Transport and release of transition elements during early diagenesis: Sequential leaching of sediments from MANOP Sites M and H. Part I. pH 5 acetic acid leach     

Mitchell Lyle  G.Ross Heath  James M. Robbins 《Geochimica et cosmochimica acta》1984,48(9):1705-1715

Sediments from MANOP sites M and H in the eastern tropical Pacific Ocean can be partitioned into operationally defined phases by means of a sequential leach procedure. This paper reports the results of the first leach in the sequence, an acetic acid solution buffered as p H 5 with sodium acetate. This leach is designed to remove carbonate-bound and sorbed cations. The only cation bound in a consistent ratio to calcium in the carbonate is strontium. The molar ratio is 2 × 10^?3. In contrast, transition metals are sorbed onto the surfaces of other sedimentary particles. The proportions sorbed range from 2 to 10% of the total manganese, about 10% of the total nickel and copper, and less than 1% of the total iron. The pool of sorbed metals in surface sediments is sufficiently large and the rate of biological stirring is sufficiently rapid for this metal reservoir potentially to dominate the porewater reservoir in supplying metals to ferromanganese nodules. A simple model for nodule growth based upon transfer of metals through this reservoir suggests that only 1% of the sedimentary sorbed metals within a radius of 2 to 9 cm is required to support typical nodule growth rates.  相似文献   

Growth rates of manganese-rich nodules at MANOP Site H (Eastern North Pacific)     

Bruce Finney  G.Ross Heath  Mitchell Lyle 《Geochimica et cosmochimica acta》1984,48(5):911-919

Estimates of the growth rates of ferromanganese nodules at MANOP Site H (6°33′N, 92°49′W) lie between 7 and 1200 mm/my. The most probable range (estimated from nodule size distributions, nodule chemistry, accumulation rates of authigenic elements and U-series modeling) is 30–300 mm/my. Such rates are much faster than measured values for most pelagic nodules. The distributions of U-series and stable elements suggest that a typical nodule consists of two compositionally distinct non-detrital components, one rich in Mn, U and Sb, and the other in Fe, Co, REE, Ni, Cu and Th. When the uncorrected U-series data, which do not show simple decay patterns with depth, are normalized to the relative proportion of the Fe-rich component, the data yield well-constrained growth rates of 55 mm/my for a nodule top and 200 mm/my for its bottom. The component enriched in Mn, which is most abundant on nodule bottoms, appears to accrete much faster than the component enriched in Fe.  相似文献   

Remobilization of transition metals in surficial pelagic sediments from the eastern Pacific   总被引：1，自引：0，他引：1  

Amy L. Graybeal  G.Ross Heath 《Geochimica et cosmochimica acta》1984,48(5):965-975

The top thirty centimeters of sediment at two sites in the eastern equatorial Pacific contain evidence of post-depositional remobilization of Mn, Fe, Co, Ni, Cu, and Zn. Remobilization takes place as Mn and Fe oxyhydroxides are released to the pore water during the microbially-mediated decomposition of organic matter. Precipitation of the dissolved metals in near-surface more oxic strata controls the solid-phase distribution of Mn, Fe, and Zn. The solid-phase redistribution of Co and Ni requires only suitable material for readsorption. Comparison of pore water fluxes with solid-phase metal distributions in the solid sediment indicates no loss of dissolved metal to the overlying water column at the present time. Loss of Mn during the Quaternary is indicated by the composition of the sediments, however. Leaching experiments suggest that portions of the mobile Mn, Fe, Co, Ni, and Cu are fixed by incorporation in authigenic smectite in the surficial sediments.  相似文献   

Tidal constants for McMurdo sound,Antarctica   总被引：1，自引：1，他引：0  

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(2):376-380

Harmonic constants were evaluated from 30 days’ tidal records at a position about 0.25 miles (0.44 km) south of Winter Quarters Bay, McMurdo Sound, Antarctica. The main components are the declinational diurnal constituents O1 and K1. Comparison of the constants with those previously evaluated from nearby Pram Point (near Scott Base) shows that the amplitudes are smaller at McMurdo Sound, and that the high tide at McMurdo occurs about one hour after that at Scott Base.  相似文献   

An occurrence of low water temperatures on the north Canterbury coast (note)     

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(2):223-226

A recorded instance of a rapid decrease in sea surface temperature on 10 April 1968 on the north Canterbury coast is found to be caused by increased transport of the Southland Current rather than by wind‐derived upwelling, and shows that gross changes in coastal current characteristics on the north Canterbury coast can occur under particular meteorological conditions.  相似文献   

Hydrology and circulation in central and southern Cook Strait,New Zealand   总被引：2，自引：2，他引：0  

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(1):178-199

The circulation and hydrology of Cook Strait are defined using both the geostrophic method and the hydrologiieal characteristics of the different water masses. Cool, low salinity water in a branch of the Southland Current, which extends along the east coast of the South Island into Cook Strait, mixes above the depth of the continental shelf with warmer, more saline Subtropical Water from both the D'UrVille Current and the East Cape Current. Subtropical Water derived from the East Cape Current occupies the Cook Strait Canyon; below 100 m this water meets the Subtropical Water of the southwest‐flowing D'Urville Current in a convergence situated in the Oook Strait Narrows. Mixed water derived from all three currents passes eastwards across Cook Strait and up the east coast of the North Island.  相似文献   

Physical oceanographic observations in Marlborough Sounds   总被引：3，自引：3，他引：0  

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(4):691-708

Results of temperature and salinity observations with depth, current drogue measurements in Pelorus and Queen Charlotte Sounds, and a current meter record from Pelorus Sound are discussed. The circulation in both Sounds is mainly tidal. Salinities in Pelorus Sound were found to be lower than in Queen Charlotte Sound; there was a rapid decrease in salinity near the head of Pelorus Sound where the Pelorus and Kaituna rivers enter it. Residence time of water in Pelorus Sound was estimated to be about 21 days.  相似文献   

Stability of some New Zealand coastal inlets   总被引：1，自引：1，他引：0  

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(4):449-457

The relation of tidal compartments to entrance cross‐sectional areas is examined for 20 coastal inlets. Sixteen inlets conform to a linear relationship, which is consistent with stable entrances the sizes of which are determined by the ability of the tidal flow to transport sediment. Based on this criterion deposition should be taking place at the entrances of the other four inlets: Wellington, Lyttelton, and Akaroa harbours, and Paterson Inlet. Available data confirm this for Wellington and Lyttelton Harbours.  相似文献   

Oceanic upwelling produced by northerly winds on the north Canterbury coast,New Zealand     

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(3):343-351

The rates of upwelling calculated from the change in temperature distribution derived from two sets of hydrological stations (0.0107 cm.r^‐1) and the rate of upwelling calculated from the wind derived transport offshore for the period between the collection of the hydrological data (0.0086 cm.s^‐1) are found to be consistent.  相似文献   

Phase distribution of tidal constituents around New Zealand   总被引：2，自引：2，他引：0  

R. A. Heath 《新西兰海洋与淡水研究杂志》2013,47(2):383-392

The phase distributions of the M₂, S₂, K₁, and O₁ tidal constituents around New Zealand are plotted from existing harmonic analyses of tidal heights. Both semidiurnal constituents exhibit a complete 360° range of phase around New Zealand, with complex areas of rapid phase change through or near the strait separating the two main islands. The K₁ amphidrome and that for O₁, which previously were thought to be centred on New Zealand, are shown to be located cast of New Zealand. The distributions plotted highlight areas where tidal observations are lacking.  相似文献