Sanchez, C. M., C. S. Fulthorpe, and R. J. Steel, Miocene shelf-edge deltas and their impact on deepwater slope progradation and Slope morphology, Northwest Shelf of Australia, Basin Res., (in press), 2012, #2460
Sanchez, C. M., C. S. Fulthorpe, and R. J. Steel, Middle Miocene-Pliocene siliciclastic influx across a carbonate shelf and influence of deltaic sedimentation on shelf construction, Northern Carnarvon Basin, Northwest Shelf of Australia, Basin Res., (in press), 2012, #2461
Fulthorpe, C. S., K. Hoyanagi, P. Blum, and Expedition 317 Scientists, Proc. IODP, 317, Integrated Ocean Drilling Program Management International, Inc., 2011, doi:10.2204/iodp.proc.317.2011, #2349
Fulthorpe, C. S., K. Hoyanagi, P. Blum, and Expedition 317 Scientists, IODP Expedition 317 explores the record of sea-level change off New Zealand, Scientific Drilling, 12, 2011, doi:10.2204/iodp.sd.12.01.2011, #2459
Liu, C., C. S. Fulthorpe, J. A. Austin, and C. M. Sanchez, Geomorphologic indicators of sea level and lowstand paleo-shelf exposure on Early-Middle Miocene sequence boundaries, Marine Geol., 280, 182-194, 2011, doi:10.1016/j.margeo.2010.12.010, #2331 
Relationships between clinoformal sequence boundaries and relative sea level change, in particular locations of lowstand shorelines and amounts of paleo-shelf exposure, represent a key topic in sequence stratigraphy. This paper uses 3D seismic data to analyze morphologies of two sequence boundaries in the early-middle Miocene section of the Northern Carnarvon Basin of the Australian Northwest Shelf. A step-like discontinuity is recognized on the outer paleo-shelf of sequence boundary DLS4 based on reflection truncation and seismic facies change. Vertical offset at this step varies from ~ 7 to 65 m, increasing along strike from SW to NE. The trace of this discontinuity comprises both linear and arcuate segments in coherence time slices. Isolated mounds and small platforms also occur on this sequence boundary, basinward of the discontinuity. Underlying sub-sequence boundary DLS3.1 displays a smaller step-like discontinuity, together with U- and V-shaped incisions as well as numerous, isolated depressions, the latter occurring within two large arcuate, concave-basinward features on coherence slices. We discuss several possible origins for these discontinuities. We conclude that step-like discontinuities on DLS4 and DLS3.1 represent buried wave-cut terraces or sea cliffs. Erosion is presumed to have occurred at or near ambient sea level. The incisions of DLS3.1 are karst. Together, these interpretations imply significant lowstand paleo-shelf exposure of early-middle Miocene sequence boundaries.
Camoin, G., A. Droxler, K. G. Miller, and C. S. Fulthorpe, Quaternary sea-level changes: Records and processes, Global and Planetary Change, 66, v-vii, 2009, 1 citation, doi:10.1016/j.gloplacha.2008.11.003, #2021
This special issue of Global and Planetary Change focuses on records, processes and modeling of Quaternary sea-level changes. The following set of papers arose from a multidisciplinary international Symposium entitled « SEALAIX'06: Sea-level changes: records, processes and modeling » which was held in Giens, France, from September 25th to September 29th, 2006 and convened by Gilbert Camoin, André Droxler, Craig Fulthorpe and Ken Miller. The Symposium was sponsored by the International Association of Sedimentologists (IAS), the Society for Sedimentary Geology (SEPM), TOTAL, the CNRS (Centre National de la Recherche Scientifique), the Provence-Alpes-Côte d'Azur Region, and the French Association of Sedimentologists (Association des Sédimentologistes Français, ASF). All sponsors are gratefully acknowledged.
Scientific themes of SEALAIX'06 included the records, sedimentary processes, and modeling of sea-level changes in carbonate, siliciclastic and mixed margins and deep-sea settings. The Symposium was structured around four themes corresponding to distinctive modes of the Phanerozoic Earth system: 1) Quaternary sea-level changes, 2) Icehouse Earth sea-level changes (last 33 Ma), 3) Greenhouse Earth sea-level changes (250-33 Ma) and 4) Paleozoic sea-level changes. SEALAIX'06 was attended by 160 participants from 21 countries (including 17 funded students and young scientists). Participants represented diverse specialities (e.g., sedimentology, geochemistry, geophysics, modeling, geodynamics, geomorphology, paleoceanography and biology) and research interests. Five keynote presentations, 45 short talks and 75 posters were presented. Workshop sessions were held on: 1) current knowledge, 2) future issues, 3) controversies regarding sea-level records, processes, and modeling, and 4) strategies to address sea-level changes within international Earth Sciences programs (e.g., IODP, IMAGES, PAGES, MARGINS). Abstracts were assembled in a Special Publication of the Association of French Sedimentologists (Camoin et al., 2006).
