: As the famous Prussian general once warned, the first priority is to ascertain what type of conflict is to be fought. Carl von Clausewitz's seminal writings laid the foundation of thinking for modern warfare defined around the needs of the nascent Westphalian nation-state. His prioritization, his wonderful trinity, and his recognition that war is but politics by other means have served both strategist and statesman well during the conventional wars of the post-Napoleonic age. Cold War that followed would make the separation of policy and war more difficult as the advent of nuclear weapons blurred the line between military necessity and political reality. With the end of the Cold War--and especially since 9/11--we have been faced with a still more complex world. From Afghanistan to Mexico, irregular threats have replaced the classic nation-on-nation or bloc-onbloc confrontations we had grown comfortable with. Afghanistan, Iraq, and Colombia catapulted the United States and its allies back to irregular efforts spanning the gamut from the high tempo operations inherent to counterinsurgency and counterterrorism to the seemingly more sedate but often no less intense commitments required for whole-of-government stability operations and nation building. Ironically, despite efforts to push forward in our full spectrum capabilities, we remain hampered by legacy attitudes of compartmentalization and linear thinking. Even more problematic and disturbing is our willingness to engage in operations and deploy forces without fully grapling with the implications of the shift to population-centric warfare as prominently assess by General Sir Rupert Smith in The Utility of Force.

Interview in three sessions in late 1979 and early 1980 with Robert P. Sharp, Sharp Professor of Geology emeritus, who chaired the Division of Geology (later the Division of Geological and Planetary Sciences) at Caltech from 1952 to 1968. Begins with his recollections of growing up in Oxnard and of life during his undergraduate years [1930-1934] at Caltech, including his career as quarterback on Caltech's football team, and his one graduate year there. In 1936 he moved to Harvard for further graduate study, doing his thesis work on the Ruby/East Humboldt Range in Nevada. From 1938 to 1943 he taught at the University of Illinois; he discusses expeditions in the Grand Canyon (1937) and the Yukon (1941). After three years with the Army Air Force in Alaska, he joined the faculty of the University of Minnesota, then returned to Caltech as a professor in 1947. He discusses the early history of Caltech's geology division under J. P. Buwalda, the importance of the Seismological Laboratory, and the demise of vertebrate paleontology at Caltech after the death of Chester Stock. Discusses the expansion of the division under his chairmanship into geochemistry and planetary science and other events of his chairmanship; chairing the search committee for a new president upon the retirement of Lee DuBridge; and the advent of Harold Brown. Recalls his participation in the efforts of Eugene Shoemaker and Leon Silver to raise money for a named chair by guiding trips in the Grand Canyon, and his establishment of field trips for the division non-academic staff. The interview concludes with a discussion of his interest in current geological phenomena, such as glaciers and wind effects, and his authorship of guidebooks on Southern California geology for laypeople.

