Paleoecology and paleoenvironment of Maastrichtian planktic foraminifera

详细信息    Paleoecology and paleoenvironment of Maastrichtian planktic foraminifera

• 出版日期：2002.
• 页数：361 p. :
• 第一责任说明：Sigal Abramovich.
• 分类号：a551.12
• ISBN：0493866124(ebk.) :

MARC全文

02h0025420 20110921160242.0 cr un||||||||| 110921s2002 xx ||||f|||d||||||||eng | AAI3067134 0493866124(ebk.) : CNY371.35 NGL NGL NGL a551.12 Abramovich, Sigal. Paleoecology and paleoenvironment of Maastrichtian planktic foraminifera [electronic resource] : examples from low and middle latitude localities / Sigal Abramovich. 2002. 361 p. : digital, PDF file. Source: Dissertation Abstracts International, Volume: 63-10, Section: B, page: 4564. ; Adviser: Gerta Keller. Thesis (Ph.D.)--Princeton University, 2002. A comprehensive study of Maastrichtian planktic foraminiferal populations from low and midlatitudes localities provides crucial knowledge on the paleoecology and life strategies of individual species, and new insights their biotic response to climatic perturbations preceding the Cretaceous-Tertiary mass extinction event. In the tropical Tethyan outer-shelf environment of Tunisia, times of critical high-stress environments are implied in the later part of the Maastrichtian (σ65.3–65.0 Ma) by the decline of ecologically sensitive species, strong fluctuations in the relative abundance of dominant species, low species diversity and blooms of the opportunistic Guembelitria species. High occurrences of Guembelitria species were also recognized in two distinct intervals of the late Maastrichtian and early Danian in the shallower neritic environment of Madagascar. These blooms are coeval with similar events in the Tethys and suggest times of widespread high stress conditions. However, in Madagascar, Guembelitria blooms last longer and include a morphovariants that are typical to midlatitude regions.;A unique faunal response to the late Maastrichtian environmental changes is observed in the deep-sea locality of the midlatitude Atlantic Site 525A. At this locality, several planktic foraminiferal species record abnormal presence of unusually small adult specimens. Highest occurrences of dwarfed specimens correspond to the interval of global greenhouse warming (65.45–65.10 Ma) and significant reduction of upper water mass stratification. Negative response to the climate warming is also evident by the reduced species diversity and/or abundance, and reduced photosymbiotic activity.;Stable isotope data of well-preserved foraminiferal tests from cold and warm time intervals at various deep-sea localities were used to reconstruct the habitat patterns and ecological characters of Late Cretaceous planktic foraminiferal species. Species records define three types of depth habitats that correspond to deep (sub-thermocline, sub-photic zone), intermediate (subsurface) and surface (mixed layer) plankton environments. However, a more distinct isotopic ordering is indicated in the cool early and late Maastrichtian intervals, which implies stronger upper-water mass stratification at these time intervals. Photosymbiotic activity was recognized among several planktic foraminiferal groups including all morphotypes of the Rosita lineage. In addition, increased strength of photosymbiosis is observed along the evolutionary developmental stages of the Racemiguembelina lineage. Foraminifera. Electronic books. aeBook. aCN bNGL http://proquest.calis.edu.cn/umi/detail_usmark.jsp?searchword=pub_number%3DAAI3067134&singlesearch=no&channelid=%CF%B8%C0%C0&record=1 NGL Bs952 rCNY371.35 ; h1 bs1107