The relation between the terra rossa and the carbonate-free residue of the underlying limestones and dolostones in Apulia, Italy

Clay Minerals ◽  
1988 ◽  
Vol 23 (4) ◽  
pp. 439-446 ◽  
Author(s):  
M. Moresi ◽  
G. Mongelli
Keyword(s):  
Carbonate Rocks ◽  
Biogenic Silica ◽  
Carbonate Rock ◽  
Chemical Weathering ◽  
Marked Decrease ◽  
Parent Material ◽  
Terra Rossa ◽  
Characteristic Distribution ◽  
Statistical Comparison ◽  
Geochemical Pattern

AbstractA statistical comparison has been made of chemical data for terra rossa and carbonate-free residues of Cretaceous limestones and dolostones in Apulia in order to evaluate the hypothesis that the terra rossa is a product of weathering of the underlying carbonate rocks. It has been shown that the differences in chemical composition between the residue of the carbonate rocks and the terra rossa are consistent with the former being the parent material of the latter. The transformation from carbonate rock residue to terra rossa was governed mainly by chemical weathering which produced a marked decrease in the K2O/Al2O3 (i.e. illite/kaolinite) ratio. The geochemical pattern of the Apulian terra rossa has been influenced by sedimentary processes which have led to a characteristic distribution of mineralogical components and a moderate contamination by biogenic silica.

Research on Carbon Source Effect of Guangxi Typical Carbonate Rock Area by Acid Rain

2013 ◽  
Vol 295-298 ◽  
pp. 314-321 ◽  
Author(s):  
Shi Yu ◽  
Hui Yang
Keyword(s):  
Carbon Source ◽  
Dissolution Rate ◽  
Acid Rain ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Chemical Weathering ◽  
Carbon Sources ◽  
Rock Surface ◽  
Representative Area ◽  
Carbonate Source

In order to have an insight into the reaction between acid rain and carbonate rock surface, and figure out the CO2carbonate source amount from the acid rain chemical weathering process of the carbonate rocks, two typical carbonate rock areas Guilin (represents limestone area) and Liuzhou (represents dolomite area) were chosen as the study areas in Guangxi. According to the dissolution rate calculated by the limestone test piece and GIS analysis, the CO2source produced by the acid rain was 41.066×108g/a, in which Guilin was 33.349×108g/a and Liuzhou was 7.717×108g/a. The carbon sources of unit area in Guilin and in Liuzhou were 66.967×105g/a•km2 and 42.777×105g/a•km2 respectively. Although the carbon sources were still less than their carbon sinks in Guilin and Liuzhou which were 273.891×105g/a•km2 and 43.660×105g/a•km2 respectively, they should not be neglected. There were two reasons that the degassing rate of carbon source in Guilin was slower than that in Liuzhou. One was the representative area of carbonate rock in Guilin were 2.77 times of that in Liuzhou, the other one was that the total intensity of acid rain of Guilin was lower than Liuzhou, so that the dissolution rate of the carbonate rocks was lower in Guilin.

Characteristics and its Environment Implications of Carbon and Oxygen Isotopic of Ordovician Carbonate Rock in Yubei Area

2015 ◽  
Vol 1092-1093 ◽  
pp. 1375-1378
Author(s):  
Qian Zhang ◽  
Wen Hui Huang ◽  
Ya Mei Zhang
Keyword(s):  
Sea Level ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Burial Depth ◽  
Oxygen Stable Isotopes ◽  
Oxygen Isotopic ◽  
Oxygen Stable Isotope ◽  
The Stability ◽  
Diagenetic Environment ◽  
Stable Isotope Data

Based on a large number of carbon and oxygen stable isotope data, researched environment characteristics of Ordovician carbonate rocks in Yubei area, Tarim Basin. According to carbon, oxygen stable isotopes (&13C, &18O) data, combining the diagenetic environment characteristics studied all kinds of geochemical characteristics of rocks in Yubei area. The research results show that: Paleosalinity feature of Ordovician carbonate rocks in this area reflected the carbonate rocks is formed in the stability of the marine environment and basically kept the composition of carbon and oxygen isotopic of the original environment. the paleo temperature characteristics indicate that the diagenetic burial depth was increased first and then decreased, the sea level characteristics indicate that the sedimentary strata by Yingshan period to Lianglitage period corresponds with a rise in sea level.

