Category:Foraminiferal zonation: Difference between revisions

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<div style="font-size: 80%">
 
{| class="wikitable" width="500pt" style="margin-left:40px; margin-bottom:20px; float:right; text-align:left;"
{| cellspacing="0" cellpadding="0" border="1"
| STAGE
| STAGE
| colspan="3" | STANDARD ZONE
| colspan="3" | STANDARD ZONE
| colspan="2" | STANDARD SUBZONE
| colspan="2" | STANDARD SUBZONE
| rowspan="2" | '''BGS foraminiferal biozone'''
| rowspan="2"  align="center" | '''BGS foraminiferal biozone'''
|-
|-valign="top"
|
|
|
|
Line 21: Line 20:
| rowspan="12" |
| rowspan="12" |
|
|
|-
|-valign="top"
| rowspan="5" | MAASTRICHTIAN
| rowspan="5" | MAASTRICHTIAN
| ''B. casimirovensis''
| ''B. casimirovensis''
| '''27'''
| align="center" | [[BGS Zone 27 | '''27''']]
|-
|-valign="top"
| ''B. junior''
| ''B. junior''
| rowspan="2" | '''26'''
| rowspan="2" align="center" |  [[BGS Zone 26(=UKB22 of Hart et al., 1989) | '''26''']]
|-
|-valign="top"
| rowspan="2" | ''B. occidentalis''
| rowspan="2" | [[Belemnella occidentalis Zone | ''B. occidentalis'']]
|-
|-valign="top"
| '''25'''
| align="center" | [[BGS Zone 25 (=UKB21 of Hart et al., 1989) | '''25''']]
|-
|-valign="top"
| ''B. lanceolata ''s.l.
| [[Belemnella lanceolata Zone s.l. | ''B. lanceolata ''s.l.]]
| '''24'''
| align="center" | [[BGS Zone 24 (=UKB20 of Hart et al., 1989) | '''24''']]
|-
|-valign="top"
| rowspan="9" | CAMPANIAN
| rowspan="9" | CAMPANIAN
| rowspan="3" | ''B. mucronata ''s.l.
| rowspan="3" | [[Belemnitella mucronata Zone s.l. | ''B. mucronata ''s.l.]]
| '''23'''
| align="center" |  [[BGS Zone 23 (=UKB19 of Hart et al., 1989) | '''23''']]
|-
|-valign="top"
| '''22'''
| align="center" | [[BGS Zone 22 (=uppermost UKB18 of Hart et al., 1989) | '''22''']]
|-
|-valign="top"
| '''21'''
| align="center" | [[BGS Zone 21 (=UKB17 and lower UKB 18 of Hart et al., 1989) | '''21''']]
|-
|-valign="top"
| rowspan="3" | ''G. quadrata''
| rowspan="3" | [[Gonioteuthis quadrata Zone | ''G. quadrata'']]
| rowspan="4" | ''I. lingua''
| rowspan="5" | [[Sphenoceramus (Inoceramus) lingua Zone  | ''I. lingua'']]
| rowspan="4" | '''Gonioteuthis ''Zone'
| rowspan="5" | [[Gonioteuthis Zone | ''Gonioteuthis'' Zone]]
| Post ''A. cretaceus''
| [[Post Applinocrinus beds | Post ''A. cretaceus'']]
| rowspan="3" | '''20'''
| rowspan="3" align="center" |  [[BGS Zone 20 (=UKB16 of Hart et al., 1989) | '''20''']]
|-
|-valign="top"
| ''A. cretaceus''
| [[Applinocrinus cretaceus Subzone | ''A. cretaceus'']]
|
|-valign="top"
|-
| [[Hagenowia (blackmorei) Horizon (Subzone) | ''Hagenowia '' horizon]]
| ''Hagenowia '' horizon
|-valign="top"
|-
| rowspan="2" | [[Offaster pilula Zone | ''O. pilula'']]
| rowspan="2" | ''O. pilula''
| [[Subzone of abundant Offaster pilula | Abundant ''O. pilula ? ?'']]
| Abundant ''O. pilula ? ?''
| [[Discoscaphites binodosus Subzone | ''?D. binodosus'']]
| ''?D. binodosus''
| rowspan="2" align="center" |  [[BGS Zone 19 (=upper UKB15 of Hart et al., 1989) | '''19''']]
| rowspan="2" | '''19'''
|-valign="top"
|-
| [[Echinocorys depressula Subzone | ''E. depressula'']]
| ''E. depressula''
| rowspan="29" |
| rowspan="29" |
|-
|-valign="top"
| ''U. anglicus''
| [[Uintacrinus anglicus Zone | ''U. anglicus'']]
| rowspan="3" |
| rowspan="3" |
| rowspan="28" |
| rowspan="28" |
| rowspan="20" |
| rowspan="20" |
| rowspan="3" | '''18'''
| rowspan="3" align="center" |  [[BGS Zone 18 (=uppermost UKB14 and lower UKB15 of Hart et al., 1989) | '''18''']]
|-
|-valign="top"
| rowspan="4" | SANTONIAN
| rowspan="4" | SANTONIAN
| ''M. testudinarius''
| [[Marsupites testudinarius Zone | ''M. testudinarius'']]
|-
|-valign="top"
| ''U. socialis''
| [[Uintacrinus socialis Zone | ''U. socialis'']]
|-
|-valign="top"
| rowspan="5" | ''M. coranguinum''
| rowspan="5" | [[Micraster coranguinum Zone/Hagenowia rostrata Zone | ''M. coranguinum'']]
| rowspan="2" | Upper ''H.'' ''rostrata''
| rowspan="2" | Upper [[Micraster coranguinum Zone/Hagenowia rostrata Zone | ''H. rostrata'']]
| '''17'''
| align="center" | [[BGS Zone 17 (=lower and middle UKB14 of Hart et al., 1989) | '''17''']]
|-
|-valign="top"
| rowspan="2" | '''16'''
| rowspan="2" align="center" |  [[BGS Zone 16 (=UKB13 of Hart et al., 1989) | '''16''']]
|-
|-valign="top"
| rowspan="4" | CONIACIAN
| rowspan="4" | CONIACIAN
| rowspan="3" | Lower ''H. rostrata''
| rowspan="3" | Lower [[Micraster coranguinum Zone/Hagenowia rostrata Zone | ''H. rostrata'']]
