scholarly journals A Magnetic Survey of the Southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
David Irwin Ross
Keyword(s):  
New Zealand ◽  
Pacific Ocean ◽  
Ross Sea ◽  
Magnetic Survey ◽  
Southwest Pacific ◽  
The North ◽  
Magnetic Pattern ◽  
The Pacific ◽  
Profiling Techniques ◽  
Ocean Ridge

<p>The design and construction of a free precession proton magnetometer which give a reading of the field directly in gamma is described. This instrument has been used to obtain magnetic profiles across the Southwest Pacific Ocean during the 1963-65 summer Antarctic supply cruises of H.M.N.Z.S. Endeavour. The magnetic and bathymetric profiler obtained on these cruises have been analysed to determine the nature and structure of the oceanic crust in this region. The region is divided into four divisions. (l) The New Zealand Plateau, with an almost continental crustal thickness. (2) The Southwest Pacific Basin, at a depth of 3,000 fathoms. (3) The Pacific-Antarctic Ridge, pert of the world encircling mind-ocean ridge system. (4) The Ross Sea, an epicontinental sea across the Antarctic continental shelf. Subtraction of the regional field form the magnetic results has enabled a regional field map of the area to be drawn. Comparison with earlier results indicates a westward drift of the earth's field of approximately 0.25 degrees /yr. Some discussion of regional anomalies (~ 100 miles period) has been given. Because of the excellent correlation of magnetic anomalies from track to track across the basin it has been possible to draw an anomaly contour map of this part. This map illustrates the predominantly east-west trend of features over the basin. To the north the features parallel the edge of the New Zealand Plateau. To the south the features swing more towards the Pacific-Antarctic Ridge. A major discontinuity is indicated along a direction 9 degrees E of S meeting the Plateau just southwest of Antipodes Islands. If this discontinuity is extrapolated south to the ridge it meets it at approximately 180 degrees E, where the ridge turns N-E towards Easter Island. Across the ridge the magnetic pattern shows three distinct regions. Over the northern flanks large anomalies are evident but the correlation of anomalies from track to track is very poor. Further south, across the upper flanks, the magnetic records are very much subdued. The extent of this region varies appreciably from track to track. Over the axis of the ridge large, steep-sided anomalies are obtained. These correlate well over part of the region studied. The southern flanks of the ridge are hidden by the Balleny Plateau which seems to form a link between Antarctica and the ridge in this region. The bathymetry records obtained indicate a step-type formation over the ridge. A narrow median valley appears to exist along the axis of the ridge. Some preliminary experimentation has been carried out with continual seismic profiling techniques over the region. The equipment that has been developed and the preliminary results obtained with it are discussed.</p>

scholarly journals A Magnetic Survey of the Southwest Pacific Ocean

2021 ◽  
Author(s):  
◽  
David Irwin Ross
Keyword(s):  
New Zealand ◽  
Pacific Ocean ◽  
Ross Sea ◽  
Magnetic Survey ◽  
Southwest Pacific ◽  
The North ◽  
Magnetic Pattern ◽  
The Pacific ◽  
Profiling Techniques ◽  
Ocean Ridge