Fulthorpe, C. S., and J. A. Austin, Assessing the significance of along-strike variations of middle to late Miocene prograding clinoformal sequence geometries beneath the New Jersey continental shelf, Basin Res., 20, 269-283, 2008, 1 citation, doi:10.1111/j.1365-2117.2008.00350.x, #1937
Seismic mapping of high-resolution multichannel seismic profiles along the New Jersey margin illustrates how characteristics of middleâlate Miocene clinoformal sequence boundaries (SBs) change markedly along strike in presumed response to local depositional and erosional processes. Most SBs converge from SW to NE, in part as a result of the influence of underlying basin morphology on accommodation space, but also in response to differential subsidence and presumed along-strike variations in sediment supply from the adjacent margin. The curvature of clinoform breaks, historically viewed as marking palaeo-shelf edges, is variable and such breaks are rarely sharp. Gently curved palaeo-shelf/slope transitions cannot be assigned precise palaeobathymetric significance and probably instead reflect post-depositional sediment reworking. The amount of erosional truncation landward of clinoform breaks varies significantly. Documented along-strike variability in SB morphology occurs, even though middleâlate Miocene palaeo-shelf edges are nearly linear in plan view. Therefore, such linearity cannot be a product of uniform sedimentary processes and/or accumulation along strike, but instead reflects elongation of depocentres of originally variable cross-sectional geometry, possibly with the assistance of along-strike currents. The observed lateral geometric heterogeneity of Neogene sequences can exert profound and unwanted influences on the outcome of scientific drilling intended to calibrate seismic stratigraphic interpretations in the absence of sufficient three-dimensional (3D) seismic control.
Fulthorpe, C. S., G. Camoin, K. G. Miller, and A. Droxler, Pre-Quaternary sea-level changes: Records and processes, Basin Res., 20, 161-162, 2008, 1 citation, doi:10.1111/j.1365-2117.2008.00365.x, #1987
Fulthorpe, C. S., K. G. Miller, A. Droxler, S. Hesselbo, G. Camoin, and M. A. Kominz, Drilling to decipher long-term sea-level changes and effects: A joint consortium for ocean leadership, ICDP, IODP, DOSECC, and Chevron workshop, Scientific Drilling, 6, 19-28, 2008, doi:10.2204/iodp.sd.6.02.2008, #2020
Mountain, G. S., R. L. Burger, H. Delius, C. S. Fulthorpe, J. A. Austin, D. S. Goldberg, M. S. Steckler, C. M. G. McHugh, K. G. Miller, D. H. Monteverde, D. L. Orange, and L. F. Pratson, The long-term stratigraphic record on continental margins, in Continental Margin Sedimentation: From Sediment Transport to Sequence Stratigraphy, edited by C. A. Nittrouer, J. A. Austin, M. E. Field, J. H. Kravitz, J. P. M. Syvitski, and P. L. Wiberg. Int. Assoc. Sedimentologists Spec. Publ., 37, 381-458, 2007, #1894
Pratson, L. F., C. A. Nittrouer, P. L. Wiberg, M. S. Steckler, J. B. Swenson, D. A. Cacchione, J. A. Karson, A. B. Murray, M. A. Wolinsky, T. P. Gerber, B. L. Mullenbach, G. A. Spinelli, C. S. Fulthorpe, D. B. O'Grady, G. Parker, N. W. Driscoll, R. L. Burger, C. Paola, D. L. Orange, M. E. Field, C. T. Friedrichs, and J. J. Fedele, Seascape evolution on clastic continental margins, in Continental Margin Sedimentation: From Sediment Transport to Sequence Stratigraphy, edited by C. A. Nittrouer, J. A. Austin., M. E. Field, J. H. Kravitz., J. P. M. Syvitski, and P. L. Wiberg Int. Assoc. Sedimentologists Spec. Publ., 37, 339-380, 2007, #1895
Gulick, S. P. S., J. A. Goff, J. A. Austin, C. R. Alexander, S. Nordfjord, and C. S. Fulthorpe, Basal inflection-controlled shelf-edge wedges off New Jersey track sea-level fall, Geology, 33, 429-432, 2005, 13 citations, doi:10.1130/G21310.1, #1741
A key marker for examining the latest Pleistocene history of the New Jersey margin is the high-amplitude, long-recognized R-horizon reflector. This time-transgressive surface was formed 47â 33 ka and represents the integrated topographic and bathymetric surface developed during the complicated sea-level oscillation associated with the regression that preceded the Last Glacial Maximum (LGM). From landward to seaward across the outer shelf, the R reflector changes from subhorizontal, in most locations <9 m beneath the modern seafloor, to seaward dipping, forming the base of two offlapping sediment wedges: the previously described outer-shelf wedge and a deep-shelf wedge seaward of it. This transition occurs across two inflection zones, where the dip of the R reflector steepens seaward, that can be traced for tens of kilometers along strike and mark the landward limits of these wedges. These inflection zones are possibly former wave-dominated shorefaces; these represent the primary topographic elements present during the last regression. We speculate that these inflections dictated both the locations for deposition of the two prograding, offlapping wedges that developed during the complex sea-level fall prior to the LGM and their successive erosion before and after the LGM. We suggest that such inflection zones and their associated wedges are important markers of regression in clastic-dominated outer-shelf settings along passive margins.
