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Journal Article

History of the Giraffe Pipe locality inferred from microfossil remains: a thriving freshwater ecosystem near the Arctic Circle during the warm Eocene Open Access

Peter A. Siver, Anne Marie Lott
Published: 01 March 2023
Journal of Paleontology (2023) 97 (2): 271–291.
DOI: https://doi.org/10.1017/jpa.2022.101
... warming on arctic environments. A core from the Giraffe Pipe fossil locality located in the Northwest Territories of Canada offers a window into the life of a thriving Arctic freshwater ecosystem in the Eocene during greenhouse conditions. The remains of an extensive deposit of microfossils, including...
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View PDF for article title, History of the <span class="search-highlight">Giraffe</span> <span class="search-highlight">Pipe</span> locality inferred from microfossil remains: a thriving freshwater ecosystem near the Arctic Circle during the warm Eocene
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FIGURE 3—Valves of Actinella morphotype Giraffe 1 from Giraffe Pipe sediments (A–D, G–H) and the modern species, A. parva, from Lake Judd, Tasmania (E–F). A– B) Internal (A) and external (B) views of whole valves. Note the varying lengths of the raphe slits and their position along the ventral surface on the valve face. C–D) Internal (C) and external (D) views of the foot pole. Note the position of the helictoglossa (C) and the presence of a rimoportula on the valve (D). E–F) Internal views depicting overall valve shape, raphe structure, and the helictoglossae. G–H) Internal (G) and external (H) views of the head pole depicting the position of the helictoglossa and rimoportula. Scale bars = 2 μm in C–H; 5μm in A–B)

FIGURE 3 —Valves of Actinella morphotype Giraffe 1 from Giraffe Pipe sedi... Available to Purchase

Published: 01 March 2009
FIGURE 3 —Valves of Actinella morphotype Giraffe 1 from Giraffe Pipe sediments (A–D, G–H) and the modern species, A. parva , from Lake Judd, Tasmania (E–F). A– B) Internal (A) and external (B) views of whole valves. Note the varying lengths of the raphe slits and their position along the ventral
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(A) Map of the Wombat and Giraffe pipe localities and locations of other kimberlites in the Lac de Gras area, Northwest Territories (NWT), Canada (adapted from Stasiuk et al., 2002). (B) Stratigraphic log summaries of Giraffe drill core BHP99-01 and Wombat drill cores DDH00-5 and CH93-29. Sample locations of the tephra layers are marked with arrows. Depth in the dipping cores is expressed as vertical equivalent depth with respect to the modern surface.

(A) Map of the Wombat and Giraffe pipe localities and locations of other ki... Available to Purchase

Published: 01 March 2024
Figure 1. (A) Map of the Wombat and Giraffe pipe localities and locations of other kimberlites in the Lac de Gras area, Northwest Territories (NWT), Canada (adapted from Stasiuk et al., 2002 ). (B) Stratigraphic log summaries of Giraffe drill core BHP99-01 and Wombat drill cores DDH00-5 and CH93
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Stratigraphic diagram of the 163 m Giraffe Pipe core, detailing the distribution of lacustrine shales and mudstones, terrestrial plant remains, and overlying Quaternary glacial sediments. Numbers indicate the transition points between the (1) Botryococcus and Aulacoseira zones; (2) Aulacoseira and Eunotioid zones; (3) Eunotioid and Heterotrophic zones; and (4) the Heterotrophic and Terminal Lake zones.

Stratigraphic diagram of the 163 m Giraffe Pipe core, detailing the distrib... Open Access

Published: 01 March 2023
Figure 1. Stratigraphic diagram of the 163 m Giraffe Pipe core, detailing the distribution of lacustrine shales and mudstones, terrestrial plant remains, and overlying Quaternary glacial sediments. Numbers indicate the transition points between the ( 1 ) Botryococcus and Aulacoseira zones
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Distribution and abundance of 15 taxa in the Giraffe Pipe core deemed significant for characterizing and distinguishing among the major aquatic zones over the history of the waterbody. (1) Chrysophyte cysts; (2) testate euglyphid plates; (3) Botryococcus colonies; (4) Mallomonas insignis scales; (5) Rabdiophrys scales; (6) Aulacoseira valves; (7) Synura recurvata scales; (8) Mallomonas lychenensis scales; (9) Mallomonas porifera scales; (10) eunotioid diatom valves; (11) Synura cronbergiae scales; (12) Raineriophrys scales; (13) paraphysomonad scales; (14) Mallomonas bangladeschica scales; and (15) Chrysosphaerella scales. T = Terminal Lake Zone, H = Heterotrophic Zone, E = Eunotioid Zone, A = Aulacoseira Zone, B = Botryococcus Zone. Examples of each organism are illustrated in Figure 3.

