Richard O. Stone

A desert glossary

Abstract The vocabulary describing desert features and desert phenomena is vast and, in various respects, repetitious. This paper presents a compilation of current terms with the intention to assist individuals interested in deserts to more easily understand published information and to provide a single source which can be enlarged in the future.

Underwater time-lapse motion picture systems

Abstract Application of underwater time-lapse motion picture cameras to the study of sediment transport phenomena provides an economical and quantitative tool for the investigation of sea floor processes. Two camera systems are described, one can be operated on the ocean bottom from a pier, boat or float and the second is completely self-contained, self-powered and divorced from surface support. Time-lapse photography was used to determine growth rates of scour pit development, migration of organisms, ripple crest advance and sediment dispersal patterns. Sea floor modification over several tidal cycles also was monitored with the self-contained unit for 47 hours of continuous activity.

‘Swellmeter’: An Apparatus for Measuring the Degree of Swelling of Clays

Abstract Swelling of clays in reservoir rocks (formation damage) is of utmost importance to petroleum engineers. Various inorganic and organic chemicals can be used to prevent swelling of clays. Design and operation of a simple apparatus for measuring the swelling of clays (a ‘swellmeter’) using various chemical solutions are presented in this paper.

Unique Playa Scraper and Furrow Near McKittrick, California: ABSTRACT

An unusual occurrence of a well-defined playa scraper and furrow in a small playa-like area was observed near McKittrick, California. A 20-foot fill, made during construction of California Highway 30, blocked a broad drainage channel in the low hills End_Page 482------------------------------ south of McKittrick. Small, flat, mud-cracked clay surfaces much like the familiar desert dry lakes developed on either side of the highway fill. The playa-like area east of the highway, where the occurrence was noted, is approximately 230 feet wide and 300 feet long. The playa scraper, which was part of the fill material, is a crudely ellipsoidal boulder of quartz conglomerate weighing about 175 pounds. Movement was from close to the fill embankment along a slightly arcuate path for a distance of 99.2 feet toward the outer margin of the dense clay surface. The playa furrow developed on the still-moist surface is 20 inches wide, its edges having been raised ½ inch above the level of the surrounding area. Depth of the trail increased from 2 inches at the starting point to 2½ inches at the terminus. Mud pushed by the moving boulder was left as a low mound of dry clay in front of the scraper. Movement of the scraper by wind does not seem to be a feasible explanation. Not only is the area sheltered from air currents, but the direction of movement is nearly at right angles to, and away from, the protective embankment. Transportation by ice floes is equally difficult to defend because the McKittrick area is one of rare freezes and it is doubtful that, even if freezing did occur, the thickness of ice formed would be sufficient to move a 175-pound boulder. Hydraulic action promoted by a drain beneath the fill is suggested as the possible motivating force for the McKittrick scraper. A similar occurrence at the Racetrack Playa in Death Valley, California, supports this supposition. End_of_Article - Last_Page 483------------

Recognition of Playa Sediments in the Geologic Column.: ABSTRACT

Playa sediments are sometimes reported in oil-well cuttings, particularly in sediments whose age End_Page 2780------------------------------ is Miocene or younger. A careful investigation of the sedimentary properties of playa sediments of the present has revealed certain characteristics which it is believed will enable the geologist to definitely recognize older sediments which were deposited in the playa environment. These diagnostic properties include the average grain size, sorting coefficient, color, organic carbon content, alkali and salt content, hydrogen-ion concentration, and the oxidation-reduction potential. In playa sediments most of these properties have rather definite ranges. This makes it possible to recognize playa sediments with a greater degree of certainty. End_of_Article - Last_Page 2781------------

Some Spectacular Effects of Wind Erosion near Palm Springs, California.: ABSTRACT

A short distance northwest of Palm Springs, California, a climbing dune has been formed in a gap in a spur of the San Jacinto Mountains that extends easterly into Coachella Valley. Wind funnelling through the pass between the San Jacinto and the San Bernardino Mountains picks up sand from the dry wash at the base of the spur and carries it up through the gap. The sand is coarse and the wind is almost constant, as a result of which spectacular wind effects have been achieved. Juniper trees that have managed to grow at all have been bent over until the trunks have broken, and they are now growing in a prone position, with smaller plants crowding closely in their lee. Small plants also cluster in the lee of the larger projecting rocks, growing laterally rather than vertically. These rocks, which are principally granitic, with some gneiss, schist, and quartzite, are pitted, grooved, and fluted in a most fantastic way. More fantastic still, however, is the fact that the grooving and fluting are continued without variation in the bushes sheltering behind the rocks. End_of_Article - Last_Page 2781------------