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GSSPs
- The Cambrian System 2019
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In 2005, the International Subcommission on Cambrian
Stratigraphy (ISCS) voted on, and
adopted, a plan to subdivide the Cambrian System
into four series and 10 stages. Each series
represents an integrated package of biotic and
oceanographic events whose signals are broadly
identifiable by multiple time-stratigraphic
methods. Stage-level subdivisions are envisioned
to represent subequal divisions of series whose
boundaries can be narrowly constrained on a global
scale using a combination of biostratigraphic,
chemostratigraphic, sequence-stratigraphic, and
other techniques. (see Babcock et al., 2005)
Defining Cambrian boundary positions involves
recommendations by the ISCS that subsequently must
be approved by the International Commission on
Stratigraphy (ICS) and the International Union of
Geological Sciences (IUGS). In the following
table, decisions on Cambrian boundaries are listed
including their year of ratification by IUGS.
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Cambrian boundaries
listed according to their year of ratification:
1992 - Cambrian System
Ratification of the GSSP at the base of the
Cambrian System also automatically defined the
bases of the Phanerozoic Eonothem, the Paleozoic
Erathem, the lowermost Cambrian series (unnamed
until 2007) and the lowermost Cambrian stage
(unnamed until 2007). Ratification of the Cambrian
GSSP automatically delimited the top of the
Ediacaran System, the Neoproterozoic Erathem and
the Proterozoic Eonothem.
The GSSP is 2.4 metres above the base of the
Mystery Lake Member of the Chapel Island
Formation, Fortune Head Section, Burin Peninsula,
Newfoundland, Canada. The horizon coincides with
the lowest known occurrence of the ichnofossil Treptichnus pedum
(also published as Phycodes pedum, Trichophycus pedum
and Manykodes
pedum) as recognized in 1992.
For definition of the Cambrian GSSP
see:
Brasier, M., Cowie, J., and Taylor, M. 1994.
Decision on the Precambrian-Cambrian boundary
stratotype. Episodes 17, 3-8.
2000 – Ordovician
System, Lower Ordovician Series and Tremadocian
Stage
Ratification of the GSSP at the base of the
Ordovician System also automatically delimited the
top of the Cambrian System. The GSSP is in the
Green Point section, Newfoundland, Canada. The
horizon coincides with the First Appearance Datum
(FAD) of the conodont Iapetognathus fluctivagus.
For definition of the Ordovician
System/Lower Ordovician Series/Tremadocian Stage
GSSP see:
Cooper, R. A., Nowlan, G. S., and Williams, H.
S. 2001. Global Stratotype Section and Point for
base of the Ordovician System. Episodes 24(1),
19-28.
2003 – Paibian Stage
and Furongian Series
The GSSP is 396 m above the base of the Huaqiao
Formation in the Paibi section, Hunan, China.
“Paibian” refers to Paibi Village, in the Wuling
Mountains, Hunan. “Furongian” refers to “Furong”,
meaning “lotus” in Chinese. It comes from a
nickname for Hunan Province, the “Lotus State”.
The horizon coincides with the FAD of the
agnostoid Glyptagnostus
reticulatus.
For definition of the Paibian Stage
and Furongian Series see:
Peng, S. C., Babcock, L. E., Robison, R. A.,
Lin, H. L., Rees, M. N., and Saltzman, M. R.
2004. Global Standard Stratotype-section and
Point (GSSP) of the Furongian Series and Paibian
Stage (Cambrian). Lethaia 37, 365-379.
2006 – Drumian Stage
The GSSP is 62 metres above the base of the
Wheeler Formation in the Stratotype Ridge section,
Drum Mountains, Millard County, Utah, USA. The
horizon coincides with the FAD of the agnostoid
Ptychagnostus atavus (also published as Acidusus atavus).
“Drumian” refers to the Drum Mountains, Utah.
For definition of the Drumian Stage
see:
Babcock, L. E., Robison, R. A., Rees, M. N.,
Peng, S. C., and Saltzman, M. R. 2007. The
Global boundary Stratotype Section and Point
(GSSP) of the Drumian Stage (Cambrian) in the
Drum Mountains, Utah, USA. Episodes 30, 85-95.
2007 – Fortunian
Stage and Terreneuvian Series
The names “Fortunian Stage” and “Terreneuvian
Series” were ratified in 2007, although the GSSP
defining their conterminant base was defined at
the time that the base of Cambrian GSSP was
ratified. “Fortunian” refers to the Fortune Head
section, and “Terreneuvian” comes from an early
French name for Newfoundland.
