Magma production rate along the Ninetyeast Ridge and its relationship to Indian plate motion and Kerguelen hot spot activity

Abstract

The Ninetyeast Ridge, a linear trace of the Kerguelen hot spot in the Indian Ocean, was emplaced on a rapidly drifting Indian plate. Magma production rates along the ridge track are computed using gravity-derived excess crustal thickness data. The production rates change between 2 and 15 m 3 /s over timescales of 3-16 Myr. Major variations in magma production rates are primarily associated with significant changes in the Indian plate velocity with low-production phases linked to high plate velocity periods. The lowest magma production rate (2 m 3 /s) at 62 Ma is associated with the rapid northward drift of Indian plate under the influence of the Reunion mantle plume. The contemporaneous slowing of the African plate coincides with increase in magma production rate along the Walvis Ridge in the Atlantic Ocean. The present study suggests that variations in the Indian plate motion and frequent ridge jumps have a major role in controlling the magma production, particularly on long-period cycles (~16 Myr). Short-period variations (~5 Myr) in magma productions may be associated with intrinsic changes in the plume, possibly due to the presence of solitary waves in the plume conduit.

Variable Melt Production Rate of the Kerguelen HotSpot Due To Long‐Term Plume‐Ridge Interaction

“…Subsequently, the magma flux fluctuates significantly and reaches a second peak after the onset of spreading at the South East Indian Ridge at 40 Ma. Our model does not reach the values of Sreejith and Krishna () during the creation of the Ninetyeast Ridge, but the total magma production of our model yields a volume of 1.98 × 10 7 km 3 , comparable to the 2.5 × 10 7 km 3 given by Coffin et al (). The reason for the fluctuations can best be seen by comparing the colors of the plume in the insets in Figure , which correspond to the degree of melting in the model.…”

“…Based on numerical models of thermal plumes, Lin and van Keken () demonstrated that the entrainment of dense material in the lowermost mantle can lead to multiple pulses of plume material and thus be another explanation for several volcanic episodes generating flood basalts. Sreejith and Krishna () reported a rapidly varying magma production rate along the Ninetyeast Ridge (see Figure a) and attributed the long‐term variations to the frequent ridge jumps and major velocity changes of the Indian Plate, whereas short‐term variations were explained by solitary waves in the plume tail. Referring to these results, Figure b shows the magma production rate in the model, derived both for the 10 Ma intervals as shown in Figure and also for 1 Ma intervals in order to visualize the short‐term variations.…”

Magma production along the Lord Howe Seamount Chain, northern Zealandia

“…This yields estimates of 0.4 m 3 s −1 and 0.27 m 3 s −1 for the Lord Howe and Tasmantid seamount chains, respectively. While the volcanic flux for the Lord Howe and Tasmantid trails is a tentative estimate, this flux similarly is an order of magnitude smaller than the present flux at Hawaii (Wessel, 2016), the Ninetyeast Ridge (Coffin et al 2002;Sreejith & Krishna, 2015) and Iceland (Mjelde et al 2010), but is closer to fluxes calculated for sections of the Hawaiian trail > 30 Ma old (Wessel, 2016) and St Helena in the South Atlantic (Adam et al 2007) and larger than those calculated for the Madeira, Yellowstone and Louisville hotspots (Mjelde et al 2010). Jones & Verdel (2015) provided a volume flux (or eruptive rate) estimate from the onshore Central Volcanic Province of 0.04 m 3 s −1 , an order of magnitude smaller than the Lord Howe Seamount Chain volcanic rocks, but this should be thought of as a significant underestimation.…”

Plume‐ridge interaction via melt channelization at Galápagos and other near‐ridge hotspot provinces

“…Although, they are generally considered to represent different regimes of mantle upwelling, these two systems are not always isolated from each other [e.g., Schilling, 1991;Ito and Lin, 1995;Ito et al, 2003;Dyment et al, 2007;Whittaker et al, 2015]. A number of mantle plumes are located on or near mid-ocean ridges either at present, e.g., Gal apagos [Schilling et al, 1982], Azores [Cannat et al, 1999], Iceland [Schilling, 1973], Tristan da Cunha [Schilling et al, 1985], Easter-Salas y G omez [Kingsley and Schilling, 1998], or in the past, e.g., Kerguelen [Sreejith and Krishna, 2015]. A nearby ( 1600 km) plume may lead to higher mantle temperatures and more fertile mantle geochemistry beneath the ridge (e.g., for Gal apagos- Schilling et al [2003]; Ingle et al [2010]).…”