A multidisciplinary approach for the quantitative provenance analysis of siltstone: Mesozoic Mandawa Basin, southeastern Tanzania

Caracciolo, Luca; Andó, Sergio; Vermeesch, Pieter; Garzanti, Eduardo; McCabe, R.; Barbarano, Marta; Paleari, Chiara Ileana; Rittner, Martin; Pearce, Tim

doi:10.1144/sp484-2018-136

Cited by 14 publications

(8 citation statements)

References 84 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Silt represents a very major part of fluvial detrital fluxes and 50% or more of sedimentary covers on Earth [1][2][3][4]. Because of the diverse difficulties involved in sample treatment and analysis, however, mud and mudrocks are infrequently considered in provenance studies (e.g., [5,6]). Silt is a main component of offshore shelf deposits, which represent the trait-d'union between fluvial sediments largely carried in suspension and deep-sea-fan turbidites.…”

Section: Introductionmentioning

confidence: 99%

Provenance of Bengal Shelf Sediments: 1. Mineralogy and Geochemistry of Silt

et al. 2019

Self Cite

View full text Add to dashboard Cite

This article illustrates a multi-technique frontier approach for the provenance study of silt-size sediments. The mineralogical composition of low-density and heavy-mineral fractions of four samples of fine to very coarse silt deposited on the Bengal shelf was analyzed separately for six different grain-size classes by combining grain counting under an optical microscope, Raman spectroscopy, and X-ray diffraction. The geochemical composition was determined on both bulk-sediment samples and on their <5-μm classes. Such a “multiple-window” approach allowed capturing the full mineralogical information contained in each sample, as well as the size-dependent intra-sample variability of all compositional parameters. The comparison between grain-size distributions obtained by different methods highlighted a notable fallacy of laser granulometry, which markedly overestimated the size of the finest mode represented by fine silt and clay. As a test case, we chose to investigate sediments of the Bengal shelf, where detritus is fed from the Meghna estuary, formed by the joint Ganga and Brahmaputra Rivers and representing the largest single entry point of sediment in the world’s oceans. The studied samples show the typical fingerprint of orogenic detritus produced by focused erosion of collision orogens. Bengal shelf silt is characterized by a feldspatho-quartzose (F-Q) composition with a Q/F ratio decreasing from 3.0 to 1.7 with increasing grain size, plagioclase prevailing over K-feldspar, and rich transparent-heavy-mineral assemblages including mainly amphibole with epidote, and minor garnet and pyroxene. Such a detrital signature compares very closely with Brahmaputra suspended load, but mineralogical and geochemical parameters, including the anomalous decrease of the Q/F ratio with increasing grain size, consistently indicate more significant Ganga contribution for cohesive fine silt. The accurate quantitative characterization of different size fractions of Bengal shelf sediments represents an essential step to allow comparison of compositional signatures characterizing different segments of this huge source-to-sink system, from fluvial and deltaic sediments of the Himalayan foreland basin and Bengal shelf to the Bengal Fan.

show abstract

Section: Introductionmentioning

confidence: 99%

Provenance of Bengal Shelf Sediments: 1. Mineralogy and Geochemistry of Silt

et al. 2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Clay-rich samples cannot be processed by wet-sieving alone in a reasonable amount of time, because the nylon meshes are quickly clogged. In these cases, a hybrid procedure is recommended to extract the silt fraction, which may be essential in heavy-mineral studies of soils, suspended load, eolian dust, lagoonal or offshore muds, or deep-sea turbidites [29][30][31][32][33][34].…”