Distribution and abundance of 15 taxa in the Giraffe Pipe core deemed signi... Open Access

Published: 01 March 2023
Figure 4. Distribution and abundance of 15 taxa in the Giraffe Pipe core deemed significant for characterizing and distinguishing among the major aquatic zones over the history of the waterbody. ( 1 ) Chrysophyte cysts; ( 2 ) testate euglyphid plates; ( 3 ) Botryococcus colonies; ( 4
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Representative images of the Giraffe Pipe core relative to the major shifts in community structure. Images are arranged from (1) near the onset of the lacustrine phase at the bottom of the core to (13) close to the termination of the lake phase and just before the transition to a terrestrial environment. (1–3) Three sections within the Botryococcus Zone from boxes 24, 21, and 20, respectively. This section of the core consists largely of crumbled rock fragments, some of which contain deposits of (1) siliceous nodules, and most of which are (2, 3) medium-brown colored organic mudstones. (4) Section of the core within box 20 showing the distinct transition from the Botryococcus Zone to the Aulacoseira Zone (arrows), the latter of which consists of massive light-brown siltstones. (5, 6) Continuation of the Aulacoseira Zone in boxes (5) 19 and (6) 18. (7) The lower portion of the Eunotioid Zone, mostly in box 16 and part of box 15, depicted by mudstones containing distinct laminations. (8, 9) The upper component of the Eunotioid Zone, which extends from (8) the middle of box 15 to (9) the upper channel of box 13, is characterized by dark-brown to black organic mudstones. The image represented in (9) depicts the distinct transition zone (arrows) marking the end of the Eunotioid Zone and the beginning of the Heterotrophic Zone, the latter zone denoted by massive siltstones. (10, 11) The massive siltstone rock represented at the onset of the Heterotrophic Zone continues through (10) the lower channel in box 12, and the end of this zone in (11) the middle channel of box 12 is characterized with siltstone rocks infiltrated with deposits of siliceous nodules. (12, 13) Eunotioid diatoms and acidic chrysophytes reappear in (12) the upper channel of box 12 where the rock transitions back to dark organic mudstone, and these organisms remain throughout most of (13) box 11 until the end of the lake phase.

Representative images of the Giraffe Pipe core relative to the major shifts... Open Access

Published: 01 March 2023
Figure 10. Representative images of the Giraffe Pipe core relative to the major shifts in community structure. Images are arranged from ( 1 ) near the onset of the lacustrine phase at the bottom of the core to ( 13 ) close to the termination of the lake phase and just before the transition
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FIGURE 1—Location map and the Giraffe Pipe core. A) Location. B) Schematic stratigraphy. C) Lithostratigraphy and location of observations.

FIGURE 1 —Location map and the Giraffe Pipe core. A) Location. B) Schematic... Available to Purchase

Published: 01 March 2009
FIGURE 1 —Location map and the Giraffe Pipe core. A) Location. B) Schematic stratigraphy. C) Lithostratigraphy and location of observations.
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FIGURE 2—Fossil Mallomonas bangladeshica scales from Giraffe Pipe sediments (A, C, E–F) and modern forms from the Paraná River delta, Argentina (B, D). A–B) Whole scales, each with a posterior upturned rim, anterior thickened margin, large anterior depression, surface papillae, and a well-developed grappling hooklike structure. C–D) Whole scales similar to those depicted in A–B, except with small rudimentary and reduced grappling hooklike structures. E) Close-up of the grappling-hook structure as viewed from the top. F) A scale with a fully formed, grappling hooklike structure as viewed from the undersurface of the scale. Scale bars = 500 nm in E–F; 1 μm in A–B, D; and 2 μm in C

FIGURE 2 —Fossil Mallomonas bangladeshica scales from Giraffe Pipe sedime... Available to Purchase

