Harding Sandstone

It is evident from test results listed in Table 3 that for hard sandstone the higher the strain rate,... 

Sansom et al. (1996) described some thelodont scales from the Harding Sandstone, which they identified as loganiid scales. Subsequent work has identified a morpho... 

In the absence of articulated specimens, it is problematic to prove the presence of jawed vertebrates in the Ordovician based upon scale morphology and histology alone. However, a number of scales recovered from the Harding Sandstone bear a remarkable resemblance to those from accepted stem and crown gnathostomes with jaws. They can be divided into two types Skiichthys halsteadi with scales bearing a... 

Incertae sedis from the Harding Sandstone (Caradoe)... 

Figure 10.4 A-B. New Genus C in dorsal (a) and antero-lateral (b) views (c) New Genus A in antero-dorsal view (d) New Genus E in antero-dorsal view (e-f) New Genus B in dorsal (e) and lateral (f) views (g) New Genus D in dorsal view (h) New Genus F in dorsal view (i) Isolated spine in lateral view. All specimens from the Harding Sandstone of Colorado.

Flower, R.H. (1952) Cephalopods from the Harding Sandstone and Manitou Formation of Colorado ,/oMfWij/ of Paleontology, 26, 506-18. 

Smith, M.M. and Sansom, I.J. (1997) Exoskeletal micro-remains of an Ordovician fish from the Harding Sandstone of Colorado , Palaeontology, 40, 645-58. 

The rate at which the drill bit penetrates the formation gives qualitative information about the lithology being drilled. For example, in a hard shale the rate of penetration ROP) will be slower than in a porous sandstone. 

Acrylamide—polymer/Ct(III)catboxylate gel technology has been developed and field tested in Wyoming s Big Horn Basin (211,212). These gels economically enhance oil recovery from wells that suffer fracture conformance problems. The Cr(III) gel technology was successful in both sandstone and carbonate formations, and was insensitive to H2S, high saline, and hard waters (212). 

Vitreous, hard, chemically-resistant free silica, the most common form in nature. The main constituent in sandstone, igneous rocks, and common sands. 

Sedimentary rock hard shales, siltstones, sandstones, requiring ... 

Most natural waters contain more hardness than bicarbonate. Only a few sources in the UK, usually from wells in sandstone strata, contain more alkalinity than hardness. In most cases the temporary hardness greatly exceeds the permanent hardness. This is especially tme of the hard alkaline waters, which come from chalk and limestone measures. 

Hard underground waters, mainly in the East and South of England, mostly from chalk, sandstone or limestone strata. 

Fig. 2.6.9 Visualization of gas flow through a cylindrical surface represents the rock, (b) Only porous sandstone rock. A 3D phase encoding a slice through the center of the rock is sequence with a hard encoding pulse was used, displayed, showing the origin of the gas that is (a) 3D representation of an isochronal surface flowing through the detector at different times at different times after the encoding step. The after the tagging [figure taken from 43].

The total Mn concentration in Israeli soils varies from 52.6-810 mg/kg and averages 367 259.8 mg/kg (Han, 1998). The average total Co content is 9.45 4.88 mg/ kg, varying from 3.35 mg/kg in a very sandy soil to 15.9 mg/kg in alluvial soil samples (Han et al., 2002b). In soils on alluvions and derived from aeolian deposits, the Co concentration is 8 mg/kg, and soils from hard limestone contain 10 mg/kg Co. The B concentration in alluvial soils is in the range of 25-85 mg/kg, while brown isohumic soils formed on alluvions contain 25-40 mg/kg B. Mediterranean red soils on limestone are rich in B (190 mg/kg). In soils on calcareous sandstone, alluvions, and aeolian deposits, total Mo content ranges from 4.6-6 mg/kg (Aubert and Pinta, 1977). 

Quartzite. Quartzite is a very compact, exceptionally hard and tough meta-morphic rock derived from sandstone. It consists mainly of rather large crystals of quartz (composed of silicon dioxide) naturally cemented by secondary quartz. Most varieties of quartzite contain over 90% quartz, and in some cases the quartz content exceeds 95% of the total weight of the stone. The color of most quartzite is white or light yellow, but if it contains iron oxide impurities it is red, while other metal oxide impurities may cause the rock to display patchy color variations. Quartzite is very hard, which makes it difficult to quarry. Nevertheless, because of its strength and resistance to weathering, it has occasionally been used for construchon, sculphng statuary, and ornamentation. 

QUARTZITE. A hard, tough, and compact metamorphic rock composed almost wholly of quartz sand grains that have been reciystallized to form a particularly massive siliceous rock. The term is also used for non-metamorphosed quartzose sandstones and grits whose clastic grains have been firmly cemented by silica lhat has grown in optical continuity around each grain. 

The lower Miocene clay rocks with sandstone blocks in thickness are considered as collectors, and as a gas-proof lid - the Upper and Middle Miocene hard clay rocks. As for the collectoral rocks, they are located at 1000-1400 meter depth. 

A continuum of subterranean environments exists, ranging from very hard rocks such as granites and basalts, through sedimentary rocks and sandstones, to as yet unconsolidated, fairly soft sediments. Two main subterranean rock environments can be defined hard rocks - those too hard and impermeable to allow microbes to pass, except via fractures, and... 

---