Metamorphic Processes in Sediments in Contact with Young Oceanic CrustEast Pacific Rise, Leg 65

Rangin, Claude; Desprairies, Alain; Fontes, Jean-Charles; Jèhanno, C.; Vernhet, S.

doi:10.2973/dsdp.proc.65.112.1983

Cited by 10 publications

(2 citation statements)

References 20 publications

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“…The same 18.9 20.7 39.9 -1.5 0. (Chamley and Bonnot-Courtois, 1981;Desprairies, 1982;Kastner, 1982;Rangin et al, 1983). The occurrence of mixed-layer chlorite-smectite in the cracks and in contact with the basalt could indicate that the clay mineral transformation took place at a temperature around 200-230°C (Tomasson and Kristmanndottir, 1972;Kristmanndottir, 1976;Desprairies and Jehanno, in press).…”

Section: Interaction Between Basalt and Terrigenous Sedimentsmentioning

confidence: 99%

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Desprairies¹,

Bonnot-Courtois²,

Jèhanno³

et al. 1984

Initial Reports of the Deep Sea Drilling Project

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Alteration products of basalts from the four holes drilled during Leg 81 were studied and found to be characterized by the widespread occurrence of trioctahedral clay minerals (Mg smectite to chlorite). In some cases zeolites (analcite, chabazite) are associated with the saponite. A more oxidizing stage is marked by a saponite-celadonite association, presenting the geochemical characteristics of hydrothermal processes. Later stages of alteration are represented by palagonitization and subaerial weathering at two sites. These different alteration processes of basalts from Leg 81 record the paleoenvironment during the first opening stages of the Northeast Atlantic Ocean in the Paleocene-Eocene periods.

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Section: Interaction Between Basalt and Terrigenous Sedimentsmentioning

confidence: 99%

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Desprairies¹,

Bonnot-Courtois²,

Jèhanno³

et al. 1984

Initial Reports of the Deep Sea Drilling Project

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“…As a first approach, we consider the simple conceptual model depicted in Figure 8, which shows a control volume in the zone of active sill emplacement in the GB troughs. In this model, we devise a basal layer approximatly 6 km thick (Lizarralde et al, 2007) made from gabbroic rocks and dehydrated greenschist/amphibolite facies metasediments (e.g., Christensen & Salisbury, 1975; Rangin et al, 1983; Stern et al, 1976). Thanks to their high thermal conductivities, these rocks draw heat from the emplacement of hot grabboic material at the base of the crust and the slow release of latent heat by crystallization.…”

Section: Discussionmentioning

confidence: 99%

Heat flow and thermal regime in the Guaymas Basin, Gulf of California: Estimates of conductive and advective heat transport

et al. 2023

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Heat flow is estimated at eight sites drilled int the Guaymas Basin, Gulf of California, during the International Ocean Discovery Program Expedition 385. The expedition sought to understand the thermal regime of the basin and heat transfer between off‐axis sills intruding the organic‐rich sediments of the Guaymas Basin, and the basin floor. The distinct sedimentation rates, active tectonics, and magmatism make the basin interesting for scientific discoveries. Results show that sedimentation corrected heat flow values range 119–221 mW/m2 in the basin and 257–1003 mW/m2 at the site of a young sill intrusion, denominated Ringvent. Thermal analysis shows that heat in the Guaymas Basin is being dissipated by conduction for plate ages >0.2 Ma, whereas younger plate ages are in a state of transient cooling by both conduction and advection. Drilling sites show that Ringvent is an active sill being cooled down slowly by circulating fluids with discharge velocities of 10–200 mm/yr. Possible recharge sites are located ca. 1 km away from the sill's border. Modelling of the heat output at Ringvent indicates a sill thickness of ca. 240 m. A simple order‐of‐magnitude model predicts that relatively small amounts of magma are needed to account for the elevated heat flow in non‐volcanic, sediment‐filled rifts like the central and northern Gulf of California in which heating of the upper crust is achieved via advection by sill emplacement and hydrothermal circulation. Multiple timescales of cooling control the crustal, chemical and biological evolution of the Guaymas Basin. Here, we recognize at least four timescales: the time interval between intrusions (ca. 103 yr), the thermal relaxation time of sills (ca. 104 yr), the characteristic cooling time of the sediments (ca. 105 yr), and the cooling of the entire crust at geologic timescales.

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Seawater-sediment-basalt interactions: stable isotope (H, O) and elemental fluxes within the Ordovician volcano-sedimentary sequence of Erquy (Brittany, France)

Lécuyer

Grandjean²,

Martineau

1995

Contr. Mineral. and Petrol.

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Metamorphic Processes in Sediments in Contact with Young Oceanic CrustEast Pacific Rise, Leg 65

Cited by 10 publications

References 20 publications

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Heat flow and thermal regime in the Guaymas Basin, Gulf of California: Estimates of conductive and advective heat transport

Seawater-sediment-basalt interactions: stable isotope (H, O) and elemental fluxes within the Ordovician volcano-sedimentary sequence of Erquy (Brittany, France)

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Metamorphic Processes in Sediments in Contact with Young Oceanic CrustEast Pacific Rise, Leg 65

Cited by 10 publications

References 20 publications

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Mineralogy and Geochemistry of Alteration Products in Leg 81 Basalts

Heat flow and thermal regime in the Guaymas Basin, Gulf of California: Estimates of conductive and advective heat transport

Seawater-sediment-basalt interactions: stable isotope (H, O) and elemental fluxes within the Ordovician volcano-sedimentary sequence of Erquy (Brittany, France)

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Metamorphic Processes in Sediments in Contact with Young Oceanic CrustEast Pacific Rise, Leg 65