scholarly journals Animal-sediment interactions: the effect of ingestion and excretion by worms on mineralogy

2004 ◽  
Vol 1 (2) ◽  
pp. 113-121 ◽  
Author(s):  
S. J. Needham ◽  
R. H. Worden ◽  
D. McIlroy

Abstract. By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.

2004 ◽  
Vol 1 (1) ◽  
pp. 533-559 ◽  
Author(s):  
S. J. Needham ◽  
R. H. Worden ◽  
D. McIlroy

Abstract. By controlled experiments that simulate marine depositional environments, it is shown that accelerated weathering and clay mineral authigenesis occur during the combined process of ingestion, digestion and excretion of fine-grained sediment by two species of annelid worms. Previously characterized synthetic mud was created using finely ground, low-grade metamorphic slate (temperature approximately 300°C) containing highly crystalline chlorite and muscovite. This was added to experiment and control tanks along with clean, wind-blown sand. Faecal casts were collected at regular intervals from the experimental tanks and, less frequently, from the control tanks. Over a period of many months the synthetic mud (slate) proved to be unchanged in the control tanks, but was significantly different in faecal casts from the experimental tanks that contained the worms Arenicola marina and Lumbricus terrestris. Chlorite was preferentially destroyed during digestion in the gut of A. marina. Both chlorite and muscovite underwent XRD peak broadening with a skew developing towards higher lattice spacing, characteristic of smectite formation. A neoformed Fe-Mg-rich clay mineral (possibly berthierine) and as-yet undefined clay minerals with very high d-spacing were detected in both A. marina and L. terrestris cast samples. We postulate that a combination of the low pH and bacteria-rich microenvironment in the guts of annelid worms may radically accelerate mineral dissolution and clay mineral precipitation processes during digestion. These results show that macrobiotic activity significantly accelerates weathering and mineral degradation as well as mineral authigenesis. The combined processes of sediment ingestion and digestion thus lead to early diagenetic growth of clay minerals in clastic sediments.


Clay Minerals ◽  
2002 ◽  
Vol 37 (3) ◽  
pp. 413-428 ◽  
Author(s):  
E. Hrischeva ◽  
S. Gier

AbstractClay minerals in early Jurassic sequences of shales, siltstones and sandstones deposited in non-marine, transitional and shallow marine environments have been examined by X-ray diffraction, electron microscopy and chemical analysis to study the relationship between clay minerals, their environment of deposition and subsequent diagenetic modifications.The inherited clay mineral composition of the fine-grained sediments reflects the influence of climate, relief, source rocks and depositional processes. Inhomogeneous clay mineral assemblages, comprising abundant kaolinite and varying proportions of illite, I-S, chlorite and vermiculite, characterize fine-grained sediments from the non-marine and transitional environments. In shallow marine depositional environments clay mineral assemblages are more uniform, dominated by illite+I-S with minor kaolinite and chlorite.The principal diagenetic process affecting fine-grained sedimentary rocks is the smectite–illite transformation. In sandstones, the authigenic formation of kaolinite, chlorite and illite appears to have been primarily determined by the environment of deposition.


Clay Minerals ◽  
1993 ◽  
Vol 28 (1) ◽  
pp. 61-84 ◽  
Author(s):  
M. Thiry ◽  
T. Jacquin

AbstractThe distribution of clay minerals from the N and S Atlantic Cretaceous deep-sea sediments is related to rifting, sea-floor spreading, sea-level variations and paleoceanography. Four main clay mineral suites were identified: two are inherited and indicative of ocean geodynamics, whereas the others result from transformation and authigenesis and are diagnostic of Cretaceous oceanic depositional environments. Illite and chlorite, together with interstratified illite-smectite and smectite occur above the sea-floor basalts and illustrate the contribution of volcanoclastic materials of basaltic origin to the sediments. Kaolinite, with variable amounts of illite, chlorite, smectite and interstratified minerals, indicates detrital inputs from continents near the platform margins. Kaolinite decreases upward in the series due to open marine environments and basin deepening. It may increase in volume during specific time intervals corresponding to periods of falling sea-level during which overall facies regression and erosion of the surrounding platforms occurred. Smectite is the most abundant clay mineral in the Cretaceous deep-sea sediments. Smectite-rich deposits correlate with periods of relatively low sedimentation rates. As paleoweathering profiles and basal deposits at the bottom of Cretaceous transgressive formations are mostly kaolinitic, smectite cannot have been inherited from the continents. Smectite is therefore believed to have formed in the ocean by transformation and recrystallization of detrital materials during early diagenesis. Because of the slow rate of silicate reactions, transformation of clay minerals requires a long residence time of the particles at the water/sediment interface; this explains the relationships between the observed increases in smectite with long-term sea-level rises that tend to starve the basinal settings of sedimentation. Palygorskite, along with dolomite, is relatively common in the N and S Atlantic Cretaceous sediments. It is not detrital because correlative shelf deposits are devoid of palygorskite. Palygorskite is diagnostic of Mg-rich environments and is indicative of the warm and hypersaline bottom waters of the Cretaceous Atlantic ocean.