Lu, H., C. S. Fulthorpe, P. Mann, and M. A. Kominz, Miocene-Recent tectonic and climatic controls on sediment supply and sequence stratigraphy: Canterbury basin New Zealand, Basin Res., 17, 311-328, 2005, 9 citations, doi:10.1111/j.1365-2117.2005.00266.x, #1757
Carter, R. M., C. S. Fulthorpe, and H. Lu, Canterbury Drifts at Ocean Drilling Program Site 1119, New Zealand: Climatic modulation of southwest Pacific intermediate water flows since 3.9 Ma
, Geology, 32, 1005-1008, 2004, 6 citations, doi:10.1130/G20783.1, #1758
We provide a record of variations in southwest Pacific Ocean intermediate water flow that shows a strong correlation between periods of vigorous flow and warm climate phases. Ocean Drilling Program Site 1119, located at 395 m water depth on the upper continental slope east of New Zealand, penetrated 514 m of silts and silty clays (glacial deposits) punctuated by muds and episodic 0.02ââ¬â1.2-m-thick terrigenous sands (interglacial deposits). The natural gamma-ray record reflects the waxing and waning of the South Island ice cap since 3.91 Ma. Below 86.19 m composite depth, the succession comprises drift sediments deposited from north-flowing intermediate Subantarctic Mode Water (SAMW, ∼250ââ¬â800 m depth) and Antarctic Intermediate Water (∼800ââ¬â1100 m depth). A change from the deposition of large, low-energy drifts on the middle slope to smaller, higher-energy drifts on the upper slope coincided with global climatic deterioration that occurred after ca. 3.25 Ma. This change marks an upward expansion of intermediate cold waters, perhaps caused by the inception of the Subantarctic Front and the consequent commencement of Southland Currentââ¬âdriven SAMW flow.
Fulthorpe, C. S., and J. A. Austin, Shallowly buried, enigmatic seismic stratigraphy on the New Jersey outer shelf: Evidence for latest Pleistocene catastrophic erosion?, Geology, 32, 1013-1016, 2004, 13 citations, doi:10.1130/G20822.1, #1709
Chirp seismic profiles reveal a prominent seismic facies boundary 0â20 m below the seafloor within an 8.6 à 10.2 km area of the New Jersey outer shelf. This irregular boundary separates seismically transparent facies from underlying stratified facies. The irregularities form two populations of incisions trending northeast and east-northeast. Stratified blocks within the transparent facies, occasionally within presumed incisions, together with lithologic evidence, indicate that some of the transparent facies was formed by disruption of the stratified facies. Preservation of steep (50°â90°) incision flanks implies that deposition of the transparent facies closely followed disruption. Catastrophic erosion and redeposition following the multiple breaching of glacial lake dams to the north ca. 19â12 ka constitute the likeliest mechanisms both for producing facies-boundary incisions and emplacing the transparent facies, implying that local forcing can generate erosional unconformities on periglacial shelves in the absence of base-level change. This facies boundary adds complexity to the already complex, shallowly buried stratigraphic record of the last glacio-eustatic cycle on the New Jersey continental shelf, long considered typical of periglacial shelves worldwide.
Lu, H., and C. S. Fulthorpe, Controls on sequence stratigraphy of a middle-Miocene-Holocene, current-swept, passive margin: offshore Canterbury Basin, New Zealand, Geol. Soc. Amer. Bull., 116, 1345-1366, 2004, 13 citations, doi:10.1130/B2525401.1, #1688
The offshore Canterbury Basin exemplifies sequence development on a prograding passive margin influenced strongly by submarine currents. Nineteen middle MioceneâHolocene, regional, sequence-bounding unconformities are interpreted by using high-resolution multichannel seismic data. The sequences can be grouped into larger units based on seismic geometry and facies that reflect different combinations of controls on sequence architecture.
Correlation with oxygen isotope records suggests that eustasy controls the timing of sequence boundaries. The number of sequences is similar to that of coeval cycles on a temperature-adjusted, Miocene and early Pliocene δ18O record. The late PlioceneâPleistocene sequence record is of lower frequency than the isotopic record of this period, either because of the limitations of seismic resolution or because of removal of sequence boundaries by erosion associated with high-amplitude eustasy. However, the last two sequence boundaries correlate well with the last two 100 k.y. isotopic cycles.
In contrast, sequence architecture is influenced strongly by local processes. Along-strike currents create large, elongate sediment drifts that control sequence thickness; current erosion in drift moats forms diachronous unconformities. Drifts focus deposition on the slope, reducing the rate of basinward advance of the shelf edge, but increasing that of the slope toe, thereby reducing slope inclination. Replacement of along-strike processes by downslope processes increases rates of shelf-edge progradation, and the slope steepens as the reduced accommodation space over the expanded slope is filled. Clinoform geometries along strike from active drifts suggest that currents might influence clinoform formation even in locations lacking seismic evidence of current reworking.