Section: Clay-rich Samples: Settling Tubes and Wet Sieving At 5 µMmentioning

confidence: 99%

Gravimetric Separation of Heavy Minerals in Sediments and Rocks

Andó

2020

Minerals

View full text Add to dashboard Cite

The potential of heavy minerals studies in provenance analysis can be enhanced conspicuously by using a state-of-the-art protocol for sample preparation in the laboratory, which represents the first fundamental step of any geological research. The classical method of gravimetric separation is based on the properties of detrital minerals, principally their grain size and density, and its efficiency depends on the procedure followed and on the technical skills of the operator. Heavy-mineral studies in the past have been traditionally focused on the sand fraction, generally choosing a narrow grain-size window for analysis, an approach that is bound to introduce a serious bias by neglecting a large, and sometimes very large, part of the heavy-mineral spectrum present in the sample. In order to minimize bias, not only the largest possible size range in each sample should be considered, but also, the same quantitative analytical methods should be applied to the largest possible grain-size range occurring in the sediment system down to 5 µm or less, thus including suspended load in rivers, loess deposits, and shallow to deep-marine muds. Wherever the bulk sample cannot be used for practical reasons, we need to routinely analyze the medium silt to medium sand range (15-500 µm) for sand and the fine silt to sand range (5-63 or > 63 µm) for silt. This article is conceived as a practical handbook dedicated specifically to Master and PhD students at the beginning of their heavy-mineral apprenticeship, as to more expert operators from the industry and academy to help improving the quality of heavy-mineral separation for any possible field of application.Minerals 2020, 10, 273 2 of 15 (e.g., aggregates of iron or titanium oxides); and anthropogenic origin (e.g., barite in core samples and moissanite) are thus neglected. Phyllosilicates are neglected as well. Transparent heavy minerals identified under the microscope are considered separately from opaque and altered heavy minerals.The study of heavy minerals, which was quite popular in the past-for a historical overview, the reader is referred to Carver, 1971 [4] and to the monumental book edited by Mange and Wright, 2007 [5])-has recently seen a renovated and increasing interest also in source-to-sink studies aimed at the search for hydrocarbon reservoirs (e.g., Morton and McGill, 2018 [6]). Laboratory practice for sample treatment and heavy-mineral separation was thoroughly investigated and illustrated a half century ago (e.g., [7][8][9][10]), but, later on, the methodology has seen a sort of standardization, and not only for the best, and the stimulus for the betterment of laboratory procedures has seen little progress since then. An updated recent publication in which the state-of-the art techniques for heavy-mineral separation are thoroughly explained through the entire process, from sampling to mineralogical analysis, thus does not exist to the best of my knowledge. The purpose of this article is to fill this gap, especially as the study of recent unconsolidated silts a...

show abstract

“…Thus, even the heavy mineral composition, first‐order information in SPA (Garzanti & Andò, 2019; Mange & Wright, 2007), is affected. To account for this inherent variability a large toolbox of methods exists (von Eynatten & Dunkl, 2012) and it is the combination of many methods that leads to a sound interpretation in SPA (Anders et al., 2021; Andò et al., 2011, 2020; Caracciolo et al., 2020; Chew et al., 2020; Garzanti, 2016; Garzanti & Andò, 2007; Limonta et al., 2015; O’Sullivan et al., 2020). In this context, single‐grain analysis, especially geochemical and geochronological data, is of particular interest because physicochemical alteration and hydrodynamic sorting are essentially constant for the same type of mineral of similar size and therefore this sort of provenance information is more closely related to the source area (von Eynatten & Dunkl, 2012).…”

Section: Introductionmentioning

confidence: 99%

From Outcrop to Spectrum—An Automated Approach to Modal Mineralogy of Silt‐Sized Sediment Applied to Central European Loess

Lünsdorf,

Újvári

et al. 2023

JGR Earth Surface

View full text Add to dashboard Cite

Provenance information from recent and ancient sedimentary archives is obscured by several factors and for disentangling these intermingled signals, analysis by multiple methods is paramount. In sedimentary provenance analysis (SPA), single‐grain methods determining mineralogy, chemical composition, or radiometric ages are of key importance but are mostly applied to sand‐sized sediments or sedimentary rocks. Finer grained sediments or sedimentary rocks are usually analyzed by whole‐rock geochemical means and seldom by single‐grain methods. Considering the abundance of fine‐grained sedimentary archives, a strong need for single‐grain, multi‐method analyses of silt‐sized sediments is obvious. Thus, we propose a workflow that is optimized for sample throughput and correlative analysis of fine‐grained sediments based on machine learning methods. The feasibility of the workflow is demonstrated by differentiating three Central European loess‐paleosol‐sequences. The increased sample throughput enables access to sedimentary archives at high spatial and/or temporal resolution, which will open up new research pathways in SPA of silt‐sized sediments.

show abstract

A multidisciplinary approach for the quantitative provenance analysis of siltstone: Mesozoic Mandawa Basin, southeastern Tanzania

Cited by 14 publications

References 84 publications

Provenance of Bengal Shelf Sediments: 1. Mineralogy and Geochemistry of Silt

Provenance of Bengal Shelf Sediments: 1. Mineralogy and Geochemistry of Silt

Gravimetric Separation of Heavy Minerals in Sediments and Rocks

From Outcrop to Spectrum—An Automated Approach to Modal Mineralogy of Silt‐Sized Sediment Applied to Central European Loess

Contact Info

Product

Resources

About