doi: 10.1130/0091-7613(1996)024<0766:SRATRD>2.3.CO;2 1996;24;766-767 Geology Robert P. Sharp, Dwight L. Carey, John B. Reid , Jr., Pratigya J. Polissar and Michael L. Williams and Reply Sliding rocks at the Racetrack, Death Valley: What makes them move?: Comment Email alerting services cite this article to receive free e-mail alerts when new articles www.gsapubs.org/cgi/alerts click Subscribe to subscribe to Geology www.gsapubs.org/subscriptions/ click Permission request to contact GSA http://www.geosociety.org/pubs/copyrt.htm#gsa click viewpoint. Opinions presented in this publication do not reflect official positions of the Society. positions by scientists worldwide, regardless of their race, citizenship, gender, religion, or political article's full citation. GSA provides this and other forums for the presentation of diverse opinions and articles on their own or their organization's Web site providing the posting includes a reference to the science. This file may not be posted to any Web site, but authors may post the abstracts only of their unlimited copies of items in GSA's journals for noncommercial use in classrooms to further education and to use a single figure, a single table, and/or a brief paragraph of text in subsequent works and to make GSA, employment. Individual scientists are hereby granted permission, without fees or further requests to Copyright not claimed on content prepared wholly by U.S. government employees within scope of their

Throughout Earth's history, CO2 is thought to have exerted a fundamental control on environmental change. Here we review and revise CO2 reconstructions from boron isotopes in carbonates and carbon isotopes in organic matter over the Cenozoic—the past 66 ...Read More

Research Article| October 01, 1983 Stripping of Keanakakoi tephra on Kilauea Volcano, Hawaii MICHAEL C. MALIN; MICHAEL C. MALIN 1Department of Geology, Arizona State University, Tempe, Arizona 85287 Search for other works by this author on: GSW Google Scholar DANIEL DZURISIN; DANIEL DZURISIN 2U.S. Geological Survey, Cascade Volcano Observatory, Vancouver, Washington 98661 Search for other works by this author on: GSW Google Scholar ROBERT P. SHARP ROBERT P. SHARP 3Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1983) 94 (10): 1148–1158. https://doi.org/10.1130/0016-7606(1983)94<1148:SOKTOK>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation MICHAEL C. MALIN, DANIEL DZURISIN, ROBERT P. SHARP; Stripping of Keanakakoi tephra on Kilauea Volcano, Hawaii. GSA Bulletin 1983;; 94 (10): 1148–1158. doi: https://doi.org/10.1130/0016-7606(1983)94<1148:SOKTOK>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Morphological characteristics, erosional processes, and effects of burial and exhumation by debris mantles on basaltic volcanic landforms have been evaluated through field study of the Keanakakoi Formation, a basaltic tephra formed in 1790 by phreato-magmatic eruptions from Kilauea caldera, Hawaii. The upper coarse lithic, intermediate fine vitric, and lower mixed members of this formation play different roles in the creation of micro-terrain elements during stripping of tephra from the underlying bedrock. Of the seven micro-terrain elements defined, bedrock, scabby upland surfaces, and lag gravels are the most distinctive and widely distributed. Different proportions and combinations of micro-terrain elements define five zones of progressive deterioration of the Keanakakoi tephra blanket southwestward from Kilauea caldera into the Kau Desert. Fluvial and eolian processes operate on different time scales and at different locations, governed by blanket thickness, debris caliber, and the formation of case-hardened crusts. Stripping of an entire mantle is probably not possible; however, materials trapped within depressions form the only clearly discernible morphological expression of previously more extensive debris blankets. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Landscapes are created by exogenic and endogenic processes acting along the interface between the lithosphere and the atmosphere and hydrosphere. Various landforms result from the attack of weathering and erosion upon the highly heterogeneous lithospheric surface. Landscapes are dynamic, acutely sensitive to natural and artificial perturbation. Undisturbed, they can evolve through a succession of stages to a plain of low relief. Often, the progression of an erosion cycle is interrupted by tectonic or environmental changes; thus, many landscapes preserve vestiges of earlier cycles useful in reconstructing the recent history of Earth's surface. Landforms are bounded by slopes, so their evolution is best understood through study of slopes and the complex of factors controlling slope character and development. The substrate, biosphere, climatic environment, and erosive processes are principal factors. Creep of the disintegrated substrate and surface wash by water are preeminent. Some slopes attain a quasisteady form and recede parallel to themselves (backwearing); others become ever gentler with time (downwearing). The lovely convex/rectilinear/concave profile of many debris-mantled slopes reflects an interplay between creep and surface wash. Landscapes of greatest scenic attraction are usually those in which one or two genetic factors have strongly dominated or those perturbed by special events. Nature has been perturbing landscapes for billions of years, so mankind can learn about landscape perturbation from natural examples.

