High-Resolution Seismic Reflection Evidence for Middle Holocene Environmental Change, Owasco Lake, New York

2001 ◽  
Vol 55 (3) ◽  
pp. 322-331 ◽  
Author(s):  
Henry T. Mullins ◽  
John D. Halfman
Keyword(s):  
New York ◽  
Seismic Reflection ◽  
Seismic Reflection Profile ◽  
East Central ◽  
Glacial Sediments ◽  
Middle Holocene ◽  
The North ◽  
Holocene Sediments ◽  
Erosion Surface ◽  
North End

AbstractApproximately 70 km of new decimeter-resolution seismic reflection profile data from Owasco Lake, New York define a middle Holocene (∼4600 14C yr B.P.) erosion surface in the north end of the lake at water depths as great as 26 m. Beneath the lake, post-glacial sediments are up to 9 m thick and represent about 10% of the total sediment fill. Early to middle Holocene sediments, ∼6 m thick, contain biogenic gas at the south end of the basin and a large (4 km × 300 m × 15 m) subaqueous slide deposit along the east-central portion of the lake. Late Holocene sediments are thinner or absent, particularly at the north end of the lake. The middle Holocene erosion surface may have been produced by a drop in lake level. Alternatively, it may represent a change in climate during the transition between the relatively warm Holocene hypsithermal and cool neoglacial. At this time (∼4600 14C yr B.P.) circulation in Owasco Lake appears to have evolved from sluggish to active. The increased circulation, which persists today, probably resulted from atmospheric cold fronts with strong southwesterly winds that piled up water at the north end of the lake. The increased water circulation may have been ultimately driven by decreasing insolation, which produced an increased pole-to-equator thermal gradient and thus, stronger global winds that began at the transition between the hypsithermal and neoglacial.

Some results of COCORP seismic reflection profiling in the Grenville-age Adirondack Mountains, New York State

1985 ◽  
Vol 22 (2) ◽  
pp. 141-153 ◽  
Author(s):  
S. L. Klemperer ◽  
L. D. Brown ◽  
J. E. Oliver ◽  
C. J. Ando ◽  
B. L. Czuchra ◽  
...  
Keyword(s):  
New York ◽  
Lower Crust ◽  
Seismic Reflection ◽  
New York State ◽  
Three Dimensional ◽  
Upper Crust ◽  
Adirondack Mountains ◽  
East Central ◽  
York State ◽  
Seismic Reflection Profiling

COCORP deep seismic reflection profiling in the Adirondack Mountains of northern New York State has revealed a prominent zone of layered reflectors in the lower crust of the east-central Adirondacks. The strong, layered reflectors (here termed the Tahawus complex) occur between 18 and 26 km depth, beneath the sparsely reflective, granulite-grade, surface terrane, which has been uplifted from depths greater than 20 km. The Tahawus complex apparently represents layered rocks of some type in the lower crust of the Adirondacks. Possibilities include gneissic layering, cumulate igneous layering, a layered sill complex, and underthrust sedimentary strata, The Tahawus complex may be spatially coincident with a previously detected, high-conductivity zone in the lower crust, suggesting that either unusual mineralogies or interstitial electrolytes are present in the Tahawus complex. In contrast to layered reflections discovered in the lower crust of the east-central Adirondacks and southeast of the Adirondacks, cross-cutting and discontinuous reflections are recorded from the upper crust on all the COCORP Adirondack lines, including lines in both the Adirondack Highlands and Lowlands. Available three-dimensional control suggests that reflections in the upper crust of the central Adirondacks are parallel to, and hence may be related to, the folded gneisses mapped at the surface. Shallow events are also observed on a COCORP profile close to the epicenter of the 7 October 1983 magnitude 5.2 earthquake in the central Adirondacks, but their relation to the earthquake is uncertain.

