Detrital Sr–Nd isotopes, sediment provenances and depositional processes in the Laxmi Basin of the Arabian Sea during the last 800 ka

2018 ◽  
Vol 157 (6) ◽  
pp. 895-907 ◽  
Author(s):  
Boo-Keun Khim ◽  
Keiji Horikawa ◽  
Yoshihiro Asahara ◽  
Ji-Eun Kim ◽  
Minoru Ikehara
Keyword(s):  
Arabian Sea ◽  
River Sediments ◽  
Sediment Provenance ◽  
Indus River ◽  
Glacial Sediments ◽  
Depositional Processes ◽  
Narmada River ◽  
Palaeomagnetic Data ◽  
International Ocean Discovery Program ◽  
Detrital Particles

Abstract87Sr/86Sr ratios and εNd values of detrital particles at International Ocean Discovery Program (IODP) Site U1456 in the Laxmi Basin of the Arabian Sea were measured to trace changes in sediment provenance over glacial–interglacial cycles. Based on the correlation of planktonic foraminiferal (Globigerinoides ruber) δ18O fluctuations with the LR04 stack of benthic foraminifera δ18O values, combined with shipboard biostratigraphic and palaeomagnetic data, the studied interval spans ∼1.2 Ma. Over the past 800 ka, 87Sr/86Sr values ranged from 0.711 to 0.726 while εNd values ranged between −12.5 and −7.3 in the detrital particles. By comparing 87Sr/86Sr ratios and εNd values of the possible sources of river sediments with our data, we found that sediments in the Laxmi Basin were influenced to various degrees by proportions of at least three sediment sources (i.e. Tapi River, Narmada River and Indus River). The Indus River might be a more important contributor to glacial sediments. Although 87Sr/86Sr ratios and εNd values varied quasi-cyclically, this pattern did not correspond precisely to the glacial–interglacial cycles. In particular, low-magnetic-susceptibility (low-MS) intervals coinciding with pelagic carbonates were characterized by low 87Sr/86Sr ratios and high εNd values, whereas high-MS intervals matching turbidite deposits showed high 87Sr/86Sr ratios and low εNd values. Thus, this study reveals that differences in the depositional processes between glacial and interglacial periods, governed by changes in sea level and monsoon activity, are an important factor in deciding 87Sr/86Sr ratios and εNd values of the detrital fraction in the Indus Fan of the Arabian Sea.

scholarly journals Nutrient retention behind a tropical mega-dam: a case study of the Sardar Sarovar Dam, India

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Harish Gupta ◽  
S. Kiran Kumar Reddy ◽  
Mounika Chiluka ◽  
Vamshikrishna Gandla
Keyword(s):  
Arabian Sea ◽  
Inorganic Nitrogen ◽  
Nutrient Retention ◽  
Significant Loss ◽  
N Removal ◽  
Narmada River ◽  
Sardar Sarovar ◽  
The Impact

AbstractIn this study, we demonstrate the impact of the construction of a mega-dam on the nutrient export regime of a large tropical river into the Arabian Sea. Long-term (11 years) fortnight nutrient parameters, upstream and downstream to Sardar Sarovar (SS) Dam, were examined to determine the periodical change in nutrient fluxes from the Narmada River, India. During this 11-year period, the average discharge of the Narmada River upstream to Rajghat (35.3 km3 year−1) was higher than that of downstream at Garudeshwar (33.9 km3 year−1). However, during the same period, the suspended sediment load was reduced by 21 million tons (MT) from 37.9 MT at Rajghat to 16.7 MT at Garudeshwar. Similarly, mean concentrations of dissolved silica (DSi) reduced from 470 (upstream) to 214 µM (downstream), dissolved inorganic phosphate (DIP) from 0.84 to 0.38 µM, and dissolved inorganic nitrogen (DIN) from 43 to 1.5 µM. It means that about 54%, 55%, and 96% flux of DSi, DIP, and DIN retained behind the dam, respectively. The estimated denitrification rate (80,000 kg N km−2 year−1) for the reservoir is significantly higher than N removal by lentic systems, globally. We hypothesize that processes such as biological uptake and denitrification under anoxic conditions could be a key reason for the significant loss of nutrients, particularly of DIN. Finally, we anticipated that a decline in DIN fluxes (by 1.13 × 109 mol year−1) from the Narmada River to the Arabian Sea might reduce the atmospheric CO2 fixation by 7.46 × 109 mol year−1.

