scholarly journals Chondritesisp. Indicating Late Paleozoic Atmospheric Anoxia in Eastern Peninsular India

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Biplab Bhattacharya ◽  
Sudipto Banerjee

Rhythmic sandstone-mudstone-coal succession of the Barakar Formation (early Permian) manifests a transition from lower braided-fluvial to upper tide-wave influenced, estuarine setting. Monospecific assemblage of marine trace fossilChondritesisp. in contemporaneous claystone beds in the upper Barakar succession from two Gondwana basins (namely, the Raniganj Basin and the Talchir Basin) in eastern peninsular India signifies predominant marine incursion during end early Permian. MonospecificChondritesichnoassemblage in different sedimentary horizons in geographically wide apart (~400 km) areas demarcates multiple short-spanned phases of anoxia in eastern India. Such anoxia is interpreted as intermittent falls in oxygen level in an overall decreasing atmospheric oxygenation within the late Paleozoic global oxygen-carbon dioxide fluctuations.

2021 ◽  
pp. 1-13
Author(s):  
Rainer R. Schoch ◽  
Gabriela Sobral

Abstract The late Paleozoic temnospondyl Sclerocephalus formed an aquatic top predator in various central European lakes of the late Carboniferous and early Permian. Despite hundreds of specimens spanning a wide range of sizes, knowledge of the endocranium (braincase and palatoquadrate) remained very insufficient in Sclerocephalus and other stereospondylomorphs because even large skulls had unossified endocrania. A new specimen from a stratigraphically ancient deposit at St. Wendel in southwestern Germany is recognized as representing a new taxon, S. concordiae new species, and reveals a completely ossified endocranium. The sphenethmoid was completely ossified from the basisphenoid to the anterior ethmoid region, co-ossified with the parasphenoid, and the basipterygoid joint was fully established. The pterygoid bears a slender, S-shaped epipterygoid, which formed a robust pillar lateral to the braincase. The massive stapes was firmly sutured to the parasphenoid. In the temnospondyl endocranium, character evolution involved various changes in the epipterygoid region, which evolved distinct morphologies in each of the major clades. UUID: http://zoobank.org/5e6d2078-eacf-4467-84cf-a12efcae7c0b


2021 ◽  
Vol 25 (12) ◽  
pp. 10-18
Author(s):  
D.S. Seetharam ◽  
H. Ramakrishna

The present palaeopalynological study deals with the significance of non - striate disaccate pollen from bore hole Q - 563 of Yellandu coalfield (Jawahar Khani - 5 coal block), Kothagudem sub-basin and to determine the age and palaeoclimatic interpretations of the study area based on the pollen morphological characters. For the palynological investigation, sixty samples were thoroughly analyzed in which fairly diversified palynofloral assemblages of Gondwanic affinity were recorded. About 30 genera and 50 species of palynomorphs, belong to Glossopteridales, Coniferales, Cordaitales of gymnospermous pollen, pteridophytic spores. In the present communication, the palynoflora belongs to Glossopteridales viz. Scheuringipollentites barakarensis, S. maximus, S. tentulus, Ibisporites diplosaccus, Primuspollenites levis, P. densus and Sahnites thomasii etc. Frequency distribution pattern of the palynotaxa reveals that the assemblage is dominated by the non - striate disaccates followed by striate disaccates, monosaccates (gymnosperms) and pteridophytic spores. The diversified palynoassemblage of both non striate and striate disaccates pollen strongly signifies that the Yellandu coal belt of Godavari graben belongs to Barakar Formation of Early Permian age (Late Sakmarian – Early Artinskian). Predominance of non - striate disaccate pollen recorded from the Yellandu sediments indicates a warm and high humid climatic condition with fluvial environment of deposition.


IAWA Journal ◽  
2014 ◽  
Vol 35 (3) ◽  
pp. 307-331 ◽  
Author(s):  
Menno Booi ◽  
Isabel M. van Waveren ◽  
Johanna H.A. van Konijnenburg-van Cittert

Although araucarioid wood is poor in diagnostic characters, well in excess of 200 Late Paleozoic species have been described. This study presents a largescale anatomical analysis of this wood type based on the fossil wood collections from the Early Permian Mengkarang Formation of Sumatra, Indonesia. Principal Component Analysis visualisation, in conjunction with uni- and multivariate statistical analyses clearly show the wood from the Mengkarang Formation to be a contiguous micromorphological unit in which no individual species can be distinguished. Pycnoxylic wood species described previously from this collection or other collections from the Mengkarang Formation fall within the larger variability described here. Based on comparison with wood from modern-day Araucariaceae, the Early Permian specimens can be differentiated from extant (but unrelated) “araucarioids” by a few (continuous) characters.


2020 ◽  
Vol 57 (12) ◽  
pp. 1478-1491 ◽  
Author(s):  
Yong-gang Sun ◽  
Bi-le Li ◽  
Feng-yue Sun ◽  
Qing-feng Ding ◽  
Ye Qian ◽  
...  

Geodynamic evolution in the late Paleozoic is significant for understanding the final amalgamation of the Central Asian Orogenic Belt (CAOB). No consensus has yet been reached regarding the late Paleozoic geodynamic evolution of the northern Great Xing’an Range (GXR) in northeastern China, the eastern CAOB. Furthermore, late Paleozoic syenogranite–diabase dyke association is present in the Xiaokele area in northern GXR. It provides an important opportunity to understand the nature of magmatism and the geodynamic evolution during this period. This paper presents new zircon U–Pb ages, zircon Hf isotopic compositions, and geochemical data of whole rocks for Xiaokele syenogranite and diabase. Zircon U–Pb dating suggests that the Xiaokele syenogranite (292.5 ± 0.9 Ma) and diabase (298.3 ± 1.5 Ma) were emplaced during the early Permian. The Xiaokele syenogranites have high SiO2 contents, low MgO contents, and enriched zircon εHf(t) values, suggesting that their primary magma was generated by the partial melting of the juvenile crustal material. The Xiaokele diabases have low SiO2 contents, high MgO contents, are enriched in large-ion lithophile elements, depleted in high-field-strength elements, and exhibit enriched zircon εHf(t) values. They derived from a lithospheric mantle source that had previously been metasomatized by slab-derived fluids. Combined with previous research results, we believe that the continent–continent collision between the Xing’an and Songliao blocks occurred during the late early Carboniferous – early late Carboniferous (330–310 Ma), and the two blocks were transformed into a post-collisional extensional setting during the latest Carboniferous – early Permian.


1996 ◽  
Vol 11 (1-4) ◽  
pp. 125-135 ◽  
Author(s):  
N. W. Archbold ◽  
S. C. Shah ◽  
J. M. Dickins

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