Terrestrial Palaeoecology and Global Change

302 Valentin A. Krassilov. Terrestrial Palaeoecology
a
b
d
c
Fig. 122. Extension of lacustrine rift deposits with Lycoptera–
Ephemeropsis–proangiosperm assemblages (of the type shown in Fig.
118) to northeastern China: (a) a fern-marsh palaeosol with Coniopteris
in tuffaceous deposits of Didao Formation representing a wetland type
that became rare after the transboundary Jurassic/Cretaceous volcanic
phase (b) a fish bed of Yixian Formation, a mass mortality case, (c)
Gurvanella, a fruit-like proangiosperm cupule common in the Yixian
Formation, (d) the same species from contemporaneous deposits of
Gurvan Eren, Mongolia (Krassilov, 1982).
catastrophes possibly related to volcanism and acid rains as well as an enhanced chemical
weathering of the granite bedrock, a massive source of Al and F in the drainage
runoff. The same factors might have been responsible for vegetation turnovers in the
adjacent wetlands.
Thus, the Jurassic to Cretaceous riftogenesis and basaltic volcanism over the trans-
Asiatic Mongolo-Okhotskian zone (V.5.2) provided an ecological situation for a highrate
macrevolutionary development. Remarkably, a comparable proangiosperm development
took place over the contemporaneous Brazilian basaltic province (Mohr & Friis,
2000). Rift valleys (Fig. 125) are hot spots of basic diversification not only for higher