ZONE
DEFINITIONS
- CM1: Neogloboquadrina
pachyderma B partial range zone
- Top:
Not defined, but the zone includes all faunas above the last appearance of Neogloboquadrina
pachyderma A
- Base:
Last appearance of Neogloboquadrina
pachyderma A
- Age:
Late Quaternary
- Taxa:
Marked by the last occurrence of N.
humerosa praehumerosa and the first occurrence of N.
dutertrei in several sites
- Reference
section: Hole 1014A
-
- CM2: Neogloboquadrina
pachyderma B-Neogloboquadrina
pachyderma A
- Overlap zone
- Top:
Last appearance of Neogloboquadrina
pachyderma A
- Base:
First appearance of Neogloboquadrina
pachyderma B
- Age:
Early Quaternary
- Reference
section: Hole 1014A
-
- CM3: Neogloboquadrina
pachyderma A partial range zone
- Top:
First appearance of Neogloboquadrina
pachyderma B
- Base:
First appearance of Neogloboquadrina
pachyderma A
- Age:
Early Quaternary
- Occurrence:
In northernmost Hole 1020B, Zone CM3 is not recognized and is included
within an undifferentiated zone: CM3 to CM5. In the southernmost sites
(Holes 1011B and 1012A), the zone is also unrecognized, being included in an
undifferentiated zone: CM3 and CM4.
- Reference
section: Hole 1014A
-
- CM4: Gap zone between
last appearance of Neogloboquadrina
kagaensis and first appearance of Neogloboquadrina
pachyderma A
- Top:
First appearance of Neogloboquadrina
pachyderma A
- Base:
Last appearance of Neogloboquadrina
kagaensis
- Age:
Latest Pliocene
- Occurrence:
In northernmost Hole 1020B, Zone CM4 is not recognized and is included
within an undifferentiated zone: CM3 to CM5. In the southernmost sites
(Holes 1011B and 1012A), the zone is also unrecognized, being included in an
undifferentiated zone: CM3 and CM4.
- Reference
section: Hole 1014A
-
- CM5: Neogloboquadrina
kagaensis partial range zone
- Top:
Last appearance of Neogloboquadrina
kagaensis
- Base:
Last appearance of Neogloboquadrina
asanoi
- Age:
Late Pliocene
- Occurrence:
In northernmost Hole 1020B, Zone CM5 is included within an undifferentiated
zone: CM3 to CM5.
- Taxa:
Includes the partial range of Neogloboquadrina
pachyderma C, which disappears at the end or within this zone
- Reference
section: Hole 1014A
-
- CM6: Neogloboquadrina
asanoi range zone
- Top:
Last appearance of Neogloboquadrina
asanoi
- Base:
First appearance of Neogloboquadrina
asanoi
- Age:
Early late Pliocene
- Taxa:
The last occurrence of Globorotalia
puncticulata is within the middle to upper part of CM6 in all
sections except in Holes 1018A and 1011B. The first appearance of Globorotalia
inflata is in the lower part of CM6 except in Hole 1018A, where
it appears in CM7. Populations of G.
inflata throughout CM6 represent early evolutionary forms of this
taxon and are likely equivalent to the "transitional" variety
identified by Keller (1979a).
- Reference
section: Hole 1014A
-
- CM7: Globorotalia
puncticulata partial range zone
- Top:
First appearance of Neogloboquadrina
asanoi
- Base:
Last appearance of Globorotalia
(Globoconella) ikebei
and Globigerina
decoraperta
- Age:
Late early Pliocene
- Taxa:
CM7 represents a gap zone for the interval between the first occurrence of Neogloboquadrina
asanoi and the last occurrence of Globorotalia
(Globoconella) ikebei and Globigerina
decoraperta. This zone takes its name from Globorotalia
puncticulata, which consistently occurs through this interval. G.
puncticulata was not observed in CM7 in Hole 1014A, probably
because of significant carbonate dissolution over this interval.
- Reference
section: Hole 1020B
-
- CM8: Globigerina
decoraperta partial range zone
- Top:
Last appearance of Globorotalia
(Globoconella) ikebei and Globigerina
decoraperta
- Base:
As yet undefined because the sequences below the zone largely lack
planktonic foraminifers in association with biosiliceous-rich sediments
- Age:
late early Pliocene
- Occurrence:
The zone is observed in Hole 1020B.
- Reference
section: Hole 1020B
