An unusual weathered profile from Orange, N.S.W., Australia

Clay Minerals ◽  
1976 ◽  
Vol 11 (1) ◽  
pp. 65-71
Author(s):  
Peter Bayliss
Keyword(s):  
Mixed Layer ◽  
Chemical Weathering ◽  
Metamorphic Rock ◽  
Chemical Analyses ◽  
Thermogravimetric Analyses

AbstractSamples were collected from a 11·4 m deep weathered profile of a metamorphic rock. The mineralogy was determined from XRD powder patterns, differential thermal and thermogravimetric analyses with CEC determinations and chemical analyses.Four stages in a weathering sequence from the profile base towards the surface are as follows : (i) a partially regular trioctahedral chlorite-chlorite mixed layer ; (ii) a random chlorite-vermiculite mixed layer; (iii) a random chlorite-smectite mixed layer, and finally (iv) a smectite. Some chloritic layers are therefore more resistant to chemical weathering than other chloritic layers. This profile indicates that the order of decreasing resistance to chemical weathering is talc > smectite > tremolite.

Typhoon and weathering processes on particles export to the ocean from a small river on the oceanic island of Taiwan

2020 ◽  
Author(s):  
Wei-rong Chen ◽  
IJy Hsieh ◽  
Kelly Lien ◽  
Saulwood Lin
Keyword(s):  
Chemical Weathering ◽  
Extreme Event ◽  
Weather Condition ◽  
Oceanic Island ◽  
Small River ◽  
Small Rivers ◽  
Chemical Analyses ◽  
Discharge Data ◽  
Physical Weathering ◽  
Dissolved Components

<p>Huge quantity of terrigenous particles was exported from oceanic island small rivers in delivering to the ocean (Dadson et al., 2003; Milliman and Syvitsky, 1992).  Quantity of river particles entering the ocean could be related to river basin area, elevation, erosion rate, and seismic activity.  However, limited data are available regarding differences between physical and chemical weathering on erosion and their effects on particles export from oceanic type of small rivers nor data on extreme event, the typhoon, and its effect on weathering at this setting. Here we report and quantify particles as well as dissolved materials export from an oceanic small river, the Lanyang River at the northeastern Taiwan, during typhoon period and those under normal weather condition.  Our objectives are to quantify river particles and dissolved components export during normal and typhoon period; to understand factors controlling their variations; to compare efficiency of chemical and physical weathering under extreme weather condition and those at normal condition.  River particles and dissolved components were sampled monthly and during typhoons at every four hours frequency and filtered, weighted for particle concentrations as well as chemical analyses of particle and dissolved compositions in lab.  Chemical analyses include solid and dissolve silica, aluminum, iron, sodium, calcium, magnesium, and potassium as well as dissolved chloride, sulfate, and alkalinity. River discharge data were from Taiwan Water Resources Agency and precipitation data from Taiwan Central Weather Bureau.</p><p> </p><p>Our results demonstrated that typhoon is the primary mechanism in driving concentration variations of both dissolved phases and solid components in the study river.  Huge amount of precipitation flushed into river during typhoon, resulting in rapid dilution of dissolved components as well as rapid increase of suspended particles concentration in reaching hyperpycnal level.  During the period of rapid increase of particles in the river, shift of types of particles as well as dissolve components were observed.  TDS (total dissolved solid) represent a small portion of the materials export to the ocean.  TSM (total suspended matter) flushed out of river during typhoon represent a major fraction (85%) of the annual total particles, however, the amount of particles for each typhoon varied significantly (from ~10 to ~45%). </p>

Beidelltie clay from Chang-yuan, Taiwan; geology and mineralogy

Clay Minerals ◽  
1976 ◽  
Vol 11 (3) ◽  
pp. 221-233 ◽  
Author(s):  
Pei-Yuan Chen ◽  
Hsien-Ming Wan ◽  
G. W. Brindley
Keyword(s):  
Ethylene Glycol ◽  
Mixed Layer ◽  
Mineral Assemblage ◽  
Exchangeable Cations ◽  
The Other ◽  
Total Charge ◽  
Hydrothermal Solutions ◽  
Chemical Analyses ◽  
Two Samples

AbstractBeidellite clays near Chang-yuan, 80 km south of Hwalien, form vein-like bodies 5-10 m wide and 20-45 m deep. Andesitic rocks have been fractured by faulting permitting hydrothermal solutions to percolate and produce an altered mineral assemblage in which beidellite is associated with a mixed-layer illite-smectite, kaolinite, dusty pyrite, microquartz, cristobalite, calcite and dolomite, plagioclase, and gypsum. Ca-clay is common on outcrops and subsurface, where the clay is leached, Na-clay is found; some outcrops are partly kaolinized. Chemical analyses of the beidellite show that the structure is charged predominantly in the tetrahedral sheets. Exchange capacities are mainly in the range 120-140 mEq/100 g clay (110°C); exchangeable cations are Na ≫ Ca ≃ Mg > K. After K saturation and heating, ten samples still expand to near 17 A with ethylene glycol, but the two samples with the highest tetrahedral charge expand only to 14·6-15·0 Å although their total charge is similar to the other samples.

