Articolele autorului Liviu Giosan
Link la profilul stiintific al lui Liviu Giosan

Indian monsoon variations during three contrasting climatic periods: The Holocene, Heinrich Stadial 2 and the last interglacial–glacial transition

In contrast to the East Asian and African monsoons the Indian monsoon is still poorly documented throughout the last climatic cycle (last 135,000 years). Pollen analysis from two marine sediment cores (NGHP-01-16A and NGHP-01-19B) collected from the offshore Godavari and Mahanadi basins, both located in the Core Monsoon Zone (CMZ) reveals changes in Indian summer monsoon variability and intensity during three contrasting climatic periods: the Holocene,

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Enhancing mud supply from the Lower Missouri River to the Mississippi River Delta USA: Dam bypassing and coastal restoration

Sand transport to the Mississippi River Delta (MRD) remains sufficient to build wetlands in shallow, sheltered coastal bays fed by engineered diversions on the Mississippi River (MR) and its Atchafalaya River (AR) distributary. But suspended mud (silt & clay) flux to the coast has dropped from a mean of 390 Mt y−1 in the early 1950s, to 100 Mt y−1 since 1970. This fine-grained sediment travels deeper into receiving estuarine basins and

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Embanking the Lower Danube: From Natural to Engineered Floodplains and Back

Anthropogenic intervention along the Danube floodplain has occurred in various degrees since ancient times. Early in this history, small and localized changes were linked to fishing as floodplain lakes and channels constituted a permanent and trusted source of fish. Large-scale, intense changes occurred primarily during the communist period when most of the floodplain was used for agriculture. As a result of this phase, 3250 km of artificial levee

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What makes a delta wave-dominated?

River deltas, low-lying landforms that host high concentrations of human population and ecosystem services, face a new, and mostly unknown, future over the coming decades and centuries. Even as some deltas experience decreased sediment supply from damming, others will see increased sediment discharge from land-use changes. There are proposals to actively use riverine sediment supply to build new land and counteract delta loss. We present a novel

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Climate change: protect the world’s deltas

River deltas need maintenance now rather than costly restoration later to prevent the collapse of vast expanses of coastline.

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

Changes in sea level are of wide interest because they shape the sedimentary geologic record, modulate flood-related hazards, and reflect Earth's climate. One driver of sea-level change is the erosion and deposition of sediment, which induces changes in sea level by perturbing Earth's crust, gravity field, and rotation axis. Here we use a gravitationally self-consistent global model to explore how sediment erosion and deposition affected sea level

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South Asian monsoon history over the past 60 kyr recorded by radiogenic isotopes and clay mineral assemblages in the Andaman Sea

The Late Quaternary variability of the South Asian (or Indian) monsoon has been linked with glacial-interglacial and millennial scale climatic changes but past rainfall intensity in the river catchments draining into the Andaman Sea remains poorly constrained. Here, we use radiogenic Sr, Nd, and Pb isotope compositions of the detrital clay-size fraction and clay mineral assemblages obtained from sediment core NGHP Site 17 in the Andaman Sea to reconstruct

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Composition and origin of authigenic carbonates in the Krishna-Godavari and Mahanadi Basins, eastern continental margin of India

The mineralogical and stable isotopic composition of authigenic carbonates from the Krishna-Godavari (KG) and Mahanadi Basin provide a deeper insight into the processes inducing carbonate formation in the sediments of the eastern continental margin of India in the Bay of Bengal. Authigenic carbonate cements, (micro) nodules, bioturbation casts and tubes from 12 core locations drilled during the Indian National Gas Hydrate Program (NGHP) Expedition

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Influence of total organic carbon deposition on the inventory of gas hydrate in the Indian continental margins

Total organic carbon (TOC) content of marine sediments represents residual carbon, originally derived from terrestrial and marine sources, which has survived seafloor and shallow subseafloor diagenesis. Ultimately, its preservation below the sulfate reduction zone in marine sediments drives methanogenesis. Within the gas hydrate stability zone (GHSZ), methane production along continental margins can supersaturate pore fluids and lead to the formation

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A late Miocene-early Pliocene biogenic silica crash in the Andaman Sea and Bay of Bengal

Variations in the mass accumulation rate of biogenic silica (BSi) in continental margin sediments can be used to reconstruct relative changes in productivity through time in these settings. In the northern Bay of Bengal a lack of long sedimentary records has historically precluded this type of reconstruction. The acquisition of 21 new long sedimentary records during the 2006 Indian National Gas Hydrate Program (NGHP) Expedition-01 has made it possible

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