Burger, R. L., C. S. Fulthorpe, and J. A. Austin, Effects of triple junction migration and glacioeustatic cyclicity on evolution of upper slope morphologies, offshore Eel River Basin, northern California, Marine Geol., 199, 307-336, 2003, 8 citations, doi:10.1016/S0025-3227(03)00194-4, #1642
The upper continental slope of the Eel River Basin is affected both by uplift and seismicity associated with the northward-migrating Mendocino Triple Junction (MTJ) and by glacioeustatic fluctuations. As a result, seismically imaged slope sequences vary dramatically along strike. The southern slope is dominated by the Humboldt Slide, a stack of nine deformed sequences. Older, undeformed sequences thicken landward, while slide sequences maintain a constant travel-time thickness. Onset of deformation was abrupt. Within the slide, reflector amplitudes alternate: high-amplitude reflectors are wavy to shingled, and suggest increasing deformation with depth. Low-amplitude reflectors are sub-parallel to wavy throughout. High- and low-amplitude sequence âcoupletsâ suggest repetitive deposition of contrasting lithologies, a response we ascribe to late Pleistocene glacioeustatic cyclicity. If each âcoupletâ represents a 100 kyr late Pleistocene sea-level cycle, then Humboldt Slide deformation began 450 ka. This is approximately coeval with onset of deformation on the adjacent shelf 500 ka, previously attributed to uplift and seismicity associated with northward encroachment of the MTJ. We believe migration of the MTJ triggered the slide, and is the cause for continuing deformation today, by sediment creep along internal glide planes. North of the Humboldt Slide, we interpret an upper slope anticline as a seaward extension of the Little Salmon Fault Zone (LSFZ) previously identified landward. Both faulting and folding extend to the seafloor, indicating that deformation continues. An adjacent buried anticline suggests that deformation has also jumped northward within the LSFZ on some parts of the upper slope. North of the LSFZ, the slope is dominated by downslope-trending channels and gullies. These features are v-shaped, vertically stacked, and increase in depth downslope. They are mostly infilled; their physiographic expression is generally subdued by sediment draping. Channel fills generally consist of basal high-amplitude reflectors, overlain by reflectors of lower amplitudes. Several large channels on older surfaces are concentrated near the northern end of the seismic coverage; smaller channels are more evenly distributed along the margin on younger surfaces. Channels also extend increasingly landward on progressively younger surfaces, indicating migration in that direction with time. These incisions are clearly inactive during highstands, as at Present; slope deposition today is dominated by draping of hemipelagic sediments. Channels form and migrate landward through headward erosion during base-level changes, when both shoreface and fluvial sediment sources are more proximal to the upper slope. The increasing lateral distribution of channels through time supports an increase in shoreface erosion north of the LSFZ. A possible explanation is a known decrease in fluvial sediment input from the north, combined with MTJ-related uplift in the south. Along-strike contrasts in upper-slope sequence morphology in the southern Eel River Basin are clearly a function of both regional tectonism and proximity to sediment sources, influenced by base-level changes. Humboldt Slide sequences, while deformed, are continuously influenced by systematic lithological variations occurring as a result of glacioeustatic cycles. Effects of base-level changes similarly control the distribution and fill of incisions on the northern slope. All of these observations reinforce previous seismic investigations of the offshore Eel River Basin shelf, and confirm that the competing effects of tectonism and glacioeustacy on the preservation of continental margin stratigraphy can be differentiated.
Lu, H., C. S. Fulthorpe, and P. Mann, Three-dimensional architecture of shelf-building sediment drifts in the offshore Canterbury Basin, New Zealand, Marine Geol., 193, 19-47, 2003, 18 citations, doi:10.1016/S0025-3227(02)00612-6, #1612
A grid of high-resolution, multichannel seismic profiles from the offshore Canterbury Basin, New Zealand, reveals that at least 11 large (up to 1000 m thick, >50 km long, along-strike, and 20 km wide, down-dip) elongate sediment drifts developed within the lower Miocene to Recent shelf-slope sediment prism. The drifts overlie a condensed section of late Eocene to late Oligocene limestone and cover an area of 5000 km2. The drifts were deposited in water depths of 300â750 m, probably by a northward-flowing contour current, and aggraded to shelf depths. The drifts exhibit mounded morphologies with channel-like moats along their landward flanks. Erosion of the landward flanks creates prominent unconformities; these unconformities are diachronous and, therefore, not sequence boundaries. The internal architecture of the drifts defines two end members of elongate drift, which we describe as simple and complex. Early (early to middle Miocene) simple drifts are small (<400 m thick, 10â28 km long and several km wide) and concentrated in the southern part of the survey area. Drift thickness increased as the shelf aggraded and the locus of drift development migrated northeastward through time. Late (late Miocene to Recent) simple drifts are, therefore, larger (up to 1000 m thick, >50 km long and up to 20 km wide) and occur in the northeastern part of the survey area. These late, simple elongate drifts are subdivided into three parts (base, core, and crest) based on seismic facies. These facies form in response to progressive confinement of current flow within the moat. Complex drifts may be multi-crested or multistage. Multi-crested drifts form in response to rapid lateral shifts in position of the moat, perhaps associated with relative sea-level change, modulated by paleoslope inclination and orientation. Such drifts, together with the observation that several drifts were often active simultaneously, indicate that flow patterns were complex and involved multiple pathways. Multistage drifts comprise superimposed subdrifts whose retrogradational and progradational stacking patterns indicate fluctuations in the rate of sediment supply. Complex drift formation may require intermediate shelf relief: high enough to sustain drift development during changes in sea level and rate of sediment supply, but low enough so that such changes are still able to influence moat position. In addition, coeval climatic cooling may amplify changes in sea level, current intensity and sediment supply, thereby contributing to complex drift formation.
