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37-638: The Wallace Pratt Lodge was the summer residence of Wallace Pratt , the principal donor of the lands that would become Guadalupe Mountains National Park . Pratt was a petroleum geologist employed by the Humble Oil Company , scouting for oilfield leases in west Texas. Pratt visited the Guadalupe Mountains in 1921, and taking a liking to the place, he bought a quarter share of the McCombs Ranch. In 1929 Pratt bought out his partners, ending up owning

74-463: A carpenter, and stonemason Adolph May were key craftsmen on the project. The cabin was built of local limestone and heart pine. The Pratt family spent summers at the cabin, which they called the Stone Cabin, and briefly lived there during Wallace Pratt's early retirement. An earlier experience being trapped at the Stone Cabin during a flood caused Pratt to reconsider its use as a full-time residence, so

111-906: A computer model for the simulation of elastic waves in semi-infinite domains; and b) an optimization framework, through which the computed response is matched to the measured response by iteratively updating an initially assumed material distribution for the soil. Civil engineering can also use remote sensing information for topographical mapping, planning, and environmental impact assessment. Airborne electromagnetic surveys are also used to characterize soft sediments in planning and engineering roads, dams, and other structures. Magnetotellurics has proven useful for delineating groundwater reservoirs, mapping faults around areas where hazardous substances are stored (e.g. nuclear power stations and nuclear waste storage facilities), and earthquake precursor monitoring in areas with major structures such as hydro-electric dams subject to high levels of seismic activity. BS 5930

148-506: A conductive overburden). These are indirect inferential methods of detecting mineralization, as the commodity being sought is not directly conductive, or not sufficiently conductive to be measurable. EM surveys are also used in unexploded ordnance , archaeological, and geotechnical investigations. Regional EM surveys are conducted via airborne methods, using either fixed-wing aircraft or helicopter-borne EM rigs. Surface EM methods are based mostly on Transient EM methods using surface loops with

185-549: A hit or miss operation without scientific exploration. But Pratt, joined by 10 more geologists during 1918–19, proved that geology was an important factor in finding oil. Among the most notable early contributions made by Pratt and his staff were geological studies that led to the correct interpretation of the structure of the huge Mexia Field, discovered in October 1920 in East Texas . On the basis of these studies, Humble bought leases on

222-477: A large portion of the canyon, which featured waterfalls flowing over travertine dams, a lush, quiet place in the high desert. In the winter of 1931-1932 Pratt started construction of a house in the canyon, designed by noted Houston architect John F. Staub , who also designed the Pratt's Houston residence. In charge of construction was Vance Phenix, Staub's former employee and residential architect. Vance's brother Dean,

259-474: A prominent role in the scientific progress of his profession. As early as 1922, others were using geophysical instruments experimentally on the Texas Gulf Coast as a new method for finding salt domes . After studying results from this work, Pratt concluded that Humble should use geophysical instruments and methods. In line with these recommendations, in 1924, Humble set up a geophysics group and established

296-410: A report in which the subsidence was definitively attributed to the extraction of petroleum. In 1926, together with D. W. Johnson, he published these findings in a scientific paper. By this year, after about ten years of active pumping, most of the productive area of the field had subsided three feet, and the submerging of the facilities had already become obvious to field operators. Pratt also played

333-576: A second home, the Ship On The Desert , was constructed outside of the canyon. At some time during construction, probably in 1945, The Stone Cabin was used as a residence by the Ship On the Desert's New York architect, Newton Bevin , and his wife Elizabeth. After moving to Tucson, Arizona , Pratt donated the Stone Cabin, the Ship On the Desert, and surrounding lands of more than 5,000 acres (2,000 ha) to

370-524: A shop in Houston for geophysics research and development, and the manufacture of a refraction seismograph recording in the field. Pratt served as Humble's chief geologist and later director, and vice president. In 1937, he joined Standard Oil Co. (Humble's parent firm in New Jersey), once again rising to director, executive committee member, and finally, vice president, a position he held until he retired from

407-787: A surface receiver, or a downhole tool lowered into a borehole which transects a body of mineralization. These methods can map out sulphide bodies within the earth in three dimensions, and provide information to geologists to direct further exploratory drilling on known mineralization. Surface loop surveys are rarely used for regional exploration, however in some cases such surveys can be used with success (e.g.; SQUID surveys for nickel ore bodies). Electric-resistance methods such as induced polarization methods can be useful for directly detecting sulfide bodies, coal, and resistive rocks such as salt and carbonates. Seismic methods can also be used for mineral exploration, since they can provide high-resolution images of geologic structures hosting mineral deposits. It

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444-451: A wide variety of mineral deposits, especially base metal sulphides via detection of conductivity anomalies which can be generated around sulphide bodies in the subsurface. EM surveys are also used in diamond exploration (where the kimberlite pipes tend to have lower resistance than enclosing rocks), graphite exploration, palaeochannel-hosted uranium deposits (which are associated with shallow aquifers, which often respond to EM surveys in

