LK1 Sedimentation > LK1 Sedimentation



The World's Deepest Well [Kola]
The earth history penetrated by the Kola well must, of course, be read from the bottom up. In the Archean complex, between 12,000 and 6,842 meters, the first stage saw the accumulation of thick sedimentary strata from the weathering of the primal granites, the weathering being punctuated by intrusive flows of plutonic granite. That these granites were rich in iron and titanium is evidenced in the contcentration of magnetite and ilmenite ores, which reaches 40 to 50 percent of the rock at 8,711 meters. In the second stage the rocks underwent folding, metamorphism and ultrametamorphism at temperatures of 750 to 900 degrees C. and pressures of 5,000 to 11,000 atmospheres.
- Geologists are able to reconstruct history in this way because rocks are highly sensitive recorders of temperature and pressure. From the same starting material supplied by the mantle metamorphic rocks develop a variety of distinguishing characteristics, "facies" which may include variation in elemental composition, depending on the pressure and temperature at their formation. In general, matamorphism results in the production of denser rock with less bound water from more hydrous rock. Elements not incorporated in the new crystal phases go into solution with the newly freed water.
- Radiocarbon dating places the culmination of the Archean metamorphism in the Kola Peninsula at 2.7 to 2.8 billion years ago. It was followed by deep eerosion by water and accumulation of sediments of the weathering crust in isolated depressions. In some regions of the world, notably South Africa, immense deposits of metal-bearing conglomerates are associated with such sedimentary deposits.
- The Proterozoic complex, from 6,842 meters to the surface, began to build up on the Archean basement 1.1 billion years ago. The rock records four major phases in the buildup of the continental crust during this period. During the first phase, sedimentary volcanic material was deposited on the Archean floor. The gravelly strata show abrupt changes in thickness, indicating they were deposited by streams in ancient valleys. The first of two cycles of plutonism brought intrusion of granitic rock, devoid of metallic elements, that overlaid the previously formed rocks and brought them under alteration through low-temperature metamorphism. In the second cycle the mantle contributed rock rich in metallic elements. These ore-bearing intrusions laid down the copper-nickel sulfide deposits that outcrop in the Pechenga region. The Kola well found such deposits at intervals down to a depth of 1,500 to 1,800 meters. The fourth phase of the Proterozoic era brought on the anamolous episode of "closed" metamorphism that resulted in the hydraulic disagrregation of the metamorphic rock first observed in the Kola well through the zone 4,500 meters thick that crosses into the Archean basement.
- Core samples show the content of chemically bound water remaining constant, at 4 percent of the rock, to 4,500 meters from the surface. There, quite abruptly, the water content of the rock decreases to 2.1 percent. It is there that the zone of disaggregation begins, with microfracturing of the rock increasing its porosity by three or four times over that observed in the rock above and correspondingly reducing the density of the rock mass from 3.1 grams per cubic centimeter to 2.9. The freed water trapped in the interstices of the fractured rock, calculations show, forced the initial total volume of rock and water to increase by 1.7 percent. The enormous hydraulic pressure thus exerted caused the microfracturing that must initially have increased the porosity of the rock to 10 times that of the overlying strata.
- The lower boundary of this zone, at ?,000 meters, is marked by an increase in the velocity of the seismic waves. This proved, of course, not to be the presumed Conrad discontinuity from granitic to basaltic rock. The increase in elastic-wave velocity simply marks the bottom of the zone of disaggregation with the return fo rock of normal density and the cessation of the inflow of thermal water into the well.
ROCK PRESSURE, derived from measurements of accoustic-wave velocity through the rock near the hole, frequently deviates from teh linear increase with depth (dotted line) expected in homogeneous material. The zone of anomalously high pressure at a depth of 3,200 meters reflects the high density of impervious strata at that depth. The disproportionately low pressures from about 4,000 to 9,000 meters mark a zone of fractured rock.
800m, 218/218kg/cm2 *** 100%
1,600m, 270/436 *** 62%
2,400m, 600/654 *** 92%
3,200m, 2,000/873 *** 229%
4,000m, 320/1090 *** 29%
4,800m, 920/1309 *** 70%
5,600m, 1100/1527 *** 72%
6,400m, 1500/1745 *** 86%
7,200m, 1500/1964 *** 76%
8,000m, 810/2182 *** 37%
8,800m, 2400/2400 *** 100%

... The hole reached 12,262 m (40,230 ft) in 1989. In that year, the hole depth was expected to reach 13,500 m (44,300 ft) by the end of 1990 and 15,000 m (49,000 ft) by 1993.[6][7] However, because of higher-than-expected temperatures at this depth and location, 180 °C (356 °F) instead of expected 100 °C (212 °F), drilling deeper was deemed infeasible and the drilling was stopped in 1992.[5] With the projected further increase in temperature with increasing depth, drilling to 15,000 m (49,000 ft) would have meant working at a temperature of 300 °C (570 °F), where the drill bit would no longer work.
... To scientists, one of the more fascinating findings to emerge from this well is that no transition from granite to basalt was found at the depth of about 7 km (4.3 mi), where the velocity of seismic waves has a discontinuity. Instead the change in the seismic wave velocity is caused by a metamorphic transition in the granite rock. In addition, the rock at that depth had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock. Another unexpected discovery was a large quantity of hydrogen gas; the mud that flowed out of the hole was described as "boiling" with hydrogen.