Published: 01 March 2009
FIGURE 2 —Fossil Mallomonas bangladeshica scales from Giraffe Pipe sediments (A, C, E–F) and modern forms from the Paraná River delta, Argentina (B, D). A–B) Whole scales, each with a posterior upturned rim, anterior thickened margin, large anterior depression, surface papillae, and a well
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FIGURE 2—SEM micrographs of Aulacoseira from Giraffe Pipe sediments. (A) Diatoms embedded in the matrix of an untreated fractured mudstone surface. (B) A complete cell with concave face and linking spines (top) and spineless terminal valve (bottom). (C–E) Various morphologies of balled protoplasmic remnants preserved inside valves, indicated by arrows. A single rimoportula (r) arises from the Ringleiste in (E). (F) Linking spines and fractured cingulum comprised of overlapping copulae. (G) Close-up of areolae showing occlusions as volae (v) and residual extracellular mucilage (m). (H) Intact velum showing the internal occlusion of mantle areolae

FIGURE 2 —SEM micrographs of Aulacoseira from Giraffe Pipe sediments. (A)... Available to Purchase

Published: 01 June 2006
FIGURE 2 —SEM micrographs of Aulacoseira from Giraffe Pipe sediments. (A) Diatoms embedded in the matrix of an untreated fractured mudstone surface. (B) A complete cell with concave face and linking spines (top) and spineless terminal valve (bottom). (C–E) Various morphologies of balled
Journal Article

Tephra zircon U-Pb geochronology of kimberlite maar sedimentary fills in subarctic Canada: Implications for Eocene paleoclimate and Late Cretaceous paleogeography Available to Purchase

Serhiy D. Buryak, Alberto V. Reyes, Christopher K. West, Britta J.L. Jensen, S. Andrew DuFrane, Joshua H.F.L. Davies, Yan Luo, Jennifer M. Galloway, Peter A. Siver, John A. Westgate, Jesse R. Reimink, D. Graham Pearson, Alexander P. Wolfe
Journal: GSA Bulletin
Published: 01 March 2024
GSA Bulletin (2024) 136 (9-10): 3921–3938.
DOI: https://doi.org/10.1130/B37276.1
...Figure 1. (A) Map of the Wombat and Giraffe pipe localities and locations of other kimberlites in the Lac de Gras area, Northwest Territories (NWT), Canada (adapted from Stasiuk et al., 2002 ). (B) Stratigraphic log summaries of Giraffe drill core BHP99-01 and Wombat drill cores DDH00-5 and CH93...
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View PDF for article title, Tephra zircon U-Pb geochronology of kimberlite maar sedimentary fills in subarctic Canada: Implications for Eocene paleoclimate and Late Cretaceous paleogeography
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Results of (1) the percentage of microfossils representing heterotrophic organisms, and (2) the ratio of chrysophyte cysts to diatom valves in the Giraffe Pipe core. The solid line represents a running average. T = Terminal Lake Zone, H = Heterotrophic Zone, E = Eunotioid Zone, A = Aulacoseira Zone, B = Botryococcus Zone.

Results of ( 1 ) the percentage of microfossils representing heterotrophic ... Open Access

Published: 01 March 2023
Figure 5. Results of ( 1 ) the percentage of microfossils representing heterotrophic organisms, and ( 2 ) the ratio of chrysophyte cysts to diatom valves in the Giraffe Pipe core. The solid line represents a running average. T = Terminal Lake Zone, H = Heterotrophic Zone, E = Eunotioid Zone
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Results of non-metric multidimensional scaled ordination (nMDS) analyses of 175 samples distributed in 16 core boxes (11–26) within the lacustrine phase of the Giraffe Pipe core based on abundances of 58 taxa. Samples within a given core box, with the exception of those in box 13, cluster close together.

Results of non-metric multidimensional scaled ordination (nMDS) analyses of... Open Access

Published: 01 March 2023
Figure 7. Results of non-metric multidimensional scaled ordination (nMDS) analyses of 175 samples distributed in 16 core boxes (11–26) within the lacustrine phase of the Giraffe Pipe core based on abundances of 58 taxa. Samples within a given core box, with the exception of those in box 13
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Results of a SIMPER analysis identifying the organisms that contribute the ... Open Access

Published: 01 March 2023
Table 4. Results of a SIMPER analysis identifying the organisms that contribute the most to the transition between the Eunotioid and Heterotrophic zones in the Eocene waterbody from the Giraffe Pipe locality. Abundance numbers represent mean log e (X + 1) values. The number in parentheses under
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Results of a SIMPER analysis identifying the organisms that contribute the ... Open Access

Published: 01 March 2023
Table 2. Results of a SIMPER analysis identifying the organisms that contribute the most to the transition between the Botryococcus and Aulacoseira Zones in the Eocene waterbody from the Giraffe Pipe locality. Abundance numbers represent mean log e (X + 1) values. The number in parentheses
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Results of a SIMPER analysis identifying the organisms that contribute the ... Open Access

