Hironao Matsumoto 교수

During the mid-Cretaceous, the Earth experienced several environmental perturbations, including an extremely warm climate and Oceanic Anoxic Events (OAEs). Submarine volcanic episodes associated with formation of large igneous provinces (LIPs) may have triggered these perturbations. The osmium isotopic ratio (¹⁸⁷Os/¹⁸⁸Os) is a suitable proxy for tracing hydrothermal activity associated with the LIPs formation, but ¹⁸⁷Os/¹⁸⁸Os data from the mid-Cretaceo

The Aptian-Albian boundary is marked by one of the major oceanic perturbations during the Cretaceous, called Oceanic Anoxic Event (OAE) 1b. Extensive volcanic episodes at the Southern Kerguelen Plateau has been suggested as the trigger of OAE1b, but compelling evidence remains lacking. Here, we reconstructed the temporal variations of marine Os isotopic ratios across the Aptian-Albian boundary in the Tethyan and Pacific pelagic sedimentary records to elucidate the causal links between OAE1b, the

Abstract The early to mid-Aptian was punctuated by episodic phases of organic-carbon burial in various oceanographic settings, which are possibly related to massive volcanism associated with the emplacement of the Ontong Java, Manihiki, and Hikurangi oceanic plateaus in the southwestern Pacific Ocean, inferred to have formed a single plateau called Ontong Java Nui. Sedimentary osmium (Os) isotopic compositions are one of the best proxies for determining the timing of voluminous submarine volcani

Abstract The 405‐kyr eccentricity cycle is a consistent orbital parameter throughout the Phanerozoic that is associated with long‐term variations in global continental weathering. However, a lack of reliable geological evidence has hampered the understanding of the relation between the 405‐kyr eccentricity cycle and continental weathering during the Cretaceous. Os isotopic ratios ( 187 Os/ 188 Os) of the sedimentary record reflect the balance between radiogenic Os derived from continental weathe

Abstract The volcanic episode that formed Ontong Java Nui (OJN) in the western Pacific ~ 120 million-year-ago is thought to have triggered Oceanic Anoxic Event (OAE) 1a, yet the cause-effect relationship remains insufficiently understood. Here, we present a Pb-Os-C isotope dataset for tracking OJN volcanism across a sedimentary sequence containing OAE1a record in the central Pacific. Lead isotopic evidence strongly supports the deposition of OJN-sourced volcanic ash layers at this site after a p

Conodonts are tooth-like apparatuses of extinct marine animals and their geochemical composition is a key tool in reconstructions of paleo-marine environmental conditions. Previous geochemical studies focused on conodont fossils with weak thermal maturation from shallow-marine sedimentary rocks. However, the geochemical features of conodont fossils in pelagic deep-sea sedimentary rocks, which are suitable for reconstructions of paleo-environmental conditions of pelagic Panthalassa, are poorly un

The volcanic episodes forming Ontong Java Nui (OJN) likely caused late Barremian to mid-Aptian paleoenvironmental perturbations, the most substantial of which was early Aptian oceanic anoxic event (OAE) 1a (120 million years ago). However, recent estimates on younger OJN eruption ages cast doubt on the link between OJN volcanism and OAE1a. Here, we further demonstrate the synchroneity between OJN volcanism and OAE1a by refining the chronology of Pacific volcanogenic sedimentary records on Magell

The Turonian age (~ 90-94 Ma) was the hottest geological interval in the Cretaceous and also marked by the K3 event, a pronounced enrichment of ³He in pelagic sediments (i.e., massive input of extraterrestrial materials). Here, we present Os isotopic (¹⁸⁷Os/¹⁸⁸Os) and platinum group element (PGE) data from Turonian sedimentary records. After a sharp unradiogenic shift during the end-Cenomanian oceanic anoxic event 2, the ¹⁸⁷Os/¹⁸⁸Os ratios d

Abstract During the Cretaceous, several massive volcanic episodes led to significant environmental perturbations, including oceanic anoxic events (OAEs). The volcanic eruption forming Ontong Java Nui (ca. 120 Ma) in the western Pacific Ocean is recognized as the largest volcanic event on Earth and is thought to have caused oceanic anoxic event 1a (OAE1a). Although metal emissions from this volcanism are believed to have played a crucial role in triggering the Aptian oceanic anoxia, no direct evi

Data sets include the osmium and carbon isotopic information of the limestone samples collected from the Fiume Bosso section (43°31'07.2N 12°34'15.4E), central Italy. Os and carbon isotopic measurements were conducted from December 2019 to October 2020 to reconstruct paleo-marine Os and carbon isotopic variations. Os isotopic ratios were measured with thermal ionization mass spectrometry (TRITON, Thermo Fisher Scientific, USA) and carbon isotopic ratio were measured with isotope ratio mass spect

Tectonic events and volcanic pulses forming large igneous provinces (LIPs) have altered Earth's paleoclimate. Osmium (Os) and strontium (Sr) isotopic ratios are key tracers of past continental weathering and LIP eruptions. However, limited Cretaceous seawater Os and riverine Os-Sr data have hindered quantitative reconstructions. In this study, we present a long-term Os isotopic record from the Cretaceous to the present, revealing ~10- to 20-million-year cycles during the Cretaceous that align wi

<p>Figs. S1–S4 and Table S1.</p>

Description of lithology and methods, Figure S1 (sampling site), Figure S2 (cross plots of δ<sup>13</sup>C<sub>carb</sub> and δ<sup>18</sup>O<sub>carb</sub>), Figure S3 (Re-Os data), Figure S4 (age-depth model), Table S1 (raw δ<sup>13</sup>C<sub>carb</sub> and δ<sup>18</sup>O<sub>carb</sub> data), Table S2 (raw Re-Os data), and Table S3 (age model).<br>