Late Quaternary development of left-bank-dominant levees in the Bounty Trough, New Zealand

Carter, L; Carter, R.M

doi:10.1016/0025-3227(88)90108-9

Cited by 50 publications

(17 citation statements)

References 11 publications

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“…The difference is likely to be influenced by the Coriolis deflection of channel overspill but the DWBC also may play a role, as attested by a significant increase in the height of the northern levee as it extends eastward into the main parth of the DWBC (Lewis,1994). A similar trend is recorded for Bounty Channel levees as they lead into the DWBC south of Chatham Rise [Carter and Carter, 1988].…”

Section: Central Basinmentioning

confidence: 93%

“…However, because the current is approaching the actively subducting boundary between the Pacific and Australian plates, this simplified vision of abyssal drift formation is complicated by deformational elements and by influxes of sediment from the rising mountain ranges and volcanoes of New Zealand. Indeed, just south of the area studied there is one major sediment input via Bounty Channel [Carter and Carter, 1988], and in the middle of the region there is a second via Hikurangi Channel (Figure 1). In addition, the whole area is periodically blanketed with ash from the Central Volcanic Zone of New Zealand's North Island.…”

Section: Deep Western Boundary Currentsmentioning

confidence: 99%

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Development of sediment drifts approaching an active plate margin under the SW Pacific Deep Western Boundary Current

Carter¹,

McCave²

1994

Paleoceanography

108

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The abyssal Pacific Ocean is fed by a 1000 km wide, deep western boundary current (DWBC) that flows northward along the continental margin, east of New Zealand. Between the passive margin of Chatham Rise and the subduction zone of Kermadec Trench, a distance of 1200 km, the DWBC has formed a suite of sediment drifts over a depth range of 2200–5700 m. Airgun and 3.5‐kHz profiles record a variety of drift types that reflect regional variations in bathymetry, sediment supply, and the tectonic/volcanic framework. On Chatham Rise the DWBC has deposited a sinuous, linear body along the south flank (3000 m), an extensive apronlike drift on the north flank (2200–4500 m), and a ridgelike drift about the rise base (4500–5200 m). The flow has also deposited a body of sediment over 400 km long within a moat at the base of the nearby Louisville Seamount Chain. Further downcurrent, the 250 km long Rekohu Drift (3600–4190 m) has developed northward to 39°S. South of this latitude, drifts comprise mainly reworked pelagic/hemipelagic material and sediment transported from distant southerly sources. In contrast, drifts north of 39°S have received a major injection of terrigenous sediment from Hikurangi Channel which runs 1400 km from New Zealand, eastward across the Hikurangi Plateau to disgorge on to the abyssal floor at the plateau edge. En route, turbidity current overspill from the channel has moved north under the influence of the shallow DWBC to contribute to a series of small ridge and patch drifts among the numerous seamounts on the plateau at 3500–4200 m. Off Hikurangi Channel mouth, a large fan has accumulated. The DWBC has extended the fan into a drift running over 250 km along the base of Hikurangi Plateau (5150–5770 m) toward Kermadec Trench. Here drift sediment becomes increasingly disrupted by mass wasting associated with the active subduction in this area. The seismic stratigraphy reveals the drifts to rest mainly on a widespread erosional surface that is interpreted to mark the inception of the DWBC in the region with the late Oligocene opening of the Australian‐Antarctic seaway. Drift construction commenced during the Miocene but was punctuated in the late Miocene by another period of erosion that coincided with increased bottom water production in Antarctica. Deposition resumed in Plio‐Pleistocene times when large quantities of sediment from the rapidly rising landmass of New Zealand were injected into the boundary current. The modern flow continues to affect drift deposition as manifest by an active boundary channel along the foot of Hikurangi Plateau and widespread scour zones and sediment wave fields.

