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Heterohelix

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Journal Article
Published: 01 October 1995
Micropaleontology (1995) 41 (4): 359-368.
Journal Article
Published: 01 April 1978
Journal of Foraminiferal Research (1978) 8 (2): 143-146.
Image
Specimens of  <b>Heterohelix</b> americana  (Ehrenberg), 1843  (1–6) and  Globohet...
Published: 01 October 2009
PLATE 6 Specimens of Heterohelix americana (Ehrenberg), 1843 (1–6) and Globoheterohelix paraglobulosa n. gen., n. sp. (7–12). 1–3 Hypotype of H. americana from the uppermost Cenomanian–lowermost Turonian ( Whiteinella archaeocretacea Biozone) of western Africa (Senegal), well Rd2, sample
Image
SEM images of  <b>Heterohelix</b> globulosa  from the Kronsmoor section. Note that...
Published: 01 July 2005
PLATE 1 SEM images of Heterohelix globulosa from the Kronsmoor section. Note that tests are recrystallized, surfaces are smooth with no overgrowth calcite and pores are open. 1–2: Heterohelix globulosa (Ehrenberg); 3–4: outer wall surface from specimens 1 and 2; 5–6: wall structure and inner
Journal Article
Published: 01 September 2017
Bulletin of Canadian Petroleum Geology (2017) 65 (3): 366-386.
...-dominated “ Heterohelix cf. reussi ” Zone. Résumé Les Formations de Carlile et de Niobrara se sont formées durant l’épisode régressif du cycle de Greenhorn et celui transgressif du cycle de Niobrara (Turonien précoce-Santonien tardif). La délimitation lithostratigraphique officielle et la corrélation de ces...
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Journal Article
Published: 01 October 2003
Journal of Foraminiferal Research (2003) 33 (4): 330-337.
... appearance of Falsotruncana maslakovae in the lower-middle Turonian. The first occurrence of Heterohelix papula in the Southern Ocean sites, correlated with the first occurrence of large heterohelicids in the Tethyan area, allows the Coniacian/Santonian boundary to be identified. The most reliable bioevents...
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Journal Article
Published: 01 April 2017
Journal of Foraminiferal Research (2017) 47 (2): 105-128.
... cushmani , 3) “Benthonic Zone”, 4) HO R. cushmani and/or Thalmaninella greenhornensis , 5) “ Heterohelix shift”, 6) LO “Anomalina W”, 7) LO Helvetoglobotruncana helvetica , 8) HO H. sp., and 9) LO Dicarinella concavata . Overall, we show that lithologic and geochemical trends through most of the Eagle Ford...
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Series: GCSSEPM
Published: 01 December 2016
DOI: 10.5724/gcs.15.35.0488
EISBN: 978-1-944966-10-2
.... In the northeast of the State of Coahuila, based on lithology, paleontological content, and TOC, Eagle Ford formation can be divided into three units: Biozone A: Heterohelix sigali and Helvetoglobotruncana helvética , dominated by limestone, in platform environments, thicknesses of 16 to 100m, and TOC...
Journal Article
Published: 01 April 2016
Journal of Foraminiferal Research (2016) 46 (2): 124-148.
... Muricohedbergella and Heterohelix , responding to water turbidity, reduced salinity, and shallow water depth. Abundances of planktic species are significantly higher in the distal core section. During the early Turonian, diversity slightly increased, with the presence of Whiteinella aprica reflecting periodic...
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Series: Geological Society, London, Special Publications
Published: 01 January 2016
DOI: 10.1144/SP434.13
EISBN: 9781862391581
... differences. Both are strongly dominated by planktic foraminifers, of which the small, biserial Heterohelix globulosa is by far the most common species. Based on variations within five significant, benthic foraminiferal morphogroups and the plankton/benthos ratio, eight specific foraminiferal intervals have...
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Journal Article
Journal: Paleobiology
Published: 08 October 2013
Paleobiology (2013) 40 (1): 24-33.