|-
|-valign="top"
| '''15'''
| align="center" | [[BGS Zone 15 (=upper UKB12 of Hart et al., 1989) | '''15''']]
|-
|-valign="top"
| '''14'''
| align="center" | [[BGS Zone 14 (=lower and middle UKB12 of Hart et al., 1989) | '''14''']]
|-
|-valign="top"
| ''M. cortestudinarium''
| [[Micraster cortestudinarium Zone | ''M. cortestudinarium'']]
| rowspan="6" |
| rowspan="6" |
| '''13'''
| align="center" | [[BGS Zone 13 (=UKB11 of Hart et al., 1989) | '''13''']]
|-
|-valign="top"
| rowspan="5" | TURONIAN
| rowspan="5" | TURONIAN
| ''S. plana''
| [[Sternotaxis plana Zone | ''S. plana'']]
| '''12'''
| align="center" | [[BGS Zone 12 (=upper UKB10 of Hart et al., 1989) | '''12''']]
|-
|-valign="top"
| rowspan="2" | ''T. lata''
| rowspan="2" | [[Terebratulina lata Zone | ''T. lata'']]
| '''11'''
| align="center" | [[BGS Zone 11 (=lower and middle UKB10 of Hart et al., 1989) | '''11''']]
|-
|-valign="top"
| rowspan="2" | '''10'''
| rowspan="2" align="center" |  [[BGS Zone 10 (=basal UKB10 of Hart et al., 1989) | '''10''']]
|-
|-valign="top"
| rowspan="2" | ''Mytiloides ''spp.
| rowspan="2" | [[Mytiloides spp. Zone | ''Mytiloides ''spp.]]
|-
|-valign="top"
| '''9'''
| align="center" | [[BGS Zone 9 (=modified UKB9 of Hart et al., 1989) | '''9''']]
|-
|-valign="top"
| rowspan="14" | CENOMANIAN
| rowspan="14" | CENOMANIAN
| ''N. juddii''
| [[Neocardioceras juddii Zone | ''N. juddii'']]
| rowspan="3" | ''S. gracile''
| rowspan="3" | [[Sciponoceras gracile Zone | ''S. gracile'']]
| rowspan="2" | '''8'''
| rowspan="2" align="center" |  [[BGS Zone 8 (=upper UKB8 and basal UKB9 of Hart et al., 1989) | '''8''']]
|-
|-valign="top"
| rowspan="2" | ''M. geslinianum''
| rowspan="2" | [[Metoicoceras geslinianum Zone | ''M. geslinianum'']]
|-
|-valign="top"
| '''7'''
| align="center" | [[BGS Zone 7 (=lower UKB 8 of Hart et al., 1989) | '''7''']]
|-
|-valign="top"
| ''C. guerangeri''
| [[Calycoceras guerangeri Zone | ''C. guerangeri'']]
| ''H. trecensis''
| [[Holaster trecensis Zone | ''H. trecensis'']]
| '''6'''
| align="center" | [[BGS Zone 6 (=modified UKB7 of Hart et al., 1989) | '''6''']]
|-
|-valign="top"
| rowspan="2" | ''A. jukesbrownei''
| rowspan="2" | [[Acanthoceras jukesbrownei Zone | ''A. jukesbrownei'']]
| rowspan="10" | ''H. subglobosus''
| rowspan="10" | [[Holaster subglobosus Zone | ''H. subglobosus'']]
| '''5'''
| align="center" | [[BGS Zone 5 (=UKB6 of Hart et al., 1989) | '''5''']]
|-
|-valign="top"
| rowspan="4" | '''4'''
| rowspan="4" align="center" |  [[BGS Zone 4 (=UKB 5 of Hart et al., 1989) | '''4''']]
|-
|-valign="top"
| rowspan="2" | ''A. rhotomagense''
| rowspan="2" | [[Acanthoceras rhotomagense Zone | ''A. rhotomagense'']]
| ''T. acutus''
| [[Turrilites acutus Subzone | ''T. acutus'']]
|-
|-valign="top"
| ''T. costatus''
| [[Turrilites costatus Subzone | ''T. costatus'']]
|-
|-valign="top"
| ''C. inerme''
| [[Cunningtoniceras inerme Zone | ''C. inerme'']]
| rowspan="3" |
| rowspan="3" |
|-
|-valign="top"
| rowspan="2" | ''M. dixoni''
| rowspan="2" | [[Mantelliceras dixoni Zone | ''M. dixoni'']]
| '''3'''
| align="center" | [[BGS Zone 3 (=UKB4 of Hart et al., 1989) | '''3''']]
|-
|-valign="top"
| '''2'''
| align="center" | [[BGS Zone 2 (UKB3 of Hart et al., 1989) | '''2''']]
|-
|-valign="top"
| rowspan="3" | ''M. mantelli''
| rowspan="3" | [[Mantelliceras mantelli Zone | ''M. mantelli'']]
| ''M. saxbii''
| [[Mantelliceras saxbii Subzone | ''M. saxbii'']]
| rowspan="3" | '''1'''
| rowspan="3" align="center" |  [[BGS Zone 1 (=UKB1 and 2 of Hart et al., 1989) | '''1''']]
|-
|-valign="top"
| ''S. schluteri''
| [[Sharpeiceras schlueteri Subzone | ''S. schluteri'']]
|-
|-valign="top"
| ''N. carcitanense''
| [[Neostlingoceras carcitanense Subzone | ''N. carcitanense'']]
|}
|}
</div style="font-size: 80%">
==Overview==
Foraminifera from the Chalk Group have been taxonomically described for many years and since the 1970’s biostratigraphical applications have also been discussed. It is becoming more evident that foraminiferal inceptions and extinctions can be tied in with lithostratigraphical markers (eg. marl seams, flint bands) and macrofaunal events (eg. sponge beds, ''Inoceramus''-rich beds), to provide a very detailed subdivision of the Chalk Group.  Unfortunately, earlier biostratigraphical accounts often failed to record detailed stratigraphical and lithological information relating to  sample positions within the succession, thus limiting their usefulness.


