediment. Consequently, the triple junction is undergoing nonaccretion or erosion, and the accretionary complex near the triple junction remains smaller than to the north or south because the current phase of rapid accretion elsewhere in the trench has bypassed the triple junction region. The interplay of subduction zone processes, such as trench sedimentation and ridge collision, has resulted in an episodic development of the margin and produced a discontinuous record of convergence history within the accretionary wedge.

Tebbens, SF, Cande SC.  1997.  Southeast Pacific tectonic evolution from early Oligocene to present. Journal of Geophysical Research-Solid Earth. 102:12061-12084.   10.1029/96jb02582   AbstractWebsite

Plate tectonic reconstructions of the Nazca, Antarctic, and Pacific plates are presented from late Oligocene to Present. These reconstructions document major plate boundary reorganizations in the southeast Pacific at chrons 6C (24 Ma), 6(o) (20 Ma), and 5A (12 Ma) and a smaller reorganization at chron 3(o) (5 Ma). During the chron 6(o) reorganization it appears that a ridge propagated into crust north of the northernmost Pacific-Antarctic Ridge, between the Chiloe fracture zone (FZ) of the Chile ridge and Agassiz FZ of the Pacific-Nazca ridge, which resulted in a northward jump of the Pacific-Antarctic-Nazca (PAC-ANT-NAZ) mid-ocean triple junction. During the chron 5A reorganization the Chile ridge propagated northward from the Valdivia FZ system to the Challenger FZ, through lithosphere formed roughly 5 Myr earlier at the Pacific-Nazca ridge. During this reorganization a shea-lived microplate (the Friday microplate) existed at the PAC-ANT-NAZ triple junction. The PAC-ANT-NAZ triple junction jumped northward 500 km as a result of this reorganization, from a location along the Valdivia FZ to a location along the Challenger FZ. The chron 5A reorganization also included a change in spreading direction of the Chile and Pacific-Antarctic ridges. The reorganization dt chron 3(o) initiated the formation of the Juan Fernandez and Easter microplates along the East Pacific rise. The manner of plate boundary reorganization at chron 6(o) and chron 5A (and possibly today at the Juan Fernandez microplate) included a sequence of rift propagation, transfer of lithosphere from one plate to another, microplate formation, and microplate abandonment and resulted in northward migration of the PAC-ANT-NAZ triple junction. The associated microplate differs from previously studied microplates in that there is no failed ridge.

Cande, SC, Raymond CA, Stock J, Haxby WF.  1995.  Geophysics of the Pitman Fracture-Zone and Pacific-Antarctic Plate Motions During the Cenozoic. Science. 270:947-953.   10.1126/science.270.5238.947   AbstractWebsite

Multibeam bathymetry and magnetometer data from the Pitman fracture zone (FZ) permit construction of a plate motion history for the South Pacific over the past 65 million years. Reconstructions show that motion between the Antarctic and Bellingshausen plates was smaller than previously hypothesized and ended earlier, at chron C27 (61 million years ago). The fixed hot-spot hypothesis and published paleomagnetic data require additional motion elsewhere during the early Tertiary, either between East Antarctica and West Antarctica or between the North and South Pacific. A plate reorganization at chron C27 initiated the Pitman FZ and may have been responsible for the other right-stepping fracture zones along the ridge. An abrupt (8 degrees) clockwise rotation in the abyssal hill fabric along the Pitman flowline near the young end of chron C3a (5.9 million years ago) dates the major change in Pacific-Antarctic relative motion in the late Neogene.

Cande, SC, Kent DV.  1995.  Revised Calibration of the Geomagnetic Polarity Timescale for the Late Cretaceous and Cenozoic. Journal of Geophysical Research-Solid Earth. 100:6093-6095.   10.1029/94jb03098   AbstractWebsite

Recently reported radioisotopic dates and magnetic anomaly spacings have made it evident that modification is required for the age calibrations for the geomagnetic polarity timescale of Cande and Kent (1992) at the Cretaceous/Paleogene boundary and in the Pliocene. An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic.

