scholarly journals Origins of The Santa Maria And Vandenberg Coastal Dune Sheets (~100-0 ka) Under Changing Sea Levels, Shoreline Orientations and Wave Directions: Long-Term Records of Coastal Sand Supply in South-Central California, USA

2017 ◽  
Vol 10 (1) ◽  
pp. 33 ◽  
Author(s):  
Curt D Peterson ◽  
Christopher Ryan ◽  
Jack Meyer ◽  
David Price ◽  
Steve W Hostetler
Keyword(s):  
Late Pleistocene ◽  
Coastal Dune ◽  
Beach Erosion ◽  
Dune Sand ◽  
South Central ◽  
Sand Supply ◽  
Coastal Sand ◽  
Santa Maria ◽  
Sand Deposition

Two large coastal dune sheets, including the Santa Maria dune sheet and Vandenberg dune sheet, have been analyzed for late-Quaternary distributions, ages and volumes of dune sand deposition. Six new thermoluminescence (TL) ages establish the age range of dune sand deposition from >106±21 ka to <4.1 ka in the study area. Seven late-Pleistocene TL and 14C dated mid-depth samples (≤30 m depth subsurface), yield a mean of 33 ka for the late-Pleistocene dune deposits. Both TL and 14C dated Holocene dune deposits establish a transition from weathered middle-Holocene dune deposits to unweathered latest-Holocene dune deposits after 4 ka. Marine sand supply to the large dune sheets occurred by 1) cross-shelf eolian transport during late-Pleistocene marine low-stands (70–13 ka), 2) shoreward wave transport during slowing of the Holocene marine transgression (9–5 ka), and 3) longshore littoral transport during the latest-Holocene marine high-sand (3.5–0 ka). Measured and dated dune deposit sections (n=66, ranging from 2 to 60 m depth) demonstrate substantial differences in preserved sand volumes between the two adjacent dune sheets, Santa Maria (~ 2,300x106 m3) and Vandenberg (~430x106 m3). Asymmetric distributions of dune deposit volumes between and within the dune sheets show that long-term sand supply was locally controlled by paleo-shoreline orientations relative to corresponding deep-water wave propagation directions (260–290° TN) from the North Pacific Low Pressure Area. Recently declining sand supplies and/or -trapping efficiencies in the dune sheet littoral subcells led to ongoing shoreline retreat (≥ 200 m) and under-cutting of late- Holocene eolian sand ramps at the south ends of the Santa Maria and Vandenberg dune sheets. The termination of transgressive cross-shelf sand supply and locally variable longshore retention of littoral sand confirm previously reported framework models of regional coastal sand supply. Such models help to identify shorelines that are most susceptible to future beach erosion from predicted sea level rise following ongoing global warming. 

scholarly journals LONG-TERM TOPOGRAPHIC CHANGES AROUND SAND SPIT AND IMPACT OF EXTRAORDINARY HIGH WAVES DURING TYPHOONS

2017 ◽  
pp. 8
Author(s):  
Toshiro San-nami ◽  
Takaaki Uda ◽  
Masashi Yamada ◽  
Toshinori Ishikawa
Keyword(s):  
Deep Sea ◽  
Field Data ◽  
Beach Nourishment ◽  
Steep Slope ◽  
Beach Erosion ◽  
Suruga Bay ◽  
Sand Supply ◽  
Sand Spit ◽  
Long Time

Around the Mihono-matsubara sand spit in Suruga Bay in Japan, the beach was eroded owing to the decrease in the fluvial sand supply from the Abe River triggered by excess riverbed mining before 1967, together with the discharge of sand into the deep sea via a steep slope near the tip of the sand spit. As a measure against beach erosion, an artificial headland (HL) composed of two detached breakwaters and the breakwaters (BWs) placed along the shoreline have been constructed along with beach nourishment, but the beach is barely maintained by these measures. In 2013, two large typhoons hit the coast, causing rapid beach changes around the structures, and these beach changes were superimposed on the long-term topographic changes that have occurred over a long time as a geomorphological process. In this study, their impact to the beaches was investigated on the basis of the field data.

scholarly journals PREDICTION OF BEACH EROSION CAUSED BY REDUCTION OF FLUVIAL SAND SUPPLY DUE TO EXCESS SAND MINING AND BEACH RECOVERY AFTER PROHIBITION OF MINING