1987 ◽  
Vol 124 (3) ◽  
pp. 261-271 ◽  
Author(s):  
Julian E. Andrews

AbstractClay minerals from Middle Jurassic lagoonal mudrocks, siltstones and silty fine-grained sandstones of the upper Great Estuarine Group (Bathonian) are divided into four assemblages. Assemblage 1, the most common assemblage, is rich in mixed-layer illite–smectite with attendant illite and kaolinite. Assemblage 2 is dominated by smectitic clay. These assemblages are indicative of primary Jurassic deposition. Illite and kaolinite were probably derived from the weathering of older rocks and soils in the basin hinterland and were deposited in the lagoons as river-borne detritus. The majority of smectite and mixed-layer illite–smectite is interpreted as the argillization product of Jurassic volcanic dust, also deposited in the lagoons by rivers. Near major Tertiary igneous intrusions these depositional clay mineral assemblages have been altered. Assemblage 3 contains smectite-poor mixed-layer illite–smectite, whilst Assemblage 4 contains no smectitic clay at all. Destruction of smectite interlayers occurred at relatively shallow burial depths (< 2500 m) due to enhanced geothermal gradients and local convective hot-water circulation cells associated with the major Tertiary igneous intrusions.


Clay Minerals ◽  
2006 ◽  
Vol 41 (1) ◽  
pp. 473-512 ◽  
Author(s):  
R. J. Merriman

AbstractLower Palaeozoic rocks crop out extensively in Wales, the Lake District of northern England and the Southern Uplands of Scotland; they also form the subcrop concealed beneath the English Midlands and East Anglia. These mainly marine sedimentary rocks were deposited in basins created during plate tectonic assembly of the various terranes that amalgamated to form the British Isles, 400-600 Ma ago. Final amalgamation occurred during the late Lower Devonian Acadian Orogeny when the basins were uplifted and deformed, producing belts of cleaved, low-grade metasediments, so-called slate belts, with a predominantly Caledonian (NE-SW) trend. The clay mineralogy of mudrock lithologies - including mudstone, shale and slate - found in these belts is reviewed. Using X-ray diffraction data from the <2 μm fractions of ~4500 mudrocks samples, clay mineral assemblages are summarized and discussed in terms of diagenetic and low-grade metamorphic reactions, and the metapelitic grade indicated by the Kübler index of illite crystallinity.Two sequences of clay mineral assemblages, or regional assemblages, are recognized. Regional Assemblage A is characterized by a greater diversity of clay minerals in assemblages from all metapelitic grades. It includes K-rich, intermediate Na/K and Na-rich white micas, chlorite and minor amounts of pyrophyllite. Corrensite, rectorite and pyrophyllite are found in the clay assemblages of contact or hydrothermally altered mudstones. K-white micas are aluminous and phengite-poor, with b cell dimensions in the range 8.98-9.02 Å. Regional Assemblage B has fewer clay minerals in assemblages from a range of metapelitic grades. Phengite-rich K-mica is characteristic whereas Na- micas are rare, and absent in most assemblages; chlorite is present and minor corrensite occurs in mudrocks with mafic-rich detritus. Minor amounts of kaolinite are sporadically present, but dickite and nacrite are rare; pyrophyllite and rectorite are generally absent. The b cell dimensions of K-white mica in Regional Assemblage B are in the range 9.02-9.06 Å. The two regional assemblages are found in contrasting geotectonic settings. Regional Assemblage A is characteristic of the extensional basin settings of Wales, the northern Lake District and the Isle of Man. These basins have a history of early burial metamorphism associated with extension, and syn-burial or post-burial intrusive and extrusive volcanic activity. Intermediate Na/K mica probably developed from hydrothermal fluids generated around submarine volcanic centres. Deep diagenetic and low anchizonal clay mineral in these basins may develop a bedding-parallel microfabric. Chlorite-mica stacks also occur in the extensional basins and the stacking planes represent another type of bedding-parallel microfabric. Both types of microfabric are non-tectonic and developed by burial during the extensional phase of basin evolution. Regional Assemblage B is developed in the plate-convergent settings of the Southern Uplands and the southern Lake District. In the accretionary complex of the Southern Uplands the processes of burial diagenesis, metamorphism and tectonism were synchronous events. In both plate- convergent basins, low temperatures and tectonic fabric-formation had an important role in clay mineral reactions, whereas hydrothermal fluids played no part in clay genesis.


