Table 1 (Cont'd).
Focus of paper and
Summary of findings as
Reference
possible indicator type
Geographic location
potential indicator
Motts 1972
Secondary
Rogers Playa,
By Jan 1967, a shifting of water back and forth was effec-
California
tive in smoothing out 7.6- to 10.2-cm-deep ruts made by a B
52 aircraft the previous September.
Motts and
Soil
Rogers Playa,
Each flood deposited a thin sedimentation unit that in many
Carpenter 1970
California
places graded from sand and silt near the base to clay near
the top. (These in turned formed mud curls on drying.)
Motts and
Surface type
Rogers and
Both playas, which are subject to fairly regular seasonal
Carpenter 1970
Rosamond Playas,
flooding, may show a change in basic surface type from one
California
year to the next. After flooding, a range of surface types
(including a "puffy surface" dissimilar from coarse-grained
puffy surfaces) was transformed into a mud-curl surface.
Rosette patterns were also seen on flooded areas that
underwent freezethaw cycles. Also reported on the north
western part of Rosamond Playa was a "wavy, undulating"
surface with a microrelief ranging from 0.6 to 1.3 cm. It was
broken by irregular "zigzag" polygonal cracks 30.4876.2 cm
across, through which groundwater discharge occurred.
Neal 1965
Hydrology
Silver Lake,
Contained water for 18 months (during 1938); maximum pan
California
evaporation was 2.6 cm per day.
Neal 1965
Hydrology
Indian Springs,
Flooded to a depth of 45.7 cm on 21 Sep 1963; completely
Nevada
evaporated by 20 Jan 1965.
Neal 1968
Surface type
Harper Lake,
After flooding during the winter of 19651966, the surface,
California
which was the soft type, became the hard type. By 1967,
some portions of the surface were reverting to the soft type
again (in the absence of flooding).
Neal 1975
Textbook treat-
ment of playas
and dry lakes
Neal and
Surface type
South Panamint
The salt-encrusted area of the playa increased at the
Motts 1967
Playa, California
expense of other surface types.
Neal and
Surface type
Troy and Coyote
Soft, puffy, porous surfaces changing to hard, dry compact
Motts 1967
Playas, California
surfaces depending on temporal changes in moisture.
Neal and
Surface type
Harper, Troy,
Many playas that have predominantly soft, puffy, porous
Motts 1967
and Coyote
surfaces will have hard, dry compact areas in the washes
Playas, California
draining into the playas.
Stone 1956
Overview of geo- Southern California
morphology and
natural history of
many of the southern
California playas
(Ph.D. dissertation)
Where groundwater or flooding reaches the surface, Dis-
Went and
Vegetation
Death Valley
tichlis spicata, Allenrolfea occidentalis, Juncus cooperi
Westergaard
1949
grow.
Went and
Vegetation
Death Valley
Where the water table is only occasionally at the surface,
the following grow (in addition to above): Sacrobatus
Westergaard
vermiculatus, Salicornia utahensis, and Suaeda torreyana.
1949
la occidentalis, Salicornia subterminalis, Suaeda spp.,
inated by phreatophytic species similar to those report-
and Sarcobatus vermiculatus as representatives of
ed by Hunt (1966) in Death Valley, while the upland
group is dominated by upland species. In contrast to
playa edges. They also report that, farther away from
the playa surface proper, the areas around playas are
the playa edge, other species of xerophytes increase in
often vegetated; sometimes this vegetation can be char-
occurrence until eventually the halophytic shrub zone
acteristic of playa edges. But a gradient does exist be-
is replaced by xerophytes or whatever other commun-
tween the occurrence of halophytic and xerophytic veg-
ity occurs in the region around playas. For Mojave
etation. Barbour and Major (1990) report succulent
Desert playas, Thompson (1929) observed what he
chenopods such as Allenrolfea occidentalis, Nitrophi-
called a characteristic vegetation around the border of
15
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