2012 ◽  
Vol 1 (33) ◽  
pp. 61 ◽  
Author(s):  
Toshiro San-nami ◽  
Takaaki Uda ◽  
Norikazu Ohashi ◽  
Hitoshi Iwamoto ◽  
Masumi Serizawa ◽  
...  
Keyword(s):  
River Mouth ◽  
Sediment Supply ◽  
Beach Erosion ◽  
Sand Mining ◽  
Natural Sand ◽  
Sand Supply ◽  
Sand Body ◽  
Bathymetric Changes ◽  
Good Agreement

Long-term topographic changes since 1968 along the entire Shizuoka and Shimizu coasts including a 17 km stretch extending between the Abe River mouth and the tip of the Mihono-matsubara sand spit were investigated. Beach erosion of these coasts was triggered by the decrease in sediment supply from the Abe River due to excessive riverbed mining until 1967. After 1982/1983, natural sand supply from the river increased and accretion occurred on these coasts. Measured topographic changes were reproduced using the contour-line-change model considering changes in grain size. Not only the movement of the sand body but also the shoreline and bathymetric changes were numerically reproduced. The calculated results were in good agreement with the measured topographic changes.

National coastal management challenges and needs

Shore & Beach ◽  
2020 ◽  
pp. 34-43
Author(s):  
Nicole Elko ◽  
Tiffany Roberts Briggs
Keyword(s):  
Coastal Management ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Local Community ◽  
Extreme Event ◽  
Technical Information ◽  
Interdisciplinary Approach ◽  
Beach Erosion ◽  
The U.S

In partnership with the U.S. Geological Survey Coastal and Marine Hazards and Resources Program (USGS CMHRP) and the U.S. Coastal Research Program (USCRP), the American Shore and Beach Preservation Association (ASBPA) has identified coastal stakeholders’ top coastal management challenges. Informed by two annual surveys, a multiple-choice online poll was conducted in 2019 to evaluate stakeholders’ most pressing problems and needs, including those they felt most ill-equipped to deal with in their day-to-day duties and which tools they most need to address these challenges. The survey also explored where users find technical information and what is missing. From these results, USGS CMHRP, USCRP, ASBPA, and other partners aim to identify research needs that will inform appropriate investments in useful science, tools, and resources to address today’s most pressing coastal challenges. The 15-question survey yielded 134 complete responses with an 80% completion rate from coastal stakeholders such as local community representatives and their industry consultants, state and federal agency representatives, and academics. Respondents from the East, Gulf, West, and Great Lakes coasts, as well as Alaska and Hawaii, were represented. Overall, the prioritized coastal management challenges identified by the survey were: Deteriorating ecosystems leading to reduced (environmental, recreational, economic, storm buffer) functionality, Increasing storminess due to climate change (i.e. more frequent and intense impacts), Coastal flooding, both Sea level rise and associated flooding (e.g. nuisance flooding, king tides), and Combined effects of rainfall and surge on urban flooding (i.e. episodic, short-term), Chronic beach erosion (i.e. high/increasing long-term erosion rates), and Coastal water quality, including harmful algal blooms (e.g. red tide, sargassum). A careful, systematic, and interdisciplinary approach should direct efforts to identify specific research needed to tackle these challenges. A notable shift in priorities from erosion to water-related challenges was recorded from respondents with organizations initially formed for beachfront management. In addition, affiliation-specific and regional responses varied, such as Floridians concern more with harmful algal blooms than any other human and ecosystem health related challenge. The most common need for additional coastal management tools and strategies related to adaptive coastal management to maintain community resilience and continuous storm barriers (dunes, structures), as the top long-term and extreme event needs, respectively. In response to questions about missing information that agencies can provide, respondents frequently mentioned up-to-date data on coastal systems and solutions to challenges as more important than additional tools.

Late Pleistocene chronology and paleoclimate of Vancouver Island determined from cave deposits

1981 ◽  
Vol 18 (11) ◽  
pp. 1643-1652 ◽  
Author(s):  
M. Gascoyne ◽  
D. C. Ford ◽  
H. P. Schwarcz
Keyword(s):  
Late Pleistocene ◽  
Growth Period ◽  
Vancouver Island ◽  
Isotopic Equilibrium ◽  
South Central ◽  
Cave Deposits ◽  
Short Period ◽  
Thermal Buffering

