Catastrophic tidal expansion in the Bay of Fundy, CanadaEarth Sciences Sector (ESS) Contribution 20090423.

2010 ◽  
Vol 47 (8) ◽  
pp. 1079-1091 ◽  
Author(s):  
John Shaw ◽  
Carl L. Amos ◽  
David A. Greenberg ◽  
Charles T. O’Reilly ◽  
D. Russell Parrott ◽  
...  
Keyword(s):  
Water Temperature ◽  
Sea Level ◽  
Empirical Data ◽  
Late Holocene ◽  
Environmental Changes ◽  
Aboriginal Peoples ◽  
Bay Of Fundy ◽  
Data Sets ◽  
Level Data ◽  
Tidal Amplification

Tidal models for the Bay of Fundy, Canada — site of the highest recorded modern tide — show that tidal amplification began in the early Holocene and by ca. 5000 BP the range was almost 80% of the present range. Empirical data consisting of 146 sea-level index points and other observations appear to contradict model results. Aggregated relative sea-level data for Chignecto Bay and Minas Basin show that rapid tidal expansion began ca. 3400 BP. However, if we separate these two geographically separate data sets, evidence for this rapid late-Holocene tidal expansion is confined to Minas Basin. We explain this singularity by positing a barrier at the mouth of Minas Basin, at the Minas Passage, that delayed tidal expansion. With the rapid breakdown of this barrier and near-instantaneous tidal expansion, water temperature dropped, tidal currents and turbidity increased, and the form of the inner estuary was changed from lagoonal–mesotidal to macrotidal. We argue that the catastrophic breakdown of the barrier is related in the aboriginal legend of Glooscap, showing that aboriginal peoples observed the rapid environmental changes and preserved an oral record for 3400 years.

Pattern of recent vertical crustal movements in Maritime Canada

1976 ◽  
Vol 13 (5) ◽  
pp. 661-667 ◽  
Author(s):  
Petr Vaníček
Keyword(s):  
New Brunswick ◽  
Sea Level ◽  
Bay Of Fundy ◽  
Vertical Movements ◽  
Crustal Movements ◽  
First Order ◽  
Level Data ◽  
Velocity Surface ◽  
Maritime Canada ◽  
Vertical Crustal Movements

A surface depicting linear vertical movements in Maritime Canada was computed from sea-level data recorded by 8 tide guages and 308 mostly disjoint, relevelled segments of the first-order Canadian levelling network. Owing to the sparsity of the available data and their distribution, the velocity surface must be regarded as indicative of the crude features only. The indications are that there is a west-northwest trending belt of faster subsidence across the eastern end of the Bay of Fundy, and that there may be an area of uplift in northeastern New Brunswick. Although the faster subsidence around the eastern Bay of Fundy seems to be well established now, more data are needed to prove or dispel the existence of the indicated uplift.

scholarly journals Changing storminess? An analysis of long-term sea level data sets

1999 ◽  
Vol 11 ◽  
pp. 161-172 ◽  
Author(s):  
W Bijl ◽  
R Flather ◽  
JG de Ronde ◽  
T Schmith
Keyword(s):  
Sea Level ◽  
Data Sets ◽  
Level Data

Flank instability of coastal and ocean island volcanoes: Why it is not enough to look at the tip of the iceberg

2020 ◽  
Author(s):  
Morelia Urlaub
Keyword(s):  
Sea Level ◽  
Ground Deformation ◽  
Structural Instability ◽  
Mount Etna ◽  
Data Sets ◽  
Tectonic Structures ◽  
Ocean Island ◽  
Natural Processes ◽  
Level Data ◽  
Edifice Collapse

<p>Volcanoes are among the most rapidly growing geological structures on Earth. Consequently, their edifices suffer structural instability that may result in lateral flank collapses, such as the 1980 Mt St Helens event or the 2018 collapse of Anak Krakatau (Indonesia). The seafloor displays the geological remnants of collapses of nearly all ocean island volcanoes, including Hawaii and the Canary Islands. Such collapses and their associated tsunamis are among the largest and most disastrous natural processes on Earth, because of the enormous energy involved. Numerous coastal and ocean island volcanoes worldwide show signs of flank instability, documented by ground deformation measurements. However, it is difficult to evaluate their hazard potential mainly due to a lack of understanding of the causes of collapse. For coastal and ocean island volcanoes, most research and the vast majority of monitoring activities are biased towards the often comparatively small part of the volcano above sea level, while the largest part of the volcanic edifice is typically submerged in water. Using the example of Mount Etna (Italy) as well as several other case studies, I demonstrate that shoreline crossing analyses of volcano-tectonic structures and edifice deformation are necessary for understanding the mechanisms that control the volcano’s structural stability. I further argue that the earliest and most important precursory signals for imminent edifice collapse may occur below sea level. Data acquisition and monitoring in the deep sea is technologically and logistically challenging, but possible. It significantly extends onshore data sets with the potential to revolutionise our current understanding and hazard monitoring.</p>

