Morphology of Detrital Zircon as a Fingerprint to Trace Sediment Provenance: Case Study of the Yangtze Delta

Abstract

Deltaic areas and marginal seas are important archives that document information on regional tectonic movement, sea level rise, river evolution, and climate change. Here, sediment samples from boreholes of the Yangtze Delta and the modern Yangtze drainage were collected. A quantitative analysis of detrital zircon morphology was used to discuss the provenance evolution of the Yangtze Delta. This research demonstrated that a dramatic change in sediment provenance occurred in the transition from the Pliocene to Quaternary. Zircon grains in the Pliocene sediments featured euhedral crystals with large elongation (>3 accounted for 13.2%) and were closely matched to tributary samples in the Lower Yangtze (>3 accounted for 11.3%), suggesting sediment provenance from the proximal river basin. However, most detrital zircon grains of the Quaternary samples exhibited lower values of elongation and increased roundness (rounded grains were 9.4%), which was similar to those found in the modern Yangtze mainstream (rounded grains were 12.5%) and the middle tributaries (rounded grains were 7.0%). The decrease in zircon elongation and improvement of its roundness in the Quaternary strata implied that the Yangtze Delta received sediments of different provenance that originated from the Middle-Upper Yangtze basin due to the uplift of the Tibetan Plateau. Statistical analysis of detrital zircon morphology has proven useful for studying the source-to-sink of sediments.Minerals 2019, 9, 438 2 of 15 intuitively determine zircon parent rocks and are potential fingerprints to be applied in sediment provenance analysis [13][14][15][16][17].Serving as an important depocenter of the Eastern China, the Yangtze Delta has preserved valuable information on sediment sources related to landform and river evolution [5,18,19]. Using different methods of clay mineral analysis, geochemistry, magnetic properties, single mineral geochronology (zircon, monazite age spectra), previous studies have identified a significant change in sediment provenance at the Pliocene-Quaternary transition [20][21][22][23]. However, sediment provenance evolution in the deltaic area is still controversial [22]. There is neither a consensus about the exact source of the Pliocene strata in the Yangtze Delta nor about the time when the Upper Yangtze sediments arrived at the delta. Different studies proposed that the Upper Yangtze sediment arrived either early in the Pliocene [21,24], in the Early-Middle Pleistocene [22,23,[25][26][27], or later in the late Pleistocene [28,29]. For these previous studies, only one borehole was used to represent the entire area of the Yangtze Delta, which may have resulted in different interpretations due to the limitations of the different methods. This is not only because of the vast area of Yangtze Delta but also because of its complex sedimentary strata.In order to extract the exact sediment provenance, several boreholes in different regions of the study area should be systematically analysed and compared to potential source sediments within ...

The Chemical Composition and Surface Texture of Transparent Heavy Minerals from Core LQ24 in the Changjiang Delta

“…No microfossils were found in the Pliocene sediments. In addition, poorly sorted gravels can be found, which indicate the origin of sedimentary facies as an alluvial fan or a meandering river [22]. The Quaternary strata comprised several sedimentary sequences, which were composed of sand at the bottom and clayey silt at the top, suggesting a fluvial environment ( Figure 2).…”

“…However, the burial depths involved in this study area are modest (the deepest thickness = ca. 400 m), and the sediments of the Changjiang Delta are very young (Neogene) [22,38]. Calcite-cemented sands in the bottom strata are not fully diagenized.…”

“…Thicknesses of 150-400 m sediments have been deposited in the Changjiang Delta since the Pliocene [22]. This area is a natural laboratory that can be used to carry out studies on sediment provenance, tectonic evolution, sedimentary environment, and river evolution [23][24][25].…”

A Natural GMS Laboratory (Granulometry-Morphometry-Situmetry): Geomorphological-Sedimentological-Mineralogical Terrain Analysis Linked to Coarse-Grained Siliciclastic Sediments at the Basement-Foreland Boundary (SE Germany)

“…The morphology of heavy and light minerals has frequently been used during provenance studies in the majority of cases within context with a meticulous mineralogical study and backed by micro-chemical analyses' heavy minerals [108][109][110][111][112]. Lithoclasts in the channels are closely linked to the wall rock lithologies exposed along the valley slope and as bedrock incised by the river forming in the straight to low sinuosity channels; typical step-and-pool couples with a spacing from the centimeter to the meter scale.…”

Tracking Sediment Provenance Applying a Linear Mixing Model Approach Using R’s FingerPro Package, in the Mining-Influenced Ocoña Watershed, Southern Peru

“…Tracers used in sediment fingerprinting studies include color properties [36][37][38], major and trace elemental composition [39,40], rare earth elements [33,[41][42][43], radionuclide characteristics [38,44,45], and organic matter [46,47]. Furthermore, authors around the world, e.g., [48,49] have used this technique to determine sediment sources; in South America, studies have been carried out in Argentina [50], Brazil [51], and Venezuela [52]. In Peru, however, sediment fingerprinting has been applied only on studies involving marine environments [53], but nothing has been carried out in inland regions of the country.…”