Zeta potential in intact natural sandstones at elevated temperatures

Supporting data are included in PDF and CSV files; any additional data may be obtained from the corresponding author (e-mail: j.vinogradov@imperial.ac.uk). TOTAL is thanked for partial support of Jackson's Chair in Geological Fluid Mechanics and for supporting the activities of the TOTAL Laboratory for Reservoir Physics at Imperial College London where these experiments were conducted. The Editor thanks Andre Revil and Paul Glover for their assistance in evaluating this paper.

Chemical composition of zeolites in sandstones at DSDP Sites 445 and 446

Andesitic volcaniclastic sandstones of Middle Eocene age recovered from DSDP Sites 445 and 446, a back-arc basin, contain clinoptilolite, heulandite and analcite as a pore-filling cement. Clinoptilolite and heulandite at Sites 445 and 446 contain different chemical composition from other deep-sea clinoptilolites and heulandites. The dominant cation of both clinoptilolite and heulandite is Na+ ion activity in pore water was greater at the time of their formation. Volcanic glass has acted as a precursor for both clinoptilolite and heulandite at Sites 445 and 446. Biogenic silica is also suggested as a precursor. High Na+ ion activity in pore water also helped to transform clinoptilolite and heulandite to analcite downhole. The necessary Na+ ions for this clinoptilolite, heulandite and analcite at Sites 445 and 446 might have been provided by hydrothermal circulation of seawater through more permeable sandstones deposited during early stages of back-arc basin rifting.

Grain counts and relative abundances of volcaniclastic sands and sandstones of ODP Leg 180 sites

Modal analysis of middle Miocene to Pleistocene volcaniclastic sands and sandstones recovered from Sites 1108, 1109, 1118, 1112, 1115, 1116, and 1114 within the Woodlark Basin during Leg 180 of the Ocean Drilling Program indicates a complex source history for sand-sized detritus deposited within the basin. Volcaniclastic detritus (i.e., feldspar, ferromagnesian minerals, and volcanic rock fragments) varies substantially throughout the Woodlark Basin. Miocene sandstones of the inferred Trobriand forearc succession contain mafic and subordinate silicic volcanic grains, probably derived from the contemporary Trobriand arc. During the late Miocene, the Trobriand outerarc/forearc (including Paleogene ophiolitic rocks) was subaerially exposed and eroded, yielding sandstones of dominantly mafic composition. Rift-related extension during the late Miocene-late Pliocene led to a transition from terrestrial to neritic and finally bathyal deposition. The sandstones deposited during this period are composed dominantly of silicic volcanic detritus, probably derived from the Amphlett Islands and surrounding areas where volcanic rocks of Pliocene-Pleistocene age occur. During this time terrigenous and metamorphic detritus derived from the Papua New Guinea mainland reached the single turbiditic Woodlark rift basin (or several subbasins) as fine-grained sediments. At Sites 1108, 1109, 1118, 1116, and 1114, serpentinite and metamorphic grains (schist and gneiss) appear as detritus in sandstones younger than ~3 Ma. This is thought to reflect a major pulse of rifting that resulted in the deepening of the Woodlark rift basin and the prevention of terrigenous and metamorphic detritus from reaching the northern rift margin (Site 1115). The Paleogene Papuan ophiolite belt and the Owen Stanley metamorphics were unroofed as the southern margin of the rift was exhumed (e.g., Moresby Seamount) and, in places, subaerially exposed (e.g., D'Entrecasteaux Islands and onshore Cape Vogel Basin), resulting in new and more proximal sources of metamorphic, igneous, and ophiolitic detritus. Continued emergence of the Moresby Seamount during the late Pliocene-early Pleistocene bounded by a major inclined fault scarp yielded talus deposits of similar composition to the above sandstones. Upper Pliocene-Pleistocene sandstones were deposited at bathyal depths by turbidity currents and as subordinate air-fall ash. Silicic glassy (high-K calc-alkaline) volcanic fragments, probably derived from volcanic centers located in Dawson and Moresby Straits, dominated these sandstones.

Sedimentary properties of salt wash sandstones as related to primary structures.

"Contract No. AT-30-1-1182."

Geology and recognition criteria for roll-type uranium deposits in continental sandstones : final report /

Mode of access: Internet.

Submarine slumps in delta-front sandstones of the Upper Cretaceous Blair Formation, Rock Springs uplift, Wyoming : syndepositional slumps on the western shores of the interior Cretaceous sea /

Mode of access: Internet.

