A contribution to the understanding of late Pleistocene dune sand-paleosol-sequences in Fuerteventura (Canary Islands)

Loess and dune sands that mantle volcanic rocks on the northwest flank of Mauna Kea volcano consist predominantly of fine-grained pyroclasts of the alkalic Laupahoehoe Volcanics produced by explosive eruptions. The loess is divided into lower and upper units, separated by a well-developed paleosol, while older and younger dune sands are separated by loess. Four interstratified tephra marker horizons aid in regional stratigraphic correlation. Radiocarbon ages of charcoal fragments within the loess, U-series ages of rhizoliths in the dune sand, and K/Ar ages and relative stratigraphic positions of lava flows provide a stratigraphic and temporal framework. The lower loess overlies lava flows less than 103,000 ± 10,000 K/Ar yr old, and14C dates from the paleosol developed at its top average ca. 48,000 yr. Loess separating the dune sand units ranges from ca. 38,000 to 25,00014C yr old; the youngest ages from the upper loess are 17,000–18,00014C yr B.P. Dips of sand-dune foreset strata, isopachs on the upper loess, and reconstructed isopachs representing cumulative thickness of tephra associated with late-Pleistocene pyroclastic eruptions suggest that vents upslope (upwind) from the sand dunes were the primary source of the eolian sediments. Average paleowind directions during the eruptive interval (ca. 50,000–15,000 yr B.P.), inferred from cinder-cone asymmetry, distribution of tephra units, orientation of dune foreset strata, and the regional pattern of loess isopachs, suggest that Mauna Kea has remained within the trade-wind belt since before the last glaciation.

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Late Pleistocene–Holocene environmental conditions in Lanzarote (Canary Islands) inferred from calcitic and aragonitic land snail shells and bird bones

Palaeogeography Palaeoclimatology Palaeoecology ◽

10.1016/j.palaeo.2013.03.020 ◽

2013 ◽

Vol 378 ◽

pp. 91-102 ◽

Cited By ~ 19

Author(s):

Yurena Yanes ◽

Antonio García-Alix ◽

María P. Asta ◽

Miguel Ibáñez ◽

María R. Alonso ◽

...

Keyword(s):

Late Pleistocene ◽

Canary Islands ◽

Environmental Conditions ◽

Land Snail

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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

Journal of Geography and Geology ◽

10.5539/jgg.v10n1p33 ◽

2017 ◽

Vol 10 (1) ◽

pp. 33 ◽

Cited By ~ 2

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.

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Emergent Littoral Deposits in the Eastern Canary Islands

Quaternary Research ◽

10.1016/0033-5894(81)90104-6 ◽

1981 ◽

Vol 15 (2) ◽

pp. 199-208 ◽

Cited By ~ 35

Author(s):

Joaquin Meco ◽

Charles E. Stearns

Keyword(s):

Late Pleistocene ◽

Canary Islands ◽

Natural Science ◽

Middle Pleistocene ◽

Gran Canaria ◽

Early Pliocene ◽

Fossil Assemblage ◽

Marine Deposits

AbstractK-Ar ages (A. Abdel-Monem, P. D. Watkins, and P. W. Gast, 1971, American Journal of Science 271, 490–521; this paper) and revised paleontological determinations (J. Meco, 1977, “Los Strombus neogenos y cuatenarios del Atlantico euroafricano”, Las Palmas, Ediciones del Excmo. Cabildo Insular de Gran Canaria) show that “Quaternary” (R. Crofts, 1967, Quaternaria 9, 247–260; G. Lecointre, K. J. Tinkler, and G. Richards, 1967, Academy of Natural Science of Philadelphia Proceedings 119, 325–344) littoral deposits on Lanzarote and Fuerteventura are early Pliocene and late Pleistocene. Early and middle Pleistocene strand lines are not represented. Early Pliocene littoral and marine deposits contain a characteristic fossil assemblage: Strombus coronatus, Nerità emiliana, Gryphaea virleti, Patella cf. intermedia, and Rothpletzia rudista. Differences in elevation record differential post-Pliocene uplift of the coastal platforms on which they lie. Late Pleistocene beach deposits at low elevations belong to two groups, an older with Strombus bubonius and a younger without. Differences in elevation of early Pliocene littoral deposits are reflected by differences in elevation of late Pleistocene beach deposits nearby.

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