Jones, EJW, Cande SC, Spathopoulos F.  1995.  Evolution of a major oceanographic pathway: the equatorial Atlantic. The tectonics, sedimentation, and palaeoceanography of the North Atlantic Region, Geological Society Special Publication. 90( Scrutton RA, Stoker MS, Shimmield GB, Tudhope AW, Eds.).:199-213., LondonTulsa, Okla.: The Geological Society ;AAPG Bookstore Abstract
Macario, A, Haxby WF, Goff JA, Ryan WBF, Cande SC, Raymond CA.  1994.  Flow Line Variations in Abyssal Hill Morphology for the Pacific-Antarctic Ridge at 65-Degrees-S. Journal of Geophysical Research-Solid Earth. 99:17921-17934.   10.1029/94jb01409   AbstractWebsite

We present the results of a statistical study on the morphological characteristics of abyssal hills recently mapped along two adjacent segments of the Pacific-Antarctic Ridge at 65 degrees S. The studied area is a densely surveyed corridor (60 km wide by 600 km long) which is centered on the Pitman Fracture Zone (PFZ) and extends to 12 Ma crust on both sides of the ridge. Abyssal hill size parameters (RMS height H and characteristic width lambda) are estimated using Hydrosweep multibeam data. Variations in abyssal hill characteristics are compared with spreading rate history and crustal structure (as inferred from the mantle Bouguer gravity) in order to indirectly quantify the evolution of this ridge crest system. The magnetic data document an abrupt acceleration in spreading rate from similar to 36 to similar to 63 mm/yr (full rate) at Chron 3a (5.7-6.4 Ma). Our results indicate a statistically significant negative correlation between abyssal hill size parameters and full spreading rates. Abyssal hills formed during the slower spreading period (ages >8 Ma; full rates 36-44 mm/yr) are 31-86% taller and 21- >100% wider than hills created during the faster spreading interval (ages <4 Ma; full rates 52-63 mm/yr). The well-resolved positive correlation between H and lambda is interpreted as an indication of temporal changes in the flexural rigidity of the lithosphere near the vicinity of the ridge crest and, by implication, axial thermal structure. However, we cannot rule out that such positive trend is due to constructional volcanism. The lack of correlation between crustal thick-ness and abyssal hill size parameters is likely to be caused by the small magnitude of crustal thickness variations along flow lines (similar to 0.4 km in contrast to similar to 2 km reported in previous studies for the Mid-Atlantic Ridge). The most significant variations in crustal thickness are seen across the PFZ (thinning from north to south by 0.5-0.7 km), which coincide with a well-resolved increase in the averaged lambda estimate. The predictions of the detachment surface model in terms of morphological and structural inside/outside corner asymmetries are not supported by our observations. The main variations in H and lambda that cannot be explained in terms of either the spreading rate or crustal thickness effect include the following: (1) anomalously large abyssal hills north of the PFZ for 4-6 Ma age crust; (2) abyssal hill size estimates for crustal ages greater than 8 Ma show significant asymmetry for opposite ridge flanks north of the PFZ; and (3) toward the segment ends, H estimates are 27-68% larger, while lambda estimates either do not significantly change (to the north of the PFZ) or are up to 40% smaller (to the south of the PFZ). We suggest that the H and lambda changes seen toward the segment ends are related to either an increase in the amount of extension (without a corresponding increase in the strength of the lithosphere) or variations in the relative contribution of constructional volcanism to overall abyssal hill morphology.

Dyment, J, Cande SC, Arkanihamed J.  1994.  Skewness of Marine Magnetic-Anomalies Created between 85-Ma and 40-Ma in the Indian-Ocean. Journal of Geophysical Research-Solid Earth. 99:24121-24134.   10.1029/94jb02061   AbstractWebsite

We have performed a detailed analysis of the skewness of marine magnetic anomalies in Indian Ocean basins created between 85 and 40 Ma as a result of the northward motion of India. Visual and semiautomated methods of skewness determination were applied to the data. Both provide consistent results, but the visual method is preferred for its ability to deal with noisy data. Plots of apparent effective remanent inclination (or skewness corrected for present geomagnetic field inclination) versus time for conjugate basins display the combination of three effects: a gradual increase with time, related to the northward motion of the ridges attached to India in the geomagnetic reference frame; a gap between conjugate curves, which represents anomalous skewness sense stricto; and short-period fluctuations, which represent the sequence effect, i.e., the effect of neighboring magnetic sources on the skewness of a given anomaly. The anomalous skewness decreases with faster spreading rate and completely disappears above 50 km/m.y., an observation which negates geomagnetic field behavior as a possible cause of the observed anomalous skewness.

