Characterizing Variability in the Distribution of High-Frequency Acoustic Backscattering in a Shallow Water Coastal Region

2007 ◽  
Author(s):  
Gareth L. Lawson ◽  
Timothy K. Stanton ◽  
Peter H. Wiebe
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Coastal Region ◽  
Acoustic Backscattering

Polychaete palaeoecology in an early Late Ordovician marine astrobleme of Sweden

2010 ◽  
Vol 148 (2) ◽  
pp. 269-287 ◽  
Author(s):  
MATS E. ERIKSSON ◽  
ÅSA M. FRISK
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Relative Frequency ◽  
Late Ordovician ◽  
Crater Floor ◽  
Drill Core ◽  
Upper Ordovician ◽  
Composition Characteristic ◽  
Post Impact ◽  
Early Late

AbstractThe post-impact Dalby Limestone (Kukruse; Upper Ordovician) of the Tvären crater, southeastern Sweden, has been analysed with regards to polychaetes, as represented by scolecodonts. A palaeoecological succession is observed in the Tvären-2 drill core sequence, as the vacant ecospace was successively filled by a range of benthonic, nektonic and planktonic organisms. Scolecodonts belong to the first non-planktonic groups to appear and constitute one of the most abundant fossil elements. The polychaete assemblage recorded has an overall composition characteristic of that of the Upper Ordovician of Baltoscandia. Oenonites, Vistulella, Mochtyella and the enigmatic ‘Xanioprion’ represent the most common genera, whereas Pteropelta, Protarabellites?, Atraktoprion and Xanioprion are considerably more rare. The assemblage differs from coeval ones particularly in its poorly represented ramphoprionid fauna and the relatively high frequency of ‘Xanioprion’. A taxonomic succession and changes in abundance and relative frequency of different taxa is observed from the deepest part of the crater and upwards towards more shallow water environments. The initial post-impact assemblage does not, however, necessarily represent a benthonic colonization of the crater floor. Instead it seems to be a taphocoenosis, as indicated by its taxonomic correspondence to the rim facies fauna recovered from Dalby Limestone erratics of the Ringsön island. The Tvären succession has yielded considerably richer scolecodont assemblages than hitherto recorded from the approximately coeval Lockne crater, possibly as a consequence of shallower water settings in the former area.

Measurements of high-frequency shallow-water acoustic phase fluctuations

2000 ◽  
Vol 25 (4) ◽  
pp. 507-515 ◽  
Author(s):  
S.J. Stanic ◽  
R.R. Goodman ◽  
R.W. Meredith ◽  
E. Kennedy
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Phase Fluctuations ◽  
Acoustic Phase

Shallow water sediment properties derived from high-frequency shear and interface waves

1992 ◽  
Vol 97 (B4) ◽  
pp. 4739 ◽  
Author(s):  
John Ewing ◽  
Jerry A. Carter ◽  
George H. Sutton ◽  
Noel Barstow
Keyword(s):  
Shallow Water ◽  
High Frequency ◽  
Sediment Properties ◽  
Interface Waves ◽  
Shallow Water Sediment
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