Mineralogical norm calculations applied to tropical weathering profiles

1997 ◽  
Vol 61 (405) ◽  
pp. 185-196 ◽  
Author(s):  
G. Voicu ◽  
M. Bardoux ◽  
D. Voicu
Keyword(s):  
South America ◽  
Chemical Weathering ◽  
Visual Basic ◽  
Metamorphic Rocks ◽  
Chemical Analyses ◽  
Calculation Methods ◽  
Weathering Profile ◽  
Calculation Algorithm ◽  
Secondary Minerals ◽  
Tropical Weathering

AbstractIn contrast with igneous and metamorphic rocks, classical petrochemical calculation methods cannot be used for tropical weathering components (saprolite, bauxitic, ferruginous, siliceous and calcareous laterite) in converting whole-rock chemical analyses into normative mineralogical weight percentages. Weathering profiles are characterized by a mixture of primary and secondary minerals, which are not considered in the classical methods of mineralogical norm calculation. A new petrochemical calculation algorithm is proposed for the conversion of whole-rock chemical analyses into weathering norm (WN) for several components of the tropical weathering profiles. The normative minerals are represented by three primary minerals, six secondary minerals, four primary/secondary mineral pairs, and five minerals which can have both primary and secondary origin. This algorithm has been used in MINNOR, a WINDOWS application written in Visual Basic, which calculates the mineralogical norm. In order to test the program, several types of different chemical weathering profiles from South America and Africa have been selected. Special attention is paid to the weathering profile from Omai, Guyana, South America.

scholarly journals Chemical weathering fluxes from Paramushir volcanic island (Kuril Island arc, Russia)

2019 ◽  
Vol 98 ◽  
pp. 08007 ◽  
Author(s):  
Elena Kalacheva ◽  
Tatiana Kotenko ◽  
Ekaterina Voloshina
Keyword(s):  
Flow Rate ◽  
Surface Waters ◽  
Chemical Weathering ◽  
Kuril Island ◽  
Silicate Weathering ◽  
Chemical Analyses ◽  
Volcanic Island ◽  
Chemical Erosion ◽  
Different Types ◽  
Kuril Island Arc

The rates of the chemical erosion for Paramushir Island, north Kuril Arc, were studied. The rates of the chemical erosion for Paramushir Island, north Kuril Arc, were studied. They were based on the results of the flow rate measurements and chemical analyses of 35 river’s water, sampled in July 2017. The silicate weathering fluxes caused by the subsurface thermal and two different types of surface waters (acid SO4 and near-neutral Na (Ca)-HCO3) of Paramushir have been estimated as 1095±200, 203 ±100 and 64 ± 20 t/km2/year, respectively. The total chemical weathering flux for Paramushir Island is estimated as 120± 40 t/km2/year.

scholarly journals Indications for ultra-high pressure metamorphism of amphibolite xenolith in the Arnea granite

2001 ◽  
Vol 34 (3) ◽  
pp. 893
Author(s):  
Ν. ΙΩΑΝΝΙΔΗΣ ◽  
Σ. ΣΚΛΑΒΟΥΝΟΣ
Keyword(s):  
High Pressure ◽  
Metamorphic Rock ◽  
Metamorphic Event ◽  
Late Triassic ◽  
Late Paleozoic ◽  
Crustal Rock ◽  
Chemical Analyses ◽  
High Pressure Metamorphism ◽  
Ultra High Pressure ◽  
Microscopic Studies

In this paper an amphibolite rock presented as xenolith into the Arnea granite close to Marathousa village has been examined. In particular, the xenolith is exposed into the aplitic granite portion of the Arnea granite at its contact with the Serbomacedonian massif. Microscopic studies and chemical analyses carried out in samples from the amphibolite xenolith and its contact zone with the aplitic granite has indicated the existence of tetrahedral and octahedral forms of "graphitized diamonds". This denotes that the amphibolite xenolith is the retrograde metamorphic rock of a previously, possibly eclogite rock, which the later was metamorphosed at least under ultra-high pressure metamorphic conditions. Mineral parageneses of the xenolith, as well as the use of the geobarothermometric methods have shown that the xenolith has been subjected to at least three metamorphic events. The first was attributed to a ultra-high pressure of at least 30-35kb, the second to a P-T conditions corresponding to 15kb and about 670 °C and the latest to 8.4 ± 1,2 kb and 380 ± 34 °C. The latest greenschist metamorphic event is the only metamorphic one imprinted in the Arnea granite. Taking account the latest dating of the Arnea granite crystallization age in Late Triassic (215 ± 1,8 Ma), we suggest that the examined xenolith was probably a part of a sedimentary crustal rock that metamorphosed to ultra-high pressure conditions associated with a deep subduction zone in the Late Paleozoic times. During Triassic it was retrograde metamorphosed to the amphibolitic metamorphic phase probably associated with a general uplifting of the area and finally it ascended as xenolith along with the Arnea granite to more shallow depths where they both subjected to the greenschist metamorphic event.

