SUMMARY The red soil sequences in southern and southeastern China provide important terrestrial archives of palaeoclimate and palaeoenvironment and are important sources of Palaeolithic settlements and, therefore, early human occupation. Here we present detailed palaeomagnetic investigation coupled with mineral magnetic and petrographic analyses of a red soil sequence at Qiliting, southeastern China. The sediments contain both strongly magnetic minerals (such as maghemite and magnetite) and weakly magnetic minerals (such as haematite and possibly goethite). Maghemite and haematite were identified as the main carriers of the natural remnant magnetisations. Only haematite dominates the characteristic remnant magnetisations. Palaeomagnetic findings suggest that the Qiliting sedimentary sequence recorded the early Brunhes Chron and the late Matuyama Chron, including the Jaramillo Subchron. Our finding, coupled with previously published magnetostratigraphy, establishes that the red soil sequences in southern China began to accumulate no later than the Jaramillo age (i.e. ∼1.0 Ma). It is further suggested that the capabilities of recording magnetic polarity stratigraphy in Chinese red soil sequences are variable between areas because of different climate regimes.

No abstract

No abstract

No abstract

No abstract

: Three Schizolepis species collected from the Lower Cretaceous layer of the Huolinhe Basin, Inner Mongolia, China are described. These fossils are Schizolepis longipetiolus Xu XH et Sun BN sp. nov., which is a new species, Schizolepis cf. heilongjiangensis Zheng et Zhang, and Schizolepis neimengensis Deng. The new species is a well‐preserved female cone, slender and cylindrical in shape. The seed–scale complexes have long petioles and are arranged on the cone axis loosely and helically. The seed scales are divided into two lobes from the base. Each lobe is semicircular or elongate ligulate in shape, widest at the middle or the lower middle part, with an obtuse or bluntly pointed apex. The inner margin is almost straight and the outer margin is strongly arched. On the surface of the lobe, there are longitudinal and somewhat radial striations from the base to the margin. The seed is borne on the adaxial surface at the base or middle of each lobe. Schizolepis was established in 1847, and, although more than twenty species have been discovered and reported, its phylogenetic position is controversial because of the imperfection of fossils. Most authors have considered there to be a close evolutionary relationship between Schizolepis and extant Pinaceae. Here, we analyze characteristics and compare Schizolepis with Picea crassifolia Kom, which is morphologically most similar to Schizolepis. The results indicate that the genus probably has a distant evolutionary relationship with extant Pinaceae. A detailed statistical analysis of the global paleogeographic distribution of Schizolepis showed that all the fossils of this genus appeared in strata ranging from the Upper Triassic to the Lower Cretaceous in the North Hemisphere, being rare in the Upper Triassic and Lower Jurassic, but being very common from the Middle Jurassic to the Lower Cretaceous, and particularly abundant in the Lower Cretaceous. According to the statistical results, we speculate that the genus originated in Europe in the Late Triassic then spread from Europe to Asia between the Late Triassic and the Late Jurassic. In the Early Cretaceous most species existed in China's three northeastern Provinces and the Inner Mongolia Autonomous Region and adjacent areas. Combining the paleogeographic distribution of the genus with ancient climatic factors, we deduced that Schizolepis began to decline and became extinct in the Early Cretaceous, and the reason for its extinction is closely related to the icehouse climate during the Early Cretaceous.

No abstract

No abstract