scholarly journals The emergence of subaerial crust and onset of weathering 3.7 billion years ago

2021 ◽  
Author(s):  
Desiree Roerdink ◽  
Yuval Ronen ◽  
Harald Strauss ◽  
Paul Mason
Keyword(s):  
Carbonate Rocks ◽  
Hydrothermal Fluid ◽  
Plate Tectonics ◽  
Chemical Weathering ◽  
Crystal Morphology ◽  
Sr Isotope ◽  
Fluid Mixtures ◽  
Mixing Ratios ◽  
Biosphere Evolution ◽  
Evolution Trend

<p>Reconstructing the emergence and weathering of continental crust in the Archean is crucial for our understanding of early ocean chemistry, biosphere evolution and the onset of plate tectonics. However, considerable disagreement exists between the various elemental and isotopic proxies that have been used to trace crustal input into marine sediments, and data are scarce prior to 3 billion years ago. Here we show that chemical weathering modified the Sr isotopic composition of Archean seawater as recorded in 3.52 to 3.20 Ga stratiform marine-hydrothermal barite deposits from three different cratons. We use a combination of barite crystal morphology, oxygen, multiple sulfur and strontium isotope data to select barite samples with the most seawater-like isotopic compositions, and subsequently use these in a hydrothermal mixing model to calculate a plausible seawater Sr isotope evolution trend from measured <sup>87</sup>Sr/<sup>86</sup>Sr data. From modeled mixing ratios between seawater and hydrothermal fluids required for barite precipitation and comparison of <sup>87</sup>Sr/<sup>86</sup>Sr in theoretical seawater-hydrothermal fluid mixtures with those recorded in the barite, we obtain a novel seawater Sr isotope evolution trend for Paleoarchean seawater that is much more radiogenic than the curve previously determined from carbonate rocks. Our findings require the presence and weathering of subaerial and evolved (high Rb/Sr) crust from 3.7 ± 0.1 Ga onwards, and demonstrate that crustal weathering affected the chemistry of the oceans 500 million years earlier than previously thought.</p>

The Automatic Identification of Aperture in Carbonate Rocks

2013 ◽  
Vol 734-737 ◽  
pp. 207-210
Author(s):  
Hui Jian Wen ◽  
Qi Wang ◽  
Dong Yun Geng
Keyword(s):  
High Precision ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Actual Data ◽  
Automatic Identification ◽  
Contour Extraction ◽  
Contour Tracing

To identify and segment automatically the apertures by using of differences between aperture area changes of the grayscale or chroma of carbonate rock and the surrounding rocks in imaging logging data. Contour extraction and contour tracing can extract the aperture boundary effectively, and calculate the aperture parameter which is unable to get quantitatively in common logging. Dealing with actual data, this method is confirmed to have a high precision.

scholarly journals Geochemical Implications of Rare Earth Elements in Terra Rossa in Tropical Karst Area: A Case Study in Northern Vietnam

2020 ◽  
Vol 10 (3) ◽  
pp. 858 ◽  
Author(s):  
Zhang Liankai ◽  
Ji Hongbing ◽  
Wang Shijie ◽  
Luo Gang ◽  
Liu Xiuming ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Chemical Weathering ◽  
Karst Area ◽  
Oxidation Condition ◽  
Terra Rossa ◽  
Northern Vietnam ◽  
Material Sources ◽  
Karst Areas ◽  
Tropical Karst

