[meteorite-list] New Papers on Triassic - Jurassic Extinctions and Boundary

[Paul]

The latest issue, vol. 244, no. 1-4 (February 9, 
2007), of Palaeogeography, Palaeoclimatology, 
Palaeoecology is devoted to “Triassic-Jurassic 
Boundary events: problems, progress, possibilities”.
It contains a number of papers, which discuss the 
various theories about what created the Triassic
- Jurassic extinctions. The table of contents can be
found at:

http://www.sciencedirect.com/science/journal/00310182

They include:

Hesselbo, S. P., McRoberts, C. A.,  and Palfy, J., 2007,
Triassic–Jurassic boundary events: Problems, progress, 
possibilities. Palaeogeography, Palaeoclimatology, 
Palaeoecology. vol. 244, no. 1-4 , pp. 1-10.

In the above paper, they stated:

"The debate about extraterrestrial versus volcanic drivers 
for environmental change has not yet been concluded, and 
it is noteworthy that all of the candidate indicators of 
extraterrestrial impact - reports of PGE's and soft sediment 
deformation - occur shortly prior to CAMP volcanic activity. 
Pure coincidence aside, this observation keeps alive the idea 
that there is an 'impact signal'-LIP connection, even if the 
mechanisms remain highly controversial; for example, 
impact decompression melting, as recently articulated by 
Elkins-Tanton and Hager (2005), or lithospheric gas 
explosion (Phipps Morgan et al., 2005)."

Another paper is:

Michalíka, J., Lintnerovab, O., Gadzickic, A., and Sotakd, 
J., 2007, Record of environmental changes in the Triassic-
Jurassic boundary interval in the Zliechov Basin, Western 
Carpathians. Palaeogeography, Palaeoclimatology, 
Palaeoecology. vol. 244, no. 1-4  pp. 71-88.

This paper states:

“The negative delta 13C excursion is correlated with a 
positive delta 18O peak and the beds containing the 
excursion are overlain by a thin layer with unusual 
lithological and mineral composition. This layer is 
composed of small calcitized microspheres showing 
complex alteration during diagenesis. The origin of this 
layer, traceable over tens of kilometres, is problematic 
(impact ejecta, volcanic glass, or altered aragonitic 
particles).”

Yours,

Paul H.


 
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