ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Cambridge University Press  (8)
  • 1
    Publication Date: 2017-12-06
    Description: The stratigraphic reinterpretation of the palynologically analysed Miocene succession of the Wijshagen borehole along the southern margin of the North Sea Basin allowed an age assessment – late Burdigalian to early Serravalian – for the Genk Sand Member of the Bolderberg Formation. The depositional environment varied during Burdigalian to Serravalian times from continental (peat formation) to open marine (glauconitic sands), respectively from south to north in the Roer Valley Rift System. The study area of the Wijshagen borehole is located in the central part of the Roer Valley Rift System between these extreme environments. During the Burdigalian, the glauconitic fine clayey sands of the Houthalen Sand Member were deposited in the study area. From the late Burdigalian onwards, the glauconite content decreased and lignite content increased as a result of high influx of clastic material in the Roer Valley Rift System, and marked the start of the deposition of the Genk Sand Member. The Genk Sand Member shows an overall coarsening-upwards trend, which is consistent with the gradual infill of the available accommodation space in the Roer Valley Rift System by northwest-prograding clastic delta sequences. Dinoflagellate cyst analyses indicate that the Genk Sand Member was largely deposited in a marginal marine environment with only short pulses of continental input. These pulses of continental input increase in a southerly or landward direction where they led to the development of thick lignite seams.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
  • 3
    Publication Date: 2013-11-01
    Description: In order to obtain a better knowledge of past oceanographic variability offshore southern Chile, this study reappraises the changes in the sources of nutrients over the last 25 ka based on a detailed comparison of previously published nitrogen isotope and microfossil records (dinoflagellate cysts, coccoliths and diatoms) from ODP Site 1233 (41°S). Our findings support the main conclusions of Martinez et al. (2006) in the sense that both the Subantarctic Surface Water and the Gunther Undercurrent are potential sources for the recorded late Quaternary sedimentary δ15N signatures at Site 1233, with variable contributions of both sources during different time periods. This study indicates that Subantarctic Surface Water forms the main source for nutrients during the last glacial maximum (25–18.6 cal ka BP), the first part of the deglaciation (18.6–15.7 cal ka BP) and the Holocene (9.8 cal ka BP until present). An increased contribution of Equatorial Subsurface Water as a source of nutrients to the photic zone offshore southern Chile is observed between 14.4 and 9.8 cal ka BP, which is indicative for upwelling conditions at least after 13.2 cal ka BP as indicated by the microfossil data.
    Print ISSN: 0033-5894
    Electronic ISSN: 1096-0287
    Topics: Geography , Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2004-05-01
    Description: Dinoflagellate cysts and other palynomorphs from the Pliocene Kattendijk and Lillo formations, exposed in two temporary outcrops in northern Belgium, provide new information on the biostratigraphic position and sequence stratigraphic interpretation of these units. Dinoflagellate cysts from the Kattendijk Formation indicate an age between about 5.0 Ma and 4.7–4.4 Ma (early Early Pliocene) in our sections, confirming a correlation with standard sequence 3.4 and implying a slightly greater age than the Ramsholt Member of the Coralline Crag Formation of eastern England. The unconformity at the base of the Kattendijk Formation was not seen, but presumably correlates with sequence boundary Me2 at 5.73 Ma. The overlying Lillo Formation is late Early Pliocene or early Late Pliocene (c. 4.2–2.6 Ma) in age, and the unconformity at its base may be correlated with sequence boundary Za2 at 4.04 Ma or Pia1 at 3.21 Ma. The Oorderen Sands and superjacent Kruisschans Sands members (Lillo Formation) are both part of the same depositional cycle. They were probably deposited before 2.74 Ma, and certainly before the onset of Northern Hemisphere cooling at c. 2.6 Ma. Evidence from dinoflagellate cysts indicates that both a shelly unit at the base of the Lillo Formation and the lower part of the overlying Oorderen Sands were deposited during a conspicuously cool climatic phase, with warmer temperatures returning during later deposition of the Oorderen Sands and Kruisschans Sands members. Many dinoflagellate cyst and acritarch species are reported here for the first time from the southern North Sea Basin. Selenopemphix conspicua (de Verteuil & Norris, 1992) stat. nov. is proposed.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2006-10-10
    Description: Organic-walled palynomorph assemblages from the Kasterlee Formation in northern Belgium provide new insights into the Late Miocene depositional history and palaeoenvironments of the southernmost North Sea Basin. Ranges of key dinoflagellate cysts constrain the unit between 7.5 and 5.32 Ma, that is, a latest Tortonian to Messinian age. The palynomorph assemblage is characterized, amongst others, by Geonettia clineae, an opportunistic species that thrives in mesotrophic, coastal embayments with a low sediment influx. This environmental setting is corroborated by the notable presence of Gramocysta verricula, a species with preference for shallow marine environments. The occurrence of species of the fresh water green alga Pediastrum indicates manifest river discharge in a near-shore environment or embayment. The coastal depositional environment mirrored by the palynomorphs of the Kasterlee Formation succeeds the distinct transgressive and fully marine environments of the underlying Diest Formation in the Campine area. The results from the palynological study, combined with lithological and geophysical data, show that both Upper Miocene formations are two distinct depositional cycles separated by an erosional or regressive phase. The upper boundary of the Kasterlee Formation is correlated with the Me2 sequence boundary at 5.73 Ma. The Kasterlee Formation is herein formally moved from the Lower Pliocene series to the Upper Miocene series. The coastal environment, probably characterized by a shoaling phase, recorded at the border of the southern North Sea Basin, matches the global record of regressive phases in Messinian sedimentary sequences, which are linked to cooling and increasing global ice volume.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2007-12-20