Depositional environment of Upper Cretaceous black sandstones of the Western Interior /

Mode of access: Internet.

Effects of rock properties on specific cutting energy in linear cutting of sandstones by picks

Specific cutting energy (SE) has been widely used to assess the rock cuttability for mechanical excavation purposes. Some prediction models were developed for SE through correlating rock properties with SE values. However, some of the textural and compositional rock parameters i.e. texture coefficient and feldspar, mafic, and felsic mineral contents were not considered. The present study is to investigate the effects of previously ignored rock parameters along with engineering rock properties on SE. Mineralogical and petrographic analyses, rock mechanics, and linear rock cutting tests were performed on sandstone samples taken from sites around Ankara, Turkey. Relationships between SE and rock properties were evaluated using bivariate correlation and linear regression analyses. The tests and subsequent analyses revealed that the texture coefficient and feldspar content of sandstones affected rock cuttability, evidenced by significant correlations between these parameters and SE at a 90% confidence level. Felsic and mafic mineral contents of sandstones did not exhibit any statistically significant correlation against SE. Cementation coefficient, effective porosity, and pore volume had good correlations against SE. Poisson's ratio, Brazilian tensile strength, Shore scleroscope hardness, Schmidt hammer hardness, dry density, and point load strength index showed very strong linear correlations against SE at confidence levels of 95% and above, all of which were also found suitable to be used in predicting SE individually, depending on the results of regression analysis, ANOVA, Student's t-tests, and R2 values. Poisson's ratio exhibited the highest correlation with SE and seemed to be the most reliable SE prediction tool in sandstones.

Effects of rock properties on specific cutting energy in linear cutting of sandstones by picks

Specific cutting energy (SE) has been widely used to assess the rock cuttability for mechanical excavation purposes. Some prediction models were developed for SE through correlating rock properties with SE values. However, some of the textural and compositional rock parameters i.e. texture coefficient and feldspar, mafic, and felsic mineral contents were not considered. The present study is to investigate the effects of previously ignored rock parameters along with engineering rock properties on SE. Mineralogical and petrographic analyses, rock mechanics, and linear rock cutting tests were performed on sandstone samples taken from sites around Ankara, Turkey. Relationships between SE and rock properties were evaluated using bivariate correlation and linear regression analyses. The tests and subsequent analyses revealed that the texture coefficient and feldspar content of sandstones affected rock cuttability, evidenced by significant correlations between these parameters and SE at a 90% confidence level. Felsic and mafic mineral contents of sandstones did not exhibit any statistically significant correlation against SE. Cementation coefficient, effective porosity, and pore volume had good correlations against SE. Poisson's ratio, Brazilian tensile strength, Shore scleroscope hardness, Schmidt hammer hardness, dry density, and point load strength index showed very strong linear correlations against SE at confidence levels of 95% and above, all of which were also found suitable to be used in predicting SE individually, depending on the results of regression analysis, ANOVA, Student's t-tests, and R-2 values. Poisson's ratio exhibited the highest correlation with SE and seemed to be the most reliable SE prediction tool in sandstones.

Lithic grain and mineral composition of sand and sandstones from the North Pacific Ocean and the Bering Sea (Table 3)

Sand and sandstone compositions from different types of basins reflect provenance terranes governed by plate tectonics. One hundred and one thin sections of Upper Miocene to Holocene sand-sized material were examined from DSDP/IPOD Sites in the North Pacific Ocean and the Bering Sea. The Gazzi-Dickinson point-counting method was used to establish compositional characteristics of sands from different tectonic settings. Continental margin forearc sands from the western North America continental margin arc system are clearly different from backarc/marginal-sea sands from the Aleutian intraoceanic arc system. The forearc sands have average QFL percentages of 29-42-29, LmLvLst percentages of 32-34-34, 3 Fmwk%M and 0.82 P/F. Aleutian backarc sands have average QFL percentages of 8-22-69. LmLvLst percentages of 9-85-6, 0.5 Fmwk%M and 0.96 P/F. A trend of increasing QFL%Q and decreasing LmLvLst%Lv westward in the backarc region of the Aleutian Ridge reflects the influence of the Asiatic continental margin. Aleutian backarc sands without continental influence have average QFL percentages of 1-20-79, LmLvLst percentages of 1-98-1, 0 Fmwk%M and 0.99 P/F. Of the continental margin forearc samples, sands on the Astoria Fan (west of the Oregon-Washington trench) contain the highest LmLvLst%Lv and lowest P/F; sands from mixed transform-fault and trench settings (Delgada Fan and Gulf of Alaska samples) have slightly higher Qp/Q (0.03); and sands from the Pacific-Juan de Fuca-North America triple junction have the highest Fmwk%M. Delgada Fan and Gulf of Alaska sands have average QFL percentages of 27-38-35, LmLvLst percentages of 37-26-37, 2 Fmwk%M and 0.86 P/F. Astoria Fan sands have average QFL percentages of 35-41-24, LmLvLst percentages of 30-47-23, 3 Fmwk%M and 0.74 P/F. The triple-junction sands have average QFL percentages of 28-59-13, LmLvLst percentages of 25-26-49, 9 Fmwk%M and 0.87 P/F. The petrologic data from the modern ocean basins examined in this study can provide useful analogs for interpretation of ancient oceanic sequences. Our data suggest some refinements of, but generally substantiate, existing petrologic models relating sandstone composition to tectonic setting.

