Heat-flow near a North Atlantic fracture zone

Foster, Stephen Eric; Simmons, Gene; Lamb, Wilson

doi:10.1016/0375-6505(74)90030-3

Cited by 12 publications

(7 citation statements)

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“…Since that study, the number of near‐axis measurements has not increased very much and in the last published heat flow compilation [ Pollack et al , 1993], there are less than 400 measurements in the MAR for age of seafloor between 0 and 10 Ma (62 in the southern hemisphere and 326 in the northern hemisphere). Most of the measurements in the northern hemisphere (Figure 1b) have been obtained in the vicinity of the Azores islands [ Bullard and Day , 1961; Birch and Halunen , 1966; Phillips et al , 1969; Hyndman and Rankin , 1972; Kasameyer et al , 1972; Foster et al , 1974; Hyndman et al , 1976; Williams et al , 1977]. These data show a large number of low values and a large dispersion (Figure 2), which are common characteristics of hydrothermal perturbations.…”

Section: Previous Heat Flow Measurements In the Atlanticmentioning

confidence: 98%

“…These data show a large number of low values and a large dispersion (Figure 2), which are common characteristics of hydrothermal perturbations. However, several studies have been carried out near fracture zones [ Phillips et al , 1969; Kasameyer et al , 1972; Foster et al , 1974; Hyndman et al , 1976; Williams et al , 1977] where the extreme topography and the proximity to a segment end within the vicinity of an adjacent older plate may result in fluid circulation and an anomalous thermal regime.…”

Section: Previous Heat Flow Measurements In the Atlanticmentioning

confidence: 99%

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Heat flow variations on a slowly accreting ridge: Constraints on the hydrothermal and conductive cooling for the Lucky Strike segment (Mid‐Atlantic Ridge, 37°N)

Lucazeau

Bonneville

Escartı́n

et al. 2006

Geochem Geophys Geosyst

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[1] We report 157 closely spaced heat flow measurements along the Lucky Strike segment in the MidAtlantic Ridge (MAR) for ages of the ocean floor between 0 and 11 Ma. On the eastern flank of a volcanic plateau delimiting off-axis and axial domains, the magnitude of heat flow either conforms to the predictions of conductive lithospheric cooling models or is affected by localized anomalies. On the western flank it is uniformly lower than conductive model predictions. We interpret the observed patterns of heat flow by lateral fluid circulation in a highly permeable oceanic basement. The circulation geometries are probably 3-D rather than 2-D and are determined by the configuration of the basement/sediment interface and the distribution of effectively unsedimented seamounts where water recharge can occur. Two major hydrothermal circulation systems can possibly explain the observations off-axis: the first would involve lateral pore water flow from west to east, and the second would have a reverse flow direction. The wavelengths and magnitudes of heat flow anomalies require Darcy velocities of the order of 1-4 m/year, which are similar to those proposed for fast-accreted crust elsewhere. However, a large proportion of this MAR domain remains unaffected by hydrothermal cooling, which is a relatively unusual observation but confirms the validity of conductive thermal models for seafloor ages between 5 and 10 Ma. Closer to the ridge axis (<5 Myr old crust), water circulation affects the overall axial domain, as larger proportions of basement are exposed. As much as 80-90% of the heat flux from the axial domain may be transferred to the Lucky Strike vent field, in agreement with the estimated discharge.

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Section: Previous Heat Flow Measurements In the Atlanticmentioning

confidence: 98%

Section: Previous Heat Flow Measurements In the Atlanticmentioning

confidence: 99%

Heat flow variations on a slowly accreting ridge: Constraints on the hydrothermal and conductive cooling for the Lucky Strike segment (Mid‐Atlantic Ridge, 37°N)

Lucazeau

Bonneville

Escartı́n

et al. 2006

Geochem Geophys Geosyst

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“…Вертикальными линиями разграничены блоки между демаркационными разломами с указанием времени начала спрединговых процессов и порядковым номером сегмента, имеющим описательный смысл. Горизонтальными линиями показано распространение доспрединговых магматических провинций с возрастом [Eldholm, Coffin, 2000]. Обозначения: ЦАМП -Центрально-Атлантическая магматическая провинция, САМП -Северо-Атлантическая магматическая провинция, МПВА -магматическая провинция Высокой Арктики.…”

Section: сейсмичность вдоль аарсunclassified

“…Черными линиями показаны демаркационные разломы, сегментирующие ААРС на блоки с разным возрастом начала спрединга (возраст указан цифрами). Большие магматические провинции (желтые поля) приведены по данным [Eldholm, Coffin, 2000]. Fig.…”

Section: Introductionunclassified

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Intensity Indicators of Geodynamic Processes Along the Atlantic-Arctic Rift System

Соколов

Чамов

Хуторской

et al. 2020

Geodin. tektonofiz.

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Seismicity, heat flow, seismic tomography data, prerift and synrift magmatism are considered as intensity indicators of geodynamic processes along the Atlantic-Arctic rift system (AARS). In this rift system, several large (over 100 km ) sub-latitudinal displacements of the rift axis are due to left-lateral strike-slip faulting. The AARS segments are distinguished by the age of splitting of continental plates from each other. A dependence is revealed between the current thermal state of the mantle under the AARS and the age of spreading start. This dependence is established from both seismic tomography and heat flow data. In section δ(Vp/Vs), the locations of the main segmenting faults and 'cold' anomalies in the upper mantle are coincident. Distributions of total seismic moments are practically synchronous in the depth intervals of 0-13, 13-35, and >35 km. The maximum values above the plumes are represented by higher seismic moments in the surface layer. The main demarcation zones differ in maximum energy release values in the AARS with shearing features. Comparison of these values against the age of the start of spreading processes shows trends of heat flow and medium field tomography in the AARS segments. The trends confirm the thermal interpretation of the seismic tomography data and suggest mantle cooling with age and a decrease in the mean temperatures of the mantle. The main factor causing the sublatitudinal asymmetry of heat flow in the AARS is the impact of Coriolis forces on the magma in the asthenospheric source. Most of the synrift igneous formations seem to be related to the influence of long-lived anomalies in the mantle, which had lower rates of magma generation than those typical of the formation of magmatic provinces. In conditions for spreading and the formation of the oceanic crust, the process followed the principle of energy cost minimization, and the prerift magmatic provinces with the pre-processed crust contributed to the choice and positioning of the AARS trajectory. The plume branches are imposed in the tomographic section and thus 'concealing' the relationship between the age and the thermal state. However, that does not change the trend to cooling of the mantle beneath the AARS, proportionally to the time since the start of spreading.

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2.2.1.1.4 East Pacific

Herzen¹

Landolt-Börnstein - Group v Geophysics

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Heat-flow near a North Atlantic fracture zone

Cited by 12 publications

References 56 publications

Heat flow variations on a slowly accreting ridge: Constraints on the hydrothermal and conductive cooling for the Lucky Strike segment (Mid‐Atlantic Ridge, 37°N)

Heat flow variations on a slowly accreting ridge: Constraints on the hydrothermal and conductive cooling for the Lucky Strike segment (Mid‐Atlantic Ridge, 37°N)

Intensity Indicators of Geodynamic Processes Along the Atlantic-Arctic Rift System

2.2.1.1.4 East Pacific

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