481-402: Is a non-invasive technique, and is used within civil construction and engineering for a variety of uses, including detection of utilities (buried water, gas, sewerage, electrical and telecommunication cables), mapping of soft soils, overburden for geotechnical characterization, and other similar uses. The Spectral-Analysis-of-Surface-Waves (SASW) method is another non-invasive technique, which

518-927: Is an indirect method for assessing the likelihood of ore deposits or hydrocarbon accumulations. Methods devised for finding mineral or hydrocarbon deposits can also be used in other areas such as monitoring environmental impact, imaging subsurface archaeological sites, ground water investigations, subsurface salinity mapping, civil engineering site investigations , and interplanetary imaging. Magnetometric surveys can be useful in defining magnetic anomalies which represent ore (direct detection), or in some cases gangue minerals associated with ore deposits (indirect or inferential detection). The most direct method of detection of ore via magnetism involves detecting iron ore mineralization via mapping magnetic anomalies associated with banded iron formations which usually contain magnetite in some proportion. Skarn mineralization, which often contains magnetite, can also be detected though

555-514: Is another widely used technique as it provides necessary high resolution information about rock and fluid properties in a vertical section, although they are limited in areal extent. This limitation in areal extent is the reason why seismic reflection techniques are so popular; they provide a method for interpolating and extrapolating well log information over a much larger area. Gravity and magnetics are also used, with considerable frequency, in oil and gas exploration. These can be used to determine

592-522: Is not just surface seismic surveys which are used, but also borehole seismic methods. All in all, the usage of seismic methods for mineral exploration is steadily increasing. Seismic reflection and refraction techniques are the most widely used geophysical technique in hydrocarbon exploration. They are used to map the subsurface distribution of stratigraphy and its structure which can be used to delineate potential hydrocarbon accumulations, both stratigraphic and structural deposits or "traps". Well logging

629-600: Is the standard used in the UK as a code of practice for site investigations. Ground penetrating radar can be used to map buried artifacts , such as graves, mortuaries, wreck sites, and other shallowly buried archaeological sites. Ground magnetometric surveys can be used for detecting buried ferrous metals, useful in surveying shipwrecks, modern battlefields strewn with metal debris, and even subtle disturbances such as large-scale ancient ruins. Sonar systems can be used to detect shipwrecks. Active sonar systems emit sound pulses into

666-604: Is where you find it, according to an old adage, but judging from the record of our experience, oil must be sought first of all in our minds." There was a limited amount to find, though: at the University of Kansas, Pratt gave a lecture "Oil in the Earth", where he speculated that the total amount of oil in the United States was 100 billion barrels. Wallace E. Pratt donated 5,632 acres (22.79 km ), which included McKittrick Canyon, to

703-489: Is widely used in practice to detect the shear wave velocity profile of the soil. The SASW method relies on the dispersive nature of Raleigh waves in layered media, i.e., the wave-velocity depends on the load's frequency. A material profile, based on the SASW method, is thus obtained according to: a) constructing an experimental dispersion curve, by performing field experiments, each time using a different loading frequency, and measuring

740-643: The Kansas Geological Survey shortly after he graduated from the University of Kansas in 1907 with a bachelor's degree. From 1909 to 1914, he worked in Philippines , becoming chief of the Division of Mines there in 1912. He returned to the U.S. in 1916, and in 1918 joined Humble Oil & Refining Co. as the company's first geologist. Prior to that time the company had treated the search for oil as largely

777-670: The National Park Service , forming the core of the Guadalupe Mountains National Park. This land includes his former homes: Pratt died December 25, 1981, in his Tucson, Arizona , home. He was 96. Exploration geophysics#Geophysical methods Exploration geophysics is an applied branch of geophysics and economic geology , which uses physical methods at the surface of the Earth , such as seismic, gravitational, magnetic, electrical and electromagnetic, to measure

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814-674: The National Park Service , forming the nucleus of Guadalupe Mountains National Park. The cabin was listed on the National Register of Historic Places on March 26, 1975. This article about a property in Texas on the National Register of Historic Places is a stub . You can help Misplaced Pages by expanding it . Wallace Pratt Born in Phillipsburg, Kansas , March 15, 1885, Pratt began his career in geology as an assistant with

851-446: The spectral signature of geochemically altered soils and vegetation. Specifically at sea, two methods are used: marine seismic reflection and electromagnetic seabed logging (SBL). Marine magnetotellurics (mMT), or marine Controlled Source Electro-Magnetics (mCSEM), can provide pseudo-direct detection of hydrocarbons by detecting resistivity changes over geological traps (signalled by seismic surveys). Ground penetrating radar