... an extraordinary window into the ecology of Guembelitria, a key genus in the K/Pg mass extinction event, as well as information on the habitats of other neritic species. Stable oxygen and carbon isotope analyses were performed on six planktic species ( Guembelitria cretacea, Globigerinelloides asper , Heterohelix...
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Series: SEPM Special Publication
Published: 01 January 2011
DOI: 10.2110/sepmsp.100.123
EISBN: 9781565763098
... and description of the upper Maastrichtian well Mullinax-1, zones CF3, CF2, and CF1 with stable isotopes, Guembelitria data and sea-level interpretation. Figure 16. Guembelitria and Heterohelix blooms during the late Maastrichtian at the Indian Ocean Ninetyeast Ridge DSDP Site 216 are related...
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Journal Article
Published: 01 October 2009
Journal of Foraminiferal Research (2009) 39 (4): 335-360.
...PLATE 6 Specimens of Heterohelix americana (Ehrenberg), 1843 (1–6) and Globoheterohelix paraglobulosa n. gen., n. sp. (7–12). 1–3 Hypotype of H. americana from the uppermost Cenomanian–lowermost Turonian ( Whiteinella archaeocretacea Biozone) of western Africa (Senegal), well Rd2, sample...
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Journal Article
Published: 01 July 2005
Journal of Foraminiferal Research (2005) 35 (3): 228-247.
...PLATE 1 SEM images of Heterohelix globulosa from the Kronsmoor section. Note that tests are recrystallized, surfaces are smooth with no overgrowth calcite and pores are open. 1–2: Heterohelix globulosa (Ehrenberg); 3–4: outer wall surface from specimens 1 and 2; 5–6: wall structure and inner...
FIGURES | View All (10)
Journal Article
Published: 01 October 1999
Journal of Foraminiferal Research (1999) 29 (4): 352-370.
... the opportunist Heterohelix proliferates. The two black shales, however, share some common features, (1) in the interval immediately preceding both OAEs calcareous nannofossil assemblages reflect higher fertility of surface waters, (2) the selected decrease in diversity within the radiolarians, whose assemblages...
Journal Article
Published: 01 October 1999
Journal of Foraminiferal Research (1999) 29 (4): 392-417.
...) compared with the most complete OAE 2 sections. While planktic species diversity shows relatively minor change across the OAE 2 interval, extinction of the rotaliporids and Globigerinelloides bentonensis, a shift to Heterohelix-dominated assemblages, and increased abundance of helvetoglobotruncanids...
Series: SEPM Concepts in Sedimentology and Paleontology
Published: 01 January 1998
DOI: 10.2110/csp.98.06.0101
EISBN: 9781565762299
...-mineral distribution in calcareous mudrocks and dark marlstones from the southwestern side of the Greenhorn Sea provide further constraints on the paleoceanography of this region. Specifically, there is a major change in planktic foraminiferal population structure (" Heterohelix shift") coupled...
Journal Article
Journal: Geology
Published: 01 January 1998
Geology (1998) 26 (1): 63-66.
... as much as 35% to only 5% of the planktic foraminifera population. Evolutionary replacement of extinct species by new forms nearly ceased in that interval. Two major opportunistic blooms of Guembelitria took place, associated with reduced abundances of keeled forms and the dominant species Heterohelix...
... in the population structure of planktonic foraminifera and in foraminiferal abundance. It is suggested that an oxygen minimum zone (OMZ) within the water column was established in the Black Mesa area during this time, based on the marked increase in relative abundance of Heterohelix. The OMZ gradually waned...
Journal Article
Journal: AAPG Bulletin
Published: 01 September 1985
AAPG Bulletin (1985) 69 (9): 1428.
... primarily of Hedbergella amabilis Loeblich and Tappan, H. brittonensis Loeblich and Tappan, H. delrioensis (Carsey), H. planispira (Tappan), H. simplex (Morrow), Rotalipora cushmani (Morrow), R. montsalvensis Mornod, R. brotzeni (Sigal), and R. greenhornensis (Morrow), although Heterohelix occur...