Highly variable magmatic accretion at the ultraslow-spreading Gakkel Ridge

Nature, Год журнала: 2024, Номер 633(8028), С. 109 - 113

Опубликована: Авг. 21, 2024

Crustal accretion at mid-ocean ridges governs the creation and evolution of oceanic lithosphere. Generally accepted models1–4 passive mantle upwelling melting predict notably decreased crustal thickness a spreading rate less than 20 mm year−1. We conducted first, to our knowledge, high-resolution ocean-bottom seismometer (OBS) experiment Gakkel Ridge in Arctic Ocean imaged structure slowest-spreading ridge on Earth. Unexpectedly, we find that ranges between 3.3 km 8.9 along axis it increased from about 4.5 7.5 over past 5 Myr an across-axis profile. The highly variable relatively large average value does not align with prediction models. Instead, can be explained by model buoyant active flow driven thermal compositional density changes owing melt extraction. influence versus is predicted increase decreasing rate. process anticipated primarily influenced temperature composition. This implies observed variability accretion, which includes varied thickness, probably inherent characteristic ultraslow-spreading ridges. Results show unexpected value, model.

Язык: Английский

Mantle evolution beneath a back-arc basin: Highly siderophile elements and Os isotope of Dongco ophiolitic peridotites, Tibet

Chemical Geology, Год журнала: 2025, Номер unknown, С. 122757 - 122757

Опубликована: Март 1, 2025

Язык: Английский