Talc-dominated seafloor deposits reveal a new class of hydrothermal system
| Autor: | Stephen Roberts, Alexander P. Webber, Matthew R. S. Hodgkinson, Douglas P. Connelly, Rachel A. Mills, Bramley J. Murton |
|---|---|
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | The Von Damm Vent Field (VDVF) is located on the flanks of the Mid-Cayman Spreading Centre, 13 km west of the axial rift, within a gabbro and peridotite basement. Unlike any other active vent field, hydrothermal precipitates at the VDVF comprise 85–90% by volume of the magnesium silicate mineral, talc. Hydrothermal fluids vent from a 3-m high, 1-m diameter chimney and other orifices at up to 215 °C with low metal concentrations, intermediate pH (5.8) and high concentrations (667 mmol kg−1) of chloride relative to seawater. Here we show that the VDVF vent fluid is generated by interaction of seawater with a mafic and ultramafic basement which precipitates talc on mixing with seawater. The heat flux at the VDVF is measured at 487±101 MW, comparable to the most powerful magma-driven hydrothermal systems known, and may represent a significant mode of off-axis oceanic crustal cooling not previously recognized or accounted for in global models. The Von Damm Vent Field comprises 85–90% talc, with hydrothermal fluids of unusual chemistry at 215 °C. Here, the authors show that the mineralogy results from seawater mixing with hydrothermal fluids and the heat output may represent a mode of crustal cooling not fully accounted for in global models. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|