1.1 Juan de Fuca Ridge - case study
In Salmi et al. (2014) they deployed thermal blankets in a 450-700m area of a segment on the Juan de Fuca Ridge to examine the effects of hydrothermal circulation on very young oceanic
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crust. The Juan de Fuca Ridge is a tectonic spreading center located off the coast of Washing- ton in the United States. The ridge is considered an intermediate spreading ridge as it spreads 5.6-5.7 cm/yr. Several methods exist to measure the heat flow, some measure the heat flow in-situ by pulsating heat into a tube and then it measures the decay. Others rely on known properties of sediment relations and thermal conductivity. All of these methods require a sediment layer on top of the outcrop as the measuring tools are …show more content…
To measure the heat flow in such an area it is necessary to deploy thermal blankets. By knowing the thermal conductivity of the blanket material and the thickness of the blanket itself and by leaving the blanket for certain time period for it to equilibrate with the underlying basement, Salmi et al. (2014) were able to produce a high-resolution map of the heat flow in a small area on the Juan de Fuca Ridge.
The heat gradient is determined by having two Antares thermistors placed on the bottom and top part of the blanket. Both thermistors are very sensitive and have a resolution of ±0.0001°C.
Figure 6 shows the results from the survey, and it is very clearly observed how the heat flow is very high in localized zones, and right next to these hot spot zones the heat flow measurements are close to zero. The study clearly shows how vigorous the effects of hydrothermal circulation are on very young oceanic crust. It also illustrates the difficulties of measuring heat flow in the ocean. Random measurements made on young oceanic crust will yield very different measure- ments and the data will have a very high standard deviation as a
In Salmi et al. (2014) they deployed thermal blankets in a 450-700m area of a segment on the Juan de Fuca Ridge to examine the effects of hydrothermal circulation on very young oceanic
2
crust. The Juan de Fuca Ridge is a tectonic spreading center located off the coast of Washing- ton in the United States. The ridge is considered an intermediate spreading ridge as it spreads 5.6-5.7 cm/yr. Several methods exist to measure the heat flow, some measure the heat flow in-situ by pulsating heat into a tube and then it measures the decay. Others rely on known properties of sediment relations and thermal conductivity. All of these methods require a sediment layer on top of the outcrop as the measuring tools are …show more content…
To measure the heat flow in such an area it is necessary to deploy thermal blankets. By knowing the thermal conductivity of the blanket material and the thickness of the blanket itself and by leaving the blanket for certain time period for it to equilibrate with the underlying basement, Salmi et al. (2014) were able to produce a high-resolution map of the heat flow in a small area on the Juan de Fuca Ridge.
The heat gradient is determined by having two Antares thermistors placed on the bottom and top part of the blanket. Both thermistors are very sensitive and have a resolution of ±0.0001°C.
Figure 6 shows the results from the survey, and it is very clearly observed how the heat flow is very high in localized zones, and right next to these hot spot zones the heat flow measurements are close to zero. The study clearly shows how vigorous the effects of hydrothermal circulation are on very young oceanic crust. It also illustrates the difficulties of measuring heat flow in the ocean. Random measurements made on young oceanic crust will yield very different measure- ments and the data will have a very high standard deviation as a