Decadal-scale evolution of a small dune field: Keeler Dunes, California 1944–2010

Historical temperature reconstructions at high altitudes are still insufficient in southwestern China, which is considered one of the most sensitive areas to climate change in the world. Here we developed a tree ring-width chronology of Faxon fir Abies fargesii var. faxoniana at the upper timber line on Zhegu Mountain, Miyaluo Scenic Area, western Sichuan, China. The climate-tree growth relationship analysis indicated temperature as the dominant regulator on radial tree growth in this region. The reconstruction of aggregated maximum temperature (TMX) of autumn and winter for the period 1856-2016 was achieved with a linear regression model that accounted for 43.6% of the actual variability in the common time series (1954-2016). The reconstruction identified 4 warm periods and 3 cold periods. Similarities of warm and cold periods with previously published reconstructions from nearby sites indicated the reliability of our reconstruction. The significant positive correlation between TMX reconstruction and the Asian-Pacific Oscillation index and the Atlantic Multi-decadal Oscillation index suggested a linkage between large-scale climate circulations and the thermal variability at a multi-decadal scale on the western Sichuan Plateau. We also found that solar activity exerted a strong influence on decadal temperature variability in this region. The cold periods were matched well with historical large volcanic eruptions. Our results strengthen the historical climatic information in southwestern China and contribute to further understanding the regional thermal variability as well as its driving mechanism.

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GEOLOGIC MAPPING OF A PALEO-DUNE FIELD NEAR BARTH CRATER, MARS

10.1130/abs/2019am-340059 ◽

2019 ◽

Author(s):

Mackenzie D. Day ◽

◽

Dominique Stumbaugh ◽

Kenneth S. Edgett

Keyword(s):

Geologic Mapping ◽

Dune Field

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DRONE ASSISTED INVESTIGATION OF DUNE FIELD MORPHOLOGY IN THE WHITE RIVER BADLANDS, SOUTH DAKOTA

10.1130/abs/2019ne-328224 ◽

2019 ◽

Author(s):

Henry D. Kramer ◽

◽

Colton W. Byers ◽

Gregory S. Baker ◽

Paul Baldauf ◽

...

Keyword(s):

South Dakota ◽

Dune Field ◽

White River

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6600–6000 cal BC Abrupt Climate Change and Neolithic Dispersal from West Asia

10.1093/oso/9780199329199.003.0003 ◽

2017 ◽

Cited By ~ 1

Author(s):

Bernhard Weninger ◽

Lee Clare

Keyword(s):

Climate Change ◽

Abrupt Climate Change ◽

Western Anatolia ◽

Southeast Europe ◽

The Balkans ◽

Farming Communities ◽

Anatolian Plateau ◽

Decadal Scale ◽

Early Farming ◽

New Hypothesis

Recent advances in palaeoclimatological and meteorological research, combined with new radiocarbon data from western Anatolia and southeast Europe, lead us to formulate a new hypothesis for the temporal and spatial dispersal of Neolithic lifeways from their core areas of genesis. The new hypothesis, which we term the Abrupt Climate Change (ACC) Neolithization Model, incorporates a number of insights from modern vulnerability theory. We focus here on the Late Neolithic (Anatolian terminology), which is followed in the Balkans by the Early Neolithic (European terminology). From high-resolution 14C-case studies, we infer an initial (very rapid) west-directed movement of early farming communities out of the Central Anatolian Plateau towards the Turkish Aegean littoral. This move is exactly in phase (decadal scale) with the onset of ACC conditions (~6600 cal BC). Upon reaching the Aegean coastline, Neolithic dispersal comes to a halt. It is not until some 500 years later—that is, at the close of cumulative ACC and 8.2 ka cal BP Hudson Bay cold conditions—that there occurs a second abrupt movement of farming communities into Southeast Europe, as far as the Pannonian Basin. The spread of early farming from Anatolia into eastern Central Europe is best explained as Neolithic communities’ mitigation of biophysical and social vulnerability to natural (climate-induced) hazards.