Literature thermodynamic values were experimentally confirmed for the Bunsen reaction producing H2SO4- and HI-rich phases. The sulfur-iodine water-splitting cycle, which uses the Bunsen reaction, has been improved by enriching the H2SO4 solution to 57% in a system involving the H2SO4 product and counter-current liquid I2 flow. The system was saturated with SO2. The decomposition of H2SO4 was investigated. Pt/SiO2, Pt/ZrO2, Pt/TiO2 and Pt/BaSO4 were all good catalysts for H2SO4 vapor decomposition to SO2 at high temperatures. Pt/Al2O3 was found to fail due to substrate sulfation. The importance of pressure to sulfation temperature is presented. A summary of catalyst studies for H2SO4 vapor decomposition compares catalyst effectiveness.

Research Article| December 01, 1980 Wind-driven sand in Coachella Valley, California: Further data ROBERT P. SHARP ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar Author and Article Information ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1980) 91 (12): 724–730. https://doi.org/10.1130/0016-7606(1980)91<724:WSICVC>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ROBERT P. SHARP; Wind-driven sand in Coachella Valley, California: Further data. GSA Bulletin 1980;; 91 (12): 724–730. doi: https://doi.org/10.1130/0016-7606(1980)91<724:WSICVC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The last 5 yr (1964–1969) of a 16-yr field experiment involving unidirectional windblown rock and mineral debris focused on study of ground-based objects. A large increase in wind-blown material crossing the plot resulted from accelerated fluvial flooding of the upwind alluvial source area starting in 1964. The plot itself was destroyed by such flooding in early 1969.Maximum cutting of 2.8 cm in 15 yr on a vertical lucite rod occurred on its oblique upwind sides, at 10 to 15 cm above ground. Cutting rate in the last 3 yr was 15 times greater than in the preceding 12 yr, coincident with the increased flux of wind-borne material. A 30-cm gypsum-cement cube showed an 11-fold increase of cutting rate during the last 4 yr (3.6 cm/yr compared to 0.34 cm/yr). Total cutting on the front face was 18 times greater than on the two side faces combined, an average cutting ratio of 36/1. Common red bricks recorded an average front- to side-face cutting ratio of 20/1, and a front-to-top ratio of 45/1. Cutting of 1 to 2 mm occurred on hard crystalline rock within 15 yr, much of it in the last 5 yr.Changes in orientation and position of gympsum-cement cubes and common bricks were produced by basal ground scour, tilting, rotation, creep, and tumbling. Newly placed hydrocal cubes developed upwind tilts as much as 17° in as little as 69 days (d), owing to basal scour. A slow upwind creep of 2 to 3 cm accompanied scour and tilt. A 90° rotation around a near-vertical axis of a brick demonstrated the importance of lever-arm length offered to the wind. Movements of many centimetres and complete reversals, bottom for top, were caused by tumbling. Separation of the base of cubes from the ground by tilting or by perching on residual pebbles, owing to scour or overturn, usually produced an instability favorable to movement. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Research Article| October 01, 1979 Intradune flats of the Algodones chain, Imperial Valley, California ROBERT P. SHARP ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1979) 90 (10): 908–916. https://doi.org/10.1130/0016-7606(1979)90<908:IFOTAC>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation ROBERT P. SHARP; Intradune flats of the Algodones chain, Imperial Valley, California. GSA Bulletin 1979;; 90 (10): 908–916. doi: https://doi.org/10.1130/0016-7606(1979)90<908:IFOTAC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A striking characteristic of the southeastern part of the remarkably linear northwest-southeast Algodones Dunes chain is a succession of regularly spaced, wholly enclosed flats exposing the alluvial substrate. Each flat is bounded on the northwest by a high active slip face of sand and on the southeast by a more gently inclined deflated sand slope, suggesting that the flats are moving southeasterly along the chain axis. Measurements over a 12-yr interval confirm this movement and indicate an average southeasterly movement of 35 to 40 cm/yr.Development of alluvium-floored intradune flats is presaged by formation of ridge-and-hollow couplets farther to the northwest. Embryonic ridge-and-hollow forms extend almost to the northwestern tip of the chain. Development of long, linear transverse, sand-trapping ridges, which are instrumental in creating downwind hollows, appears to be an inherent characteristic of eolian transport under conditions of relatively smooth terrain, scanty vegetation, and a limited flux of sand supplied approximately orthogonally to a dominant resultant direction of drift.Principal resultant sand drift produced by a multidirectional wind regime over the dunes is southeast; northeast is the next most favored direction. Secondary influences of faulting may account for the unusual linearity of the chain, which is probably a belt of shoreline dunes about 37,000 yr old. Intradune flats are large enough to be resolved on orbiter photos of Mars, and some of the patterns on the martian surface attributed to eolian processes may involve intradune flats. