نتایج جستجو برای: early cambrian schists

تعداد نتایج: 688211  

2010
D. A. Fike

An anomalous enrichment in marine sulfate dSSO4 is preserved in globally-distributed latest Ediacaran–early Cambrian strata. The proximity of this anomaly to the Ediacaran–Cambrian boundary and the associated evolutionary radiation has invited speculation that the two are causally related. Here we present a high-resolution record of paired sulfate (dSSO4 ) and pyrite (dSpyr) from sediments span...

Journal: :Developmental biology 2002
Jun-Yuan Chen Paola Oliveri Feng Gao Stephen Q Dornbos Chia-Wei Li David J Bottjer Eric H Davidson

The evolutionary divergence of cnidarian and bilaterian lineages from their remote metazoan ancestor occurred at an unknown depth in time before the Cambrian, since crown group representatives of each are found in Lower Cambrian fossil assemblages. We report here a variety of putative embryonic, larval, and adult microfossils deriving from Precambrian phosphorite deposits of Southwest China, wh...

Journal: :International Geology Review 2022

Detrital zircon populations of the South Qiangtang terrane (SQT) provide vital information for reconstructing Tethyan evolution Tibetan Plateau but are obscured by undefined affiliation detrital samples and superimposition multiple tectonothermal events. We outlined SQT based on geological mapping collated Cambrian-Triassic to investigate representative populations. Although diachronous strata ...

Journal: :Current Biology 2015
Javier Ortega-Hernández

The Cambrian fossil record of euarthropods (extant arachnids, myriapods, crustaceans, hexapods) has played a major role in understanding the origins of these successful animals and indicates that early ancestors underwent an evolutionary transition from soft-bodied taxa (lobopodians) to more familiar sclerotized forms with jointed appendages [1-3]. Recent advances in paleoneurology and developm...

1999
GRAHAM A. SHIELDS HARALD STRAUSS STEPHEN S. HOWE HENDRIK SIEGMUND

The Meishucun Section (Yunnan Province, South China) is considered to be an important Precambrian–Cambrian boundary section, primarily because of its rich small shelly fossil record. In this article, we report the results of a sulphur isotope study of phosphate-bound sulphate from the Meishucun Section and several correlative sections in South China. Forty clastic, granular phosphorites from Me...

1999
Jon E. Mound Jerry X. Mitrovica David A. D. Evans Joseph L. Kirschvink

The possibility of inertial interchange true polar wander (IITPW) events, in which the rotation pole moves 90° with respect to the solid Earth in a matter of ~10 Myr, has been discussed in the geophysical literature for more than three decades. Recent evidence for an IITPW event in Early Cambrian time has renewed interest in the issue; however, the veracity of supporting palaeomagnetic evidence...

Journal: :Proceedings. Biological sciences 2010
Zhifei Zhang Jian Han Yang Wang Christian C Emig Degan Shu

The classic Chengjiang Lagerstätte (Lower Cambrian, Atdabanian stage: Yu'anshan Formation) Yunnan, southwestern China, has yielded, besides the exceptional and often controversial soft-bodied fossils, a fauna of primitive/early lingulid brachiopods. Diandongia pista (Rong 1974) is one of the commonest and most strongly mineralized of the phosphatic brachiopods from the Lagerstätte. The shells o...

2004
R. G. COLEMAN

Tectonic inclusions within the New Idria serpentine body contain jadeite in two distinct assemblages: (1) Lenslike inclusions containing a monomineralic green jadeite core surrounded by a calc-silicate rim. (2) Jadeite veins cross-cutting albite-crossite schist inclusions. In these veins jadeite coexists with low albite; green jadeite (Jd 75 Ac+Di+He 25) coexists with low albite within the host...

Journal: :Geological Magazine 1951

1999
L. A. Derry R. M. Corfield A.Yu. Rozanov A.Yu Zhuravlev

We report 87Sr/86Sr measurements on a suite of well preserved sedimentary carbonates from Lower Cambrian strata of the Lena River region of Siberia. Stable isotopes and major and trace element chemistry have been used to identify potentially unaltered samples for Sr isotopic measurements. The Sr data define a smooth curve of paleoseawater 87Sr/86Sr values from the Tommotian through to the early...

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