The foraminifera of the Chalk Group in the North Sea Basin were outlined by Wilkinson ''et al''. (1993, 1994). The biomarkers were selected for borehole samples collected by open-hole methods and those chosen were well known, easily identified and based on those commonly used by industry. Definitions were based on the first down-hole occurrences (i.e. extinctions) and a pragmatic approach was taken; a refined or detailed biostratigraphical subdivision of the Chalk Group was not attempted. As the biomarkers offshore were based on 'tops', they do not fit exactly with the onshore biozonation outlined by Wilkinson (2000), which was based on inceptions, extinction and acmes (biomarkers or bioevents within the zones were also recognised). Nevertheless, the biomarkers of the North Sea succession can be related to the onshore biozones, and the purpose of this report is to relate the two schemes.
The unpublished scheme used herein for the Chalk Group of the UK  recognises a maximum of 27 foraminiferal zones, and has been compiled from a variety of published and unpublished sources (Bailey, 1978; Swiecicki, 1980; Bailey ''et al''., 1983, 1984; Hart ''et al''., 1989; Carter & Hart, 1977, Hart, 1982; Jarvis ''et al''., 1988; Mortimore, 1986). Data for offshore areas (King ''et al''., 1989) mostly relates to uncored hydrocarbon wells, and the biostratigraphical scheme for these is based on the extinction horizon (‘Last Appearance Datum’ or ‘First Downhole Occurrence’) of key taxa.; caving in these boreholes makes the first appearance uphole, or inception, an unreliable datum.