Trace metal concentrations and OH defects in quartz from Amazon River sands & and perspectives for application to the marine record

2021 ◽  
Author(s):  
Dominik Jaeger ◽  
Roland Stalder ◽  
Cristiano Chiessi ◽  
André Sawakuchi ◽  
Michael Strasser
Keyword(s):  
Trace Metal ◽  
Drainage Basin ◽  
River Sediments ◽  
Sediment Provenance ◽  
Future Application ◽  
Amazon River ◽  
Analysis Tool ◽  
Metal Concentrations ◽  
Oh Defects ◽  
Quartz Grains

<p>Trace metal concentrations and associated hydrous lattice point defects (OH defects) in quartz can help reveal its host rock’s crystallization history and are easily quantified using electron microprobe and infrared spectroscopy, respectively. These chemical impurities are preserved throughout the sedimentary cycle and thus lend themselves as tracers for sediment provenance analyses, particularly in settings where “traditional” provenance tools, e.g., thermochronology and heavy mineral analysis, are difficult due to factors like low mineral fertility and aggressive tropical weathering.</p><p>In this study, we apply this provenance analysis tool to detrital, sand-sized quartz grains from the Amazon River and its major tributaries, draining the Andean orogen as well as the Guiana- and Central Brazil Shields. Trace metal and OH defect concentrations from individual catchments are spread out over wide and mutually overlapping ranges of values. This means that each individual quartz grain cannot be unequivocally attributed to one catchment. However, evaluation of a statistically sound number of grains reveals that Andean quartz is, on average, richer in the trace metal aluminum (and Al-related OH defects) than quartz derived from one of the shield sources.</p><p>We evaluate our findings in the context of previous provenance studies on Amazon River sediments and discuss a potential future application of analyzing trace metals and OH defects in quartz in the offshore sediment record. Any past, major rearrangements in the Amazon watershed affecting the ratio of Andean vs. Shield-derived quartz grains should be detectable and our approach may therefore contribute to the reconstruction of Amazon drainage basin evolution.</p>

scholarly journals Supplemental Material: Late Pleistocene–Holocene flood history, flood-sediment provenance and human imprints from the upper Indus River catchment, Ladakh Himalaya

2021 ◽  
Author(s):  
Choudhurimayum Pankaj Sharma ◽  
Pradeep Srivastava
Keyword(s):  
Late Pleistocene ◽  
Growth Curve ◽  
Detrital Zircon ◽  
Sediment Provenance ◽  
Indus River ◽  
River Catchment ◽  
Recovery Test ◽  
Infrared Stimulated Luminescence ◽  
Ladakh Himalaya ◽  
Radial Plot

Figure S1: (A) Infrared Stimulated Luminescence (IRSL) of LD-1818 exhibiting feldspar contamination. (B) IRSL counts of all samples after complete etching including LD-1818 after re-etching. (C) Optical Stimulated Luminescence (OSL) decay curves of all samples; Figure S2: (A) Pre heat test (dotted line represents 220 °C plateau) and (B) Dose recovery test of LD-3170; Figure S3: OSL characteristics of LD-2011. (A) Probably distribution of ED all discs and (B) Sensitivity corrected luminescence growth curve; Figure S4: Radial plot of all OSL samples with ages; Table S1: Elemental, isotopic and age details of detrital zircon U-Pb geochronology of paleoflood deposits.