888-433: The above techniques, have been developed and are currently used. However these are not as common due to cost-effectiveness, wide applicability, and/or uncertainty in the results produced. Exploration geophysics is also used to map the subsurface structure of a region, to elucidate the underlying structures, to recognize spatial distribution of rock units, and to detect structures such as faults, folds and intrusive rocks. This

925-612: The company in 1945. In the same year that he had joined Standard Oil, the company named one of their tankers after him, the SS Wallace E Pratt. After retirement, Pratt served on the National Security Resources Board for two years and began a long career as a consultant geologist. Pratt wrote more than 100 geological papers during his lifetime, including Oil in the Earth , one of the most widely read books in his profession. An often repeated quote from this book is, "Gold

962-486: The dysfunction or non-explosion of military explosives. Examples of these include, but are not limited to: bombs , flares , and grenades . It is important to be able to locate and contain unexploded ordnance to avoid injuries, and even possible death, to those who may come in contact with them. The issue of unexploded ordnance originated as a result of the Crimean War (1853-1856). Before this, most unexploded ordnance

999-441: The geometry and depth of covered geological structures including uplifts , subsiding basins , faults , folds , igneous intrusions , and salt diapirs due to their unique density and magnetic susceptibility signatures compared to the surrounding rocks; the latter is particularly useful for metallic ores. Remote sensing techniques, specifically hyperspectral imaging , have been used to detect hydrocarbon microseepages using

1036-417: The ground surface. These waves propagate through the soil, and due to the heterogeneous geological structure of the site under investigation, multiple reflections and refractions occur. The response of the site to the seismic vibrator is measured by sensors ( geophones ), also placed on the ground surface. Two key-components are required for the profiling based on full-waveform inversion. These components are: a)

1073-406: The ocean, rather than measuring the range or orientation of an object. Ground penetrating radar can be used to detect grave sites. This detection is of both legal and cultural importance, providing an opportunity for affected families to pursue justice through legal punishment of those responsible and to experience closure over the loss of a loved one. Unexploded ordnance (or UXO) refers to

1110-636: The ore minerals themselves would be non-magnetic. Similarly, magnetite, hematite, and often pyrrhotite are common minerals associated with hydrothermal alteration , which can be detected to provide an inference that some mineralizing hydrothermal event has affected the rocks. Gravity surveying can be used to detect dense bodies of rocks within host formations of less dense wall rocks. This can be used to directly detect Mississippi Valley Type ore deposits , IOCG ore deposits, iron ore deposits, skarn deposits, and salt diapirs which can form oil and gas traps. Electromagnetic (EM) surveys can be used to help detect

1147-445: The physical properties of the subsurface, along with the anomalies in those properties. It is most often used to detect or infer the presence and position of economically useful geological deposits, such as ore minerals; fossil fuels and other hydrocarbons ; geothermal reservoirs; and groundwater reservoirs. It can also be used to detect the presence of unexploded ordnance . Exploration geophysics can be used to directly detect

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1184-414: The soil. Full-waveform-inversion (FWI) methods are among the most recent techniques for geotechnical site characterization, and are still under continuous development. The method is fairly general, and is capable of imaging the arbitrarily heterogeneous compressional and shear wave velocity profiles of the soil. Elastic waves are used to probe the site under investigation, by placing seismic vibrators on

1221-459: The structure and developed substantial reserves and production. This work and leasing of large amounts of land that proved productive in Powell, Texas , in 1923 firmly established Humble as an oil producer. By 1920, the exploitation of Goose Creek Oil Field by Humble Oil led to the subsidence of the land over the oil field. Pratt was tasked with the investigation of this novel phenomenon and produced

1258-456: The surface wave-speed for each frequency; b) constructing a theoretical dispersion curve, by assuming a trial distribution for the material properties of a layered profile; c) varying the material properties of the layered profile, and repeating the previous step, until a match between the experimental dispersion curve, and the theoretical dispersion curve is attained. The SASW method renders a layered (one-dimensional) shear wave velocity profile for

1295-419: The target style of mineralization by measuring its physical properties directly. For example, one may measure the density contrasts between the dense iron ore and the lighter silicate host rock, or one may measure the electrical conductivity contrast between conductive sulfide minerals and the resistive silicate host rock. The main techniques used are: Many other techniques, or methods of integration of

1332-504: The water which then bounce off of objects and are returned to the sonar transducer. The sonar transducer is able to determine both the range and orientation of an underwater object by measuring the amount of time between the release of the sound pulse and its returned reception. Passive sonar systems are used to detect noises from marine objects or animals. This system does not emit sound pulses itself but instead focuses on sound detection from marine sources. This system simply 'listens' to

1369-461: Was locally contained in smaller volumes, and was thus not a huge public issue. However, with the introduction of more widespread warfare, these quantities increased and were thus easy to lose track of and contain. According to Hooper & Hambric in their piece Unexploded Ordnance (UXO): The Problem , if we are unable to move away from war in the context of conflict resolution, this problem will only continue to get worse and will likely take more than

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