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Section: Central Basinmentioning

confidence: 93%

Section: Deep Western Boundary Currentsmentioning

confidence: 99%

Development of sediment drifts approaching an active plate margin under the SW Pacific Deep Western Boundary Current

Carter¹,

McCave²

1994

Paleoceanography

108

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“…This tilt (and any secondary circulation) means that overbanking sediment flows are more likely to occur on the right hand side of the channel (looking downstream) for mid-and high latitude systems in the Northern Hemisphere, leading to an asymmetry between levee bank heights [Menard, 1955;Komar, 1969]. Observations at higher latitudes have found that the right hand side channel levee is consistently higher in the Northern Hemisphere [Klaucke et al, 1997] while the left hand side channel levee is higher in the Southern Hemisphere [Carter and Carter, 1988;Bruhn and Walker, 1997]. In addition, Coriolis forces generate Ekman boundary layers in gravity currents [Wåhlin, 2004] as illustrated in Figures 1b and 1c, for the case of the Northern and Southern Hemisphere respectively.…”

Section: Introductionmentioning

confidence: 99%

Coriolis forces influence the secondary circulation of gravity currents flowing in large‐scale sinuous submarine channel systems

Cossu

Wells

2010

Geophysical Research Letters

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A combination of centrifugal and Coriolis forces drive the secondary circulation of turbidity currents in sinuous channels, and hence determine where erosion and deposition of sediment occur. Using laboratory experiments we show that when centrifugal forces dominate, the density interface shows a superelevation at the outside of a channel bend. However when Coriolis forces dominate, the interface is always deflected to the right (in the Northern Hemisphere) for both left and right turning bends. The relative importance of either centrifugal or Coriolis forces can be described in terms of a Rossby number defined as Ro = U/fR, where U is the mean downstream velocity, f the Coriolis parameter and R the radius of curvature of the channel bend. Channels with larger bends at high latitudes have ∣Ro∣ < 1 and are dominated by Coriolis forces, whereas smaller, tighter bends at low latitudes have ∣Ro∣ ≫ 1 and are dominated by centrifugal forces.

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“…For instance, figure 2c shows the levee asymmetry in the NAMOC where levee differences are 65 m on average along a 950 km section [13]. In the Southern Hemisphere, the left-hand side levee is observed to be higher [22][23][24].…”

Section: Field Observations Of Sinuous Channel-levee Systemsmentioning

confidence: 99%

The possible role of Coriolis forces in structuring large-scale sinuous patterns of submarine channel–levee systems

Wells

Cossu

2013

Phil. Trans. R. Soc. A.

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Submarine channel–levee systems are among the largest sedimentary structures on the ocean floor. These channels have a sinuous pattern and are the main conduits for turbidity currents to transport sediment to the deep ocean. Recent observations have shown that their sinuosity decreases strongly with latitude, with high-latitude channels being much straighter than similar channels near the Equator. One possible explanation is that Coriolis forces laterally deflect turbidity currents so that at high Northern latitudes both the density interface and the downstream velocity maximum are deflected to the right-hand side of the channel (looking downstream). The shift in the velocity field can change the locations of erosion and deposition and introduce an asymmetry between left- and right-turning bends. The importance of Coriolis forces is defined by two Rossby numbers, Ro W = U / Wf and Ro R = U / Rf , where U is the mean downstream velocity, W is the width of the channel, R is the radius of curvature and f is the Coriolis parameter. In a bending channel, the density interface is flat when Ro R ∼−1, and Coriolis forces start to shift the velocity maximum when | Ro W |<5. We review recent experimental and field observations and describe how Coriolis forces could lead to straighter channels at high latitudes.

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Late Quaternary development of left-bank-dominant levees in the Bounty Trough, New Zealand

Cited by 50 publications

References 11 publications

Development of sediment drifts approaching an active plate margin under the SW Pacific Deep Western Boundary Current

Development of sediment drifts approaching an active plate margin under the SW Pacific Deep Western Boundary Current

Coriolis forces influence the secondary circulation of gravity currents flowing in large‐scale sinuous submarine channel systems

The possible role of Coriolis forces in structuring large-scale sinuous patterns of submarine channel–levee systems

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