The Brooks River Archaeological District (BRAD) in Katmai National Park and Preserve is a classical site for the study of early humans in Alaska. Because of proximity to the active Aleutian volcanic arc, there are numerous tephra deposits in the BRAD, which are potentially useful for correlating among sites of archaeological investigations. Microprobe analyses of glass separates show, however, that most of these tephra deposits are heterogeneous mixtures of multiple glass populations. Some glasses are highly similar to pyroclasts of Aniakchak Crater (160 km to the south), others are similar to pyroclasts in the nearby Valley of Ten Thousand Smokes, and some are similar to no other tephra samples from the Alaska Peninsula. Moreover, tephra deposits in any one archaeological study site are not always similar to those from nearby sites, indicating inconsistent preservation of these mainly thin, fine-grained deposits. At least 15, late Holocene tephra deposits are inferred at the BRAD. Their heterogeneity is the result of either eruptions of mixed or heterogeneous magmas, like the 1912 Katmai eruption, or secondary mixing of closely succeeding tephra deposits. Because most cannot be reliably distinguished from one another on the basis of megascopic properties, their utility for correlations is limited. At least one deposit can be reliably identified because of its thickness (10 cm) and colour stratification. Early humans seem not to have been significantly affected by these tephra falls, which is not surprising in view of the resilience exhibited by both plants and animals following the 1912 Katmai eruption.

Miocene strata in the Middlegate area, Churchill County, Nevada, consist of the Middlegate Formation unconformably overlain by the Monarch Mill Formation. The Middlegate Formation is about 110m thick and consists of a lower member of fluvial and lacustrine tuffaceous sandstone and conglomerate and an upper member of lacustrine diatomaceous siltstone. Megabreccia landslide deposits are common in the Middlegate Formation. Tephrochronologic studies indicate that the Middlegate Formation is about 15.2 Ma. The Monarch Mill Formation consists of lacustrine, fluvial, and alluvial-fan deposits that are at least 700 m thick in the central part of the Middlegate basin. Coarse, near-source, alluvial-fan deposits of the Monarch Mill Formation interfinger with finergrained fluvial and lacustrine deposits from source areas to the north and east and southeast of the Middlegate basin. Local megabreccia deposits are present in the Monarch Mill Formation in the southern and eastern parts of the basin. Tephrochronologic studies indicate that the Monarch Mill Formation ranges from about 14.7 to 9.8 Ma. The Middlegate Formation is mostly a quiet-water lake deposit that appears to have been deposited in an environment distinctly different from the present-day environment that is dominated by alluvial-fan deposits. It does, however, contain megabreccia deposits, indicative of nearby escarpments that produced far-traveled landslide deposits. The Monarch Mills Formation represents a distinct change in the paleogeographic setting in the Middlegate area. It contains coarse near-source deposits that indicate local high-relief, probably related to the development of faults and topographic relief that led to the presentday structural setting of the Middlegate area. This change occurred at about 14 Ma.

The 1932 Cedar Mountain earthquake (M-S 7.2) was one of the largest historical events in the Walker Lane region of western Nevada, and it produced a complicated strike-slip rupture pattern on multiple Quaternary faults distributed through three valleys. Primary, right-lateral surface ruptures occurred on north-striking faults in Monte Cristo Valley; small-scale lateral and normal offsets occurred in Stewart Valley; and secondary, normal faulting occurred on north-northeast-striking faults in the Gabbs Valley epicentral region. A reexamination of the surface ruptures provides new displacement and fault-zone data: maximum cumulative offset is estimated to he 2.7 m, and newly recognized faults extend the maximum width and end-to-end length of the rupture zone to 17 and 75 km, respectively.A detailed Quaternary allostratigraphic chronology based on regional alluvial-geomorphic relationships, tephrochronology, and radiocarbon dating provides a framework for interpreting the paleoseismic history of the fault zone. A late Wisconsinan alluvial-fan and piedmont unit containing a 32-36 ka tephra layer is a key stratigraphic datum for paleoseismic measurements.Exploratory trenching and radiocarbon dating of tectonic stratigraphy provide the first estimates for timing of late Quaternary faulting along the Cedar Mountain fault zone. Three trenches display evidence for six faulting events, including that in 1932, during the past 32-36 ka. Radiocarbon dating of organic soils interstratified with tectonically ponded silts establishes best-fit ages of the pre-1932 events at 4, 5, 12, 15, and 18 ka, each with +/-2 ka uncertainties. On the basis of an estimated cumulative net slip of 6-12 m for the six faulting events, minimum and maximum late Quaternary slip rates are 0.2 and 0.7 mm/yr, respectively, and the preferred rate is 0.4-0.5 mm/yr. The average recurrence (interseismic) interval is 3600 Sr. The relatively uniform thickness of the ponded deposits suggests that similar-size, characteristic rupture events may characterize late Quaternary slip on the zone. A comparison of event timing,vith the average late Quaternary recurrence interval indicates that slip has been largely regular (periodic) rather than temporally clustered.To account for the spatial separation of the primary surface faulting in Monte Cristo Valley from the epicenter and for a factor-of-two-to-three disparity between the instrumentally and geologically determined seismic moments associated with the earthquake, rye hypothesize two alternative tectonic models containing undetected subevents. Either model would adequately account for the observed faulting on the basis of wrench-fault kinematics that may be associated with the Walker Lane.The 1932 Cedar Mountain earthquake is considered an important modern analogue for seismotectonic modeling and estimating seismic hazard in the Walker Lane region. In contrast to most other historical events in the Basin and Range province, the 1932 event did not occur along a major range-bounding fault, and no single, throughgoing basement structure can account for the observed rupture pattern. The 1932 faulting supports the concept that major earthquakes in the Basin and Range province can exhibit complicated distributive rupture patterns and that slip rate may not be a reliable criterion for modeling seismic hazard.