Behrmann, JH, Lewis SD, Cande SC, Musgrave R, Bangs N, Boden P, Brown K, Collombat H, Didenko AN, Didyk BM, Froelich PN, Golovchenko X, Forsythe R, Kurnosov V, Lindsleygriffin N, Marsaglia K, Osozawa S, Prior D, Sawyer D, Scholl D, Spiegler D, Strand K, Takahashi K, Torres M, Vegafaundez M, Vergara H, Wasada A.  1994.  Tectonics and Geology of Spreading Ridge Subduction at the Chile Triple Junction - A Synthesis of Results from Leg-141 of the Ocean Drilling Program. Geologische Rundschau. 83:832-852. AbstractWebsite

An active oceanic spreading ridge is being subducted beneath the South American continent at the Chile Triple Junction. This process has played a major part in the evolution of most of the continental margins that border the Pacific Ocean basin. A combination of high resolution swath bathymetric maps, seismic reflection profiles and drillhole and core data from five sites drilled during Ocean Drilling Program (ODP) Leg 141 provide important data that define the tectonic, structural and stratigraphic effects of this modern example of spreading ridge subduction. A change from subduction accretion to subduction erosion occurs along-strike of the South American forearc. This change is prominently expressed by normal faulting, forearc subsidence, oversteepening of topographic slopes and intensive sedimentary mass wasting, overprinted on older signatures of sediment accretion, overthrusting and uplift processes in the forearc. Data from drill sites north of the triple junction (Sites 859 - 861) show that after an important phase of forearc building in the early to late Pliocene, subduction accretion had ceased in the late Pliocene. Since that time sediment on the downgoing oceanic Nazca plate has been subducted. Site 863 was drilled into the forearc in the immediate vicinity of the triple junction above the subducted spreading ridge axis. Here, thick and intensely folded and faulted trench slope sediments of Pleistocene age are currently involved in the frontal deformation of the forearc. Early faults with thrust and reverse kinematics are overprinted by later normal faults. The Chile Triple Junction is also the site of apparent ophiolite emplacement into the South American forearc. Drilling at Site 862 on the Taitao Ridge revealed an offshore volcanic sequence of Plio-Pleistocene age associated with the Taitao Fracture Zone, adjacent to exposures of the Pliocene-aged Taitao ophiolite onshore. Despite the large-scale loss of material from the forearc at the triple junction, ophiolite emplacement produces a large topographic promontory in the forearc immediately after ridge subduction, and represents the first stage of forearc rebuilding.

Pitman III, WC, Cande SC, Labrecque JL, Pindell J.  1993.  Fragmentation of Gondwana: the separation of Africa from South America. Biological relationships between Africa and South America. ( Goldblatt PO, Ed.).:15-34., New Haven: Yale University Press Abstract
Cande, SC, Kent DV.  1992.  A New Geomagnetic Polarity Time Scale for the Late Cretaceous and Cenozoic. Journal of Geophysical Research-Solid Earth. 97:13917-13951.   10.1029/92jb01202   AbstractWebsite

We have constructed a magnetic polarity time scale for the Late Cretaceous and Cenozoic based on an analysis of marine magnetic profiles from the world's ocean basins. This is the first time, since Heirtzler et al. (1968) published their time scale, that the relative widths of the magnetic polarity intervals for the entire Late Cretaceous and Cenozoic have been systematically determined from magnetic profiles. A composite geomagnetic polarity sequence was derived based primarily on data from the South Atlantic. Anomaly spacings in the South Atlantic were constrained by a combination of finite rotation poles and averages of stacked profiles. Fine-scale information was derived from magnetic profiles on faster spreading ridges in the Pacific and Indian Oceans and inserted into the South Atlantic sequence. Based on the assumption that spreading rates in the South Atlantic were smoothly varying but not necessarily constant, a time scale was generated by using a spline function to fit a set of nine age calibration points plus the zero-age ridge axis to the composite polarity sequence. The derived spreading history of the South Atlantic shows a regular variation in spreading rate, decreasing in the Late Cretaceous from a high of almost 70 mm/yr (full rate) at around anomaly 33-34 time to a low of about 30 mm/yr by anomaly 27 time in the early Paleocene, increasing to about 55 mm/yr by about anomaly 15 time in the late Eocene, and then gradually decreasing over the Oligocene and the Neogene to the recent rate of about 32 mm/yr. The new time scale has several significant differences from previous time scales. For example, chron C5n is approximately 0.5 m.y. older and chrons C9 through C24 are 2-3 m.y. younger than in the chronologies of Berggren et al. (1985b) and Harland et al. (1990). Additional small-scale anomalies (tiny wiggles) that represent either very short polarity intervals or intensity fluctuations of the dipole field have been identified from several intervals in the Cenozoic including a large number of tiny wiggles between anomalies 24 and 27. Spreading rates on several other ridges, including the Southeast Indian Ridge, the East Pacific Rise, the Pacific-Antarctic Ridge, the Chile Ridge, the North Pacific, and the Central Atlantic, were analyzed in order to evaluate the accuracy of the new time scale. Globally synchronous variations in spreading rate that were previously observed around anomalies 20, 6C, and in the late Neogene have been eliminated. The new time scale helps to resolve events at the times of major plate reorganizations. For example, anomaly 3A (5.6 Ma) is now seen to be a time of sudden spreading rate changes in the Southeast Indian, Pacific-Antarctic, and Chile ridges and may correspond to the time of the change in Pacific absolute plate motion proposed by others. Spreading rates in the North Pacific became increasingly irregular in the Oligocene, culminating in a precipitous drop at anomaly 6C time.