For definition of the Fortunian
Stage and Terreneuvian Series see:
Landing, E., Peng, S. C., Babcock, L. E., Geyer,
G., and Moczydlowska-Vidal, M. 2007. Global
standard names for the lowermost Cambrian series
and stage. Episodes 30, 287-289.
2008 – Guzhangian
Stage
The GSSP is 121.3 m above the base of the Huaqiao
Formation, Luoyixi section, exposed along a
roadcut on the south bank of the Youshui River, 4
km northwest of the town of Luoyixi, Guzhang
County, China. The horizon coincides with the FAD
of the agnostoid Lejopyge laevigata.
“Guzhangian” refers to Guzhang County, in the
Wuling Mountains, Hunan.
For definition of the Guzhangian
Stage see:
Peng, S. C., Babcock, L. E., Zuo, J. X., Lin, H.
L., Zhu, X. J., Yang, X. F., Robison, R. A.,
Chi, Y. P., Bagnoli, G., and Chen, Y. 2009. The
Global boundary Stratotype Section and Point
(GSSP) of the Guzhangian Stage (Cambrian) in the
Wuling Mountains, northwestern Hunan, China.
Episodes 32, 41-55.
2011 –
Jiangshanian Stage
The GSSP is 108.12 m above the base of the
Huayansi Formation in the Duibian B section,
Jiangshan County, Zhejiang Province, China. The
horizon coincides with the FAD of the agnostoid Agnostotes
orientalis. “Jiangshanian” refers to
Jiangshan County, Zhejiang. The ASSP is 61.2 m
above the base of Unit 8 of the Zhumabai
Formation, Kyrshabakhty section, Malyi Karatau,
Kazakhstan.
For definition of the Jiangshanian
Stage see:
Peng, S. C.,
Babcock, L. E., Zuo, J. X., Lin, H. L., Zhu, X.
J., Yang, X. F., Qi, Y. P., Bagnoli, G., and
Wang, L. W. 2012. Global Standard
Stratotype-section and Point (GSSP) for the base
of the Jiangshanian Stage (Cambrian: Furongian)
at Duibian, Jiangshan, Zhejiang, Southeast
China. Episodes 35(4), 1-16.
2018 – Wuliuan
Stage and Maolingian Series
The Wuliuan Stage is the lowermost stage of the
Miaolingian Series. The conterminous base of the
Wuliuan Stage and Miaolingian Series is defined by
a GSSP coinciding with the widely distributed
oryctocephalid trilobite Oryctocephalus
indicus. The stage name is derived from
Wuliu, a small hill near Balang Village, Jianhe
County, about 2.5 km northwest of Jianhe township,
eastern Guizhou, China. The GSSP is 58.2 m above
the base of the Kaili Formation in the
Wuliu-Zengjiayan section. The stratotype section
is exposed in natural outcrops situated along a
ridge between Wuliu and Zengjiayan, which is about
0.5 km north of the Balang Village (Zhao et al.,
2012).
For definition of the Wuliuan Stage
and Maolingian Series see:
Zhao, Y.L., Peng,
J., Yuan, J.L., Guo, Q.J., Tai, T.S., Yin, L.M.,
Parsley, R.L., Yang, Y.N., Yang, X.L., Zhang,
P.X., 2012. Stop 5: The Kaili Formation and
Kaili Biota at the Wuliu-Zengjiayan section of
Guizhou Province, China and proposed Global
Standard Stratotype-section and Point (GSSP) of
the unnamed Cambrian Series 3, Stage 5. Journal
of Guizhou University (Natural Sciences) 29
(Supplement 1): 108–124.
Zhao, Y., Yuan, J., Babcock, L.E.,
Guo, Q., Peng, J., Yin, L., Yang, X., Peng, S.,
Wang, C., Gaines, R.R., Esteve, J., Tai, T.,
Yang, R., Wang, Y., Sun, H., Yang, Y., 2019.
Global Standard Stratotype-Section and Point
(GSSP) for the
conterminous base of the Miaolingian Series and
Wuliuan Stage (Cambrian) at Balang, Jianhe,
Guizhou, China. Episodes, 42: 165-184.
Provisional
stages and series in the Cambrian
Stages 2, 3, 4, and 10, and series 2 are undefined
by GSSPs (as of July 2013). The use of numbers to
identify these units is provisional. When a GSSP
for each of these units has been ratified, the
provisional name will be replaced by a new name
based on a geographic locality.
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A brief
history of Cambrian subdivisions and goals of the
ISCS by Shergold and Geyer (2002) can be
downloaded here.
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