MEASURING LATE QUATERNARY UPLIFT RATES OF MARINE TERRACES USING HIGH-RESOLUTION CHIRP SUB-BOTTOM DATA, NORTHERN CHANNEL ISLANDS, CALIFORNIA, USA

2018 ◽  
Author(s):  
Alexander W. Laws ◽  
◽  
Jillian M. Maloney ◽  
Shannon A. Klotsko ◽  
Amy E. Gusick ◽  
...  
Keyword(s):  
High Resolution ◽  
Late Quaternary ◽  
Channel Islands ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Northern Channel Islands

Submerged paleoshoreline mapping using high-resolution Chirp sub-bottom data, Northern Channel Islands platform, California, USA

2019 ◽  
Vol 93 ◽  
pp. 1-22 ◽  
Author(s):  
Alexander W. Laws ◽  
Jillian M. Maloney ◽  
Shannon Klotsko ◽  
Amy E. Gusick ◽  
Todd J. Braje ◽  
...  
Keyword(s):  
High Resolution ◽  
Sea Level ◽  
Channel Islands ◽  
Uplift Rate ◽  
Oxygen Isotope Stage ◽  
Uplift Rates ◽  
Northern Channel Islands ◽  
The Last Glacial Maximum ◽  
Local Uplift ◽  
The Last Glacial

AbstractHigh-resolution Chirp sub-bottom data were obtained offshore from the Northern Channel Islands (NCI), California, to image submerged paleoshorelines and assess local uplift rates. Although modern bathymetry is often used for modeling paleoshorelines, Chirp data image paleoshorelines buried beneath sediment that obscures their seafloor expression. The NCI were a unified landmass during the last glacial maximum (LGM; ~20 ka), when eustatic sea level was ~120 m lower than present. We identified seven paleoshorelines, ranging from ~28 to 104 m in depth, across this now-submerged LGM platform. Paleoshoreline depths were compared to local sea-level curves to estimate ages, which suggest that some were reoccupied over multiple sea-level cycles. Additionally, previous studies determined conflicting uplift rates for the NCI, ranging from 0.16 to 1.5 m/ka. Our results suggest that a rate on the lower end of this range better fits the observed submerged paleoshorelines. Using the uplift rate of ~0.16 m/ka, we estimate that paleoshorelines formed during Marine Oxygen Isotope Stage 3, the LGM, and the Younger Dryas stade are preserved on the NCI platform. These results help clarify uplift rates for the NCI and illustrate the importance of sub-bottom data for mapping submerged paleoshorelines.

scholarly journals Dating and morphostratigraphy of uplifted marine terraces in the Makran subduction zone (Iran)

2018 ◽  
Author(s):  
Raphaël Normand ◽  
Guy Simpson ◽  
Frédéric Herman ◽  
Rabiul Haque Biswas ◽  
Abbas Bahroudi ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Surface Deformation ◽  
Late Quaternary ◽  
Makran Subduction Zone ◽  
Megathrust Earthquakes ◽  
Surface Uplift ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Tectonically Active ◽  
East West

Abstract. The western part of the Makran subduction zone (Iran) has not experienced a great megathrust earthquake in recent human history, yet, the presence of emerged marine terraces along the coast indicates that the margin has been tectonically active during at least the late Quaternary. To better understand the surface deformation of this region, we mapped the terraces sequences of seven localities along the Iranian Makran. Additionnaly, we performed radiocarbon, 230Th/U and optically stimulated luminescence (OSL) dating of the layers of marine sediments deposited on top of the terraces. This enabled us to correlate the terraces regionally and to assign them to different Quaternary sea level highstands. Our results show east-west variations in surface uplift rates mostly between 0.05 and 1.2 mm y−1. We detected a region of anomalously high uplift rate, where two MIS 3 terraces are emerged, yet we are uncertain how to insert these results in a geologically coherent context. Although it is presently not clear whether the uplift of the terraces is linked with the occurrence of large megathrust earthquakes, our results highlight heterogeneous accumulation of deformation in the overriding plate.

The Origin of Island Mammoths and the Quaternary Land Bridge of the Northern Channel Islands, California

1978 ◽  
Vol 10 (2) ◽  
pp. 204-225 ◽  
Author(s):  
Donald Lee Johnson
Keyword(s):  
Late Quaternary ◽  
Channel Islands ◽  
Santa Barbara Channel ◽  
Santa Barbara ◽  
Land Bridge ◽  
Geological Evidence ◽  
Sea Levels ◽  
Environmental Setting ◽  
Northern Channel Islands ◽  
New Evidence

Pygmy proboscidean remains of Mammuthus exilis occur abundantly in late Quaternary deposits on the Northern Channel Islands, California. On the assumption that ancestral elephants could not have swum to the islands and must therefore have walked out, various land bridges have been hypothesized that link the northern islands to the mainland by a peninsula. Geological evidence for a land bridge, however, is lacking, and new evidence shows that elephants are excellent swimmers and skilled at crossing watergaps. The Santa Barbara Channel was narrowed to only 6 km during glacially lowered sea levels. Modern elephants swim much further, and at speeds ranging from 0.96–2.70 km/hr. Motives for California elephants to cross Pleistocene watergaps are inferred from motives that lead modern elephants in Asia and Africa to cross watergaps. These are the visual and olfactory sensing of islands and of insular food during times of drought or fire-induced food shortage. Diminutive size of M. exilis principally reflects lack of island predators, an adaption to periodic food stress in a finite forage area affected by periodic drought and fire, and an adaptation for keeping population numbers high to maintain genetic variability and to ensure survival despite accidents. A late Quaternary scenario describes the environmental setting of the Santa Barbara Channel and the conditions that led to proboscidean dispersal to the preexistent super-island Santarosae.

scholarly journals Coastal tectonics on the eastern margin of the Pacific Rim: late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

2014 ◽  
Vol 105 ◽  
pp. 209-238 ◽  
Author(s):  
Daniel R. Muhs ◽  
Kathleen R. Simmons ◽  
R. Randall Schumann ◽  
Lindsey T. Groves ◽  
Stephen B. DeVogel ◽  
...  
Keyword(s):  
Sea Level ◽  
National Park ◽  
Late Quaternary ◽  
Pacific Rim ◽  
Channel Islands ◽  
Eastern Margin ◽  
The Pacific ◽  
Uplift Rates ◽  
Channel Islands National Park

High-resolution portable-OSL analysis of Vegetated Linear Dune construction in the margins of the northwestern Negev dunefield (Israel) during the late Quaternary

2021 ◽  
Vol 50 ◽  
pp. 100680
Author(s):  
Lotem Robins ◽  
Noam Greenbaum ◽  
LuPeng Yu ◽  
Revital Bookman ◽  
Joel Roskin
Keyword(s):  
High Resolution ◽  
Late Quaternary

New Zealand Marine Terraces: Uplift Rates

Science ◽  
1988 ◽  
Vol 240 (4853) ◽  
pp. 803-804 ◽  
Author(s):  
C. M. WARD
Keyword(s):  
New Zealand ◽  
Marine Terraces ◽  
Uplift Rates
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