Sedimentary and Volcanic History: East Mariana Basin and Nauru Basin

Abstract

The sedimentary section recovered during Leg 89 at Deep Sea Drilling Project Site 525 provided a record of volcanism, plate motion, and other events of the Cretaceous and Cenozoic history of the East Mariana Basin. This part of the Pacific lithosphere had formed in the Jurassic; by late Aptian time it was at about 22°S and had subsided to a depth of about 5000 m. In the Aptian and Albian, eruptions built major volcanic edifices nearby that were the sources of massive volcaniclastic debris flows and turbidites found at Site 525. The now deeply altered sediment originally was of quartz-normative tholeiitic basalt composition, with some later alkalic basalt contributions. Reefal debris, ooids, and displaced benthic foraminifers within the hyaloclastic and other volcanogenic components show that some of the volcanoes reached shallow water. They are now the seamounts and guyots north and south of the eastern end of the East Mariana Basin. Recovered cores show evidence of the Cenomanian-Turonian oceanic anoxic event in debris rich in organic carbon redeposited in turbidites, of passage under the equator in Campanian-Maestrichtian time from core Paleomagnetism, and of the Oligocene (P21-P22) fall of sea level that exposed seamounts and thereby caused renewed turbidite activity.The Nauru Basin igneous complex discovered during Leg 61 yielded cores of 12 additional volcanic units as a result of the deepening of Hole 462A during Leg 89. The mineralogical and geochemical homogeneity within these (and overlying) sheet flows, as well as their little-altered nature and small amount of interlayered sediment, indicate that the great volume of midplate magma was generated and erupted rapidly. The lowest flows drilled during Leg 89 probably are 130 Ma (Valanginian). They lie on M26-aged ridge-crest crust (about 145 Ma, Oxfordian), and underlie volcanogenic sediment and sills representing at least two other episodes of midplate igneous activity, namely in the Aptian and Albian (about 100 Ma) and in the Campanian (about 75 Ma).

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

“…Seafloor, hosting global lithosphere‐hydrosphere‐atmosphere interactions, forms at mid‐ocean ridges (MORs) and covers roughly 70% of the Earth's surface [ Showman and Dowling , ]. The Pacific seafloor occupies approximately 50% of the world's ocean basins [e.g., Longhurst , ] and is marked by numerous intraplate volcanic features such as large oceanic plateaus [e.g., Coffin and Eldholm , ], seamounts [e.g., Menard , ; Heezen et al ., ], and deep‐sea sills/flows [e.g., Larson and Schlanger , ; Schlanger and Moherly , ]. Volcanic activity and crustal emplacement mechanisms, including seamounts at on and off‐axis regions of MORs have been extensively studied [e.g., Hess , ; Vine , ; Haymon et al ., , ; Carbotte and Macdonald , ; Hooft et al ., ; Fornari et al ., ; Curewitz and Karson , ; Chadwick and Embley , ]; however, the origin and implications of plate scale intraplate volcanism leaves much to be studied because of its great extent [cf.…”

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

“…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).…”

Petrography and Geochemistry of Graded Volcaniclastic Sediments and Their Clasts, Leg 129

“…Interpretation of seismic profiles and correlation with drilled sections suggests that much of the floor of the western Pacific may be carpeted with volcaniclastites of mid-Cretaceous age (Winterer, 1973;Schlanger et al, 1981;Schlanger and Moberly, 1986). For example, sites in the Mariana Basin, such as Hole 585 , encountered thick, midCretaceous, turbiditic volcaniclastites, which are generally considered to have been shed from the debris covered flanks of adjacent seamounts of similar age.…”

“…Many of these volcanogenic sediments are representative of the "midCretaceous" volcanic event Schlanger and Moberly, 1986;Larson and Schlanger, 1981) that roughly covered the period from the Aptian to the Campanian. During this time extensive regional volcanism built both edifice structures, oceanic plateaus (for example, Ontong-Java), and submarine extrusive complexes, such as Nauru Basin (Larson and Schlanger, 1981) and possibly the sequence at Site 802 (Floyd et al, this volume).…”