Speleothems from four caves in south-central Vancouver Island have been analysed by the 230Th/234U method. Only speleothems from one cave, Cascade Cave, near Port Alberni, contained sufficient uranium for them to be dated. Twenty-seven ages determined for seven speleothems were found to cluster in two periods: 67–28 ka, corresponding to the Olympia interstadial, and <23–10 ka (or <15 ka if corrected for detrital thorium contamination), corresponding to the Fraser (late Wisconsin) deglaciation and Holocene periods. Two speleothems were found to be deposited in isotopic equilibrium with their seepage waters. Profiles of variations in δ18O of the calcite (δ18Oc) of each of the two deposits show a decrease of 1.3‰ over the growth period, 64–28 ka. At all times, δ18Oc was less than δ18O of modern calcite in the cave. Using modern cave temperature and the variation of δ18O of seawater over the dated period, the profiles of δ18Oc are interpreted in terms of a paleotemperature record for the Olympia interstadial in Vancouver Island. The results show a gradual cooling from 4 °C at 64 ka, to 0 °C between 35 and 28 ka. These results are consistent with conditions necessary for speleothem growth and with published work on surficial Wisconsin deposits in the area. No distinct, short-period warming or cooling events are seen in the record, probably due to thermal buffering by the adjacent ocean.

scholarly journals Reconstructing Late Pleistocene paleoclimate at the scale of human behavior: an example from the Neandertal occupation of La Ferrassie (France)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Pederzani ◽  
Vera Aldeias ◽  
Harold L. Dibble ◽  
Paul Goldberg ◽  
Jean-Jacques Hublin ◽  
...  
Keyword(s):  
Human Behavior ◽  
Late Pleistocene ◽  
Tooth Enamel ◽  
Climatic Conditions ◽  
Climatic Data ◽  
Human Scale ◽  
Winter Temperatures ◽  
Archaeological Materials ◽  
Climatic Records

AbstractExploring the role of changing climates in human evolution is currently impeded by a scarcity of climatic information at the same temporal scale as the human behaviors documented in archaeological sites. This is mainly caused by high uncertainties in the chronometric dates used to correlate long-term climatic records with archaeological deposits. One solution is to generate climatic data directly from archaeological materials representing human behavior. Here we use oxygen isotope measurements of Bos/Bison tooth enamel to reconstruct summer and winter temperatures in the Late Pleistocene when Neandertals were using the site of La Ferrassie. Our results indicate that, despite the generally cold conditions of the broader period and despite direct evidence for cold features in certain sediments at the site, Neandertals used the site predominantly when climatic conditions were mild, similar to conditions in modern day France. We suggest that due to millennial scale climate variability, the periods of human activity and their climatic characteristics may not be representative of average conditions inferred from chronological correlations with long-term climatic records. These results highlight the importance of using direct routes, such as the high-resolution archives in tooth enamel from anthropogenically accumulated faunal assemblages, to establish climatic conditions at a human scale.

Pans in humus podzols (Humods and Aquods) in coastal southern Queensland

Soil Research ◽  
1996 ◽  
Vol 34 (1) ◽  
pp. 161 ◽  
Author(s):  
CH Thompson ◽  
EM Bridges ◽  
DA Jenkins
Keyword(s):  
Soil Depth ◽  
Sand Dunes ◽  
Coastal Dunes ◽  
Particle Packing ◽  
Sand Mining ◽  
Coastal Sand Dunes ◽  
Organic Complex ◽  
Coastal Sand ◽  
Coastal Lowlands

An exploratory examination has been made of three different kinds of hardpans found in humus podzols (Humods and Aquods) of the coastal lowlands of southern Queensland, by means of slaking tests, a reactive aluminium test, acid oxalate and pyrophosphate extractions and electron microscopy. Samples from three indurated layers exposed by erosion or sand-mining in large coastal dunes were included for comparison. The investigation confirmed that, a pan in a bleached A2 (albic E) horizon is most likely caused by particle packing and that a pan in a black B2h (spodic) horizon is cemented by an aluminium-organic complex. Yellow-brown pans underlying black organic pans (spodic horizons) were found to be cemented by both a proto-imogolite/allophane complex and an organic substance. An inorganic reactive Al complex differing from the proto-imogolite allophane recorded in the overlying giant podzols appeared to be main cement of three indurated layers in the nearby coastal sand dunes. Mechanical disturbance of the pans, e.g. ripping, is unlikely to improve drainage and effective soil depth in the long term, because the disturbed zones are expected to be re-sealed by packed particles or by the aluminium-organic complex cement.