Sea-level responses to erosion and deposition of sediment in the Indus River basin and the Arabian Sea

2015 ◽  
Vol 416 ◽  
pp. 12-20 ◽  
Author(s):  
Ken L. Ferrier ◽  
Jerry X. Mitrovica ◽  
Liviu Giosan ◽  
Peter D. Clift
Keyword(s):  
Sea Level ◽  
River Basin ◽  
Arabian Sea ◽  
Indus River ◽  
Erosion And Deposition ◽  
Indus River Basin

scholarly journals A new depositional model for the Tuaheni Landslide Complex, Hikurangi Margin, New Zealand

2020 ◽  
Vol 500 (1) ◽  
pp. 551-566 ◽  
Author(s):  
Benjamin Couvin ◽  
Aggeliki Georgiopoulou ◽  
Joshu J. Mountjoy ◽  
Lawrence Amy ◽  
Gareth J. Crutchley ◽  
...  
Keyword(s):  
Seismic Data ◽  
Lateral Spreading ◽  
3D Seismic ◽  
Depositional Processes ◽  
Attribute Analysis ◽  
Internal Structures ◽  
Show Evidence ◽  
Levee System ◽  
Central Ridge ◽  
International Ocean Discovery Program

AbstractThe Tuaheni Landslide Complex (TLC) is characterized by areas of compression upslope and extension downslope. It has been thought to consist of a stack of two genetically linked landslide units identified from seismic data. We used 3D seismic reflection, bathymetry data and International Ocean Discovery Program Core U1517C (Expedition 372) to understand the internal structures, deformation mechanisms and depositional processes of the TLC deposits. Units II and III of U1517C correspond to the two chaotic units in 3D seismic data. In the core, Unit II shows deformation, whereas Unit III appears more like an in situ sequence. Variance attribute analysis showed that Unit II is split into lobes around a coherent stratified central ridge and is bounded by scarps. By contrast, we found that Unit III is continuous beneath the central ridge and has an upslope geometry, which we interpreted as a channel–levee system. Both units show evidence of lateral spreading due to the presence of the Tuaheni Canyon removing support from the toe. Our results suggest that Units II and III are not genetically linked, are separated substantially in time and had different emplacement mechanisms, but they fail under similar circumstances.

Long-term history of sediment inputs to the eastern Arabian Sea and its implications for the evolution of the Indian summer monsoon since 3.7 Ma

2018 ◽  
Vol 157 (6) ◽  
pp. 908-919 ◽  
Author(s):  
Mingjiang Cai ◽  
Zhaokai Xu ◽  
Peter D. Clift ◽  
Boo-Keun Khim ◽  
Dhongil Lim ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Arabian Sea ◽  
Sediment Supply ◽  
Deccan Traps ◽  
Indus River ◽  
Eastern Arabian Sea ◽  
Monsoon Intensity ◽  
History Of

AbstractWe present a new set of clay mineral and grain-size data for the siliciclastic sediment fraction from International Ocean Discovery Program (IODP) Site U1456 located in the eastern Arabian Sea to reconstruct the variabilities in the continental erosion and weathering intensity in the western Himalaya, elucidate the sediment source-to-sink processes and discuss the potential controls underlying these changes since 3.7 Ma. The clay minerals mainly consist of smectite (0–90%, average 44%) and illite (3–90%, average 44%), with chlorite (1–26%, average 7%) and kaolinite (0–19%, average 5%) as minor components. The compositional variations in the clay minerals at IODP Site U1456 suggest four phases of sediment provenance: the Indus River (phase 1, 3.7–3.2 Ma), the Indus River and Deccan Traps (phase 2, 3.2–2.6 Ma), the Indus River (phase 3, 2.6–1.2 Ma) and the Indus River and Deccan Traps (phase 4, 1.2–0 Ma). These provenance changes since 3.7 Ma can be correlated with variations in the Indian summer monsoon intensity. The siliciclastic sediments in the eastern Arabian Sea were mainly derived from the Indus River when the Indian summer monsoon was generally weak. In contrast, when the Indian summer monsoon intensified, the siliciclastic sediment supply from the Deccan Traps increased. In particular, this study shows that the smectite/(illite+chlorite) ratio is a sensitive tool for reconstructing the history of the variation in the Indian summer monsoon intensity over the continents surrounding the Arabian Sea since 3.7 Ma.

scholarly journals A database of marine and terrestrial radiogenic Nd and Sr isotopes for tracing earth-surface processes

2018 ◽  
Author(s):  
Cécile L. Blanchet
Keyword(s):  
River Sediments ◽  
Original Data ◽  
Isotopic Signature ◽  
Transport Processes ◽  
Sediment Provenance ◽  
Published Data ◽  
Sample Type ◽  
Management Service ◽  
Time Intervals ◽  
Available Information