Burger, R. L., C. S. Fulthorpe, J. A. Austin, and S. P. S. Gulick, Lower Pleistocene to present structural deformation and sequence stratigraphy of the continental shelf, offshore Eel River Basin, northern California, Marine Geol., 185, 249-281, 2002, 15 citations, doi:10.1016/S0025-3227(02)00196-2, #1595
Seismic stratigraphic sequences and deformational features are mapped beneath the continental shelf of the offshore Eel River Basin of northern California, using a closely spaced, high-resolution multichannel seismic grid. Geometries of sequences and morphologies of bounding unconformities reflect competing tectonic and glacioeustatic influences, producing shifting sedimentation patterns in the offshore basin during the last 1 Myr. Estimated timing of unconformity formation correlates generally with a deep-ocean global δ18O curve, both before and after a 500-kyr transition from 41-kyr to 100-kyr dominated cycles. We suggest that glacioeustatic fluctuations are the dominant control on unconformity formation basinwide. However, regional tectonic influences on sequence development are also observed. Folding associated with GordaâNorth America Plate convergence ended progressively from south to north between 1.0 Ma and 500 ka, in response to northward migration of the Mendocino Triple Junction (MTJ). Since 500 ka, continued encroachment of the MTJ produces rotation of preexisting structures, uplift of the Table Bluff Anticline (TBA), related periods of channel incision south of the TBA, and generally reduced sediment preservation across the shelf. MTJ-related uplift may also have induced formation of Eel Canyon. Over the past 1.0 Myr, a dominant northern sediment source becomes progressively less important; a southern source, probably the paleo-Eel River, has become dominant since 750 ka. Seismic unconformities fall into two categories: (1) irregular surfaces of limited mappable extent, interpreted as incision/exposure surfaces forming during relative sea-level lowstands, and (2) smooth, laterally extensive regional unconformities, interpreted as ravinement surfaces that erode lowstand surfaces in all but deeply incised areas during sea-level transgressions. A sequence stratigraphic model for sediment deposition and preservation on the Eel River shelf predicts that preserved sediment on the Eel margin is dominated by fluvially derived highstand silts and muds, deposited by longshore-directed currents and waves. Lowstand sediments are preserved only in fluvial channels infilled during late lowstand/early transgression. Preserved transgressive sediments are likely limited to a thin veneer of well-sorted coarse sediment or shell debris, deposited above the transgressive ravinement. Future deep coring will be required to confirm these predictions.
He, L., R. T. Buffler, and C. S. Fulthorpe, Late Cenozoic sequence stratigraphy, Main Pass area, northeastern Gulf of Mexico, Trans., Gulf Coast Assn. Geol. Socs., 52, 385-394, 2002, #1598
Burger, R. L., C. S. Fulthorpe, and J. A. Austin, Late Pleistocene channel incisions in the southern Eel River basin, northern California: Implications for tectonic vs. eustatic influences on shelf sedimentation patterns, Marine Geol., 177, 317-330, 2001, 21 citations, doi:10.1016/S0025-3227(01)00166-9, #1547
High-resolution multichannel seismic (MCS) profiles from the southern offshore Eel River Basin off northern California show multiple, superimposed buried channels beneath the continental shelf. These channels display consistent southwest orientations. Their dendritic map pattern and low but consistent cross-shelf gradients suggest that they formed by fluvial erosion during periods of shelf exposure associated with relative sea-level lowstands. All of the channels were incised after 500 ka, the age of the onshoreâoffshore Hookton Datum. Their frequency of incision exceeds that of known glacioeustatic lowstands since 500 ka, confirming that some of the surfaces must have formed during relative lowstands initiated by local tectonic uplift.
Sedimentation patterns in the Eel River Basin shift dramatically in response to relative sea-level fluctuations. Today, sediments from the Eel River move north and west on the shelf, in response mainly to large winter storm events. In contrast, fluvial incision on the exposed shelf during relative lowstands directed sediments to the southwest, most likely into the head of the Eel Canyon. Shelf channels were probably fed not only by ancestral rivers, but also by local uplifts like the Table Bluff Anticline. Increases in gradient and channel depths at the southern end of the MCS coverage indicate that canyon-forming processes modified fluvial channels as they converge towards embayments near the head of the Eel Canyon. Cyclic recurrence and consistent orientation of these channels demonstrate that the Eel Canyon has been extant through numerous relative sea level cycles, and is perhaps as old as 500 ka.
