INVESTIGATIONS OF URBAN FLOODPLAIN SEDIMENT TEXTURE, DEPOSITIONAL RATE AND CONTAMINATION IN KNOXVILLE, TN

2018 ◽  
Author(s):  
Leah Wenhold ◽  
◽  
Larry D. McKay
2021 ◽  
Vol 11 (7) ◽  
pp. 3030
Author(s):  
Marcos A. Martínez-Segura ◽  
Carmelo Conesa-García ◽  
Pedro Pérez-Cutillas ◽  
Pedro Martínez-Pagán ◽  
Marco D. Vásconez-Maza

Differences in deposit geometry and texture with depth along ephemeral gravel-bed streams strongly reflect fluctuations in bedload which are due to environmental changes at the basin scale and to morphological channel adjustments. This study combines electrical resistivity tomography (ERT) with datasets from borehole logs to analyse the internal geometry of channel cross-sections in a gravel-bed ephemeral stream (southeast Spain). The survey was performed through longitudinal and transverse profiles in the upper channel stretch, of 14 to 30 m in length and 3 to 6 m in depth, approximately. ERT values were correlated with data on sediment texture as grain size distribution, effective grain sizes, sorting, and particle shape (Zingg’s classification). The alluvial channel-fills showed the superposition of four layers with uneven thickness and arrangement: (1) the softer rocky substrate (<1000 Ω.m); (2) a thicker intermediate layer (1000 to 2000 Ω.m); and (3) an upper set composed of coarse gravel and supported matrix, ranging above 2000 Ω.m, and a narrow subsurface layer, which is the most resistive (>5000 Ω.m), corresponding to the most recent armoured deposits (gravel and pebbles). The ERT results coupled with borehole data allowed for determining the horizontal and vertical behaviour of the materials in a 3D model, facilitating the layer identification.


Author(s):  
Joanna Gmitrowicz-Iwan ◽  
Sławomir Ligęza ◽  
Jacek Pranagal ◽  
Halina Smal

The Holocene ◽  
2018 ◽  
Vol 29 (2) ◽  
pp. 244-261 ◽  
Author(s):  
Pablo G Messineo ◽  
Marcela S Tonello ◽  
Silvina Stutz ◽  
Alfonsina Tripaldi ◽  
Nahuel Scheifler ◽  
...  

The main objective of this work is to generate and integrate interpretations of human occupation strategies and inferences of the environmental-climatic conditions in the central Pampas during the middle and late Holocene. We present a novel archeological–geological–paleoecological analysis in the area of the Cabeza de Buey lake, placed in an aeolian landscape. During the middle Holocene, two events of human occupations were recognized at Laguna Cabeza de Buey 2 archeological site. Both events present a small amount of lithic materials, a low diversity of tools and activities developed with them (principally hard material), and the hunting and primary processing of artiodactyls. These evidences suggest a locus of specific activity associated with an ephemeral human settlement under climate conditions drier than present and the presence of small, brackish, and shallow water bodies. For the late late Holocene, the hunter-gatherer occupation has a higher depositional rate of lithic assemblage, stones with diverse origins, presence of pottery fragments, a great lithic tool diversity, knapping techniques, and activities developed with these tools (processing wood, bone, hide, non-woody plant, and soft material). These evidences reveal an occupation with a higher degree of recurrence represented by a locus of multiple activities associated with a more stable landscape, such as an environment of dunes fixed by grass vegetation, and the establishment of a permanent water body. The different environmental characteristics for the middle and late Holocene in this area promoted that human groups develop two different patterns of mobility, settlement and use of space.


2005 ◽  
Vol 98 (1) ◽  
pp. 96-109 ◽  
Author(s):  
Daphne van der Wal ◽  
Peter M.J. Herman ◽  
Annette Wielemaker-van den Dool

Geochemistry ◽  
2020 ◽  
pp. 89-109
Author(s):  
Cheng Hangxin ◽  
Shen Xiachu ◽  
Guangsheng Yan ◽  
Gu Tiexin ◽  
Lai Zhimin ◽  
...  

2020 ◽  
Vol 9 (2) ◽  
pp. 125-132
Author(s):  
Triyanti Nurhidayah ◽  
Lilik Maslukah ◽  
Sri Yulina Wulandari ◽  
Kurnia Kurnia