A petrographic investigation into the durability of common replacement sandstones to the crystallisation of de-icing salts

Scottish sandstone buildings are now suffering the long-term effects of salt-crystallisation damage, owing in part to the repeated deposition of de-icing salts during winter months. The use of de-icing salts is necessary in order to maintain safe road and pavement conditions during cold weather, but their use comes at a price. Sodium chloride (NaCl), which is used as the primary de-icing salt throughout the country, is a salt known to be damaging to sandstone masonry. However, there remains a range of alternative, commercially available de-icing salts. It is unknown however, what effect these salts have on porous building materials, such as sandstone. In order to protect our built heritage against salt-induced decay, it is vital to understand the effects of these different salts on the range of sandstone types that we see within the historic buildings of Scotland. Eleven common types of sandstone were characterised using a suite of methods in order to understand their mineralogy, pore structure and their response to moisture movement, which are vital properties that govern a stone’s response to weathering and decay. Sandstones were then placed through a range of durability tests designed to measure their resistance to various weathering processes. Three salt crystallisation tests were undertaken on the sandstones over a range of 16 to 50 cycles, which tested their durability to NaCl, CaCl2, MgCl2 and a chloride blend salt. Samples were primarily analysed by measuring their dry weight loss after each cycle, visually after each cycle and by other complimentary methods in order to understand their changing response to moisture uptake after salt treatment. Salt crystallisation was identified as the primary mechanism of decay across each salt, with the extent of damage in each sandstone influenced by environmental conditions and pore-grain properties of the stone. Damage recorded in salt crystallisation tests was ultimately caused by the generation of high crystallisation pressures within the confined pore networks of each stone. Stone and test-specific parameters controlled the location and magnitude of damage, with the amount of micro-pores, their spatial distribution, the water absorption coefficient and the drying efficiency of each stone being identified as the most important stone-specific properties influencing salt-induced decay. Strong correlations were found between the dry weight loss of NaCl treated samples and the proportion of pores <1µm in diameter. Crystallisation pressures are known to scale inversely with pore size, while the spatial distribution of these micro-pores is thought to influence the rate, overall extent and type of decay within the stone by concentrating crystallisation pressures in specific regions of the stone. The water absorption determines the total amount of moisture entering into the stone, which represents the total amount of void space for salt crystallisation. The drying parameters on the other hand, ultimately control the distribution of salt crystallisation. Those stones that were characterised by a combination of a high proportion of micro-pores, high water absorption values and slow drying kinetics were shown to be most vulnerable to NaCl-induced decay. CaCl2 and MgCl2 are shown to have similar crystallisation behaviour, forming thin crystalline sheets under low relative humidity and/or high temperature conditions. Distinct differences in their behaviour that are influenced by test specific criteria were identified. The location of MgCl2 crystallisation close to the stone surface, as influenced by prolonged drying under moderate temperature drying conditions, was identified as the main factor that caused substantial dry weight loss in specific stone types. CaCl2 solutions remained unaffected under these conditions and only crystallised under high temperatures. Homogeneous crystallisation of CaCl2 throughout the stone produced greater internal change, with little dry weight loss recorded. NaCl formed distinctive isometric hopper crystals that caused damage through the non-equilibrium growth of salts in trapped regions of the stone. Damage was sustained as granular decay and contour scaling across most stone types. The pore network and hydric properties of the stones continually evolve in response to salt crystallisation, creating a dynamic system whereby the initial, known properties of clean quarried stone will not continually govern the processes of salt crystallisation, nor indeed can they continually predict the behaviour of stone to salt-induced decay.