Info On On Fossil Plants

Miles

Figure 9.6 Map of New Zealand showing approximate positions of K-T boundary locaities on the South Island (numbers 103-105 in Table 2.1 and Appendix).

Vajda et al. found a double fern-spore spike at two localities, a fully nonmarine site at the Moody Creek coal mine, and a second one in nearshore marine rocks along the Waipara River on the east coast of the South Island (Figure 9.6). The boundary is also marked by the extinction of two species of angiosperm pollen, Tricolpites lilliei and Nothofagidites kaitangata. A large iridium anomaly (71 ppb) is present at Moody Creek Mine (locality 103). At both Moody Creek Mine and Mid-Waipara River (locality 105), the fern-spore spike is composed of high percentages of Laevigatosporites and other spores, interpreted as having been produced by ground ferns, followed by Cyathidites and a second spore species, both interpreted as being from tree ferns (Figure 9.7). Tree ferns that produce spores of the morphology of Cyathidites are common in the modern flora of New Zealand; thus, the interpretation of the fossil spores above the K-T boundary as representing tree ferns is quite reasonable, although that interpretation has not been made for the ferns that produced the North American fern-spore spikes dominated by Cyathidites spores.

In 2003, a special issue of the New Zealand Journal of Geology and Geophysics published several papers on the K-T boundary in both marine and nonmarine rocks in New Zealand. Six of the 20 K-T boundary sections now known in New Zealand were reviewed by Hollis (2003). Vajda and Raine (2003) and Hollis and Strong (2003) discussed the Mid-Waipara River locality in considerable detail. This locality is in nearshore marine rocks, and the microfossil record includes

Trscfl element

K^T boundary markers Main Broup* o1 fern apotos ami poller

Trscfl element

K^T boundary markers Main Broup* o1 fern apotos ami poller

Fossil Data Before After Boundary

Figure 9.7 Fern-spore spikes above the K-T boundary in New Zealand (from Vajda et al. 2001). Copyright 2001 AAAS; reprinted by permission.

Figure 9.7 Fern-spore spikes above the K-T boundary in New Zealand (from Vajda et al. 2001). Copyright 2001 AAAS; reprinted by permission.

pollen and spores of terrestrial origin as well as marine dinoflagellate cysts, foraminifera, radiolarians, and calcareous nannofossils. In addition, the site preserves Cretaceous marine reptiles in large concretions not far below the K-T boundary horizon. The pollen and spore record at the Mid-Waipara River locality documents the existence of a temperate rainforest composed largely of podocarpaceous conifers and tree ferns in latest Maastrichtian time, which was destroyed by the K-T boundary event. Ground ferns temporarily replaced the forest vegetation. Both gymnosperms and angiosperms returned after an estimated several thousand years and reestablished the forest. Vajda and Raine (2003) presented detailed occurrence data and photomicrographs of the palyno-morphs. They assert that the turnover in vegetation at the K-T boundary is comparable to that documented by palynological records from North America and Japan (see Sections 7.8 and 8.3). In their description of the Mid-Waipara River locality, Hollis and Strong (2003) noted that a weak iridium anomaly is present; but suggested that it is relatively weak because of post-depositional bioturbation of the sediments in this neritic paleoenvironment.

A third K-T boundary locality in New Zealand with nonmarine palynomorphs was reported by Vajda et al. (2004). Compressor Creek (locality 104) adds to the records of fern-spore spikes from the Southern Hemisphere. Vajda and McLoughlin (2007) summarized the features of the New Zealand palynofloral record at the K-T boundary and discussed using it as a tool for determining causes

Peninsulapollis

Figure 9.8 Some key pollen species from the Mid-Waipara locality in New Zealand (number 105 in Table 2.1 and Appendix), some specimens photographed at two levels of focus. 1a, 1b - Hexpollenites clifdenensis; 2- Tricolpites secarius; 3- Triorites minor, 4- Triorites minor, 5a, 5b - Nothofagidites kaitangata; 6 - Nothofagidites waipawaensis; 7 - Dicotetradites clavatus; 8 -Paripollis sp.; 9 - Peninsulapollis askiniae; 10- PeninsulapoUisgiUii; 11 -Proteacidites sp.; 12 -Proteacidites palisadus; 13a, 13b - Tricolpites reticulatus; 14- Quadraplanus brossus; 15- Tricolpites liUiei; 16- Tricolpites lilliei; 17- Tricolpites phiUipsii; 18- Tricolporites sp. Specimens range from 20 to 55 micrometers in diameter. From Vajda and Raine (2003); reprinted by permission.

Figure 9.8 Some key pollen species from the Mid-Waipara locality in New Zealand (number 105 in Table 2.1 and Appendix), some specimens photographed at two levels of focus. 1a, 1b - Hexpollenites clifdenensis; 2- Tricolpites secarius; 3- Triorites minor, 4- Triorites minor, 5a, 5b - Nothofagidites kaitangata; 6 - Nothofagidites waipawaensis; 7 - Dicotetradites clavatus; 8 -Paripollis sp.; 9 - Peninsulapollis askiniae; 10- PeninsulapoUisgiUii; 11 -Proteacidites sp.; 12 -Proteacidites palisadus; 13a, 13b - Tricolpites reticulatus; 14- Quadraplanus brossus; 15- Tricolpites liUiei; 16- Tricolpites lilliei; 17- Tricolpites phiUipsii; 18- Tricolporites sp. Specimens range from 20 to 55 micrometers in diameter. From Vajda and Raine (2003); reprinted by permission.

of the end-Permian mass extinction. Representatives of the uppermost Cretaceous and lowermost Paleocene palynofloras of New Zealand are shown in Figure 9.8.

Discovery of fern-spore spikes at the otherwise palynologically subtle K-T boundary in New Zealand has important implications for the history of plants at

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