Name
Agarkov Yuri Vasilievich
Scholastic degree
•
Academic rank
—
Honorary rank
—
Organization, job position
Scientific Research Center
Web site url
—
snic@sochi.com yagarkov2011@yandex.ru
Articles count: 1
The dynamics of changes in the species diversity of
radiolarians during the last 150 million years with
accuracy to one geological century was determined.
The basic patterns of species and taxa of high rank
change had been established for the boundary
between Cretaceous and Paleogene. There were
revealed topomorphic features of bipolar species,
which have succeeded from the Cretaceous into the
Paleogene and became ancestors of Cenozoic
radiolarian fauna. Changes in the species number in
the boundary between Cretaceous and Paleogene
periods, and also significant variations in the species
diversity in Paleocene and Eocene are connected to a
combination of a number of factors. The most
important of those factors are geological processes,
causing extensive transgressions and regressions,
climate variability, the overall evolution direction of
the Earth biota and competition for important
chemical components for the Radiolaria’s livelihood.
The emergence of powerful tropical forests on the
land with their huge bio-production and bio-chemical
erosion is connected to late Cretaceous era. This
resulted increasing of the dissolved material
proceeding into the sedimentation pool, what is
confirmed by classical bauxites emergence. Because
aluminium oxide and silicon oxide are geochemically
connected, we can state as well about
increasing of dissolved silica flow initiated
development of Diatoms, which became competitors
to Radiolaria in their battle for silica. The last ones
are lost this battle, what caused the species
decreasing. That was not a catastrophic event with
immediate extinction, but a long process