Gordon & Brigit, The following seems to show that the 12 km deep Kola borehole project found mostly igneous rock nearly all the way down. There are some thin layers of sedimentary rock down to 6 km and a very thin layer at 7 km. There may be some melted metamorphic rock that was formerly sedimentary down to 7 km. Then it's just metamorphic rock that was formerly igneous, i.e. granite below 7 km (or below 4.4 miles). Gordon, do you have comments on this?
Data on the Kola Superdeep Borehole
0-1k) Augite Diabases with Pyroxene & Porphyrites
----- ([Igneous] Diabase = subvolcanic rock equivalent to volcanic basalt or plutonic gabbro)
0>1k, 2>4k) Basic Tuffs & Tuffites
----- ([Igneous] predominantly pyroclasts = volcanic ash)
0>2k) Phyllites, Silkstones with Tuff layers
----- ([Metamorphic/Sedimentary] from shale, silt etc)
0>3k) Gabbro-Diabases
----- ([Igneous] See Diabase above)
0>3k) Laminated Sandstones
----- ([Sedimentary] from sand)
0>3-5k) Achnolitic Diabases
----- ([Igneous] See Diabase above)
0>5+6k) Dolomites, polynistic Sandstones
----- ([Sedimentary] from lime & sand)
4>5k) Sericitic Schists
----- ([Metamorphic] possibly from melted/hardened sand or shale)
3>5-6k) Metadiabases
----- ([Metamorphic] diabase from [Igneous]: see Diabase above)
5>6-7k) Diabase Porphyrites & Schists
----- ([Igneous] See Diabase above; & [Metamorphic] see Schists above)
6>7k) Conglomerates
----- ([Sedimentary] from cemented rounded rocks, larger than sand grains)
6>7-12k) Muscovite-biotite-plagioclase gniesses with high alumina content minerals
-AND Epidote-biotite-plagioclase gniesses with amphibolites, amphibolite schists & ultramafites
----- ([Metamorphic] from Igneous granite or Sedimentary rock)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ Postby webolife» Tue Jan 12, 2016 3:51 am
The bore hole sampling confirms my assertion that the strata below Cambrian are primordial, ie. original crust modified when the first continent raised up above the global sea in Day 2, an event which would have been accompanied by erosion and initial depositional sequences, along with igneous upheaval and intrusive/granitic formation, and "country" rock metamorphism due to pressure and heat. Since life first appeared on the surface of this continent, it is expected that there would be limited fossils found in the "surface" layers of the "Pre-Cambrian".

It can be envisaged that continuous planetary degassing and related reorganization of the Earth’s interior mass has modified both the internal and the outer regions of the Earth progressively since early Archaean time – transforming an initially thick proto-crust as well as progressively, and episodically, increasing the volume of surface water (cf. Storetvedt, 2003 and 2011). The gradual accumulation of fluids and gases in the upper mantle and lower crust must have led to a considerable increase in the confining pressure at these levels. At each depth level, rocks and fluids would naturally be subject to a common pressure – producing a kind of high pressure vessel situation – with fractures being kept open just like those in near-surface rocks at low pressures (Gold’s pore theory, see Hoyle, 1955; Gold, 1999). This principle is well demonstrated in the Kola and KTB (S. Germany) deep continental boreholes (which reached maximum depths of 12 and 9 km, respectively) where open fractures filled with hydrous fluids were found throughout the entire sections drilled (e.g., Möller et al., 1997; Smithson et al., 2000); brines were seen to coexist with crustal rocks and, in the KTB site, the salinity of the formation water turned out to be about twice that of present-day normal sea water (Möller et al., 2005). In both drill sites, a variety of dissolved gases and fluids was found; primitive helium was observed at different depth levels indicating that the fluids were of deep interior origin (Smithson et al., 2000). As there is no observational evidence that deep oceanic depressions existed prior to the middle-late Mesozoic (see below), the bulk of present-day surface water must, in fact, have been exhaled from the deep interior during later stages of the Earth’s history. Nevertheless, there are reasons for believing that most of the planet’s water is still residing in the deep interior.

