Drumian

Key events in the Cambrian
view • discuss • 
-550 —
–
-540 —
–
-530 —
–
-520 —
–
-510 —
–
-500 —
–
-490 —
–
N
e
o
p
r
o
t
e
r
o
z
o
i
c
P
a
l
e
o
z
o
i
c
Ediacaran
C
a
m
b
r
i
a
n
Ordovician
T
e
r
r
e
n
e
u
v
i
a
n

S
e
r
i
e
s

2
S
e
r
i
e
s

3
F
u
r
o
n
g
i
a
n
Fortunian
"Stage 2"
"Stage 3"
"Stage 4"
"Stage 5"
Drumian
Guzhangian
Paibian
Jiangshanian
"Stage 10"
 
 
 
 
* * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * * * * * * *
Baykonurian glaciation
Baykonurian glaciation
* * * * * * * * * * * *
* * * * * * * * * * * * * * * * * * * * * * * * *
←
Orsten Fauna
←
Burgess Shale
←
Kaili biota
←
Archaeocyatha extinction
←
Emu Bay Shale
←
Sirius Passet biota
←
Chengjiang biota
←
First Trilobites
←
SSF diversification, first brachiopods & archaeocyatha
←
First halkieriids, mollusсs, hyoliths SSF
←
Treptichnus pedum trace
Large negative peak δ 13Ccarb excursion
←
First Cloudina & Namacalathus mineral tubular fossils
Stratigraphic scale of the ICS subdivisions and Precambrian/Cambrian boundary.

Coordinates: 39°30′42″N 112°59′29″W / 39.5117°N 112.9915°W / 39.5117; -112.9915 The Drumian is a stage of 3rd series of the Cambrian. It succeeds still unnamed 5th stage of the Cambrian and precedes the Guzhangian. The base is defined as the first appearance of the trilobite Ptychagnostus atavus around 504.5 million years ago. The top is defined as the first appearance of another trilobite Lejopyge laevigata around 500.5 million years ago.

The GSSP is defined in the Drumian section (39°30′42″N 112°59′29″W / 39.5117°N 112.9915°W / 39.5117; -112.9915) in the Drum Mountains, Millard County, Utah, United States.[1] The stage was also named after the Drum Mountains. The section is an outcrop of the Wheeler Formation, a succession of calcareous shales. The precise base of the Drumian is a laminated limestone 62 m (203 ft) above the base of the Wheeler Formation.[2]

References

  1. ↑ Babcock, Loren E.; Richard A. Robison; Margaret N. Rees; Shanchi Peng; Matthew R. Saltzman (2007). "The Global boundary Stratotype Section and Point (GSSP) of the Drumian Stage (Cambrian) in the Drum Mountains, Utah, USA" (PDF). Episodes. 30 (2): 85–95. Retrieved 14 September 2012.
  2. ↑ "GSSP for Drumian Stage". Retrieved 12 November 2012.
Preceded by Proterozoic Eon Phanerozoic Eon
Paleozoic Era Mesozoic Era Cenozoic Era
Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene 4ry


This article is issued from Wikipedia - version of the 11/17/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.