Cande, SC, Kent DV.  1992.  Ultrahigh Resolution Marine Magnetic Anomaly Profiles - a Record of Continuous Paleointensity Variations. Journal of Geophysical Research-Solid Earth. 97:15075-15083.   10.1029/92jb01090   AbstractWebsite

A distinctive pattern of small-scale marine magnetic anomalies (25-100 nT amplitude, 8-25 km wavelength: tiny wiggles) is superimposed on the more generally recognized seafloor spreading pattern between anomalies 24 and 27 in the Indian Ocean. By normalizing and stacking multiple profiles, it is demonstrated that this pattern of tiny wiggles is a high-resolution recording of paleodipole field behavior between chrons C24 and C27. The pattern of tiny wiggles between anomalies 26 and 27 is compared to an ultrafast spreading (82 mm/yr half rate) profile from the southeast Pacific where a similar signal is observed, confirming the paleodipole field origin of the anomalies. Two basic models are considered in which the tiny wiggles are attributed either to short polarity intervals or to paleointensity fluctuations. We conclude that tiny wiggles are most likely caused by paleointensity fluctuations of the dipole field and are a ubiquitous background signal to most fast spreading magnetic profiles. The implications of this study are that (1) tiny wiggles may provide information on the temporal evolution of the geomagnetic dynamo; (2) the small-scale anomalies observed in the Jurassic quiet zones may be due to paleointensity fluctuations; (3) tiny wiggles are potential time markers in large regions of uniform crustal polarity such as the Cretaceous quiet zones; and (4) much of the variance in anomaly profiles normally attributed to crustal emplacement processes, particularly at fast and ultrafast spreading rates, is actually due to intensity variations in the paleomagnetic field.

Royer, JY, Sclater JG, Sandwell DT, Cande SC, Schlich R, Munschy M, Dyment J, Fisher RL, Mueller RD, Coffin MF, Patriat P, Bergh HW.  1992.  Indian Ocean plate reconstructions since the Late Jurassic. Geophysical Monograph. 70( Duncan RA, Rea DK, Kidd RB, von Rad U, Weissel JK, Eds.).:471-475., Washington, DC, United States (USA): American Geophysical Union, Washington, DC AbstractWebsite
Bangs, N, Cande SC, Lewis SD, Miller J.  1992.  Structural framework of the Chile margin at the Chile ridge collision zone. Proceedings of the Ocean Drilling Program, Initial Reports. 141:11-21.   10.2973/   Abstract