scholarly journals THE GEOLOGICAL ASPECTS OF COASTAL ENGINEERING

2010 ◽  
Vol 1 (1) ◽  
pp. 13
Author(s):  
John W. Handin
Keyword(s):  
Erosion Rate ◽  
Coastal Engineering ◽  
Beach Erosion ◽  
Supply Rate ◽  
Secular Equilibrium ◽  
Equilibrium Conditions ◽  
Beach Sediment ◽  
Stable Position ◽  
Shore Line ◽  
Sand Supply

A natural beach system is in equilibrium when there is a balance between sand supply and erosion such that the volumes of material entering and leaving the system are just equal. If the erosion rate exceeds the supply rate, a beach retrogrades; if the erosion rate is less than the supply rate, a beach progrades. Unfortunately, coastal engineering works, which are meant to improve the shore for commerce or recreation, often upset this delicate balance with very deleterious results: great accretions of sand and high dredging costs, accelerated beach erosion and much property damage. It is the task of the geologist to determine the secular equilibrium conditions of a beach system and to supply the coastal engineer with the information he needs to control the natural forces acting on the shore in such a way that this equilibrium is maintained. In order to accomplish this task, the geologist needs to make a thorough study of the source, transportation, and deposition of beach sediment. He must determine the stable position of the shore line and the profile of equilibrium of the beaches through detailed physiographic investigations. The geological report can and should close with the prediction of just what will happen to a natural beach system if man introduces a disturbing element.

scholarly journals Aeroallergens and Climate Change in Tulsa, Oklahoma: Long-Term Trends in the South Central United States

2021 ◽  
Vol 2 ◽  
Author(s):  
Estelle Levetin
Keyword(s):  
Climate Change ◽  
United States ◽  
Pollen Season ◽  
Maximum Temperature ◽  
The South ◽  
South Central ◽  
Pollen Types ◽  
Central United States ◽  
Total Pollen

Climate change is having a significant effect on many allergenic plants resulting in increased pollen production and shifts in plant phenology. Although these effects have been well-studied in some areas of the world, few studies have focused on long-term changes in allergenic pollen in the South Central United States. This study examined airborne pollen, temperature, and precipitation in Tulsa, Oklahoma over 25 to 34 years. Pollen was monitored with a Hirst-type spore trap on the roof of a building at the University of Tulsa and meteorology data were obtained from the National Weather Service. Changes in total pollen intensity were examined along with detailed analyses of the eight most abundant pollen types in the Tulsa atmosphere. In addition to pollen intensity, changes in pollen season start date, end date, peak date and season duration were also analyzed. Results show a trend to increasing temperatures with a significant increase in annual maximum temperature. There was a non-significant trend toward increasing total pollen and a significant increase in tree pollen over time. Several individual taxa showed significant increases in pollen intensity over the study period including spring Cupressaceae and Quercus pollen, while Ambrosia pollen showed a significant decrease. Data from the current study also indicated that the pollen season started earlier for spring pollinating trees and Poaceae. Significant correlations with preseason temperature may explain the earlier pollen season start dates along with a trend toward increasing March temperatures. More research is needed to understand the global impact of climate change on allergenic species, especially from other regions that have not been studied.

scholarly journals Knowledge of excellence, the artisans and the rebozodeSanta Maríadel Río, Mexico.

2020 ◽  
Author(s):  
Claudia Ramirez Martinez
Keyword(s):  
Economic Conditions ◽  
Arts And Crafts ◽  
Technical Knowledge ◽  
Del Rio ◽  
Santa Maria

<p>The rebozo is a traditional clothe similar to shawls; it implies knotting, tinctured, waving of threads and ending subprocess. Its use is quite popular within all the women in Mexico. Traditional techniques, materials and knowledge of rebozo differ throughout the country, as well as its costs. The artisans from Santa Maria del Rio have one of the most renown <i>rebozo</i> techniques at Mexico, where there are not only <i>rebozo</i> workers, but an amplitude of arts and crafts. This research aims to show how social and economic conditions have affected profoundly the knowledge of rebozo process. Through historical documentation, observation and interviews a community of artisans shows a strong technical knowledge of the preparation of the threads, dyed, knotting, weaving and ending of the rebozo. Artisans were asked about their knowledge by vernacular naming of tools and subparts of the processes of ancestral techniques. Two parts of the process: the tinctured and the ending <i>(empuntado),</i> were especially rich in content; however, it was revealed lacks at the long term knowledge of the handcraft of silk rebozo, paradoxically and for far, the most famous product of rebozos. </p>

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