Research on weathered crusts on carbonate rock is essential for paleoenvironmental studies in karst areas. Terra rossa, widely distributed in tropical karst areas, has not been studied in terms of its material sources and geochemistry. Two typical terra rossa profiles on dolomite (SC profile located at Sang Cai, Hoa Binh province) and limestone (TG profile located at Tong Gia, Lao Cai province) in Northern Vietnam were selected to examine the geochemical characteristics and the evolutionary processes of rare earth elements (REEs). Chondrite and bedrock normalized patterns indicated that these two profiles are in situ weathering crusts, meaning they are the residual material remaining after chemical weathering of the lower carbonate rocks. The average value of total REE in the SC profile is 381.19 ppm, which is 30 times higher than the bedrock. In the TG profile, the value is 386.26 ppm, 13 times higher than the bedrock. Compared with the profiles in nearby subtropical areas in Southeast China, the REE enrichment coefficients of terra rossa in Northern Vietnam are much higher. The REE depletion was also different between the SC and TG profiles. The light and heavy REE fractionations in the SC profile are higher than in the TG profile. Paleoclimate inversion analysis shows that the SC profile experienced a stable oxidation condition, whereas the TG profile was subjected to several reducing environments since a weathering crust formed.

scholarly journals An integrated analysis of mineralogical and microstructural characteristics and petrophysical properties of carbonate rocks in the lower Indus Basin, Pakistan

2019 ◽  
Vol 11 (1) ◽  
pp. 1151-1167
Author(s):  
Waheed Ali Abro ◽  
Abdul Majeed Shar ◽  
Kun Sang Lee ◽  
Asad Ali Narejo
Keyword(s):  
Thin Section ◽  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Indus Basin ◽  
Reservoir Quality ◽  
Data Sets ◽  
Petrophysical Properties ◽  
X Ray ◽  
Lower Indus Basin

Abstract Carbonate rocks are believed to be proven hydrocarbon reservoirs and are found in various basins of Pakistan including Lower Indus Basin. The carbonate rock intervals of the Jakkher Group from Paleocene to Oligocene age are distributed in south-western part of Lower Indus Basin of Pakistan. However, there are limited published petrophysical data sets on these carbonate rocks and are essential for field development and risk reduction. To fill this knowledge gap, this study is mainly established to collect the comprehensive high quality data sets on petrophysical properties of carbonate rocks along with their mineralogy and microstructure. Additionally, the study assesses the impact of diagenesis on quality of the unconventional tight carbonate resources. Experimental techniques include Scanning Electronic Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), and X-ray diffraction (XRD), photomicrography, Helium porosity and steady state gas permeability. Results revealed that the porosity was in range of 2.12 to 8.5% with an average value of 4.5% and the permeability was ranging from 0.013 to 5.8mD. Thin section study, SEM-EDS, and XRD analyses revealed that the samples mostly contain carbon (C), calcium (Ca), and magnesium (Mg) as dominant elemental components.The main carbonate components observed were calcite, dolomite, micrite, Ferron mud, bioclasts and intermixes of clay minerals and cementing materials. The analysis shows that: 1) the permeability and porosity cross plot, the permeability and slippage factor values cross plots appears to be scattered, which showed weaker correlation that was the reflection of carbonate rock heterogeneity. 2) The permeability and clay mineralogy cross plots have resulted in poor correlation in these carbonate samples. 3) Several diagenetic processes had influenced the quality of carbonates of Jakkher Group, such as pore dissolution, calcification, cementation, and compaction. 4) Reservoir quality was mainly affected by inter-mixing of clay, cementation, presence of micrite muds, grain compactions, and overburden stresses that all lead these carbonate reservoirs to ultra-tight reservoirs and are considered to be of very poor quality. 5) SEM and thin section observations shows incidence of micro-fractures and pore dissolution tended to improve reservoir quality.

scholarly journals Facies Development of Carbonate Rock and System Tract Influence Based on Fullbore Formation Microimager (FMI) and Well Log Analysis on Carbonate Reservoir Tuban Formation, North East Java Basin

2018 ◽  
Vol 73 ◽  
pp. 02021
Author(s):  
Fahrudin ◽  
Eka Sainyakit ◽  
Ahmad Syauqi Hidayatillah ◽  
Purnaning Tuwuh Triwigati ◽  
Muhajir
Keyword(s):  
Carbonate Rocks ◽  
Carbonate Rock ◽  
Gamma Ray ◽  
Research Area ◽  
Carbonate Reservoir ◽  
Log Analysis ◽  
Reef Facies ◽  
North East ◽  
The North ◽  
System Tract

