scholarly journals Siliceous sponge spicules, silicoflagellates, and ebridians from Hole 918D, continental rise of the Greenland Margin

1998 ◽  
Author(s):  
L.K. Lurvey ◽  
K. McCartney ◽  
W. Wei
Keyword(s):  
Siliceous Sponge ◽  
Continental Rise ◽  
Sponge Spicules ◽  
Greenland Margin

Carbon Replicas of Siliceous Sponge Spicules

Science ◽  
1967 ◽  
Vol 157 (3788) ◽  
pp. 581-582
Author(s):  
Ryan W. Drum
Keyword(s):  
Siliceous Sponge ◽  
Sponge Spicules ◽  
Carbon Replicas

scholarly journals A Solid State NMR Investigation of Recent Marine Siliceous Sponge Spicules

Minerals ◽  
2016 ◽  
Vol 6 (1) ◽  
pp. 21 ◽  
Author(s):  
Sylvie Masse ◽  
Andrzej Pisera ◽  
Guillaume Laurent ◽  
Thibaud Coradin
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Siliceous Sponge ◽  
Sponge Spicules

Ordovician sponge spicules from New South Wales, Australia

1993 ◽  
Vol 67 (1) ◽  
pp. 28-41 ◽  
Author(s):  
B. D. Webby ◽  
J. Trotter
Keyword(s):  
Debris Flows ◽  
New South ◽  
New South Wales ◽  
Late Ordovician ◽  
New Genera ◽  
Siliceous Sponge ◽  
Upper Cambrian ◽  
South Wales ◽  
Sponge Spicules ◽  
First Time

An abundant, varied, and well-preserved assemblage of discrete sponge spicules of late Ordovician age is described from the Malongulli Formation of central New South Wales. It is associated with one of the most diverse Ordovician siliceous sponge faunas known. The assemblage occurs in allochthonous limestone blocks within breccia deposits of a predominantly graptolitic and spiculitic siltstone succession, and is composed mainly of hexactinellid spicule types. Included are a number of distinctive forms, recognized as new taxa—Silicunculus bengtsoni, Kometia cruciformis, Chelispongia prima, and Pseudolancicula exigua. All are new genera except Silicunculus Bengtson, 1986, which was previously described from the upper Cambrian of Queensland. The problematical Anomaloides reticulatus Ulrich, 1878, is reported for the first time from Australia. A wide variety of other diagnostic, but more generalized, spicule types also occurs, including stauractines, pinnular and nonpinnular pentactines and hexactines, ornamented oxyhexasters and echinhexasters, clavules, anchorate root-tufts, and uncinates. The pinnular pentactines may be assigned to the form genus Palaeorubus Ishiga (in Ishiga et al., 1987), interpreted incorrectly by Ishiga as a radiolarian. The sponges, discrete spicules, and radiolarians of these limestone clasts were transported in debris flows to a basinal setting from peri-platform oozes that formed on the flanks of the shallow offshore island-arc platform of the Molong High.

scholarly journals Siliceous Sponge Spicules from Site 795

1992 ◽  
Author(s):  
R. Zolnik ◽  
K. McCartney ◽  
L.D. White
Keyword(s):  
Siliceous Sponge ◽  
Sponge Spicules

scholarly journals Siliceous Sponge Spicules from Site 795

1992 ◽  
Author(s):  
R. Zolnik ◽  
K. McCartney ◽  
L.D. White
Keyword(s):  
Siliceous Sponge ◽  
Sponge Spicules

scholarly journals Assessing the relationship between the <i>δ</i><sup>18</sup>O signatures of siliceous sponge spicules and water in a~tropical lacustrine environment (Minas Gerais, Brazil)

2013 ◽  
Vol 10 (8) ◽  
pp. 12887-12918 ◽  
Author(s):  
M. C. Matteuzzo ◽  
A. Alexandre ◽  
A. F. D. C. Varajão ◽  
C. Volkmer-Ribeiro ◽  
A. C. S. Almeida ◽  
...  
Keyword(s):  
Water Temperature ◽  
Pond Water ◽  
Minas Gerais ◽  
Positive Temperature ◽  
Freshwater Species ◽  
Siliceous Sponge ◽  
Isotopic Equilibrium ◽  
Oxygen Isotopic ◽  
Sponge Spicules ◽  
Siliceous Spicules

Abstract. Siliceous sponge spicules constitute an important siliceous component of lacustrine sediments, together with widespread diatom frustules. In contrast to diatom frustules, siliceous spicules are formed in sponges in an enzymatic way. Previous attempts to use their oxygen isotopic signature (δ18Osilica) as a paleoenvironmental proxy have led to contradictory conclusions. These attempts demonstrated the need to further assess whether sponges form their silica in oxygen isotopic equilibrium with water. For this reason, we measured the δ18O signature of sponge spicules from a single freshwater species (Metania spinata) grown on natural and artificial supports over nine months in a small Brazilian pond (Lagoa Verde, northwestern Minas Gerais). The δ18Osilica values were obtained using the infrared (IR) laser-heating fluorination technique following a controlled isotopic exchange (CIE). The δ18O values (δ18Owater) and temperature of the pond water were periodically measured and reconstructed over the course of the sponge growth. Assuming that silica may form continuously in the spicules, temperature and δ18Owater values over the months of growth were weighted using a sponge growth coefficient previously established for Metania spinata. The δ18Osilica values of sponges grown simultaneously and on similar substrates were scattered. No relationships were observed between the Δ18Osilica-water and water temperature when the reconstructed values were considered. Conversely, a positive correlation was obtained, with a coefficient of 0.3‰ °C–1 (R2 = 0.63), when δ18Owater values and water temperature at the time of sample collection were considered. Such a positive temperature coefficient clearly indicates that the freshwater sponge Metania spinata does not form its siliceous spicules in oxygen isotopic equilibrium with the pond water. Instead, one or several biologically controlled kinetic fractionation mechanisms may be in play during the various steps of silica formation. Our results suggest that the latest precipitation gives its δ18O imprint to the entire spicules assemblage. The amplitude of the apparent fractionations increases with temperature, but other controlling parameters, such as dissolved Si concentration and nutrient availability, co-varying with temperature may intervene. These results prevent the use of δ18Osilica values from the spongillites of northwestern Minas Gerais as a direct proxy for past δ18Owater and/or temperature changes.

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