<p>The design and construction of a free precession proton magnetometer which give a reading of the field directly in gamma is described. This instrument has been used to obtain magnetic profiles across the Southwest Pacific Ocean during the 1963-65 summer Antarctic supply cruises of H.M.N.Z.S. Endeavour. The magnetic and bathymetric profiler obtained on these cruises have been analysed to determine the nature and structure of the oceanic crust in this region. The region is divided into four divisions. (l) The New Zealand Plateau, with an almost continental crustal thickness. (2) The Southwest Pacific Basin, at a depth of 3,000 fathoms. (3) The Pacific-Antarctic Ridge, pert of the world encircling mind-ocean ridge system. (4) The Ross Sea, an epicontinental sea across the Antarctic continental shelf. Subtraction of the regional field form the magnetic results has enabled a regional field map of the area to be drawn. Comparison with earlier results indicates a westward drift of the earth's field of approximately 0.25 degrees /yr. Some discussion of regional anomalies (~ 100 miles period) has been given. Because of the excellent correlation of magnetic anomalies from track to track across the basin it has been possible to draw an anomaly contour map of this part. This map illustrates the predominantly east-west trend of features over the basin. To the north the features parallel the edge of the New Zealand Plateau. To the south the features swing more towards the Pacific-Antarctic Ridge. A major discontinuity is indicated along a direction 9 degrees E of S meeting the Plateau just southwest of Antipodes Islands. If this discontinuity is extrapolated south to the ridge it meets it at approximately 180 degrees E, where the ridge turns N-E towards Easter Island. Across the ridge the magnetic pattern shows three distinct regions. Over the northern flanks large anomalies are evident but the correlation of anomalies from track to track is very poor. Further south, across the upper flanks, the magnetic records are very much subdued. The extent of this region varies appreciably from track to track. Over the axis of the ridge large, steep-sided anomalies are obtained. These correlate well over part of the region studied. The southern flanks of the ridge are hidden by the Balleny Plateau which seems to form a link between Antarctica and the ridge in this region. The bathymetry records obtained indicate a step-type formation over the ridge. A narrow median valley appears to exist along the axis of the ridge. Some preliminary experimentation has been carried out with continual seismic profiling techniques over the region. The equipment that has been developed and the preliminary results obtained with it are discussed.</p>

The Recent Cypraeidae of Northern New Zealand from the Kermadec Islands to the Poor Knights Islands, Southwest Pacific Ocean (Mollusca: Gastropoda: Cypraeidae)

The Festivus ◽  
2018 ◽  
Vol 50 (1) ◽  
pp. 36-54
Author(s):  
John Daughenbaugh
Keyword(s):  
New Zealand ◽  
Pacific Ocean ◽  
Continental Shelf ◽  
East Coast ◽  
Species Distributions ◽  
East Side ◽  
Tropical Eastern Pacific ◽  
The North ◽  
The Poor ◽  
Coastal Shelf

For researchers, isolated regions at the periphery of species’ distributions hold a peculiar fascination. The causes of their remoteness vary based on: distance (e.g. the Tropical Eastern Pacific), distance and countervailing currents (e.g. the Marquesas), location in a present day gyre (e.g. the Pitcairn Group) or the absence of present day means of veliger transport (e.g. the Vema Seamount). (Daughenbaugh & Beals 2013; Daughenbaugh 2015a & b, 2017). The northern New Zealand Region from the Kermadec Islands (Kermadecs) to the coastal and shelf areas in the northernmost part of New Zealand’s North Island (Northland), including the Poor Knights Islands (PKI), constitute the distributional boundaries for a number of Cypraeidae species. The boundaries are the result of the absence of coastal shelves along the east side of the Kermadec Ridge (Ridge) and precipitous drops to abyssal depths along Northland’s east coast continental shelf. Tropical waters, with their potential to transport Cypraeidae larvae, flow eastward from southern Queensland, Australia, entrained in the Tasman Front which terminates when reaching North Cape, the northernmost tip of Northland. There, the North Cape Eddy captures most of this flow while the remainder, the East Auckland Current (EAUC), flows intermittently southward along the eastern coastal, shelf and offshore areas of Northland into waters incapable of supporting Cypraeidae populations.

scholarly journals The Pacific Ocean and Global OBIS: A New Zealand Perspective

Oceanography ◽  
2000 ◽  
Vol 13 (3) ◽  
pp. 41-47 ◽  
Author(s):  
Dennis Gordon
Keyword(s):  
New Zealand ◽  
Pacific Ocean ◽  
The Pacific ◽  
The Pacific Ocean

scholarly journals Ashinkailepas kermadecensis, a new species of deep-sea scalpelliform barnacle (Thoracica: Eolepadidae) from the Kermadec Islands, southwest Pacific

Zootaxa ◽  
2009 ◽  
Vol 2021 (1) ◽  
pp. 57-65 ◽  
Author(s):  
JOHN S. BUCKERIDGE
Keyword(s):  
New Species ◽  
New Zealand ◽  
Deep Sea ◽  
Cold Water ◽  
The Other ◽  
Cold Seeps ◽  
Central Japan ◽  
Southwest Pacific ◽  
The North ◽  
A New Species

A new deep-sea stalked barnacle, Ashinkailepas kermadecensis sp. nov. has been recovered from a cold-water seep at depths of 1165 metres in the vicinity of the Kermadec Ridge to the northeast of the North Island, New Zealand. There are now two species of Ashinkailepas—the other, Ashinkailepas seepiophila Yamaguchi, Newman & Hashimoto, 2004, occurs in deep, cold seeps off central Japan. As there are two species within Ashinkailepas, formal diagnoses are provided for both taxa.

