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H.E. Malde

Publications and source records attributed to H.E. Malde.

17 recordsLinked to original sources
USGS2017

Geologic evidence for age of deposits at Hueyatlaco archeological site, Vasequillo, Mexico

Direct tracing of beds during excavation in May 1973, confirmed that the artifact-bearing layers at Hueyatlaco underlie 10 m of fine-grained, water-laid deposits that constitute part of the wide-spread Valsequillo gravels. Dissection of these deposits by the adjacent Río Atoyac has reached a depth of 50 m. The stratigraphic section at Hueyatlaco includes four distinctive tephra units. The oldest one occupies a small channel in a series of cut-and-fill stream deposits that have yielded bifacial tools. It lies more than a meter above flat-lying, fine-grained beds from which edge-retouched tools have been recovered. The three other tephra units occur higher in the section. Fission-track ages on zircon phenocrysts from two of the younger tephra layers (370,000 ± 200,000 and 600,000 ± 340,000 yr, 2σ) agree with concordant uranium-series dates for a camel pelvis that was found associated with bifacial tools at Hueyatlaco (245,000 ± 40,000 yr by 230 Th and > 180,000 yr by 231 Pa). These dates are compatible with the depth of burial and subsequent dissection of the Hueyatlaco deposits, as well as with the degree of hydration of volcanic glass shards and with the extent of etching of heavy-mineral phenocrysts from within the tephra layers. These findings suggest to us that further search for archaeological remains in deposits as old as those at Hueyatlaco would be warranted.

Vasequillo Reservoir↗
USGS2017

Geological age of the Claypool site, northeastern Colorado

Artifacts related to the Cody complex occur in medium-grained sand that is spread as a blanket eolian deposit a few feet thick in the Claypool site area, Washington County, Colorado . The artifact-bearing sand lacks noticeable dunal topography and lies unconformably on marl of Yarmouth age and on waterlaid coarse sand and fine gravel of Kansan age that underlie the marl. The deposits underlying the artifact-bearing sand are much too old to date the artifacts precisely, but the physical characteristics of the artifact-bearing sand suggest that it was deposited under conditions cool and dry, rather than warm and dry, possibly during retreat of Valders ice that began about 10,000 years ago. A moderately mature Brown Soil about 5 feet thick developed on the sand, possibly about 7000 to 5000 years ago during a moist phase of the Thermal Maximum. Thus, the artifacts are possibly 10,000 to 7000 years old. Deposits which overlie the artifact-bearing sand reflect several episodes of erosion and sedimentation that are inferred to represent climatic changes.

Colorado↗
USGS1969

Dilemma posed by uranium-series dates on archaeologically significant bones from Valsequillo, Puebla, Mexico

In an attempt to date stone artifacts of Early Man excavated from several sites at the Valsequillo Reservoir, a few kilometers south of Puebla, Mexico, Szabo applied the uranium-series method on bone samples known to be either from the same geologic formation as the sites or in direct association with the artifacts. The geologic context of the bones was studied by Malde, and the archaeological sites were excavated by Irwin-Williams. A date determined for bone associated with an artifact (Caulapan sample M-B-6, see below) agrees with a radiocarbon date for fossil mollusks in the same bed and indicates man's presence more than 20 000 years ago. However, some of these bone dates exceed 200 000 years. Because such dates for man in North America conflict with all prior archaeological evidence here and abroad, we are confronted by a dilemna — either to defend the dates against an onslaught of archaeological thought, or to abandon the uranium method in this application as being so much wasted effort. Faced with these equally undesirable alternatives, and unable to decide where the onus fairly lies (if a choice must be made), we give the uranium-series dates as a possible stimulus for further mutual work in isotopic dating of archaeological material. A sample from the Lindenmeier archaeological site north of Fort Collins and another from a Pleistocene terrace along the Arkansas River, both in Colorado, were also dated.

Puebla↗
USGS1959

Fault zone along northern boundary of western Snake River Plain

Gravity, seismic, and geologic studies indicate that at least 9000 ft of aggregate throw along a zone of northwest-trending, high-angle faults has displaced the western Snake River Plain downward relative to highlands on the north. At least 5000 ft of movement occurred between the early and middle Pliocene. Progressively diminishing movement since then amounts to 4000 ft.

Idaho, Oregon, Washington↗