A Method for Quantitative Evaluation of Carbonate Dissolution in Deep-Sea Sediments and its Application to Paleoceanographic Reconstruction

1978 ◽  
Vol 10 (1) ◽  
pp. 112-129 ◽  
Author(s):  
Teh-Lung Ku ◽  
Tadamichi Oba
Keyword(s):  
Quantitative Evaluation ◽  
Deposition Rate ◽  
Deep Sea ◽  
Bottom Water ◽  
Carbonate Dissolution ◽  
Present Value ◽  
Dissolution Rates ◽  
Sea Floor ◽  
The Pacific ◽  
The Difference

A method is proposed by which the degree of attrition of the tests of certain foraminifera species, such as Globorotalia menardii and Globorotalia tumida, is used to “scale” the amount of CaCO3 that has been dissolved from sediment. The scale is calibrated experimentally in the laboratory. The method has been applied to three calcareous cores from the Pacific and the Indian Oceans. It is shown that the original CaCO3 contents in these cores were high (82–95%) and relatively uniform compared to the present down-core values. About 65 to 85% of the originally deposited CaCO3 has been dissolved, corresponding to dissolution rates on the order of 0.1-0.3 moles/cm2/yr. These results indicate that appreciable solution could have occurred on sea floor rich in calcareous sediments and that the variation in CaCO3 content in a core may have resulted largely from dissolution. The difference in the degree of solution between glacial and interglacial sediments in these cores is not so distinct, with ⋍ 10% less intense dissolution during glacial times on the average. However, the dissolution minimum occurring around the late Wisconsin glaciation (10,000–20,000 yr B.P.) previously noted in several cores elsewhere is confirmed. At that time, near the site of core M70 PC-20 in the southwest Pacific, the CO32− concentration of the bottom water is estimated to have been approximately 5% higher than the present value, and the calcite lysocline was about 300 m deeper. To evaluate possible variations in CaCO3 deposition rate across the glacial-interglacial transitions requires precise age control, which the present study lacks.

2. Seafloor spreading and magnetic anomalies

2015 ◽  
pp. 17-35
Author(s):  
Peter Molnar
Keyword(s):  
Sea Level ◽  
Deep Sea ◽  
Magnetic Anomalies ◽  
Seafloor Spreading ◽  
Ocean Floor ◽  
Sea Level Changes ◽  
Ocean Ridges ◽  
The Pacific ◽  
History Of ◽  
The Difference

‘Seafloor spreading and magnetic anomalies’ begins with the Vine–Matthews Hypothesis, which proposed that strips of seafloor parallel to the mid-ocean ridges, where two plates diverge from one another, were magnetized in opposite directions because the Earth’s field had reversed itself many times. A test of the Vine–Matthews Hypothesis, which required determining the age of the seafloor, became a test of seafloor spreading. Dating the ocean floor using magnetic anomalies detected by magnetometers towed behind ships and core samples extracted during the Deep-Sea Drilling Project confirmed the hypothesis. With magnetic anomalies to date the seafloor and a curve relating seafloor depth and age, the difference between the Atlantic, with its ‘ridge’, and the Pacific and its ‘rise’ became comprehensible. With a theory for predicting the depths of oceans, it was also possible to understand the history of sea-level changes.

scholarly journals A Method for Quantifying Deep-Sea Carbonate Dissolution Using 14C Dating

Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 585-592 ◽  
Author(s):  
S.A. Van Kreveld ◽  
G. M. Ganssen ◽  
J.E. Van Hinte ◽  
M. M. Melkert ◽  
S. R. Troelstra ◽  
...  
Keyword(s):  
Water Depth ◽  
Deep Sea ◽  
Accumulation Rate ◽  
Sedimentation Rates ◽  
Carbonate Dissolution ◽  
Sudden Increase ◽  
14C Dating ◽  
High Quality ◽  
The Difference ◽  
Mass Accumulation

We quantified the rate of carbonate dissolution with increasing water depth by taking the difference in the carbonate mass accumulation rate of deep (3393–4375 m) core top sediments from the shallowest one (3208 m), which we assumed was unaffected by dissolution. This method depends on high quality 14C dates that we calibrated to calendar years for calculating sedimentation rates. Our results show low (ranging from 0 to 0.3 g cm−2 ka−1) and high (ranging from 1.5 to 1.7 g cm−2 ka−1) carbonate dissolution rates, above and below 4000 m, respectively. Therefore, we interpret the sudden increase in the carbonate dissolution rate at 4000-m water depth to mark the lysocline.