scholarly journals On the article “Weathered potassic volcanic rocks as protoliths of the hematitic phyllites of the southern Serra do Espinhaço (MinasGerais)”: a discussion

2021 ◽  
Vol 35 (1) ◽  
pp. 1-6
Author(s):  
Alexandre Cabral ◽  
Francisco de Abreu
Keyword(s):  
Trace Element ◽  
Continental Crust ◽  
Metamorphic Rock ◽  
Volcanic Rocks ◽  
Alkaline Basalt ◽  
Chemical Analyses ◽  
Three Samples ◽  
Trace Element Contents ◽  
Selection Of ◽  
Hematitic Phyllite

Chaves and Knauer (2020) have presented three new whole-rock chemical analyses of phyllitic hematite, a unique metamorphic rock of the southern Serra do Espinhaço. Based on their three samples and a selection of other three samples from the literature, Chaves and Knauer have proposed that the geochemical uniqueness of the rock – i.e., high contents of K2O, Al2O3 and Fe2O3, and depletion in SiO2 – would represent a weathered, feldspathoid-rich alkaline basalt. This contribution is a discussion of their new data, the trace-element contents of which are at odds with those of a potassic, mantle-derived volcanic protolith for the hematitic phyllite. Its Nb/Th ratios of ~3 and chondrite-normalised La/Yb ratios of ~9–17, for instance, are typical of the continental crust. We also point out aspects that escaped the attention of Chaves and Knauer (2020), one of which is the ubiquitous occurrence of tourmaline in the hematitic phyllite.

MÖSSBAUER AND CHEMICAL ANALYSES OF SOME SEDIMENTS FROM THE ROMANIAN SHORE OF THE BLACK SEA

1979 ◽  
Vol 40 (C2) ◽  
pp. C2-445-C2-448
Author(s):  
D. Barb ◽  
L. Diamandescu ◽  
M. Morariu ◽  
I. I. Georgescu
Keyword(s):  
Black Sea ◽  
The Black Sea ◽  
Chemical Analyses

TEMPERATURE VARIABILITY AT SENUNU BAY, WEST SUMBAWA

2013 ◽  
Vol 5 (2) ◽  
Author(s):  
Syamsul Hidayat ◽  
Mulia Purba ◽  
Jorina Waworuntu
Keyword(s):  
Layer Thickness ◽  
Mixed Layer ◽  
Cross Correlation ◽  
Sea Surface ◽  
Thermocline Depth ◽  
Kelvin Wave ◽  
The West ◽  
Sea Bottom ◽  
Annual Period ◽  
Regional Processes

The purposes of this study were to determine the variability of temperature and its relation to regional processes in the Senunu Bay. The result showed clear vertical stratifications i.e., mixed layer thickness about 39-119 m with isotherm of 27°C, thermocline layer thickness about 83-204 m with isotherm of 14–26°C, and  the deeper layer from the thermocline lower limit to the sea bottom with isotherm <13°C. Temperature and the thickness of each layers varied with season in which during the Northwest Monsoon the temperature was warmer and the mixed layer was thicker than those during Southeast Monsoon. During Southeast Monsoon, the thermocline layer rose  about 24 m. The 2001, 2006, and 2009 (weak La Nina years),  the Indonesia Throughflow (ITF) carried warmer water, deepening thermocline depth and reducing upwelling strength.  In 2003 and 2008 thickening of mixed layer occurred in transition season  was believed  associated with the  arrival of Kelvin Wave from the west. In 2002 and 2004 (weak El Nino period,) ITF carries colder water shallowing thermocline depth and enhancing upwelling strength. In 2007 was believed to be related with positive IODM where the sea surface temperature were decreasing due to intensification of southeast wind which induced strong upwelling. The temperature spectral density of mixed layer and thermocline was influenced by annual, semi-annual, intra-annual and inter-annual period fluctuations. The cross-correlation between wind and temperature showed significant value in the annual period.  Keywords: temperature, thermocline, variability, ENSO, IODM.

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