Mid- to late Holocene environmental and climatic changes in New Caledonia, southwest tropical Pacific, inferred from the littoral plain Gouaro-Déva

2011 ◽  
Vol 76 (2) ◽  
pp. 229-242 ◽  
Author(s):  
Denis Wirrmann ◽  
Anne-Marie Sémah ◽  
Jean-Pierre Debenay ◽  
Magali Chacornac-Rault
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
New Caledonia ◽  
High Energy ◽  
Climatic Changes ◽  
Tropical Pacific ◽  
Energy Conditions ◽  
Enso Variability ◽  
Freshwater Swamp

AbstractMultiproxy analysis of three littoral cores from western New Caledonia supports the hypothesis that the main controlling factors of environmental changes are sea-level change, ENSO variability and extra-tropical phenomena, such as the Medieval Warm Period (MWP) marked by a tendency for La Niña-like conditions in the tropical Pacific. The record starts during the late Holocene sea-level rise when the terrestrial vegetation indicated wet and cool conditions. The site was a coastal bay definitely transformed into a freshwater swamp at around 3400 cal yr BP, after the rapid drawdown of sea level to its current level. Sediments and foraminiferal assemblages indicated subsequent episodes of freshwater infillings, emersion or very high-energy conditions, likely related to climatic changes and mostly controlled by ENSO variability. Between 2750 and 2000 cal yr BP, relatively dry and cool climate prevailed, while wetter conditions predominated between ca. 1800 and 900 cal yr BP. The Rhizophoraceae peak between ca. 1080 and 750 cal yr BP, coeval with the MWP, may indicate a global phenomenon. Microcharcoal particles present throughout the record increased after 1500 cal yr BP, suggesting an anthropogenic source. From ca. 750 cal yr BP the appearance of current type of vegetation marks the human impact.

Crustal subsidence inferred from reconstruction of the Pleistocene–Holocene palaeogeography in the northern Lake Inba area, central Japan

2019 ◽  
Vol 94 ◽  
pp. 61-79
Author(s):  
Takashi Chiba ◽  
Shigeo Sugihara ◽  
Yoshiaki Matsushima ◽  
Yusuke Arai ◽  
Kunihiko Endo
Keyword(s):  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
Sea Level Changes ◽  
Diatom Assemblages ◽  
Central Japan ◽  
Lower Salinity ◽  
The Holocene ◽  
Holocene Transgression

ABSTRACTTo help characterise the palaeogeographic and lacustrine environmental changes that resulted from the Holocene transgression and residual subsidence in the eastern Kanto Plain of central Japan, we analysed four drill cores and reviewed other core data from the southern part of the Lake Inba area. Fossil diatom assemblages yielded evidence of centennial-scale palaeogeographic and salinity responses to sea-level changes since the late Pleistocene. We determined that the seawater incursion into the Lake Inba area during the Holocene transgression occurred at approximately 9000 yr. We also recognised a late Holocene regression event corresponding to the Yayoi regression, considered to have occurred from ca. 3000 to ca. 2000 yr, and a subsequent transgression. Our data clarify some of the palaeogeographic changes that occurred in the Lake Inba area and document an overall trend toward lower salinity in the lake during the regression. In particular, the environment in Lake Inba changed from brackish to freshwater no later than 1000 yr. From the detailed palaeogeographic and palaeo-sea-level reconstruction, we recognised that residual subsidence occurred during the Holocene in this area. Thus, comparison of sea-level reconstructions based on modelling and fossil diatom assemblages is effective in interpreting Holocene long-term subsidence.

scholarly journals Foraminiferal Evidence of Late Holocene Sea-Level Change and Amerindian Site Distribution at Montague Harbour, British Columbia

2007 ◽  
Vol 50 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Eduard G. Reinhardt ◽  
Norman A. Easton ◽  
R. Timothy Patterson
Keyword(s):  
British Columbia ◽  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
Tectonic Subsidence ◽  
Archaeological Remains ◽  
Sea Level Changes ◽  
Site Distribution ◽  
Low Salinity ◽  
Holocene Sea Level

