Past emergent phase of Shatsky Rise deep-marine igneous plateau

Abstract

The Cretaceous Period stands out in Earth's geologic history by ubiquitous and sustained massive eruption of lava, forming several enormous igneous plateaus in the ocean basins worldwide. It has been proposed that the subaerial phases of Cretaceous oceanic plateau formation spurred the global environmental deterioration, yet this view is supported by patchy fossil and/or rock evidence for uplifting of the plateau summits above the sea level. Reported here is by far the most comprehensive case of Cretaceous plateau emergence at northern Shatsky Rise, Northwest Pacific, based on the integration of unique micropalaeontological and seismic evidence. From just above the flat-topped igneous edifice, recent Integrated Ocean Drilling Program (at Site U1346) recovered early Cretaceous (Hauterivian) ostracod and foraminiferal assemblages showing marked shallow-marine preferences. Most intriguing discovery is an ostracod taxon with well-developed eye tubercles, which serves as compelling palaeobiological evidence for a very shallow, euphotic setting. By linking the nearshore biofacies (<20 m water depth) to the basement topography undoubtedly shaped by subaerial weathering and/or erosion, it is obvious that northern Shatsky Rise was remarkably emergent during its final emplacement phase. We suggest that early Cretaceous surface environments might have been affected, at least in part, by Shatsky Rise subaerial volcanism.

Biostratigraphy, paleobathymetry and paleobiogeography of Lower Cretaceous benthic foraminifera from Shatsky Rise (ODP Leg 198) in the central Pacific Ocean

“…In this study, an outer neritic setting (100 -200 m) is inferred for the Tamu Massif (ODP holes 1213A and 1213B; Fig. 5B), contrasting with the inner neritic (<20m) setting suggested for the Shirshov Massif during the Hauterivian (Yasuhara et al, 2017).…”

“…Hauterivian benthic foraminifera (e.g., Astacolus, Citharina, Dentalina, Frondicularia, Laevidentalina, Lenticulina, Planularia, Psilocitharella, Saracenaria, and Vaginulinopsis) and ostracods recorded at IODP Site U1346, which is located at the Shirshov Massif close to ODP Hole 1207B, have been interpreted by thrived in an inner neritic setting shallower than 20 m (Yasuhara et al, 2017).…”

Finding the VOICE: organic carbon isotope chemostratigraphy of Late Jurassic – Early Cretaceous Arctic Canada

“…However, new U-Pb ages from Argentina and Mexico suggest that the numerical age of the Jurassic-Cretaceous boundary may lie between 140.7 and 140.9 Ma; this evidence would place an age of c. 145 Ma (the current ICS age for the base of the Berriasian stage) into the middle of the Tithonian age (Lena et al 2019), whether the base of the Tithonian is 152.1 Ma (Cohen et al 2013; updated 2018/08) or 148 Ma (Lena et al 2019) or somewhere between. Sub-aerial volcanism and summit weathering and/or erosion of the emergent phase of the Shatsky Rise is thought to have occurred as early as during the Valanginian age (Yasuhara et al 2017), suggesting possible further complications in the interpretation of significance of the age of the sills associated with the Shatsky Rise. The ages of the base of the Tithonian and Berriasian stages are yet to be confirmed (e.g.…”

Phanerozoic Large Igneous Province, Petroleum System, and Source Rock Links

“…LIPs may begin erupting in an oceanic environment, transition to continental settings due to isostatic and dynamic effects of the buoyant plume head, and then return to oceanic settings due to subsidence associated with thermal cooling of the lithosphere. In fact, the Shatsky Rise LIP, now located in the interior of the Pacific Ocean in deep water ( >3 km) experienced shallow water or subaerial phases early in its history (Yasuhara et al, 2017).…”