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Research Article| December 01, 1976 Sliding stones, Racetrack Playa, California ROBERT P. SHARP; ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 Search for other works by this author on: GSW Google Scholar DWIGHT L. CAREY DWIGHT L. CAREY 2Department of Geology, University of California at Los Angeles, Los Angeles, California 90024 Search for other works by this author on: GSW Google Scholar Author and Article Information ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 DWIGHT L. CAREY 2Department of Geology, University of California at Los Angeles, Los Angeles, California 90024 Publisher: Geological Society of America First Online: 01 Jun 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (1976) 87 (12): 1704–1717. https://doi.org/10.1130/0016-7606(1976)87<1704:SSRPC>2.0.CO;2 Article history First Online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ROBERT P. SHARP, DWIGHT L. CAREY; Sliding stones, Racetrack Playa, California. GSA Bulletin 1976;; 87 (12): 1704–1717. doi: https://doi.org/10.1130/0016-7606(1976)87<1704:SSRPC>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Twenty-eight of 30 monitored stones on the southern part of Racetrack Playa moved within a seven-yr interval, leaving distinct tracks. Movements occurred principally during the winters of 1968–1969, 1972–1973, and 1973–1974. Some stones moved in all three episodes, some only in one or two, and a few on other occasions. Movement is clearly related to wet stormy weather.Greatest cumulative movement, 262 m, and greatest single-episode movement, 201 m, were by a small, 250-g stone. Other monitored stones weighing as much as 25 kg moved cumulative distances of 60 to 219 m. Net direction of movement was north-northeasterly with deviations to east and southeast on occasions by some stones. Movement most likely occurs within one to several days after playa wetting, and velocities on the order of 0.5 to 1 m/sec are inferred from track characteristics.Thin sheets of ice form in winter on this playa, and eyewitness accounts of ice sheets, some with infrozen stones, being driven by wind across other southern California playas indicate that stone tracks may be made in this manner, as earlier advocated. However, movement of stones out of an encirclement of iron stakes, large changes in neighboring stone separation during movement, disproportionate corresponding reaches within contemporaneous tracks of neighboring stones, and other relationships strongly suggest that monitored stone movements occurred without the aid of extensive ice sheets.Wind acting directly on the individual stones is considered the prime moving force. A critical element promoting movement may be deposition of a thin layer of fine slippery clay, the material that last settles from suspension after playa flooding. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Research Article| May 01, 1975 Channels on Mars ROBERT P. SHARP; ROBERT P. SHARP 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91109 Search for other works by this author on: GSW Google Scholar MICHAEL C. MALIN MICHAEL C. MALIN 1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91109 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1975) 86 (5): 593–609. https://doi.org/10.1130/0016-7606(1975)86<593:COM>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation ROBERT P. SHARP, MICHAEL C. MALIN; Channels on Mars. GSA Bulletin 1975;; 86 (5): 593–609. doi: https://doi.org/10.1130/0016-7606(1975)86<593:COM>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract By showing that parts of equatorial and mid-latitudinal Mars have a variety of channels and channel-like forms, Mariner 9 photographs provide a basis for speculations concerning surface processes, crustal events, climatological environment, and evolutionary history.Some large outflow channels display characteristics suggesting scour and plucking by torrential floods similar to the Spokane and Bonneville events of western United States, although such channels are probably not solely the product of flood action. Other channels with dendritic tributaries