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Catastrophic flooding of an aeolian dune field: Jurassic Entrada and Todilto Formations, Ghost Ranch, New Mexico, USA

Sedimentology ◽

10.1046/j.1365-3091.2000.00341.x ◽

2000 ◽

Vol 47 (6) ◽

pp. 1069-1080 ◽

Cited By ~ 31

Author(s):

Cheikh A. Ahmed Benan ◽

Gary Kocurek

Keyword(s):

New Mexico ◽

Dune Field

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Integrating Geomorphological Data, Geochronology and Archaeological Evidence for Coastal Landscape Reconstruction, the Case of Ammoudara Beach, Crete

Water ◽

10.3390/w13091269 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1269

Author(s):

George Alexandrakis ◽

Stelios Petrakis ◽

Nikolaos A. Kampanis

Keyword(s):

Bronze Age ◽

Coastal Area ◽

Luminescence Dating ◽

Coastal Sediments ◽

Aerial Photographs ◽

Coastal Landscape ◽

Archaeological Evidence ◽

Dune Field ◽

Coastal Landscapes ◽

Coastal Deposits

Understanding the processes that govern the transformation of the landscape through time is essential for exploring the evolution of a coastal area. Coastal landscapes are dynamic sites, with their evolution strongly linked with waves and sea level variations. Geomorphological features in the coastal area, such as beachrock formations and dune fields, can function as indicators of the coastal landscape evolution through time. However, our knowledge of the chronological framework of coastal deposits in the Aegean coasts is limited. Optically Stimulated Luminescence dating techniques are deemed to be very promising in direct dating of the coastal sediments, especially when they are linked with archaeological evidence. The dating of the sediments from different sediment core depths, determined by the method of luminosity, allowed us to calculate the rate of sediment deposition over time. More recent coastal evolution and stability were examined from 1945 to 2020 with the use of aerial photographs and satellite images. This paper presents the 6000 ka evolution of a coastal landscape based on geomorphological, archaeological, and radio-chronological data. Based on the results, the early stages of the Ammoudara beach dune field appears to have been formed ~9.0–9.6 ka BP, while the OSL ages from 6 m depth represented the timing of its stabilization (OSL ages ~5–6 ka). This indicates that the dune field appears to already have been formed long before the Bronze Age (5–10 ka BP). It became stabilized with only localized episodes of dune reactivation occurring. In contrast, while high coastal erosion rates were calculated for modern times.

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Supporting Restoration Decisions through Integration of Tree-Ring and Modeling Data: Reconstructing Flow and Salinity in the San Francisco Estuary over the Past Millennium

Water ◽

10.3390/w13152139 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2139

Author(s):

Paul H. Hutton ◽

David M. Meko ◽

Sujoy B. Roy

Keyword(s):

San Francisco ◽

Tree Ring ◽

San Francisco Estuary ◽

Salinity Intrusion ◽

Estuarine Ecosystem ◽

Freshwater Flow ◽

The Past ◽

Decadal Scale ◽

Tree Ring Data ◽

Past Millennium

This work presents updated reconstructions of watershed runoff to San Francisco Estuary from tree-ring data to AD 903, coupled with models relating runoff to freshwater flow to the estuary and salinity intrusion. We characterize pre-development freshwater flow and salinity conditions in the estuary over the past millennium and compare this characterization with contemporary conditions to better understand the magnitude and seasonality of changes over this time. This work shows that the instrumented flow record spans the range of runoff patterns over the past millennium (averaged over 5, 10, 20 and 100 years), and thus serves as a reasonable basis for planning-level evaluations of historical hydrologic conditions in the estuary. Over annual timescales we show that, although median freshwater flow to the estuary has not changed significantly, it has been more variable over the past century compared to pre-development flow conditions. We further show that the contemporary period is generally associated with greater spring salinity intrusion and lesser summer–fall salinity intrusion relative to the pre-development period. Thus, salinity intrusion in summer and fall months was a common occurrence under pre-development conditions and has been moderated in the contemporary period due to the operations of upstream reservoirs, which were designed to hold winter and spring runoff for release in summer and fall. This work also confirms a dramatic decadal-scale hydrologic shift in the watershed from very wet to very dry conditions during the late 19th and early 20th centuries; while not unprecedented, these shifts have been seen only a few times in the past millennium. This shift resulted in an increase in salinity intrusion in the first three decades of the 20th century, as documented through early records. Population growth and extensive watershed modification during this period exacerbated this underlying hydrologic shift. Putting this shift in the context of other anthropogenic drivers is important in understanding the historical response of the estuary and in setting salinity targets for estuarine restoration. By characterizing the long-term behavior of San Francisco Estuary, this work supports decision-making in the State of California related to flow and salinity management for restoration of the estuarine ecosystem.

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