Intraplate volcanism of the western Pacific: New insights from geological and geophysical observations in the Pigafetta Basin

Abstract

Understanding intraplate volcanism is a key to deciphering the Earth's magmatic history.One of the largest intraplate volcanic events occurred during the mid-Cretaceous, roughly 75-125 Ma in the western Pacific. To investigate the origin of this volcanism we present the first comprehensive study of volcanism in the Pigafetta Basin using seismic surveys, magnetic and gravity modeling, and Ocean Drilling Program (ODP) drill core and well log data from Site 801. Our results show that intraplate volcanism in the Pigafetta Basin coincides with the rest of the western Pacific seamount provinces, supporting the previously suggested plumelets scenario for the origin of intraplate volcanism during the mid-Cretaceous volcanic events. Our magnetic modeling suggests that the late-stage volcanism does not overprint the remanant magnetization acquired by the Jurassic ocean crust in the Pigafetta Basin, and hence, marine magnetic anomalies recorded in the Jurassic basement are preserved. Also, the formerly identified Rough-Smooth Boundary (RSB) is indistinguishable from any other rough-smooth topographic boundaries throughout the survey area suggesting that the RSB is unlikely to be a Cretaceous sill-Jurassic basement boundary. Lastly, the apparent ages and spatial distribution of volcanic features suggests a dynamic history of hydrothermal circulation in the Pigafetta Basin, indicating that hydrothermal circulation was ongoing well past 100 Ma.

Seismic Structure of the Lithosphere‐Asthenosphere System Beneath the Oldest Seafloor Revealed by Rayleigh‐Wave Dispersion Analysis

“…They obtained one-dimensional depth profiles of compressional-wave (P-wave) velocity in the southwestern and northeastern parts of the Oldest-1 Array region. The total crustal thickness was between ∼7-8 km, and subsequent studies obtained consistent results in the northeastern part of the Oldest-1 Array (Kaneda et al, 2010;Stadler & Tominaga, 2015). Abrams et al (1993) observed no seismically resolvable systematic differences both in crustal thickness and in P-wave velocity between the southwestern and northeastern areas.…”

A New Middle to Late Jurassic Geomagnetic Polarity Time Scale (GPTS) From a Multiscale Marine Magnetic Anomaly Survey of the Pacific Jurassic Quiet Zone

“…While the crust of the western Pacific was formed by Jurassic mid‐ocean ridge seafloor spreading, broad areas of the Pacific plate were subjected to Cretaceous volcanism in the form of numerous seamounts and large igneous provinces (Larson, 1991; Stadler & Tominaga, 2015). Most of the large volcanic features are documented by satellite altimetry data, but it is common to observe small seafloor volcanic features using ship multibeam sonar and high‐resolution MCS data (e.g., D. K. Smith & Jordan, 1987, 1988; Stadler & Tominaga, 2015).…”

“…While the crust of the western Pacific was formed by Jurassic mid‐ocean ridge seafloor spreading, broad areas of the Pacific plate were subjected to Cretaceous volcanism in the form of numerous seamounts and large igneous provinces (Larson, 1991; Stadler & Tominaga, 2015). Most of the large volcanic features are documented by satellite altimetry data, but it is common to observe small seafloor volcanic features using ship multibeam sonar and high‐resolution MCS data (e.g., D. K. Smith & Jordan, 1987, 1988; Stadler & Tominaga, 2015). Furthermore, in addition to extrusive volcanics apparent at the seafloor, seismic profiles provide evidence of subseafloor volcanic features, such as volcanic sills within sediments and upper crust (Abrams et al., 1992; Feng, 2016; Kaneda et al., 2010; Lancelot, Larson, & Fisher, 1990; Lancelot, Larson, & Shipboard Scientific Party, 1990; Mochizuki et al., 2005; Schlanger & Moberly, 1986; Stadler & Tominaga, 2015; Tominaga et al., 2008).…”

“…The western Pacific is also subject to widespread intraplate volcanism of Cretaceous age that impacts the entire western Pacific basin (Hamilton, 1956;Koppers, Staudigel, & Duncan, 2003;Koppers, Staudigel, Pringle, et al, 2003;Morgan, 1972;Ohira et al, 2017) (Figure 1). Seismic imaging studies suggest that there were late-stage volcanic features such as sills and lava flows throughout the western Pacific basin (Abrams et al, 1992;Feng, 2016;Kaneda et al, 2010;Stadler & Tominaga, 2015). Radiometric 40 Ar/ 39 Ar dating of seamounts in the Marcus-Wake and Magellan Seamount chains yield ages ranging from 75 to 125 Ma (e.g., Clouard & Bonneville, 2004;Koppers, Staudigel, & Duncan, 2003;Koppers, Staudigel, Pringle, et al, 2003;Saito & Ozima, 1977).…”

Petrogenesis of Basaltic Lavas From the West Pacific Seamount Province: Geochemical and Sr‐Nd‐Pb‐Hf Isotopic Constraints

“…Competing models have been presented to explain the existence of four mantle sources (DMM-EMI-EMII-HIMU) of OIBs (e.g., Ballmer et al, 2010Ballmer et al, , 2007Koppers, Staudigel, Pringle, et al, 2003;Staudigel et al, 1991). More recent models to explain the WPSP invoke a main magmatic plume head source with multiple contemporaneous plumelets in an extensional setting (e.g., Janney & Castillo, 1999;Koppers, Staudigel, Pringle, et al, 2003;Stadler & Tominaga, 2015). Others competing models include lithospheric cracking as a response to superplume uplift and deformation (McNutt & Judge, 1990), differential plate cooling resulting in lithospheric cracking (Sandwell & Fialko, 2004).…”