A U.S. Geological Survey report is presented on the tephhrochronologic studies of sediment cores from Walker Lake, Nevada.

Eight widespread Pleistocene ash layers of east-central and southern California are characterized and correlated on the basis of chemical composition of volcanic glass (determined by neutron activation, electron probe, and energy-dispersive X-ray fluorescence analysis), stratigraphic criteria, and petrographic characteristics.Irt order of increasing age, these are the Lava Creek B ash bed (formerly referred to as the Pearlette type 0 ash bed; about 0.6 m.y.), the Bishop ash bed (0.73 m.y.), the Glass Mountain-D ash bed (estimated to be about 0.8-0.9m.y.), the Glass Mountain-G ash bed (estimated to be about 1.0-1.1 m.y.), the Bailey ash (1.2 m.y.), the middle white ash of the Manix basin (estimated to be about 1.9 m.y.), the Huckleberry Ridge ash bed (formerly referred to as the Pearlette type B ash bed; about 1.9 m.y.), and the lowermost gray ash of the South Mountain area (Huckleberry Ridge?ash bed; estimated to be about 1.9 m.y.).Three chemical types of the Bishop ash are recognized and assigned to an informal Bishop ash-bed group.The Friant Pumice Member (of the Turlock Lake Formation) of east-central San Joaquin Valley is one of the members of this group.The apparent 0.1-m.y.difference in K-Ar ages of the Friant Pumice Member (0.6 m.y.) and the Bishop Tuff (about 0.7 m.y.) may be due to factors other than differences in the true ages of these tephra units; alternatively, there may be two ash layers that have very similar glass chemistry and are here recognized as belonging to the Friant Pumice Member, but differ in age by as much as 0.1 m.y.The Huckleberry Ridge ash in the Manix basin is correlated with the same ash in Meade County, Kansas, over a distance of about 1,500 km.Results of chemical analyses permit correlation of sedimentary strata deposited in diverse environments: marine, fluvial, and lacustrine.Chemical characteristics of ash layers also permit identification of source areas from which tephra was erupted; the main eruptive centers were the Long Valley-Glass Mountain area of east-central California, the Coso volcanic field of southeastern California, and the Yellowstone area of northwestern Wyoming and eastern Idaho.Systematic chemical depletion trends with time provide a possible independent method of estimating ages of ash layers of the Long Valley-Glass Mountain family.

Antibiotikum U-22324 ist ein zyklisches Peptid, das aus Kulturflüssigkeit vonTrichoderma viride isoliert wurde. Das Peptid hat die Aminosäurenzusammensetzung (GluN)2(Glu)1(Pro)2(Gly)1(Ala)2(Dimethyl ala)8(Val)2(Leu)1.

Includes 5 topical chapters covering paleoclimates, dating methods, volcanism, tephrochronology, and Pacific margin tephrochronologic correlation, and 15 chapters of regional synthesis covering: the Pacific margin; the Columbia Plateau; the Snake River Plain; the major pluvial lakes of the Great Basin; the Basin and Range in California, Arizona, and New Mexico; the Colorado Plateau; the Southern and Central Rocky Mountains; the Northern and Southern Great Plains, Osage Plains, and Interior Highlands; the Lower Mississippi Valley; the Gulf of Mexico Coastal Plain and Florida; the Appalachian Highlands and Interior Low Plateaus; and the Atlantic Coastal Plain. A large, full-color geologic map of the Quaternary deposits of the Lower Mississippi Valley, in addition to correlation charts, tables, and cross-sections relating to other chapters, is also included.