The Pacific Ocean as Highway to Gold Mountain

2017 ◽  
Author(s):  
Elizabeth Sinn
Keyword(s):  
United States ◽  
New Zealand ◽  
Pacific Ocean ◽  
Capital Flows ◽  
The United States ◽  
The West ◽  
New Era ◽  
The Pacific ◽  
History Of ◽  
The Pacific Ocean

This chapter takes a broad look at the Pacific Ocean in relation to Chinese migration. As trade, consumption and capital flows followed migrants, powerful networks were woven and sustained; in time, the networks fanned across the Pacific from British Columbia along the West Coast of the United States to New Zealand and Australia. The overlapping personal, family, financial and commercial interests of Chinese in California and those in Hong Kong, which provide the focus of this study, energized the connections and kept the Pacific busy and dynamic while shaping the development of regions far beyond its shores. The ocean turned into a highway for Chinese seeking Gold Mountain, marking a new era in the history of South China, California, and the Pacific Ocean itself.

scholarly journals Biogeochemistry of the North Atlantic during oceanic anoxic event 2: role of changes in ocean circulation and phosphorus input

2014 ◽  
Vol 11 (4) ◽  
pp. 977-993 ◽  
Author(s):  
I. Ruvalcaba Baroni ◽  
R. P. M. Topper ◽  
N. A. G. M. van Helmond ◽  
H. Brinkhuis ◽  
C. P. Slomp
Keyword(s):  
Pacific Ocean ◽  
Ocean Circulation ◽  
North Atlantic ◽  
Primary Productivity ◽  
Low Oxygen ◽  
Deep Basin ◽  
The North ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The North Atlantic

Abstract. The geological record provides evidence for the periodic occurrence of water column anoxia and formation of organic-rich deposits in the North Atlantic Ocean during the mid-Cretaceous (hereafter called the proto-North Atlantic). Both changes in primary productivity and oceanic circulation likely played a role in the development of the low-oxygen conditions. Several studies suggest that an increased input of phosphorus from land initiated oceanic anoxic events (OAEs). Other proposed mechanisms invoke a vigorous upwelling system and an ocean circulation pattern that acted as a trap for nutrients from the Pacific Ocean. Here, we use a detailed biogeochemical box model for the proto-North Atlantic to analyse under what conditions anoxia could have developed during OAE2 (94 Ma). The model explicitly describes the coupled water, carbon, oxygen and phosphorus cycles for the deep basin and continental shelves. In our simulations, we assume the vigorous water circulation from a recent regional ocean model study. Our model results for pre-OAE2 and OAE2 conditions are compared to sediment records of organic carbon and proxies for photic zone euxinia and bottom water redox conditions (e.g. isorenieratane, carbon/phosphorus ratios). Our results show that a strongly elevated input of phosphorus from rivers and the Pacific Ocean relative to pre-OAE2 conditions is a requirement for the widespread development of low oxygen in the proto-North Atlantic during OAE2. Moreover, anoxia in the proto-North Atlantic is shown to be greatly influenced by the oxygen concentration of Pacific bottom waters. In our model, primary productivity increased significantly upon the transition from pre-OAE2 to OAE2 conditions. Our model captures the regional trends in anoxia as deduced from observations, with euxinia spreading to the northern and eastern shelves but with the most intense euxinia occurring along the southern coast. However, anoxia in the central deep basin is difficult to achieve in the model. This suggests that the ocean circulation used in the model may be too vigorous and/or that anoxia in the proto-North Atlantic was less widespread than previously thought.

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