Abstract. The database presented here contains radiogenic neodymium and strontium isotope ratios measured on both terrestrial and marine sediments. The main purpose of this dataset is to help assessing sediment provenance and transport processes for various time intervals. This can be achieved by either mapping sediment isotopic signature and/or fingerprinting source areas using statistical tools. The database has been built by incorporating data from the literature and the SedDB database and harmonizing the metadata, especially units and geographical coordinates. The original data were processed in three steps. Firstly, a specific attention has been devoted to provide geographical coordinates to each sample in order to be able to map the data. When available, the original geographical coordinates from the reference (generally DMS coordinates) were transferred into the decimal degrees system. When coordinates were not provided, an approximate location was derived from available information in the original publication. Secondly, all samples were assigned a set of standardized criteria that help splitting the dataset in specific categories. For instance, samples were discriminated according to their location Region, Sub-region and Location that relate to location at continental to city/river scale) or the sample type (terrestrial samples – aerosols, soil sediments, river sediments – or marine samples – marine sediment or trap sample). Finally, samples were distinguished according to their deposition age, which allowed to compute average values for specific time intervals. Graphical examples illustrating the functionality of the database are presented and the validity of the process was tested by comparing the results with published data. The dataset will be updated bi-annually and might be extended to reach a global geographical extent and/or add other type of samples. It is publicly available (under CC4.0-BY Licence) on the GFZ data management service at http://doi.org/10.5880/GFZ.5.2.2018.001.

scholarly journals DAM[N]ED: Mechanizing a Sacred River Landscape Redrawing Territorial Systems in the Narmada River Valley

2018 ◽  
Author(s):  
María Arquero de Alarcón ◽  
◽  
Nishant Mittal ◽  
Dhara Mittal ◽  
Olaia Chivite Amigo ◽  
...  
Keyword(s):  
Arabian Sea ◽  
Development Project ◽  
Sacred Landscape ◽  
Current State ◽  
Narmada River ◽  
Cultural Imaginary ◽  
Cultural Systems ◽  
The World ◽  
Water Conveyance ◽  
Territorial Systems

This essay traces the story of the Narmada River and its transformation from a sacred landscape to one of the largest mechanized territorial systems in the world. The Narmadatravelssome 1,300 kilometers from Amarkantaktothe Arabian Sea; enabling the livelihood of millions, shaping distinct regional identities and embodying a rich cultural imaginary for those worshiping her holy waters. The infrastructural potential of the river was first formulated as a megaregional project in the 1940s to modernize and bring prosperity to the watershed. Under implementation since the 1980s, the “Narmada Valley Development Project” is incrementally transforming the river into an interstate infrastructural network of water conveyance and energy generation. Through a cartographic and photographic inventory, the project traces the transformation of the natural and cultural systems associated with the Narmada River over time. Pausing at Omkareshwar, a major pilgrimage destination, the essay unfolds the current state of uncertainty and civic unrest that the massive infrastructural works are placing in the fragile lives of the valley dwellers.

scholarly journals Observations of tunnel channels in glacial sediments with shallow land-based seismic reflection

1996 ◽  
Vol 22 ◽  
pp. 176-180 ◽  
Author(s):  
A. Pugin ◽  
S. E. Pullan ◽  
D. R. Sharpe
Keyword(s):  
Seismic Reflection ◽  
Three Dimensional ◽  
Seismic Profiles ◽  
Glacial Sediments ◽  
Oak Ridges Moraine ◽  
Depositional Processes ◽  
Hydrogeological Study ◽  
Seismic Sections ◽  
Seismic Reflection Profiles ◽  
Subglacial Meltwater

A regional hydrogeological study conducted by the Geological Survey of Canada acquired 35 line-km of 12-fold seismic reflection profiles on or adjacent to the Oak Ridges moraine, north of Toronto, Ontario, Canada. The three-dimensional geometry provided by these data aids in understanding the erosional and depositional processes that occurred beneath the Laurentide ice sheet during the late stages of glaciation. The seismic sections indicate large infilled channels in the subsurface which are interpreted as tunnel channels eroded by large, subglacial meltwater discharges. Two seismic profiles from different areas of the moraine show channel-cutting events of different ages and different types of infilling.

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