Imaging a shallow aquifer in temperate glacial sediments using seismic reflection profiling with DMO processing

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1248-1256 ◽  
Author(s):  
John H. Bradford ◽  
Dale S. Sawyer ◽  
Colin A. Zelt ◽  
John S. Oldow
Keyword(s):  
Seismic Reflection ◽  
Velocity Structure ◽  
Puget Sound ◽  
Shallow Aquifer ◽  
Small Island ◽  
Seismic Reflection Profile ◽  
Glacial Sediments ◽  
Aquifer System ◽  
Reflection Profile ◽  
Weight Drop

We acquired a seismic reflection profile to image a shallow (<100 m) aquifer system on a small island in Puget Sound, north of Seattle, Washington. The aquifer system is comprised of temperate glacial sedimentary strata, with the primary aquifer lying approximately 45 m below the surface. We chose the site because there are water‐well boring descriptions available and a sea cliff parallels the profile location, providing stratigraphic control. A 20-lb (9-kg) weight drop was used as an energy source to acquire a 30-fold common‐midpoint (CMP) reflection profile along a 400-m line. Analysis of the recorded wavefield was not straightforward because of complex stratigraphy and the presence of a laterally variable thin bed (∼5–15 m) of high‐impedance lodgement till within a few meters of the surface. We used finite‐difference modeling to determine that conventional CMP processing would provide a reasonable approximation for imaging strata in the primary target zone, roughly 20 m below the high velocity till. For CMP processing, we analyzed the velocity structure using iterative dip moveout (DMO) velocity analysis. Use of this method results in a velocity field that dramatically improves the poststack depth‐migrated section.

Constraints on Reelfoot Rift Evolution from a Reflection Seismic Profile in the Northern Rift

1992 ◽  
Vol 63 (3) ◽  
pp. 233-241 ◽  
Author(s):  
M.B. Goldhaber ◽  
C.J. Potter ◽  
C.D. Taylor
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Seismic Profile ◽  
Fault System ◽  
Seismic Reflection Profile ◽  
The South ◽  
Dome A ◽  
Reflection Seismic ◽  
The North ◽  
Northwestern Margin

Abstract An 82.8 km segment of a northwest-southeast trending seismic-reflection profile across the northernmost part of the Reelfoot rift shows that the Cambrian rift geometry there is quite distinct from that of the main part of Reelfoot rift to the south, and that of the Rough Creek graben to the east. The profile is within the area of intersection of the Reelfoot rift and Rough Creek graben and shows a systematic southeastward thickening of the Cambrian synrift clastic sequence with as much as 1940 meters of section present against the Pennyrile fault system as compared to 970 meters near the Lusk Creek and Shawneetown fault systems, towards the northwestern margin of the rift. This contrasts with the more symmetric rift pattern in the seismically active zone to the south, where the maximum thickness of synrift sediments is along the rift axis, and with an opposite sense of rift asymmetry in the Rough Creek graben, where the synrift sequence thickens to the north against the Rough Creek - Shawneetown fault. Reflection patterns in the vicinity of Hicks dome, a “cryptovolcano”, are consistent with the hypothesis that the dome originated by explosive release of mantle-derived gases associated with alkali volcanism. The seismic data also reveal that the fluorine mineralization in the area is associated with faults that offset basement; this is further evidence that deeply-derived fluids are significant in the geologic evolution of the area.

An interpretation of the gravity anomaly at Warlingham, Surrey

1996 ◽  
Vol 133 (5) ◽  
pp. 619-624
Author(s):  
P. Kearey ◽  
A. M. Rabae
Keyword(s):  
Gravity Anomaly ◽  
Seismic Reflection ◽  
The Body ◽  
Seismic Reflection Profile ◽  
Seismic Reflection Data ◽  
Shaped Body ◽  
The North ◽  
Reflection Data ◽  
Platform Comparison ◽  
Upper Boundary

AbstractAn interpretation of the negative gravity anomaly at Warlingham, Surrey, controlled by a seismic reflection profile and several boreholes, suggest that it may be caused by a wedge-shaped body of lowdensity Upper Palaeozoic rocks. The seismic reflection data suggest that the upper boundary of the body may be thrust-controlled and originated during Variscan compression. The location of the thrusting appears to be controlled by the southern margin of the stable London Platform. Comparison with similar structures of this type elsewhere suggests that the Variscan Front in this area lies just to the north of Warlingham.