The biomarkers identified for offshore sequences were, by necessity, defined from the top down.  Each biomarker represents a single event and no attempt was made to place them into a zonal scheme.  The biomarkers of the Chalk Group in the North Sea Basin are placed, herein, within the context of the biozones recognised in southern and eastern England.
The zones, numbered 1 to 27 from oldest to youngest, are pre-fixed 'BGS' to differentiate them from previously published schemes, and where possible, they are related to the UKB zones of Hart ''et al''. (1989), macrofaunal zones and lithostratigraphical marker horizons.


==Descriptions of offshore foraminiferal biomarkers in the Chalk Group==
==Descriptions of foraminiferal biozones in the Chalk Group==
The foraminifera biomarkers recognised in the Upper Cretaceous Shetland Group are not included in this synthesis. Being based on First Downhole Occurrences (FDOs), the highest possible stratigraphical positions for the Biomarkers are given here. However, in some cases, similar faunas may be found lower compared to the foraminiferal zones.  Distributions are related to the species ranges of southern and eastern England.


In the following account Biomarkers in the offshore UK Chalk Group are systematically described from youngest (Biomarker 1) to oldest (Biomarker 15). Alternatively, for information about a particulat Biomarker, select it from the summary table (summary correlation of offshore foraminiferal biomarkers and BGS foraminiferal zones).
In the following account the BGS foraminiferal zones of the Chalk Group are systematically described from oldest (BGS 1) to youngest (BGS 27). Alternatively, for information about a particular zone, select it from the summary table (summary correlation of foraminiferal and macrofaunal zones)


[[category:Biostratigraphy of the Chalk Group]]
[[category:Biostratigraphy of the Chalk Group | 009]]

Latest revision as of 12:53, 1 October 2013

STAGE STANDARD ZONE STANDARD SUBZONE BGS foraminiferal biozone
Northern England East Anglia Northern England
DANIAN
MAASTRICHTIAN B. casimirovensis 27
B. junior 26
B. occidentalis
25
B. lanceolata s.l. 24
CAMPANIAN B. mucronata s.l. 23
22
21
G. quadrata I. lingua Gonioteuthis Zone Post A. cretaceus 20
A. cretaceus
Hagenowia horizon
O. pilula Abundant O. pilula ? ? ?D. binodosus 19
E. depressula
U. anglicus 18
SANTONIAN M. testudinarius
U. socialis
M. coranguinum Upper H. rostrata 17
16
CONIACIAN Lower H. rostrata
15
14
M. cortestudinarium 13
TURONIAN S. plana 12
T. lata 11
10
Mytiloides spp.
9
CENOMANIAN N. juddii S. gracile 8
M. geslinianum
7
C. guerangeri H. trecensis 6
A. jukesbrownei H. subglobosus 5
4
A. rhotomagense T. acutus
T. costatus
C. inerme
M. dixoni 3
2
M. mantelli M. saxbii 1
S. schluteri
N. carcitanense

Overview

Foraminifera from the Chalk Group have been taxonomically described for many years and since the 1970’s biostratigraphical applications have also been discussed. It is becoming more evident that foraminiferal inceptions and extinctions can be tied in with lithostratigraphical markers (eg. marl seams, flint bands) and macrofaunal events (eg. sponge beds, Inoceramus-rich beds), to provide a very detailed subdivision of the Chalk Group. Unfortunately, earlier biostratigraphical accounts often failed to record detailed stratigraphical and lithological information relating to sample positions within the succession, thus limiting their usefulness.

The unpublished scheme used herein for the Chalk Group of the UK recognises a maximum of 27 foraminiferal zones, and has been compiled from a variety of published and unpublished sources (Bailey, 1978; Swiecicki, 1980; Bailey et al., 1983, 1984; Hart et al., 1989; Carter & Hart, 1977, Hart, 1982; Jarvis et al., 1988; Mortimore, 1986). Data for offshore areas (King et al., 1989) mostly relates to uncored hydrocarbon wells, and the biostratigraphical scheme for these is based on the extinction horizon (‘Last Appearance Datum’ or ‘First Downhole Occurrence’) of key taxa.; caving in these boreholes makes the first appearance uphole, or inception, an unreliable datum.

The zones, numbered 1 to 27 from oldest to youngest, are pre-fixed 'BGS' to differentiate them from previously published schemes, and where possible, they are related to the UKB zones of Hart et al. (1989), macrofaunal zones and lithostratigraphical marker horizons.

Descriptions of foraminiferal biozones in the Chalk Group

In the following account the BGS foraminiferal zones of the Chalk Group are systematically described from oldest (BGS 1) to youngest (BGS 27). Alternatively, for information about a particular zone, select it from the summary table (summary correlation of foraminiferal and macrofaunal zones)

Subcategories

This category has only the following subcategory.
The number of included categories (C), pages (P) and files (F) is stated in brackets.