The superdeep Kola drill hole (to a depth of some 12 km) gave the surprising results that fracture spacing increases exponentially versus depth in the upper crust, and similar unexpected observations have been obtained in the 9 km deep crustal drilling site in SE Germany (KTB). A most unexpected discovery of the two continental sections was that the characteristic system of open fractures was filled with hydrous fluids which, under pressure and temperature conditions predicted for the middle and lower crust, would be in its strongly buoyant supercritical state (cf. Storetvedt, 2013 for references and discussion); hence, the strong buoyancy of supercritical hydrous fluids is likely to be the main cause of the increasing fracture volume versus depth in the continental crust. In fact, it appears that the crust does not represent a solid carapace but constitutes rather a highly fractured and increasingly fluid/gas-filled cover layer. Thus, even for the upper crust, the shear strength is likely to be much lower than what traditionally has been assumed. Accordingly, conventional estimates of tectonic twisting forces are clearly outdated; such guesses have little, if any, significance.
Unexpected discoveries from the world’s deepest well
- Hot mineralized water was found almost everywhere along the drill path.
- Helium, hydrogen, nitrogen, and even carbon dioxide (from microbes) were found all along the borehole.
- There is no basalt under the continent’s granite. This was a huge surprise. Seismic suggested that at 9,000 metres the granite would give way to basalt. It doesn’t. The seismic anomaly that suggested basalt was caused by metamorphosed granite instead.
- There are fossils in granite 6,700 metres below the surface.
The most intriguing discovery made by the Kola Superdeep Borehole researchers was the detection of microscopic plankton fossils four miles beneath the surface of the earth. Usually fossils can be found in limestone and silica deposits, but these "microfossils" were encased in organic compounds that remained surprisingly intact despite the extreme pressures and temperatures of the surrounding rock.
... the most intriguing discovery made by the Kola borehole researchers is undoubtedly the detection of biological activity in rocks more than two billion years old. The clearest evidence of life came in the form of microscopic fossils: the preserved remains of twenty-four species of single-cell marine plants, otherwise known as plankton. Usually fossils can be found in limestone and silica deposits, but these “microfossils” were encased in organic compounds that remained surprisingly intact despite the extreme pressures and temperatures of the surrounding rock.
... While the temperature gradient conformed to predictions down to a depth of about 10,000 feet, temperatures after this point increased at a higher rate until they reached 180 °C (or 356 °F) at the bottom of the hole. This was a drastic difference from the expected 100 °C (212 °F). Also unexpected was a decrease in rock density after the first 14,800 feet. Beyond this point the rock had greater porosity and permeability which, paired with the high temperatures, caused the rock to behave more like a plastic than a solid and made drilling near impossible.
Scientists found microscopic fossils of single-celled organisms at 4.3 miles (7 kilometers) down. And at nearly the same depth, they discovered water. They also found that the temperature at the bottom of the hole reached a blistering 356°F (180°C). Too hot to continue, drilling officially halted in 1994.
... geologists had expected to find a transition from granite to basalt rock at the point where the upper and lower layers of the earth’s crust intersect, about 23,000 feet down (7,000 meters). Instead, samples revealed nothing but granite until drilling ceased, much deeper than anticipated. Drilling also uncovered water at around 23,000 feet. Theoretically, this was not possible, but scientists hypothesized that this was due to oxygen and hydrogen atoms being forced together into water molecules due to the intense pressure at such depths, and then trapped by the rock layer above. The team also uncovered ancient microfossils of 24 different single-celled planktons, a fascinating discovery made all the more remarkable by the fact that the fossils were preserved in such extremes of heat and pressure.
Another unexpected find was a menagerie of microscopic fossils as deep as 6.7 kilometers below the surface. Twenty-four distinct species of plankton microfossils were found, and they were discovered to have carbon and nitrogen coverings rather than the typical limestone or silica. Despite the harsh environment of heat and pressure, the microscopic remains were remarkably intact.

The Lone Star Producing Co. 1–27
- Bertha Rogers hole or well was an oil-exploratory hole drilled in Washita County, Oklahoma in 1974, and was formerly the world's deepest hole until in 1979 surpassed by the Kola Superdeep Borehole, dug by the USSR.
- It took Lone Star a little over a year and a half to reach 31,441 feet (9,583 m), a depth of almost six miles. During drilling, the well encountered enormous pressure – almost 25,000 psi (172,369 kPa). No commercial hydrocarbons were found before drilling hit a molten sulfur deposit (which melted the drill bit). The well was plugged back and completed in the Granite Wash from 11,000 to 13.200 feet as a natural gas producer.

Anadarko Basin cross section


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