    Description: A high-resolution palynological analysis and a detailed palaeomagnetic study of a marine sequence recovered during IODP Expedition Leg 307 in the Porcupine Basin southwest of Ireland provide new insights into the regional depositional history and palaeoenvironmental evolution during Early Neogene times. The Hole 1318B studied was drilled on the upper slope of the continental margin in a water depth of 409 m, upslope from a province of carbonate mounds (the Belgica mound province). The diverse and well-preserved dinoflagellate cyst associations consist typically of deep neritic and oceanic species, mixed with a neritic component transported from the shelf, reflecting the deep depositional setting at the continental margin. The palaeomagnetic record together with the ranges of key dinoflagellate cyst species constrain the age of the studied sequence between 16.7 Ma and 12.01 Ma, that is, between the late Burdigalian and late Serravallian. The distinct unconformity terminating the Miocene sequence correlates to the global sequence boundary Ser4/Tor1 dated at 10.5 Ma, and represents, according to previous extensive seismic studies, a basin-wide erosional event. The overlying sediments are of Middle Pleistocene or younger age. Downslope from IODP Site 1318, carbonate mounds root on the erosional surface. The dinoflagellate cyst associations from the Porcupine Basin distinctly mirror the global cooling phase following the Middle Miocene Climatic Optimum. Cooling phase Mi3, a short-lived glaciation, is particularly well expressed and here dated at 13.6 Ma. The palynomorph record furthermore indicates a reduction of the productivity and an increase of oceanic oligotrophic species after 14 Ma, suggesting a reduction or perhaps even a shutdown of the upwelling.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2008-09-30
    Description: Dinoflagellate cysts and sequence stratigraphy are used to date accurately the Tunnel-Canal Dock section, which contains the most complete record of marine Pliocene deposits in the Antwerp harbour area. The Zanclean Kattendijk Formation was deposited between 5.0 and 4.4 Ma during warm-temperate conditions on a shelf influenced by open-marine waters. The overlying Lillo Formation is divided into four members. The lowest is the Luchtbal Sands Member, estimated to have been deposited between 3.71 and 3.21 Ma, under cooler conditions but with an open-water influence. The Oorderen Sands, Kruisschans Sands and Merksem Sands members of the Lillo Formation are considered a single depositional sequence, and biostratigraphically dated between 3.71 andc. 2.6 Ma, with the Oorderen Sands Member no younger than 2.72–2.74 Ma. Warm-temperate conditions had returned, but a cooling event is noted within the Oorderen Sands Member. Shoaling of the depositional environment is also evidenced, with the transgressive Oorderen Sands Member passing upwards into (near-)coastal high-stand deposits of the Kruisschans Sands and Merksem Sands members, as accommodation space decreased. Applying sequence stratigraphy to our section implies that the Kattendijk/Lillo Formation boundary corresponds to the sequence boundary (SB) Za2 (4.04 Ma), the Luchtbal/Oorderen sands boundary to SB Pia1 (3.21 Ma), and the top of the Merksem Sands to SB Pia2 (2.76 Ma). Finally, the Belgian deposits are compared with marine Pliocene deposits of eastern England.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2010-03-22
    Description: A palynological analysis with marine palynomorphs (dinoflagellate cysts, acritarchs, green algae) and terrestrial palynomorphs (pollen and spores) of the Kasterlee and Poederlee formations provides new insights in the depositional history at the southern border of the North Sea basin (northern Belgium) around the Miocene–Pliocene transition. Dinoflagellate cyst stratigraphy constrains the age of the Kasterlee Formation in the Oud-Turnhout borehole between 7.5 and 5.32 Ma. The upper boundary of the formation can be correlated with sequence boundary Me2 at 5.73 Ma of Hardenbol and co-workers, which further constrains its age to the time interval 7.5–5.73 Ma. The palynomorph assemblages reflect a near-coast depositional environment. Where present, the Kasterlee Formation thus terminates the Miocene series in northern Belgium. The overall shallow nature of the latest Miocene deposits is related to a sea-level lowering caused by the onset of globally cooling conditions. For the first time, palynology is applied to estimate the age of the Poederlee Formation, suggesting it was deposited during the Mid-Pliocene warm period. Dinoflagellate cysts and sequence stratigraphy together constrain the age of the unit between 3.21 and 2.76 Ma, and possibly even between 3.21 and 3.15 Ma. The Poederlee Formation was deposited in neritic environments, which shoaled in the upper part of the unit as a consequence of the decreasing availability of accommodation space. We demonstrate that the magnitude of the hiatus between the Miocene and Pliocene series varies strongly at the southern boundary of the North Sea Basin, and lasts in the Antwerp areac. 3.2 million years andc. 2.52 million years in the Campine area.
    Print ISSN: 0016-7568
    Electronic ISSN: 1469-5081
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...