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Estella B. Leopold

Publications and source records attributed to Estella B. Leopold.

10 recordsLinked to original sources
USGS2017

Holocene relative sea level changes along the Seattle Fault at Restoration Point, Washington

At a marsh on the hanging wall of the Seattle fault, fossil brackish water diatom and plant seed assemblages show that the marsh lay near sea level between ∼7500 and 1000 cal yr B.P. This marsh is uniquely situated for recording environmental changes associated with past earthquakes on the Seattle fault. Since 7500 cal yr B.P., changes in fossil diatoms and seeds record several rapid environmental changes. In the earliest of these, brackish conditions changed to freshwater ∼6900 cal yr B.P., possibly because of coseismic uplift or beach berm accretion. If coseismic uplift produced the freshening ∼6900 cal yr B.P., that uplift probably did not exceed 2 m. During another event about 1700 cal yr B.P., brackish plant and diatom assemblages changed rapidly to a tidal flat assemblage because of either tectonic subsidence or berm erosion. The site then remained a tideflat until the most recent event, when an abrupt shift from tideflat diatoms to freshwater taxa resulted from ∼7 m of uplift during an earthquake on the Seattle fault ∼1000 cal yr B.P. Regardless of the earlier events, no Seattle fault earthquake similar to the one ∼1000 cal yr B.P. occurred at any other time in the past 7500 years.

Quaternary Research↗
USGS1970

Aquilapollenites (Rouse) Funkhouser — Selected Rocky Mountain taxa and their stratigraphic ranges

The genus Aquilapollenites and its type species, A. quadrilobus, are redescribed, and the latter is illustrated. This report summarizes our present information on stratigraphic ranges of selected Rocky Mountain species and varieties of Aquilapollenites. Of the 17 taxa included in this report, 10 are previously named species, 4 are new species, and 3 are new varieties. One species is transferred from the genus Mancicorpus and another from the genus Parviprojectus. The stratigraphic data concerning Aquilapollenites incorporate available information from U.S. Geological Survey pollen collections.

Alaska, Colorado, Montana, North Dakota, South Dak↗
USGS1967

Pre-Olympia Pleistocene stratigraphy and chronology in the central Puget Lowland, Washington

Drifts of two pre-Olympia glaciations separated by nonglacial sediments are widespread in the central Puget Lowland of western Washington. The Double Bluff Drift (older) and Possession Drift represent advances of the Puget lobe of the Cordilleran ice sheet more than 40,000 years ago. The nonglacial Whidbey Formation between the drifts was formed in streams and lakes. During its deposition, climate was initially cool and moist, as inferred from pollen in peat beds, but subsequently it became much like that of the present in the lowland. The Possession Drift is tentatively correlated with glacial deposits of Salmon Springs age in the southern part of the lowland. The Whidbey Formation may correlate with nonglacial deposits between two Salmon Springs Drifts or with the Puyallup Formation.

Washington↗
USGS1965

Plant and miscellaneous microfossils of the Pierre Shale

This preliminary report summarizes part of a Survey program to study, in detail, the stratigraphy and paleontology of a nearly complete sequence of Pierre Shale near Redbird, Wyoming. The physical stratigraphy and correlations are being analyzed by James Gill and W. A. Cobban. Various groups of invertebrate fossils are under study by Mr. Cobban, N. F. Sohl, and James Mello. Plant microfossils are the responsibility of Estella Leopold, assisted by Bernadine Tschudy.