Pantai Marunda terletak di Teluk Jakarta dan berdekatan dengan muara Sungai Tiram. Kegiatan antropogenik di sekitar Pantai Marunda sangat tinggi, sehingga dapat menyumbang limbah yang mengandung logam berat Pb, Zn dan Cr. Limbah logam berat yang terakumulasi dalam perairan, akan  mengendap dalam sedimen dan seiring berjalannya waktu akan mengalami peningkatan. Tujuan dari penelitian ini, untuk mengetahui konsentrasi Pb, Zn, dan Cr berdasarkan kedalaman vertikal, hubungannya dengan karbon organik total (KOT) dan ukuran butir sedimen di Pantai Marunda. Sampel sedimen diambil menggunakan polietylen sediment core dan dipisahkan berdasarkan kedalamannya (1-3 cm, 4-6 cm, dan 7-9 cm). Logam berat dalam sedimen dianalisis menggunakan metode destruksi asam dan diukur nilai absorbansinya menggunakan AAS, karbon organik total menggunakan metode loss of ignition (LOI) dan analisa tekstur sedimen dengan metode pengayakan dilanjutkan pemipetan. Hasil menunjukkan bahwa konsentrasi rerata logam berat Pb, Zn, Cr secara berurutan pada lapisan atas sebesar 5,14; 107,19; dan 12,79 ppm, lapisan tengah sebesar 4,41; 100,20; 12,28  ppm serta lapisan bawah sebesar 4,8; 101,30; 14,10 ppm. Logam berat Zn dan Cr berkorelasi positif kuat terhadap KOT dan persentase lumpur, sedangkan terhadap Pb berkorelasi negatif. Hasil penelitian ini menggambarkan bahwa distribusi logam berat Pb, Zn dan Cr secara vertikal menunjukkan konsentrasi tinggi pada lapisan permukaan yaitu pada kedalaman sedimen 1-3 cm dan keberadaanya ditentukan oleh konsesntrasi  KOT dan fraksi sedimen jenis lumpur. The Marunda Beach is located on the Jakarta Bay and adjacent to the mouth of the Tiram River. Anthropogenic activity around Marunda Beach is very high, so it can contribute the heavy metals such as Pb, Zn and Cr. The heavy metal will accumulate in the sediment and over time will be increase. The purpose of this study was to determine the vertical distribution of Pb, Zn, Cr, and their relationship to total organic carbon (TOC) and the grain size. Sediment samples were taken using polyethylene cores and this sample separated based on their depth (1-3 cm, 4-6 cm, and 7-9 cm). The heavy metals were analyzed using acid destruction and absorbance values were measured using AAS, TOC using the loss of ignition (LOI) and sediment texture with a sifting method, followed by pipetting. The results showed that the average concentration of Pb, Zn, Cr in the upper layer was 5.14; 107.19; 12.79 ppm, in the middle layer of 4.41; 100.20; 12.28 ppm and in the lower layer 4.8; 101.30; 14.10 ppm, respectively. Zn and Cr are strongly positively correlated to TOC and mud, and vice versa, the relationship to Pb is negative. The results of this study found that the vertical distribution of Pb, Zn and Cr was high in the surface layer (1-3 cm) and their presence was determined by TOC concentration and mud fraction.


1983 ◽  
Vol 61 (1) ◽  
pp. 148-156 ◽  
Author(s):  
Richard W. Haag

Sediment samples were collected in May 1980 from 11 stations at five sites in Lake Wabamun. Emergence of seedlings was recorded in a greenhouse at 19 °C for 120 days. The sediments were then chilled at 4 °C for 120 days and reexposed to greenhouse conditions for a further 90 days. Total seedling densities varied from 0 to 2335 m−2. Depth and sediment texture each accounted for 20% of the variance in seedling numbers. Discharge of thermal effluent from the Wabamun generating station also caused substantial variation in seedling number; seedling numbers at the shallowest Wabamun Outlet station were over four times those at any other site. Chilling of the sediment samples in the laboratory caused further emergence of seedlings from the four sites with the highest seedling densities in the initial treatment. Total numbers were up to 50% of those for seedlings that emerged during the initial exposure to greenhouse conditions. Potamogeton pectinatus and P. pusillus were most common among the seedlings of six species. Two of the three most common macrophytes in the lake were rare as seedlings, while no seedlings were recorded for the most common angiosperm, Myriophyllum exalbescens. Reproduction by seed makes a secondary contribution to the dynamics of the vegetation of Lake Wabamun.


1976 ◽  
Vol 13 (12) ◽  
pp. 1683-1693 ◽  
Author(s):  
D. A. Grieve ◽  
W. K. Fletcher

Co, Cu, Fe, Mn, Ni, Pb, and Zn, together with sand content and loss of ignition, have been determined for surflcial sediments from the Fraser River delta-front and upper foreslope. Both geochemical maps and statistical analysis disclose close relationships between trace-metal concentrations, sediment texture, and Fe and Mn content. Detailed studies of the distribution of labile and non-labile trace metals within sediments indicate that these relationships reflect increased concentrations of trace metals associated with both the detrital minerals and hydrous Fe oxides coatings in the finer fractions of the sediment. Abnormally high concentrations of labile trace metals are found on the tidal flats at two stations influenced by discharge of metal-rich sewage.


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