Gomez, B., C. S. Fulthorpe, L. M. Carter, K. Berryman, G. Growne, M. Green, M. Hicks, and N. Trustrum, Continental margin sedimentation to be studied in New Zealand, Eos, Trans. Amer. Geophys. Un., 82, 161, 166-67, 2001, doi:10.1029/01EO00082, #1564
Duncan, C. S., J. A. Goff, J. A. Austin, and C. S. Fulthorpe, Tracking the last sea level cycle: Seafloor morphology and shallow stratigraphy of the latest Quaternary New Jersey middle continental shelf, Marine Geol., 170, 395-421, 2000, 48 citations, doi:10.1016/S0025-3227(00)00082-7, #1505
Seafloor geomorphology and surficial stratigraphy of the New Jersey middle continental shelf provide a detailed record of sea-level change during the last advance and retreat of the Laurentide ice sheet (120 kyr B.P. to Present). A NWâSE-oriented corridor on the middle shelf between water depths of 40 m (the mid-shelf âpaleo-shoreâ) and 100 m (the Franklin âpaleo-shoreâ) encompasses 500 line-km of 2D Huntec boomer profiles (500â3500 Hz), an embedded 4.6 km2 3D volume, and a 490 km2 swath bathymetry map. We use these data to develop a relative stratigraphy. Core samples from published studies also provide some chronological and sedimentological constraints on the upper <5 m of the stratigraphic succession.
The following stratigraphic units and surfaces occur (from bottom to top): (1) âRâ, a high-amplitude reflection that separates sediment >46.5 kyr old (by AMS 14C dating) from overlying sediment wedges; (2) the outer shelf wedge, a marine unit up to 50 m thick that onlaps âRâ; (3) âChannelsâ, a reflection sub-parallel to the seafloor that incises âRâ, and appears as a dendritic system of channels in map view; (4) âChannelsâ fill, the upper portion of which is sampled and known to represent deepening-upward marine sediments 12.3 kyr in age; (5) the âTâ horizon, a seismically discontinuous surface that caps âChannelsâ fill; (6) oblique ridge deposits, coarse-grained shelly units comprised of km-scale, shallow shelf bedforms; and (7) ribbon-floored swales, bathymetric depressions parallel to modern shelf currents that truncate the oblique ridges and cut into surficial deposits.
We interpret this succession of features in light of a global eustatic sea-level curve and the consequent migration of the coastline across the middle shelf during the last 120 kyr. The morphology of the New Jersey middle shelf shows a discrete sequence of stratigraphic elements, and reflects the pulsed episodicity of the last sea-level cycle. âRâ is a complicated marine/non-marine erosional surface formed during the last regression, while the outer shelf wedge represents a shelf wedge emplaced during a minor glacial retreat before maximum Wisconsin lowstand (i.e., marine oxygen isotope stage 3.1). âChannelsâ is a widespread fluvial subarial erosion surface formed at the late Wisconsin glacial maximum 22 kyr B.P. The shoreline migrated back across the mid-shelf corridor non-uniformly during the period represented by âChannelsâ fill. Oblique ridges are relict features on the New Jersey middle shelf, while the ribbon-floored swales represent modern shelf erosion. There is no systematic relationship between modern seafloor morphology and the very shallowly buried stratigraphic succession.
Fulthorpe, C. S., J. A. Austin, and G. S. Mountain, Morphology and distribution of Miocene slope incisions off New Jersey: Are they diagnostic of sequence boundaries?, Geol. Soc. Amer. Bull., 112, 817-828, 2000, 16 citations, doi:10.1130/0016-7606(2000)112<817:MADOMS>2.0.CO;2, #1436
Fulthorpe, C. S., J. A. Austin, and G. S. Mountain, Buried fluvial channels off New Jersey: Did sea-level lowstands expose the entire shelf during the Miocene?, Geology, 27, 203-206, 1999, 27 citations, doi:10.1130/0091-7613(1999)027<0203:BFCONJ>2.3.CO;2, #1417
High-resolution multichannel seismic profiles from the New Jersey continental margin reveal that some middle to late Miocene sea-level falls exposed the entire continental shelf. At several sequence boundaries, fluvial channels occur landward of the clinoform breakpoints that mark paleo-shelf edges. The seismically observed progradation therefore resulted from sediment delivery to the shelf edge by rivers during lowstands. Suspended sediment crossing the relatively shallow water (30â40 m) shelf also fostered progradation during highstands. River systems reaching the outermost shelf were small and closely spaced; they approximated a line source of sediment. This finding helps to explain the observed linearity of Miocene shelf edges. Although these systems discharged near clinoform tops, they did not form canyons incising the clinoforms; such canyons were rare in this active depositional setting, in contrast to their prevalence on the modern continental slope.
