Sediment accumulation rate in the lakes of Kumaun Himalaya, India using210Pb and226Ra

1994 ◽  
Vol 23 (2) ◽  
pp. 114-118 ◽  
Author(s):  
B. K. Das ◽  
M. Singh ◽  
M. D. Borkar
Keyword(s):  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Sediment Accumulation Rate ◽  
Kumaun Himalaya

scholarly journals Combined Magnetostratigraphy From Three Localities of the Rainstorm Member of the Johnnie Formation in California and Nevada, United States Calibrated by Cyclostratigraphy: A 13 R/Ma Reversal Frequency for the Ediacaran

2021 ◽  
Vol 9 ◽  
Author(s):  
Kenneth P. Kodama
Keyword(s):  
United States ◽  
High Resolution ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Critical Time ◽  
Sediment Accumulation Rate ◽  
Accumulation Rates ◽  
Field Reversal ◽  
South Central ◽  
Reversal Frequency

A combined magnetostratigraphy for the Rainstorm Member of the Ediacaran Johnnie Formation was constructed using the sediment accumulation rates determined by rock magnetic cyclostratigraphy for three localities of the Rainstorm Member to provide a high resolution, time-calibrated record of geomagnetic field reversal frequency at a critical time period in Earth history. Two previously reported magnetostratigraphy records from Death Valley, California, the Nopah Range and Winters Pass Hills (Minguez et al., 2015), were combined with new paleomagnetic and cyclostratigraphic results from the Desert Range locality of the Rainstorm Member in south central Nevada, United States . The Johnnie oolite marker bed is at the base of each of the three sections and allows their regional correlation. The Nopah Range and Desert Range localities have similar sediment accumulation rates of ∼5 cm/ka, so their stratigraphic sections can be combined directly. The Winters Pass Hills locality has a higher sediment accumulation rate of 8.4 cm/ka, therefore its stratigraphic positions are multiplied by 0.6 to combine with the Desert Range and Nopah Range magnetostratigraphy. The thermal demagnetization results from the Desert Range locality isolates characteristic remanent magnetizations that indicate two nearly antipodal east-west and shallow directions and a mean paleopole (11.7˚N, 348.4˚E) that is consistent with “shallow” Ediacaran directions. The Desert Range also yields a magnetic susceptibility rock magnetic cyclostratigraphy that records short eccentricity, obliquity, and precession astronomically-forced climate cycles in the Ediacaran. The high-resolution combined magnetostratigraphy with nearly meter-scale stratigraphic spacing (nominally 23 ka, based on the Desert Range sediment accumulation rate), indicates 11 polarity intervals in a cyclostratigraphy-calibrated duration of 849 ka, indicating a reversal frequency of 13 R/Ma. The Rainstorm Member records the Shuram carbon isotope excursion, hence its age is ∼574 Ma. Given the recent cyclostratigraphy-calibrated reversal frequency of 20 R/Ma from the Zigan Formation (Levashova et al., 2021) at 547 Ma, our results show that reversal frequency was high but fluctuated during the Ediacaran.

scholarly journals Linking the Variation of Sediment Accumulation Rate to Short Term Sea-Level Change Using Cyclostratigraphy: Case Study of the Lower Berriasian Hemipelagic Sediments in Central Tunisia (Southern Tethys)

2021 ◽  
Vol 9 ◽  
Author(s):  
Hamdi Omar ◽  
Anne-Christine Da Silva ◽  
Chokri Yaich
Keyword(s):  
Magnetic Susceptibility ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Sediment Accumulation Rate ◽  
Carbonate Content ◽  
Milankovitch Cycles ◽  
Central Tunisia ◽  
Level Change ◽  
Two Samples ◽  
Lower Berriasian