A Decade of Challenge the Future of Biogeography

1985 ◽  
Vol 4 (2) ◽  
pp. 187-196 ◽  
Author(s):  
Gareth Nelson
Keyword(s):  
Critical Evaluation ◽  
Pacific Basin ◽  
Main Task ◽  
Radial Expansion ◽  
Sea Floor ◽  
Biogeographic Patterns ◽  
The Pacific ◽  
The Difference ◽  
Sea Floor Spreading ◽  
East West

According to Croizat's global synthesis, the main biogeographic patterns include trans-Atlantic, trans-Pacific, trans-Indoceanic, Boreal, and Austral. Geological and geophysical theories vary, but agree that sea-floor spreading in the Pacific is different in its effect from that in other ocean basins. The difference allows for radial expansion of the basin and not merely east-west displacement of continental areas. Biogeographic data suggest that bipolar (boreal + austral) distributions are to be reckoned among the results of sea-floor spreading in the Pacific. Data from one group of inshore fishes (family Engraulidae) exemplify this notion and add, as terminal parts of the differentiation of the Pacific Basin, trans-Panama marine vicariance and a collateral occurrence in freshwater of tropical South America. These findings corroborate Croizat's synthesis. They suggest that the critical evaluation of that synthesis will be the main task of biogeography over the next decade. They indicate that within the area of systematics, evaluation will require a cladistic approach and the elimination of paraphyletic groups from classification.

Proposed names of features on the deep-sea floor 1. The Pacific Ocean

1955 ◽  
Vol 2 (2) ◽  
pp. 93-106 ◽  
Author(s):  
John D.H. Wiseman ◽  
Cameron D. Ovey
Keyword(s):  
Pacific Ocean ◽  
Deep Sea ◽  
Sea Floor ◽  
The Pacific ◽  
The Pacific Ocean

scholarly journals North West Pacific deep-sea barnacles (Cirripedia, Thoracica) collected by the TAIWAN expeditions, with descriptions of two new species

Zootaxa ◽  
2010 ◽  
Vol 2405 (1) ◽  
pp. 1 ◽  
Author(s):  
BENNY K. K. CHAN ◽  
ROMANUS EDY PRABOWO ◽  
KWEN-SHEN LEE
Keyword(s):  
New Species ◽  
Deep Sea ◽  
Sea Floor ◽  
North West ◽  
Pacific Waters ◽  
The Pacific ◽  
Large Island ◽  
Two New Species ◽  
The Pacific Ocean ◽  
North Western

Taiwan is a large island in north western Pacific waters with the sea floor connecting to two major deep-sea basins, the eastern waters facing the Pacific Ocean (to 4000 m depth) and linking to the Philippine Basin, whilst south western waters are associated with the South China Sea Basin (up to 1000 m). Previously, the biodiversity of Taiwanese deep-sea barnacles had not been studied extensively, due to a lack of deep-sea expeditions and sampling. Recently, several TAIWAN deep-sea cruises investigated the biodiversity of the deep-sea fauna of Taiwan and sampling was conducted to depths of 4000 m. The present study reports on the biodiversity of the deep-sea barnacles of Taiwan, a total of 18 species. One species was previously recorded from Taiwanese waters and 17 are new records, including two new species belong to the genera Litoscalpellum and Altiverruca.

scholarly journals Beta-diversity on deep-sea wood falls reflects gradients in energy availability

2014 ◽  
Vol 10 (4) ◽  
pp. 20140129 ◽  
Author(s):  
Craig McClain ◽  
James Barry
Keyword(s):  
Deep Sea ◽  
Beta Diversity ◽  
Taxonomic Composition ◽  
Energy Availability ◽  
Energy Usage ◽  
Sea Floor ◽  
The Pacific ◽  
Composition And Structure ◽  
The Pacific Ocean ◽  
Wood Fall

Wood falls on the deep-sea floor represent a significant source of energy into the food-limited deep sea. Unique communities of primarily wood- and sulfide-obligate species form on these wood falls. However, little is known regarding patterns and drivers of variation in the composition of wood fall communities through space and time, and thus, how wood falls contribute to deep-sea biodiversity. Eighteen Acacia logs varying in size were placed and retrieved after five years at a 3200 m site in the Pacific Ocean. We found that the taxonomic composition and structure of deep-sea wood fall communities varied considerably and equated with considerable differences in energy usage and availability. Our findings suggest that natural variability in wood falls may contribute significantly to deep-sea diversity.

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