Carter, R. M., C. S. Fulthorpe, and T. R. Naish, Sequence concepts at seismic and outcrop scale: The distinction between physical and conceptual stratigraphic surfaces, Sedimentary Geol., 122, 165-179, 1998, 31 citations, doi:10.1016/S0037-0738(98)00104-3, #1449
The sequence stratigraphic terms maximum flooding surface and downlap surface, as currently applied, are ambiguous. Examples of these intra-sequence surfaces are summarised from high frequency mid-Pleistocene sequences and from a CretaceousâRecent seismic megasequence, both from New Zealand. At any one locality, a mid-Pleistocene sequence contains up to four stratal discontinuities, in ascending order: the sequence boundary, ravinement surface, local flooding surface and downlap surface. These physical surfaces, which occur in outcrop, are regionally diachronous and should be differentiated from theoretical isochronous horizons such as the time of maximum flooding (horizon corresponding to maximum shoreline transgression) and the time of peak eustatic or local relative sea-level (horizons corresponding to the highpoint of the eustatic and relative sea-level cycles, respectively). In seismic studies, the boundary between the transgressive and highstand systems tracts is usually located at the downlap surface. On the basis of a major thermo-tectonic sea-level cycle in the Canterbury Basin, it is shown that the downlap surface is not a single regional surface, and that the change in slope associated with toes of successive prograding clinoforms rises in stratigraphic height basinwards. The downlap surface therefore does not usually coincide with the maximum flooding horizon. In PlioâPleistocene cyclothems, a discrete unit â the mid-cycle shellbed â straddles the contact between the transgressive and highstand systems tracts. This unit might be classified within its own systems tract (the condensed section systems tract; CSST). Alternatively, the position of the boundary between the transgressive and highstand systems tracts can remain unspecified or unknowable.
Fulthorpe, C. S., and J. A. Austin, Anatomy of rapid margin progradation: Three-dimensional geometries of Miocene clinoforms, New Jersey margin, AAPG Bull., 82, 251-273, 1998, 39 citations, #1272
Documentation of along-strike variations in the morphologies of continental-margin clinoforms is essential for understanding mechanisms of progradation, one of the fundamental relationships between depositional processes and preserved stratigraphy. Maps based on a grid of commercial multichannel seismic data offshore New Jersey, extending more than 70 km along strike and approximately 50 km downdip, reveal the three-dimensional morphology and evolution of four buried surfaces correlated with middle-upper Miocene sequence boundaries calibrated by drilling on the adjacent continental slope.
Fulthorpe, C. S., (Book review): Geology of the United States Seafloor: The View from GLORIA, by J. V. Gardner, M. E. Field and D. C. Twitchell, Eos, Trans. Amer. Geophys. Un., 78, 249, 1997, doi:10.1029/97EO00168, #1314
Austin, J. A., C. S. Fulthorpe, G. S. Mountain, D. L. Orange, and M. E. Field, Continental-margin seismic stratigraphy: Assessing the preservation potential of heterogeneous geologic processes operating on continental shelves and slopes, Oceanography, 9 (3), 173-177, 1996, 22 citations, #1233
Fulthorpe, C. S., R. M. Carter, K. G. Miller, and J. Wilson, Marshall paraconformity: A mid-Oligocene record of the Antarctic cirumpolar current and coeval glacioeustatic lowstand?, Marine Petroleum Geol., 13, 61-77, 1996, 41 citations, doi:10.1016/0264-8172(95)00033-X, #837
The sedimentary fill of the Canterbury Basin, New Zealand, is the product of a long-term (80 Ma), tectonically controlled relative sea-level cycle with a megasequence geometry analogous to the sequence stratigraphic model of Vail (Am. Assoc. Petrol. Geol. Stud. Geol No. 27, 1, 1â10, 1987). The condensed section of the megasequence, resolvable in detail in outcrop and on seismic profiles, comprises a basin-wide pelagic to hemipelagic limestone interval. A regional mid-Oligocene unconformity, the Marshall Paraconformity, lies within the limestone interval onshore and correlates with hiatuses in at least two, and possibly three, offshore exploration wells and with a temporary lithological change from limestone to quartz sand at a fourth. Strontium isotopic age estimates confirm that a 2â4 Ma hiatus is associated with onshore outcrops of the Marshall Paraconformity (between 32 and 29 Ma), which correlates with the opening of the Pacific sector of the Southern Ocean and the postulated mid-Oligocene sea-level fall of Haq et al. (Science 235, 1156â1167, 1987; Spec. Publ. Soc. Econ. Paleonotol. Mineral. No. 42, 71â108, 1988). Lowering of base level, coupled with cooling and enhancement of current activity, may have caused the temporary cessation of limestone deposition and a regional hiatus. This hypothesis reconciles the apparently contradictory palaeogeographical evidence for a regional highstand. The Marshall Paraconformity may exemplify the signature by which similar glacio-eustatic events can be recognized in offshore platform facies.