High-resolution magnetic susceptibility and % CaCO3 records (5 to 10 cm sampling interval) are used to track astronomical cycles from a Lower Berriasian record from central Tunisia. Six hundred and twenty two samples were measured for magnetic susceptibility and carbonate content as paleoclimate proxies for the detection of potential Milankovitch cycles. Elemental data using X-Ray fluorescence analyses was acquired from 19 samples to prove the reliability of the MS signal on recording the past paleoclimatic changes. We performed multiple spectral analyses and statistical techniques on the magnetic susceptibility signal, such as Multi-taper Method, Evolutive Harmonic Analysis, Correlation Coefficient, Time-optimization, and Average Spectral Misfit to obtain an optimal astronomical model. The application of these spectral analysis techniques revealed a pervasive dominance of E405-kyr and e100-kyr cycles showing that the climate turnover across the early Berriasian—middle Berriasian seems to had been governed by the long and short orbital eccentricity cycles. The identification of Milankovitch cycles in the record also allowed to propose a floating astronomical timescale of the studied section, with ~4 long eccentricity cycles (E405) extracted, which points to a duration estimate of ~1.6 Myr with an average sediment accumulation rate (SAR, after compaction) of 2.77 cm/kyr. The inferred floating ATS was tuned to the La2004 astronomical solution. In addition, we applied the DYNOT and ρ1 methods for seal-level change modeling to reconstruct a local eustatic profile which matches the previously published local and global eustatic charts.

scholarly journals SEDIMENT ACCUMULATION PROFILE IN MANGROVE RESTORATION AREA OF LEMBAR BAY-LOMBOK ISLAND

2017 ◽  
Vol 9 (1) ◽  
pp. 301-313
Author(s):  
Mohammad Sumiran Paputungan ◽  
Alan Frendy Koropitan ◽  
Tri Prartono ◽  
Ali Arman Lubis
Keyword(s):  
Accumulation Rate ◽  
Sediment Cores ◽  
Sediment Accumulation ◽  
Coastal Region ◽  
Sediment Accumulation Rate ◽  
Ecosystem Functions ◽  
Sampling Location ◽  
Mangrove Restoration ◽  
Mangrove Area ◽  
Lombok Island

Mangrove restoration is really needed for restoring its ecosystem functions, so that it could be able to support fisheries activity and to protect coastal by extreme weather. In addition, mangrove is able to accumulate sediment that important in protecting the coastal area from sea level rise. Therefore,  the aim of this study is to investigate sediment accumulation rate in mangrove area during post restoration. Sampling location were divided into three different stations based on estimated restoration ages, such as ≥ 15  years old (Station 1), 4 - 10 years old (Station 2) and 2 - 8 years old (Station 3). Sediment cores were carried out by inserting 7.6 cm diameter and 100 cm length of polyvinyl chloride pipes. Sedimentation rate is measured by using Pb-210 radionuclide analysis. The results show that the sediment accumulation rate in the last 20th years from all station ranges from 0.17 to 0.42 g/cm2/year. The highest accumulation rate is found at oldest year old station while the lowest accumulation rate is found at younger year old station of mangrove restoration area. Restoration process is clearly able to recover the mangrove’s role in trapping sediment in coastal region. Keywords: sediment accumulation, mangrove restoration, Lembar Bay-                   Lombok Island 

Supplemental Material: A sub-centennial-scale optically stimulated luminescence chronostratigraphy and late Holocene flood history from a temperate river confluence

2020 ◽  
Author(s):  
Ben Pears
Keyword(s):  
Statistical Analysis ◽  
Accumulation Rate ◽  
Sediment Accumulation ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Sediment Accumulation Rate ◽  
Data Sets ◽  
Raw Data ◽  
Summary Sheet ◽  
Agglomerative Hierarchical Cluster Analysis

S1–S16; Figures S1 (sediment accumulation rate modeled by OxCal and Bacon) and S2 (relative moisture values between OSL and LOI analytical methods); Table S1 (OSL procedure from the Rivers Severn-Teme confluence at Powick, UK); and Data Sets S1 (raw data for the modeled calendric dates, sediment accumulation rate, and sedimentological analyses), S2 (raw and log normalized data for ITRAX XRF analysis and key elements Zr, Rb, Fe, Mn, and heavy metals illustrated in Fig. 2), S3 (individual raw data sets for each 5 cm pOSL run alongside a background sediment sample and a summary sheet of all data and replicates), S4 (raw data, log normalized data, and statistical analysis used in the agglomerative hierarchical cluster analysis illustrated in Fig, 2), S5 (calculated log data of sedimentary analyses by 50 yr period and the statistical analysis used in the principal component analysis illustrated in Fig. 3), and S6 (20 yr grouping for the sediment deposition models for the Severn-Teme confluence at Powick, Broadwas, and Buildwas and climatic datasets illustrated in Fig. 4)<br>

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