suggest runoff fed by seepage and headward growth and enlargement by sapping.Some Martian channels and channel-like forms were probably created or initiated by endogenic processes such as faulting, subsidence, volcanism, fracturing, and crustal extension; others may be due to wind or lava erosion, but the features and relationships of many channels are best accounted for by fluvial action.Reconciliation of fluvial erosion and the current hostile Martian environment may be possible if the channels are as old as 3 b.y. Such an age is suggested by recent re-evaluations of meteoroidal flux impacting Mars, Moon, and Earth and the chronology of lunar maria. A residual primitive atmosphere possibly congenial to running water on Mars may have permitted fluvial erosion 3 to 3.5 b.y. ago. Haphazard scattering of channels and the likelihood of seepage and sapping suggest that water was supplied to the Martian surface from the lithosphere, not the atmosphere. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Velocity and strain-rate patterns in a small temperate valley glacier display flow effects of channel geometry, ice thickness, surface slope, and ablation. Surface velocities of 20–55 m/year show year-to-year fluctuations of 1.5–3 m/year. Transverse profiles of velocity have the form of a higher-order parabola modified by the effects of flow around a broad bend in the channel, which makes the velocity profile asymmetric, with maximum velocity displaced toward the outside of the bend. Marginal sliding rates are 5–22 m/year against bedrock and nil against debris. Velocity vectors diverge from the glacier center-line near the terminus, in response to surface ice loss, but converge toward it near the firn line because of channel narrowing. Plunge of the vectors gives an emergence flow component that falls short of balancing ice loss by about 1 m/year. Center-line velocities vary systematically with ice thickness and surface slope. In the upper half of the reach studied, effects of changing thickness and slope tend to compensate, and velocities are nearly constant; in the lower half, the effects are cumulative and velocities decrease progressively down-stream. Where the slope increases down-stream from 7° to 9°, reflecting a bedrock step, there is localized longitudinal extension of 0.03 year –1 followed by compression of 0.08 year –1 where the slope decreases. Marginal shear (up to 0.5 year –1 ) is strongly asymmetric due to flow around the bend: the stress center-line, where one of the principal axes becomes longitudinal, is displaced 150 m toward the inside of the bend. This effect is prominently visible in the crevasse pattern. Ice fluxes calculated independently by “laminar” flow theory and by continuity disagree in a way which shows that internal deformation of the ice is controlled not by local surface slope but by an effective slope that is nearly constant over the reach studied.

Ice unquestionably exists on Mars. Annual polar-region frost blankets are principally solid CO2, and perennial residual ice caps near each pole are probably water ice, except for a part of the north polar cap which may consist of a 1 km thick mass of solid CO2. Minor amounts of carbon-dioxide clathrate (CO2 · ≈ 6H2O) presumably accompany the solid CO2. The annual frost blankets may have a concentric banding with an outermost very thin layer of water frost, an intermediate narrow zone of clathrate, and a major central core of solid CO2. Layered deposits and underlying homogeneous materials mantle large areas within both polar regions. These blankets are probably composed of dust, volcanic ash, or both, and possibly contain frozen volatiles. They may comprise the largest reservoir of water substance on the Martian surface. Ground ice formed by the freezing of ascending de-gassed water substance may underlie the surface of Mars. Localized collapse of small areas may be due to ground-ice deterioration, and recession of steep slopes may have been caused by ground-ice sapping. If liquid water ever existed in significant quantities on the Martian surface, intense frost shattering, widespread creep, and prolific development of patterned structures should have occurred because the thermal regimen of the surface is highly favorable to the freeze–thaw process. It is ineffective at present owing to the lack of liquid water. No evidence suggests that the residual ice caps have ever acted like terrestrial glaciers in terms of erosion and deposition. Currently, they are too thin, too cold, and presumably frozen to their substrates. Their most important function is to buffer the atmosphere in terms of its H2O and CO2 content, thereby exerting a modifying influence on the surface environment of the entire planet.