ABSTRACT Foraminiferal and sedimentological analysis of an underwater stratigraphie section from an Amerindian habitation site at Montague Harbour, British Columbia has further documented late Holocene sea level changes. It appears that part of the documented transgression was caused by tectonic subsidence of the area (Event 1 at approx. 3500 calendar years BP and Event 2 sometime before 1100 calendar years BP) and was recognized in the stratigraphie record by rapid environmental changes. The environmental changes caused by rapid shifts in water depth were recognized through sedimentological and foraminiferal evidence. The tectonic subsidence events, coupled with gentle late Holocene transgression, caused the breaching of Montague Harbour's northwestern channel. The breaching of the channel improved water circulation and increased salinity within the harbour. The salinity changes are reflected in the shift from a low salinity Cribroelphidium excavatum (Terquem, 1876) phenotype "clavata" dominated biofacies (1) at the base of the section to a higher salinity Buccella tenerrima (Bandy, 1950) and Elphidiella hannai (Cushman and Grant, 1927) dominated biofacies (2) at the top. These sea-level changes would have eventually forced local Amerindian settlements inland. The 14C dating of wood and shell, indicates that the recovery of archaeological remains of the Charles culture (ca.6500-3200 years BP) requires investigation in deeper waters.

scholarly journals PERUBAHAN LINGKUNGAN DAN EVOLUSI MANGROVE DI PULAU BELITUNG SELAMA HOLOSEN AKHIR BERDASARKAN REKAMAN POLEN

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
Woro Sri Sukapti ◽  
Eko Yulianto ◽  
Praptisih Praptisih
Keyword(s):  
Environmental Change ◽  
Sea Level ◽  
Late Holocene ◽  
Environmental Changes ◽  
Onset Time ◽  
Pollen Record ◽  
Shelf Area ◽  
Level Fluctuation ◽  
Sunda Shelf ◽  
Sea Level Fluctuation

Studi sejarah fluktuasi muka air laut dan perubahan lingkungan di Paparan Sunda masih sedikit dilakukan. Ada dua isu yang saling terkait yang menjadi permasalahan utama terkait dengan perubahan muka air laut di wilayah ini yaitu kurangnya rekaman data fluktuasi muka air laut dan perubahan lingkungan selama kurun waktu mid-late Holosen dengan kualitas yang bagus. Hal itu memiliki konsekwensi terhadap munculnya isu kedua yaitu tidak terdefinisikannya secara jelas dan tepat baik waktu maupun besaran posisi muka air laut pada saat mid-Holosen. Penelitian ini dilakukan untuk merekonstruksi perubahan lingkungan selama Holosen Akhir di wilayah Paparan Sunda menggunakan rekaman polen endapan mangrove. Pemboran tangan dilakukan guna pengamatan stratigrafi dan pengambilan sampel untuk analisis-analisis sedimentologi dan mikropaleontologi di laboratorium. Hasil studi ini menunjukkan bahwa perubahan lingkungan terjadi di Pulau Belitung selama setidaknya 1500 tahun terakhir sebagai akibat dari proses progradasi. Proses ini menyebabkan garis pantai terus maju hingga mencapai posisi saat ini. Endapan mangrove di lokasi penelitian juga merekam kejadian insidentil yang secara hipotetis diduga sebagai peristiwa tsunami akibat letusan Krakatau yang terjadi pada tahun 1883 AD dan sekitar 535-536 AD.Kata Kunci: Belitung, polen, mangrove, Mid-Holosen, Krakatau, muka laut, perubahan lingkungan.There is only minor study on sea-level fluctuation and environmental change in Sunda Shelf. The main isues in this area are lacking good quality of sea-level fluctuation and environmental change record during mid-late Holocene in which accordingly the onset time and sea-level height of the Mid-Holocene Maximum Transgression event have not been well defined. This study aims to reconstruct environmental changes during late Holocene in the Sunda Shelf area based on mangrove pollen record. Hand-auger was applied to make stratigraphic observation and sampling for sedimentological and micropaleontological analyses in the laboratory. Result of this study shows environmental changes occured within the last ca.1500 years due to coastal progradation in Belitung. This progradation shifted the coastal line seaward to attain the present position. The pollen record also reflects rapid and brief changes that may hypothetically be interpreted as the 535-536 AD and 1883 AD Krakatau tsunamis.Keywords: Belitung, pollen, mangroves, Mid-Holocene, Krakatau, sea level, environmental changes.

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