Nematophytes          下载免费PDF全文

Marcelina Kondas 《Geology Today》2018,34(2):73-78

The Nematophyta is an enigmatic group of organisms, probably with a varied origin, that achieved world‐wide distribution during Ordovician–Devonian times. Nematophytes differ in size, from only a few millimetre‐sized structures, to giants, several metres long. Their morphology is very specific. Generally, they consist of tubes and cuticles of various size and shapes. The complexity of these organisms varies, from single tubes (with or without internal ornamentation) to very complex forms. Until now, these organisms have remained a very mysterious group. We do not know much about their biology, affinity and the role they played in ecological systems, but we suspect that they were an important component of environments before the colonization of land by higher plants.  相似文献   

Environment and Age of the Upper Devonian‒Carboniferous Zhulumute and Hongguleleng Formations, Junggar Basin, NW China: Ichnological and Palynological Aspects     

Michal STACHACZ  Marcelina KONDAS  MA Xueping  Pawel FILIPIAK 《《地质学报》英文版》2021,95(3):724-739

Two Upper Devonian to Lower Carboniferous sections, namely the Bulongguoer and Haer(Gennaren area) in the Junggar Basin, Central Asian Orogenic Belt, in northwestern China were examined with regard to ichnology and palynology. The deposits of the Hongguleleng Formation and Namu Member of the Heishantou Formation, respectively, are mostly unbioturbated or poorly bioturbated, with poorly diversified trace fossils, which indicate unfavourable conditions for the burrowing benthic community during the Late Devonian and Early Carboniferous. The main factor governing the growth of the bioturbating population was the rapid sedimentation of fine-grained, volcanic material documented as tempestites, which buried the benthic fauna. In the Bulongguoer section, the presence of miospores Teichertospora torquata and Grandispora gracilis enabled identification of the broad Teichertospora torquata–Grandispora gracilis Miospore Zone from the transitional Frasnian/Famennian interval. More accurate identification of palynostratigraphical levels(DE and CZ Miospore zones) is only tentative. On the basis of palynofacies analysis, samples from the lower Bulongguoer section indicate deposition in more proximal conditions, whereas samples from the top of the section indicate deposition in a more distal environment. In the Haer section, only a general biostratigraphic indication for the Tournaisian was possible, owing to poor preservation of organic matter.  相似文献