Open-File Report↗
USGS1964

Studies of pre-Selma Cretaceous core samples from the outcrop area in western Alabama

In 1954 four core holes were drilled in the pre-Selma Cretaceous strata of the Alabama Coastal Plain in order to get unweathered samples within a few miles of the outcrops. During the next few years several specialists studied the cores, and their reports are published as consecutive parts of this bulletin. Watson H. Monroe, who spent many years studying the Coastal Plain strata in Alabama and Mississippi, conceived and supervised the drilling and planned the later studies. His earlier published report (W. H. Monroe, 1955, Cores of pre-Selma Cretaceous rocks in the outcrop area in western Alabama: Gulf Coast Geol. Societies Trans., v. 5, p. 11-37) contains a brief description of the stratigraphy, together with logs and other information regarding the core holes, and he has provided the introductory chapter to this bulletin. Richard E. Bergenback studied the petrology of the cores, which included finding the distribution of grain sizes, determining the mineralogy of the grains and the matrix of the sediments, and having X-Ray identifications made of the clay minerals. Norman F. Sohl studied the mollusks and other large fossils obtained from the cores and compared them with other faunal suites collected in Alaban1a and Texas. Esther R. Applin studied the sparse microfauna, comparing it with faunas obtained from deep wells downdip in Georgia, Alabama, and Mississippi and with outcrop samples fron1 Texas, and has described a new species of Foraminifera. Estella B. Leopold and Helen M. Pakiser obtained a large pollen and spore assemblage by digesting carbonaceous layers of some of the cores in acid; this flora includes much new material, which is not described here. The Bergenback, Sohl, and Applin reports discuss the probable environment in which the sediments accumulated. Louis C. Conant, who spent several years studying and mapping these sediments, has written a summary chapter integrating some of the surface and subsurface information. Quarter-cuts of the cores belonging to the U.S. National Museum have been deposited on indefinite loan with the Alabama Geological Survey at University, Ala., and with the Shell Oil Co. at Jackson, Miss. They are available there for inspection and study.

Bulletin↗
USGS1963

Some climatic indicators in the period A.D. 1200-1400 in New Mexico

Three centuries before Columbus landed in America, the alluvial valleys of the south-western United States teemed with activity. The indigenous peoples had been building for 300 years a culture centred around community life based on flood-water farming and on hunting. A large number of pueblos had developed on sites earlier occupied by pit-house people. Community organization had brought advances in the ceramic and decorative arts, and changes in these artistic activities were sufficiently rapid that accurate chronologies have become available through the work of archaeologists during the twentieth century. These chronologies were at first unrelated to absolute dates, but the excavations of the 1920s at Chaco Canyon (New Mexico) provided the materials through which absolute dates could be established. This was accomplished by matching the changes in tree-ring width backward in time from living trees through successively older samples. Trees overlapping in age provided, by unique successions of distinctive tree-ring widths, a calendar by which individual logs could be dated. Beams found in the excavations at Chaco Canyon gave the first material by which the cultural developments culminating about A.D. 1300 could be dated. As a result of the time sequence provided by the tree-ring calendar, the dates within which different pottery types were developed could be accurately established. The dates of pottery types have been checked at a sufficiently large number of sites throughout the south-western United States that absolute dating of a large number of distinctive patterns can be considered unassailable. The sequence of tree-ring widths gives some climatic indications of great interest both to archaeologists and to climatologists. A relatively large number of logs spanning the period from A.D. 1200 to 1300 and, in particular, the years between 1276 and 1299, indicate that this period was generally characterized by smaller tree-ring widths than in the centuries immediately before and after. As a first approximation, the hundred years of narrow tree-ring widths were interpreted as a time of relative aridity, and have been referred to as the “Pueblo Drought”. More recent studies of tree-ring widths using sophisticated statistical techniques have thrown some doubts on any direct correlation of tree-ring widths with rainfall. Such doubts have been put forward before by Glock (1955) whose studies have been aimed at separating the various effects of seasonal occurrence of precipitation, the amount falling in various seasons, and other climatic factors in their relative influence on tree-ring widths. At present, then, tree-ring widths may be considered more satisfactory for reading chronology than for reading climate. It is this concern about direct correlation of tree-ring width with climate that led to initiation of the present study. This work is a preliminary attempt to obtain independent evidence from pollen concerning the probable nature of the vegetation and thus the climate in a period known to be characterized by narrow tree rings.

New Mexico↗