1992 ◽  
Vol 29 (3) ◽  
pp. 432-445 ◽  
Author(s):  
S. J. Sutton ◽  
J. B. Maynard

Confusion exists over the usefulness of chemical data from Precambrian weathering profiles in constraining models of atmospheric evolution. One difficulty is in correctly identifying ancient weathering effects and isolating them from numerous other processes that are likely to have affected such ancient rocks. In this study of a middle Precambrian granitic weathering profile, we have used several analytical techniques to separate weathering-related chemical and mineralogical changes from those resulting from other processes. The profile is exposed beneath the Huronian at Lauzon Bay in the Blind River area of Ontario and has a complex history of alteration events, addition of allochthonous material, and low-grade metamorphism. Much of this history can be deciphered, and changes in mineralogy and bulk and mineral chemistry can be assigned to separate alteration events. Specifically, the granite has undergone preweathering albitization, resulting in Na enrichment, followed by chemical weathering that corroded K-feldspar and nearly destroyed plagioclase feldspar and mica in the regolith. Clay minerals replaced feldspars, resulting in enrichment in Al, Ti, and Zr and depletion in Na, Ca, Sr, and K. Fe has also been leached. After weathering, a fine-grained 0.5 m layer of strongly weathered allochthonous material was deposited on the regolith, followed by deposition of the Matinenda Formation. Sometime after Matinenda deposition, K- and Rb-metasomatim affected the regolith and overlying sediments, converting some clays to illite and depositing secondary K-feldspar. Greenschist-facies metamorphism probably postdated this metasomatism and converted clay minerals to white mica and chlorite.


Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 353 ◽  
Author(s):  
Lingkang Chen ◽  
Xiongwei Jin ◽  
Haixia Chen ◽  
Zhengwei He ◽  
Lanrong Qiu ◽  
...  

Although clay mineral content in ion-absorbed rare earth ores is crucial for migrating and releasing rare earth elements, the formation, distribution, and migration of clay minerals in supergene rare earth ores have not been fully understood. Therefore, this study analyzes the characteristics of clay mineral type and content, soil particle size, pH value, leaching solution concentration, and leaching rate. This analysis was performed using different methods, such as regional rare earth mine soil surveys, in situ leaching profile monitoring, and indoor simulated leaching. The results showed that the grain size and volume curve of rare earth ore have unimodal and bimodal shapes, respectively. X-ray diffraction showed the differences in clay mineral types formed by different weathered bedrocks. The principal clay minerals were kaolinite, illite, chlorite, and vermiculite, with their relative abundance varying with parent rock lithology (granite and low-grade metamorphic rocks). In the Ganxian granite weathering profile, the kaolinite content increased from top to bottom. The decomposition of feldspar minerals to kaolinite was enhanced with an increase in the SiO2 content during weathering. The in situ leaching profile analysis showed that the kaolinite content increased initially and then decreased, whereas the illite/mica content exhibited the opposite trend. Under stable leaching solution concentration and leaching rate, clay mineral formation is favored by lower pH. Low pH, low leaching rate, and highly-concentrated leaching solution (12 wt%) resulted in a slow increase in kaolinite content in the upper part of the profile (30 cm). A lower concentration of the leaching solution (4 wt%) resulted in rapid enrichment of kaolinite after 15 days. Low pH, leaching solution concentration, and leaching rate promoted the formation of distinct kaolinite horizons. We suggest that by disregarding other control factors, rare earth recovery of over 90% can be achieved through leach mining with solutions of 8 wt% and a pH of 5 at a leaching rate of 5 mL/min.


Clay Minerals ◽  
2018 ◽  
Vol 53 (4) ◽  
pp. 579-602 ◽  
Author(s):  
Tatiana Maison ◽  
Sébastien Potel ◽  
Pierre Malié ◽  
Rafael Ferreiro Mählmann ◽  
Frank Chanier ◽  
...  

ABSTRACTClay minerals and organic matter occur frequently in fault zones. Their structural characteristics and their textural evolution are driven by several formation processes: (1) reaction by metasomatism from circulating fluids; (2)in situevolution by diagenesis; and (3) neoformation due to deformation catalysis. Clay-mineral chemistry and precipitated solid organic matter may be used as indicators of fluid circulation in fault zones and to determine the maximum temperatures in these zones. In the present study, clay-mineral and organic-matter analyses of two major fault zones – the Adams-Tinui and Whakataki faults, Wairarapa, North Island, New Zealand – were investigated. The two faults analysed correspond to the soles of large imbricated thrust sheets formed during the onset of subduction beneath the North Island of New Zealand. The mineralogy of both fault zones is composed mainly of quartz, feldspars, calcite, chabazite and clay minerals such as illite-muscovite, kaolinite, chlorite and mixed-layer minerals such as chlorite-smectite and illite-smectite. The diagenesis and very-low-grade metamorphism of the sedimentary rock is determined by gradual changes of clay mineral ‘crystallinity’ (illite, chlorite, kaolinite), the use of a chlorite geothermometer and the reflectance of organic matter. It is concluded here that: (1) the established thermal grade is diagenesis; (2) tectonic strains affect the clay mineral ‘crystallinity’ in the fault zone; (3) there is a strong correlation between temperature determined by chlorite geothermometry and organic-matter reflectance; and (4) the duration and depth of burial as well as the pore-fluid chemistry are important factors affecting clay-mineral formation.