Fulthorpe, C. S., G. S. Mountain, and K. G. Miller, Mapping Neogene depositional geometries, New Jersey continental slope, Leg 150 drilling area, Proc. Ocean Drill. Prog., Sci. Results, 150, 269-282, 1996, 10 citations, #1224
Mountain, G. S., J. E. Damuth, C. M. G. McHugh, J. M. Lorenzo, and C. S. Fulthorpe, Origin, reburial, and significance of a middle Miocene canyon, New Jersey continental slope, Proc. Ocean Drill. Prog., Sci. Results, 150, 283-292, 1996, 15 citations, #1178
Kendall, C. G.St.C., G. L. Whittle, C. S. Fulthorpe, P. Moore, T. D. Hickey, R. Cannon, and D. Hellmann, Geometric responses in Neogene sediments of offshore New Zealand: Simulated as products of changes in depositional base level driven by eustasy and/or tectonics, in Sequence Stratigraphy and Depositional Responses to Eustatic, Tectonic and Climatic Forcing, edited by B. U. Haq, Kluwer Academics Press, Dordrecht, Netherlands, 113-136, 1995, #1107
Mountain, G. S., J. M. Lorenzo, and C. S. Fulthorpe, Underway geophysics, Proc. Ocean Drilling Prog., Init. Rept., 150, 43-50, 1994, #1094
Carter, R. M., S. T. Abbott, C. S. Fulthorpe, D. W. Haywick, and R. A. Henderson, Application of global sea-level and sequence stratigraphic models in southern hemisphere Neogene strata from New Zealand, in Sea Level and Active Plate Margins, edited by D. MacDonald, Int. Assoc. Sedimentologists Spec. Publ., 12, 41-65, 1991, 80 citations, #1971
Fulthorpe, C. S., Geological controls on seismic sequence resolution, Geology, 19, 61-65, 1991, 30 citations, doi:10.1130/0091-7613(1991)019<0061:GCOSSR>2.3.CO;2, #1379
A seismic sequence analysis of the Canterbury basin, eastern South Island of New Zealand, has illustrated the roles of subsidence, sediment supply, and current activity as controls on sequence resolution and architecture during basin evolution. The rates of sediment supply and subsidence determine the background depositional regime (transgressive or regressive),and effectively determine the frequency response of the continental margin sedimentary section to input signals with a broad range of frequencies, including eustasy. A regressive (progradational) depositional regime and minimal current erosion favor the preservation of high-frequency sequences, particularly at fourth-order level. Under less favorable conditions, the record of sequences is incomplete or ambiguous. Such frequency response characteristics must be considered when inverting sequence records to derive the frequency of the input cyclicity, and when making global comparisons of regional sequence stratigraphic studies. Clastic basins with simple subsidence histories and uniform or increasing rates of sediment supply develop from a transgressive phase, characterized by ramplike major sequence boundaries, to a mature, progradational shelf phase with clinoform sequences and optimum sequence resolution. The mature phase constitutes the preferred setting for sequence stratigraphic analyses.
Fulthorpe, C. S., and R. M. Carter, Continental-shelf progradation by sediment-drift accretion, Geol. Soc. Amer. Bull., 103, 300-309, 1991, 28 citations, doi:10.1130/0016-7606(1991)103<0300:CSPBSD>2.3.CO;2, #1970
Multi-channel seismic profiles from the Canterbury Basin on the eastern margin of the South Island of New Zealand reveal the importance of current activity in shaping a Neogene shelf sediment prism. The shelf prism prograded across a broad, near-horizontal platform in water depths of 1,000 to 1,750 m. The platform was formed above a condensed section of late Eocene to late Oligocene limestones which overlie Cretaceous to Paleogene rift-fill and transgressive sediments.
The Neogene sediment prism contains sediment drifts which are as much as 25 km long and 15 km wide and extend up to 1,600 m (uncompacted) vertically. Individual drifts migrated westward and can be traced between dip profiles, revealing that the long axes of most are subparallel to the present coastline and shelf-edge. Channel-like features at the landward edges of the drifts correspond to residual space left between the landward-prograding off-shelf sediment drift and the adjacent shelf foreslope. Erosion or slow deposition characterized the foreslope. Progradation of the shelf was by the accretion of successive sediment drifts. Before ca. 11.5 Ma (= Pink Horizon), the shelf-edge-parallel drifts were distributed across the central part of the basin, whereas subsequently they were concentrated to the northeast.
The seismic architecture of the Neogene sediment prism results from the interplay of an abundant western sediment source and an offshore boundary current system. Present-day ocean circulation involves northward flow along the east coast of the South Island. The basin may have been subjected to a middle Miocene to late Pliocene phase of intensified flow, caused by local topographic enhancement and/or global paleoceanographic events. Current activity has played a crucial role in the sedimentary evolution of the Canterbury Basin Neogene shelf prism.
Austin, J. A., C. S. Fulthorpe, and the ODP Leg 101 Shipboard Scientific Party, Megabank found? Flanks record sea level, Geotimes, 30 (11), 12-15, 1985, #622