The North East Java Basin is known to be one of the basins that consist of Miocene carbonate rocks, like the reef carbonate of Tuban Formation. It has the potential hydrocarbons that can be explored. Therefore, the FMI log analysis is very important to identify carbonate rocks of Tuban Formation to know facies and characteristics of that carbonate rocks. The method used descriptive and analysis process of FMI and Gamma Ray log to determine facies of the carbonate rock and the system tract. Based on the result of FMI log analysis, there are variations lithofasies include mudstone, wackestone, packstone, grainstone, floatstone, rudstone and claystone. A collection of rock associations can interpret the reef facies. It involves back reef facies, reef core facies, and fore reef facies. The changes of lithofasies and reef facies are caused by sea level fluctuations and subsidence resulting in the system tract. The system tracts generated in the research area include transgressive and highstand system tract.

scholarly journals Role of sulfuric acid in chemical weathering of carbonate rocks for evaluating of carbon sinks in the Yangtze River Basin, China

2019 ◽  
Vol 98 ◽  
pp. 06015
Author(s):  
Liankai Zhang ◽  
Xiaoqun Qin ◽  
Qibo Huang ◽  
Pengyu Liu
Keyword(s):  
Sulfuric Acid ◽  
River Basin ◽  
Carbonate Rocks ◽  
Yangtze River ◽  
Chemical Weathering ◽  
Consumption Rate ◽  
Yangtze River Basin ◽  
Rock Weathering ◽  
The Yangtze River ◽  
The Yangtze River Basin

Chemical weathering of rock by river systems is an important process in the global carbon cycle. Sulfuric acid produced from anthropogenic sources in the Yangtze River basin of China has the potential to change rock weathering processes and the carbon cycle. Monitoring and analysis of the dissolved constituents of the main channel and major tributaries of the Yangtze River indicate that the sulfuric acid has enhanced the carbonate rock weathering rate by an average of 28% and reduced the CO2 consumption rate by 12%. Analysis of dissolved sources for SO42- in the Yangtze River indicates that 36% of SO42- can be attributed to rainwater, 26% to dissolution of evaporitic rocks, and 38% to input from coal. Calculations indicate that the annual output flux of CO2 from the Yangtze River Basin to the sea is 3495×104 tons, 80% of which is attributed to the weathering of carbonate rocks. Whilst the average consumption rate of atmospheric CO2 is 20.6 t/km2 y-1.

scholarly journals Influences of forested and grassland vegetation on late Quaternary ecosystem development as recorded in lacustrine sediments

2019 ◽  
Vol 92 (1) ◽  
pp. 201-215 ◽  
Author(s):  
Kendra K. McLauchlan ◽  
Ioan Lascu ◽  
Emily Mellicant ◽  
Robert J. Scharping ◽  
Joseph J. Williams
Keyword(s):  
Chemical Weathering ◽  
Forest Type ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Lacustrine Sediments ◽  
Parent Material ◽  
Elemental Abundance ◽  
Sediment Delivery ◽  
Sedimentary Sequences ◽  
Northern United States

AbstractGeosphere-biosphere interactions are ubiquitous features of the Earth surface, yet the development of interactions between newly exposed lithologic surfaces and colonizing plants during primary succession after glaciation are lacking temporal detail. To assess the nature, rate, and magnitude of vegetation influence on parent material and sediment delivery, we analyzed ecosystem and geochemical proxies from lacustrine sediment cores at a grassland site and a forested site in the northern United States. Over time, terrigenous inputs declined at both sites, with increasing amounts of organic inputs toward present. The similarities between sites were striking given that the grassland sequence began in the Early Holocene, and the forested sequence began after the last glacial maximum. Multiple mechanisms of chemical weathering, hydrologic transport, and changes in source material potentially contribute to this pattern. Although there were strong links between vegetation composition and nitrogen cycling at each site, it appears that changes in forest type, or from oak woodland to grassland, did not exert a large influence on elemental (K, Ti, Si, Ca, Fe, Mn, and S) abundance in the sedimentary sequences. Rather, other factors in the catchment-lake system determined the temporal sequence of elemental abundance.

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