Kunio Kaiho 교수

Research Article| August 01, 1994 Benthic foraminiferal dissolved-oxygen index and dissolved-oxygen levels in the modern ocean Kunio Kaiho Kunio Kaiho 1Institute of Geology and Paleontology, Tohoku University, Sendai 980, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information Kunio Kaiho 1Institute of Geology and Paleontology, Tohoku University, Sendai 980, Japan Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 P

Our studies in southern China have revealed a remarkable sulfur and strontium isotope excursion at the end of the Permian, along with a coincident concentration of impact-metamorphosed grains and kaolinite and a significant decrease in manganese, phosphorous, calcium, and microfossils (foraminifera). These data suggest that an asteroid or a comet hit the ocean at the end of Permian time and caused a rapid and massive release of sulfur from the mantle to the ocean-atmosphere system, leading to si

A major extinction of intermediate‐water (500–1000 m) benthic foraminiferal species coincided with a major decrease in δ 13 C (2.8‰) of terrestrial organic matter (n‐C 29 alkane) and δ 34 S (20‰) of whole rock sulfide in a continuous siltstone sequence in the Tawanui Section (46°S paleolatitude) along the Akitio River, southeastern North Island, New Zealand, in the middle part of the uppermost Paleocene nannofossil zone (CP8). The benthic extinction (25% of species) occurred over ∼3 kyr at ∼55.5

The mass extinction of life 66 million years ago at the Cretaceous/Paleogene boundary, marked by the extinctions of dinosaurs and shallow marine organisms, is important because it led to the macroevolution of mammals and appearance of humans. The current hypothesis for the extinction is that an asteroid impact in present-day Mexico formed condensed aerosols in the stratosphere, which caused the cessation of photosynthesis and global near-freezing conditions. Here, we show that the stratospheric

Thirty‐six different geochemical and foraminiferal analyses were conducted on samples collected at closely spaced intervals across the Cretaceous/Tertiary (K/T) boundary exposed at Caravaca, Spain. A rapid reduction in the gradient between δ 13 C values in fine fraction carbonate and benthic foraminiferal calcite and a decrease in the abundance of phosphorus (a proxy for organic carbon) and calcium were recorded in sediments 0–0.5 cm above the K/T boundary. These trends imply that an abrupt mass

Abstract Eruption of the Siberian Traps large igneous province (LIP) is thought to have triggered the Permian-Triassic biological crisis, the largest of the Phanerozoic mass extinctions. Mercury concentration enrichments have been widely used as a proxy for volcanic inputs to sediments, especially for ancient LIP eruptions. However, detailed correlations of magmatic pulses with extinction events in the terrestrial and marine realms are not fully resolved. Here we use paired coronene (a six-ring

Research Article| April 01, 1999 Catastrophic extinction of planktonic foraminifera at the Cretaceous-Tertiary boundary evidenced by stable isotopes and foraminiferal abundance at Caravaca, Spain Kunio Kaiho; Kunio Kaiho 1Institute of Geology and Paleontology, Tohoku University, Sendai 980-8578, Japan Search for other works by this author on: GSW Google Scholar Marcos A. Lamolda Marcos A. Lamolda 2Paleontologia Facultad de Ciencias, Universidad del Pais Vasco, 48940 Lejona, Spain Search for othe

ABSTRACT In order to evaluate the possible influence of oceanic crust production on climatic changes during the past 100Myr variations in total oceanic crust for this period including production at mid‐ocean ridges, oceanic plateaus, and back‐arc basins were calculated using the most recent and accurate time‐scales. The rates presented here differ from those of Larson (1991a, b) on Cenozoic fluctuations and show that (1) maximum production values occurred during the Cenomanian, Palaeocene, and l