کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4699488 1637650 2012 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Siliceous deep-sea sponge Monorhaphis chuni: A potential paleoclimate archive in ancient animals
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
پیش نمایش صفحه اول مقاله
Siliceous deep-sea sponge Monorhaphis chuni: A potential paleoclimate archive in ancient animals
چکیده انگلیسی

The deep-sea sponge Monorhaphis chuni forms giant basal spicules, which can reach lengths of 3 m; they represent the largest biogenic silica structures on Earth that is formed from an individual metazoan. The spicules offer a unique opportunity to record environmental change of past oceanic and climatic conditions. A giant spicule collected in the East China Sea in a depth of 1110 m was investigated. The oxygen isotopic composition and Mg/Ca ratios determined along center-to-surface segments are used as geochemical proxies for the assessment of seawater paleotemperatures. Calculations are based on the assumption that the calculated temperature near the surface of the spicule is identical with the average ambient temperature of 4 °C. A seawater temperature of 1.9 °C is inferred for the beginning of the lifespan of the Monorhaphis specimen. The temperature increases smoothly to 2.3 °C, to be followed by sharply increased and variable temperatures up to 6–10 °C. In the outer part of the spicule, the inferred seawater temperature is about 4 °C. The lifespan of the spicule can be estimated to 11,000 ± 3000 years using the long-term trend of the inferred temperatures fitted to the seawater temperature–age relationships since the Last Glacial Maximum. Specimens of Monorhaphis therefore represents one the oldest living animals on Earth. The remarkable temperature spikes of the ambient seawater occurring 9500–3100 years B.P. are explained by discharges of hydrothermal fluids in the neighborhood of the spicule. The irregular lamellar organization of the spicule and the elevated Mn concentrations during the high-temperature growth are consistent with a hydrothermal fluid input.

Figure optionsDownload as PowerPoint slideHighlights
► Giant spicules can be used as paleoenvironmental archives.
► Oxygen isotopes and Mg/Ca in glass sponges are proxies of seawater temperatures.
► Lifespan of a deep-sea sponge Monorhaphis chuni from the China Sea is estimated to be 11 kyr.
► Temperature spikes of the seawater indicate a hydrothermal fluid input.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Geology - Volumes 300–301, 18 March 2012, Pages 143–151
نویسندگان
, , , , ,