Crustal structure across the Caledonides from the ‘WINCH’ seismic reflection profile: influences on the evolution of the Midland Valley of Scotland

1984 ◽  
Vol 75 (2) ◽  
pp. 97-109 ◽  
Author(s):  
J. Hall ◽  
J. A. Brewer ◽  
D. H. Matthews ◽  
M. R. Warner
Keyword(s):  
Crustal Structure ◽  
Crustal Deformation ◽  
Seismic Reflection ◽  
Deep Structure ◽  
Sedimentary Basins ◽  
Seismic Reflection Profile ◽  
Crustal Shortening ◽  
The North ◽  
Reflection Profile ◽  
Deep Seismic Reflection Profile

ABSTRACTThe Western Isles–North Channel (‘WINCH’) deep seismic reflection profile runs through the North Channel across the extension of the Midland Valley into the Firth of Clyde.A variety of shallow Carboniferous and younger sedimentary basins dominates the upper crustal structure. The deep structure includes a reflective lower crust, bounded downwards by the Moho, and dipping ‘thrusts’. No margins to the Midland Valley are observed equivalent to the bounding faults on land. Thrusts below both the Highlands and the Southern Uplands have a variety of dip directions indicative of zig-zag crustal shortening of 100 km in the Highlands and 60 km in the Southern Uplands.The Moho varies only a little in depth, despite the gross crustal deformation in the Caledonides. Isostatic recovery of the Moho on unlocking of collided crustal blocks may explain the formation of some sedimentary basins.

Two major Wisconsin lithostratigraphic units in southwest British Columbia

1977 ◽  
Vol 14 (7) ◽  
pp. 1471-1480 ◽  
Author(s):  
J. E. Armstrong ◽  
J. J. Clague
Keyword(s):  
British Columbia ◽  
The South ◽  
Glacial Sediments ◽  
The North ◽  
Lithostratigraphic Units ◽  
Head Formation ◽  
Sand And Gravel ◽  
Part Plant ◽  
North End

Two lithostratigraphic units, Quadra Sand and the Cowichan Head Formation, are overlain by Vashon till and associated glacial sediments and underlain by Dashwood and Semiahmoo drift deposits in coastal southwest British Columbia. Each unit is formally described and stratotypes are presented.Quadra Sand consists of cross-stratified, well-sorted sand, minor gravel, and silt deposited as outwash in front of glaciers advancing into the Georgia Depression at the beginning of the Fraser Glaciation. It is diachronous, deposition having commenced earlier than 29 000 years BP at the north end of the Georgia Depression but not until after 15 000 years BP at the south end of the Puget Lowland.The Cowichan Head Formation, deposited during the Olympia nonglacial interval, underlies Quadra Sand and consists of parallel-bedded silt, sand, and gravel, in part plant-bearing. The unit is divisible into a lower marine member and an upper fluvial and estuarine member.

Mafias on the Move

2011 ◽  
Author(s):  
Federico Varese
Keyword(s):  
United States ◽  
New York ◽  
Organized Crime ◽  
The United States ◽  
The West ◽  
Market Expansion ◽  
The North ◽  
Economic Transformations ◽  
At Will

Organized crime is spreading like a global virus as mobs take advantage of open borders to establish local franchises at will. That at least is the fear, inspired by stories of Russian mobsters in New York, Chinese triads in London, and Italian mafias throughout the West. As this book explains, the truth is more complicated. The author has spent years researching mafia groups in Italy, Russia, the United States, and China, and argues that mafiosi often find themselves abroad against their will, rather than through a strategic plan to colonize new territories. Once there, they do not always succeed in establishing themselves. The book spells out the conditions that lead to their long-term success, namely sudden market expansion that is neither exploited by local rivals nor blocked by authorities. Ultimately the inability of the state to govern economic transformations gives mafias their opportunity. In a series of matched comparisons, the book charts the attempts of the Calabrese 'Ndrangheta to move to the north of Italy, and shows how the Sicilian mafia expanded to early twentieth-century New York, but failed around the same time to find a niche in Argentina. The book explains why the Russian mafia failed to penetrate Rome but succeeded in Hungary. A pioneering chapter on China examines the challenges that triads from Taiwan and Hong Kong find in branching out to the mainland. This book is both a compelling read and a sober assessment of the risks posed by globalization and immigration for the spread of mafias.

Archive of digital boomer seismic reflection data collected offshore east-central Florida during USGS cruise 00FGS01, July 14-22, 2000

Data Series ◽  
10.3133/ds496 ◽  
2009 ◽  
Author(s):  
Janice A. Subino ◽  
Shawn V. Dadisman ◽  
Dana S. Wiese ◽  
Karynna Calderon ◽  
Daniel C. Phelps
Keyword(s):  
Seismic Reflection ◽  
Seismic Reflection Data ◽  
East Central ◽  
Central Florida ◽  
Reflection Data
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