2019 ◽  
Vol 10 (1) ◽  
pp. 140
Author(s):  
Suratta BUNSOMBOONSAKUL ◽  
Penjai SOMPONGCHAIYAKUL ◽  
Zhifei LIU ◽  
Akkaneewut CHABANGBORN ◽  
Anond SNIDVONGS

This study presents high-resolution clay mineralogy of Core MASS-III-10, located in the southeastern Andaman Sea. The study aimed to investigate terrigenous sedimentary input from various potential provenances throughout different periods of geological time. The clay mineral assemblages of MASS-III-10 reveal a high amount of smectite at 73% (65-79%), a moderate kaolinite at 12% (10-17%), and a low illite and chlorite content(<15%) over the last 45 ka. Provenance analysis suggests the most fine-grained terrigenous sediments originated from the Irrawaddy Delta Shelf (IDS), with minor sediments deriving from the Andaman Islands, the East Continental Shelf (ECS), and Sumatra provenance. The results show that IDS were predominantly smectite (~44%) while the ECS largely produced kaolinite (47%). The provenance interpretation based on the smectite content revealed that over time there has been no change in the main source of sediment in the Andaman Sea, despite changes in the volume of sedimentary input. Since the last glaciation, the Myanmar provenance (including IDS) has always contributed clay minerals, while other sources made up only minor contributions to the Andaman Sea. The clay minerals from the Myanmar provenance increased when the sea level was at a low stand (MIS 2), potentially due to shoreline retreat which enabled easier transportation of sediment from other sources. During the interglacial period (MIS 1 and 3), the study found a decrease in Myanmar-sourced clay minerals, which may be because the higher sea level made clay mineral deposition more difficult.


2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Mohamed Mahmoud

The sandstone rocks' integrity and consolidation may be highly affected by the type and the strength of the stimulation fluids. Strong acids such as HF/HCl impair the rock consolidation. The reduction in the sandstone rock consolidation will trigger the sand production. Sand causes erosion of downhole and surface equipment especially when it is produced with high gas flow rates. In this study, gentle stimulation fluids for sandstone that consists of chelating agents and catalyst were proposed. The chelating agents are diethylene triamine penta acetic acid (DTPA) and ethylene diamine tetra acetic acid (EDTA). This is the first time to introduce a catalyst (potassium carbonate) in sandstone acidizing. Potassium carbonate was found to work as a clay stabilizer and catalyst that enhances the dissolution of chlorite clay mineral in the sandstone rock. The objective of introducing the catalyst is to enhance the solubility of the insoluble minerals such as chlorite clay minerals. The change in the mechanical properties of sandstone rocks (Bandera and Berea) was evaluated. The possibility of the formation damage after using seawater-based chelating agents was investigated and compared to HF/HCl mud acid. Coreflooding experiments were conducted to evaluate the effect of these fluids on the rock integrity. Computed tomography (CT) scanner was used to assess the formation damage. Different models were used to predict the sand production possibility after the stimulation with chelating agent/catalyst, and this was compared to the HF/HCl mud acid. The results showed that the permeability of sandstone core increased after acidizing. The reduction in CT-number after acidizing confirmed that no formation damage occurred. Rock mechanics evaluation showed no major changes occurred in the rock moduli and no sand production was observed. The model results showed that using chelating gents to stimulate Berea (BR) and Bandera (BN) sandstone cores did not cause sand production. Applying the same models for cores stimulated by HF/HCl acids indicated high possibility of sand production. The addition of potassium carbonate to DTPA chelating agents enhanced the chlorite clay mineral dissolution based on the inductively coupled plasma (ICP) analysis. Potassium carbonate as a catalyst did not affect the sandstone integrity because it only enhanced the dissolution of chlorite clay minerals (selective dissolution) and did not affect the solubility of carbonate minerals which are the primary cementing materials in the sandstone cores. A new dimensionless number was developed that describes the relation between the number of pore volumes (PVs) contacted the rock and the radial distance from the wellbore.


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