Published: 01 March 2023
Table 5. Results of a SIMPER analysis identifying the organisms that contribute the most to the transition between the Heterotrophic and Terminal Lake zones in the Eocene waterbody from the Giraffe Pipe locality. Abundance numbers represent mean log e (X + 1) values. The number in parentheses
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FIGURE 1—Color LM micrographs of diatoms from thin sections of Giraffe Pipe lacustrine mudstone. Arrows indicate protoplasmic remnants encased within intact frustules. Scale bars=10 μm. Discrete green masses occur at the junction between valve face and mantle (A), clustered near the central lumen (B), or disseminated as irregularly shaped bodies (C, D)

FIGURE 1 —Color LM micrographs of diatoms from thin sections of Giraffe Pip... Available to Purchase

Published: 01 June 2006
FIGURE 1 —Color LM micrographs of diatoms from thin sections of Giraffe Pipe lacustrine mudstone. Arrows indicate protoplasmic remnants encased within intact frustules. Scale bars=10 μm. Discrete green masses occur at the junction between valve face and mantle (A), clustered near the central lumen
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Scanning electron micrographs of untreated rock fragments from four representative stratigraphic intervals of the Giraffe Pipe core dominated by (1) chrysophyte cysts; (2) scales of Mallomonas insignis Penard, 1919; (3) the diatom Aulacoseira giraffensis Siver, Wolfe, and Edlund in Siver et al., 2019; and (4) Choanocystis heliozoan scales. Scale bars = (1, 2) 20 μm; (3, 4) 10 μm.

Scanning electron micrographs of untreated rock fragments from four represe... Open Access

Published: 01 March 2023
Figure 2. Scanning electron micrographs of untreated rock fragments from four representative stratigraphic intervals of the Giraffe Pipe core dominated by ( 1 ) chrysophyte cysts; ( 2 ) scales of Mallomonas insignis Penard, 1919 ; ( 3 ) the diatom Aulacoseira giraffensis Siver, Wolfe
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Results of a SIMPER analysis identifying the organisms that contribute the ... Open Access

Published: 01 March 2023
Table 3. Results of a SIMPER analysis identifying the organisms that contribute the most to the transition between the Aulacoseira and Eunotia Zones in the Eocene waterbody from the Giraffe Pipe locality. Abundance numbers represent mean log e (X + 1) values. The number in parentheses under
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FIGURE 4—Examples of mummified Metasequoia glyptostroboides remains from Giraffe Pipe terrestrial sediments immediately overlying the lacustrine sequence. A) Litter dominated by M. glyptostroboides from a depth of 85 m in the core (62 m equivalent vertical depth; cf. Fig. 1). B) Higher magnification scanning electron micrograph of Metasequoia needles reveal their exceptional preservation. Scale bars = 1 cm in A, 500 μm in B

FIGURE 4 —Examples of mummified Metasequoia glyptostroboides remains from... Available to Purchase

Published: 01 March 2009
FIGURE 4 —Examples of mummified Metasequoia glyptostroboides remains from Giraffe Pipe terrestrial sediments immediately overlying the lacustrine sequence. A) Litter dominated by M. glyptostroboides from a depth of 85 m in the core (62 m equivalent vertical depth; cf. Fig. 1 ). B) Higher
Journal Article

TROPICAL OCHROPHYTE ALGAE FROM THE EOCENE OF NORTHERN CANADA: A BIOGEOGRAPHIC RESPONSE TO PAST GLOBAL WARMING Available to Purchase

PETER A. SIVER, ALEXANDER P. WOLFE
Journal: PALAIOS
Published: 01 March 2009
PALAIOS (2009) 24 (3): 192–198.
DOI: https://doi.org/10.2110/palo.2007-p07-077r
...FIGURE 3 —Valves of Actinella morphotype Giraffe 1 from Giraffe Pipe sediments (A–D, G–H) and the modern species, A. parva , from Lake Judd, Tasmania (E–F). A– B) Internal (A) and external (B) views of whole valves. Note the varying lengths of the raphe slits and their position along the ventral...
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View PDF for article title, TROPICAL OCHROPHYTE ALGAE FROM THE EOCENE OF NORTHERN CANADA: A BIOGEOGRAPHIC RESPONSE TO PAST GLOBAL WARMING
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