Three multichannel seismic reflection lines collected as part of the site survey for drilling Leg 141 examine the structure of the active Chile margin in the vicinity of the Chile Triple Junction. These data are used to compare the margin structure along three cross sections that characterize the interaction of the Chile seafloor-spreading ridge as it collides with the Chile Trench and is subducted beneath the South American continent. Line 745 is located where the ridge is expected to collide with the lower trench slope in approximately 100 k.y. At Line 751 the ridge was subducted at approximately 50 ka. Line 762 examines the Taitao Ridge, which is thought to be an ophiolite that has been obducted onto the margin at the Taitao Fracture Zone.The margin prior to ridge collision is characterized by a small accretionary complex and forearc basin that lie along the lower trench slope and abut attenuated continental crust underlying the middle and upper slopes. The tectonic interaction of the ridge with the margin appears minimal at this stage, with effects limited to those incurred by subducting a few large basement features that are not completely buried by the 100-400 m of trench-fill sediments. Where the ridge has recently been subducted, the tectonic interaction of the ridge is more pronounced. The toe of the small accretionary complex appears to have collapsed as the ridge passed beneath the lower trench slope and filled part of the large bathymetric depressions of the ridge axis that have not been filled by trench sediments. Comparison of the middle and upper slopes along the margin implies a large control by the continental crust on the morphology of the middle and upper slopes. Examination of the Taitao Ridge section shows considerable contrast in structure with the northern line. Here, much of the consinental slope is composed of a large igneous body thought to be ophiolite, and the thick trench-fill sequence shows no compressional deformation or active accretion.

Cande, SC, Haxby WF.  1991.  Eocene Propagating Rifts in the Southwest Pacific and Their Conjugate Features on the Nazca Plate. Journal of Geophysical Research-Solid Earth. 96:19609-19622.   10.1029/91jb01991   AbstractWebsite

We have mapped a 1200 km long NW-SE trending lineament in Seasat and Geosat radar altimeter data crossing a remote portion of the Southwest Pacific Basin. This lineament runs obliquely both to the fracture zones (FZs) and magnetic lineations between the Austral and Agassiz FZs. By examining shipboard magnetics, gravity, and bathymetric profiles in this region and in the conjugate regions of the Nazca plate, we identify this feature as the site of a series of small ridge jumps, highly asymmetrical spreading and small propagating rifts, during the mid-to-late Eocene (chron C21 to chron C13). Between the Austral and Agassiz FZs there is roughly 250 to 350 km of missing Pacific plate crust, which must have been transferred to the Nazca plate by the propagating rifts and small ridge jumps. On the Nazca plate, the conjugate area to the gravity lineament is now being subducted beneath the Chile Trench. North of the Challenger FZ this area corresponds to a region of undecipherable magnetic anomalies. South of the Challenger FZ, there is evidence for a small 50 km ridge jump offshore of the Chile Trench. This small ridge jump by itself is not sufficient to account for the missing crust on the Pacific plate, and we conclude that there must have been repeated small ridge jumps at the same site. One consequence of these ridge jumps is that crust on the Nazca plate entering the trench is not as old as would be predicted by simply mirror imaging the anomaly pattern on the Pacific plate.

Shaw, PR, Cande SC.  1990.  High-Resolution Inversion for South-Atlantic Plate Kinematics Using Joint Altimeter and Magnetic Anomaly Data. Journal of Geophysical Research-Solid Earth and Planets. 95:2625-2644.   10.1029/JB095iB03p02625   AbstractWebsite

We present an inversion for plate kinematics that solves for finite rotation parameters using fracture zone (FZ) and magnetic anomaly location data jointly. We define misfit functions that incorporate properties unique to each data type; in particular, the FZ misfit function does not depend upon alignment of conjugate FZ traces in the same way as magnetic lineations under the finite rotations. This property is useful for FZ locations, in which the signals on conjugate sides of the ridge may include systematic differences, or where data from one side of the ridge are sparse or missing. Formal error bounds estimated for the pole parameters show that the magnetic and FZ data are complementary in their information content. Error bounds computed for the joint inversion are substantially smaller than for either the FZ or magnetics data used separately, indicating that simultaneous use of the data in an inversion is crucial. We apply this method to Seasat altimeter data and magnetic anomaly picks in the South Atlantic. We solve for finite poles corresponding to magnetic anomalies 5, 6, 8, 13, 21, 22, 25, 30, 33, 33r, and 34; these define a smooth path over the past 84 m.y. indicating that the plate motions have not been as erratic as found previously.

Batiza, R, Fox PJ, Vogt PR, Cande SC, Grindlay NR, Melson WG, Ohearn T.  1989.  Morphology, Abundance, and Chemistry of near-Ridge Seamounts in the Vicinity of the Mid-Atlantic Ridge Approximately 26-Degrees-S. Journal of Geology. 97:209-220. AbstractWebsite
Cande, SC, Labrecque JL, Larson RL, Pittman III WC, Golovchenko X.  1989.  Magnetic lineations of the world's ocean basins. :13-13., Tulsa, OK, United States (USA): Am. Assoc. Pet. Geol., Tulsa, OK Abstract