Early Holocene Times Research Articles

A statistical study of <i>Weinmannia</i> pollen trajectories across the Andes

Abstract. Recent airborne pollen records data from Northern Patagonia (San Carlos de Bariloche, Argentina, Lat. 41.1435° S, Long. 71.375° W, 800 m elevation) suggest that pollen transport takes place from the west to the east slope of the Andes. However, the atmospheric characteristics responsible of this transport have not yet been studied. The aim of this paper is to assess potential source areas and to describe the involved atmospheric mechanisms of the trans-Andean pollen transport. Methodology relies on the analysis of backward trajectories of air masses calculated with the HYSPLIT 4.9 regional model for particular days where airborne pollen of Weinmannia trichosperma Cav. was detected east of the Andes. This pollen type was selected because it is found regularly at localities in eastern Patagonia beyond its present-day distribution. Weinmannia's substantial presence during early Holocene times would also benefit from better knowledge of its transport mechanisms. Correspondence between atmospheric trajectories and the position of sources was checked using GIS maps. Mode T, Principal Component Analysis (PCA) with Varimax rotation was used to identify the main spatial structure of geopotential height anomalies producing the calculated trajectories. Eighty-eight cases showed that the calculated directions of trajectories trended from the Northwest to Southwest passing over the Chilean region of W. trichosperma distribution. PCs results showed two patterns of negative anomalies over southern Patagonia. The prevailing circulation pattern which drives airborne transport is the presence of a trough located south of 37 to 40° S with its axis over western Patagonia. The synoptic situations for two cases highly correlated with principal component scores were described.

Lateglacial to Holocene relative sea‐level changes in the Bjarkarlundur area near Reykhólar, North West Iceland

AbstractThis paper presents results from seven isolation basins to investigate the relative sea‐level history from the Lateglacial and the mid to late Holocene from the Bjarkarlundur area near Reykhólar on the Reykjanes peninsula in North West Iceland. Results presented help to constrain the timing and rate of relative sea‐level (RSL) change since deglaciation and also the timing of deglaciation itself in the Bjarkarlundur area. The marine limit is estimated to be approximately 80 m above sea level based on an isolation basin with sill altitude at 79.1 m. The maximum age of this marine limit and, hence, local deglaciation is estimated at 12.2 14C ka BP. Relative sea level then fell rapidly during the late Bölling–early Alleröd at a rate of approximately −35 mm 14C a−1 to below 50 m by 11.4 14C ka BP. After this the rate of RSL fall decreased significantly during the late Alleröd and Younger Dryas Chronozones (averaging −6 mm 14C a−1 between 11.4 and 9.7 14C ka BP). Based on isolation basins with sill altitudes of 51.1 and 41.1 m, our data constrain any possible fluctuation in RSL produced by regrowth of ice during the Younger Dryas to below 10 m. After 9.7 14C ka BP the rate of RSL fall increased significantly to approximately −23 mm 14C a−1 to at least 9.0 14C ka BP. If eustatic sea‐level rise is taken into account and the calibrated timescale is used, actual crustal uplift rates are estimated at +56 and +46 mm cal. a−1 during Lateglacial and early Holocene times, respectively. During the mid to late Holocene RSL then rose to at least 1 m above present‐day levels, gradually falling to the present‐day level from 3.1 14C ka BP. These results demonstrate the potential of isolation basin data for investigating the timing and rate of RSL change in Iceland. This can add important well‐constrained information on RSL when combined with data from raised beaches. Copyright © 2009 John Wiley & Sons, Ltd.

Fluctuations of local glaciers in Greenland during latest Pleistocene and Holocene time

This paper is the first to summarize research on fluctuations of local glaciers in Greenland (e.g. ice caps and mountain glaciers independent of the Greenland Ice Sheet) during latest Pleistocene and Holocene time. In contrast to the extensive data available for fluctuations of the Greenland Ice Sheet, surprisingly little data exist to constrain local glacier extents. Much of the available research was conducted prior to wide-spread use of AMS radiocarbon dating and the advent of surface-exposure and luminescence dating. Although there is a paucity of data, generally similar patterns of local glacier fluctuations are observed in all regions of Greenland and likely reflect changes in paleoclimate, which must have influenced at least the margins of the Inland Ice. Absolute-age data for late-glacial and early Holocene advances of local glaciers are reported from only two locations: Disko (island) and the Scoresby Sund region. Subsequent to late-glacial or early Holocene time, most local glaciers were smaller than at present or may have disappeared completely during the Holocene Thermal Maximum. In general, local glacier advances that occurred during Historical time (1200–1940 AD) are the most extensive since late-glacial or early Holocene time. Historical documents and more recent aerial photographs provide useful information about local glacier fluctuations during the last ∼100 yrs. In all but one area (North Greenland), local glaciers are currently receding from Historical extents.

Origin and evolution of formation water at the Jujo–Tecominoacán oil reservoir, Gulf of Mexico. Part 2: Isotopic and field-production evidence for fluid connectivity

Abstract The chemical and isotopic characterization of formation water from 18 oil production wells, extracted from 5200 to 6100 m b.s.l. at the Jujo–Tecominoacan carbonate reservoir in SE-Mexico, and interpretations of historical production records, were undertaken to determine the origin and hydraulic behavior of deep groundwater systems. The infiltration of surface water during Late Pleistocene to Early Holocene time is suggested by 14C-concentrations from 2.15 to 31.86 pmC, and by 87Sr/86Sr-ratios for high-salinity formation water (0.70923–0.70927) that are close to the composition of Holocene to modern seawater. Prior to infiltration, the super-evaporation of seawater reached maximum TDS concentrations of 385 g/L, with lowest δ18O values characterizing the most hypersaline samples. Minor deviations of formation water and dolomite host rocks from modern and Jurassic 87Sr/86Sr-seawater composition, respectively, suggest ongoing water–rock interaction, and partial isotopic equilibration between both phases. The abundance of 14C in all sampled formation water, 87Sr/86Sr-ratios for high-salinity water close to Holocene – present seawater composition, a water salinity distribution that is independent of historic water-cut, and a total water extraction volume of 2.037 MMm3 (1/83–4/07) excludes a connate, oil-leg origin for the produced water of the Jurassic–Cretaceous mudstone-dolomite sequence. Temporal fluctuations of water chemistry in production intervals, the accelerated migration of water fronts from the reservoir flanks, and isotopic mixing trends between sampled wells confirms the existence of free aquifer water below oil horizons. Vertical and lateral hydraulic mobility has probably been accelerated by petroleum extraction. The combination of interpreting historical fluctuations of salinity and water percentage in production wells with chemical-isotopic analysis of formation water resulted in a successful method to distinguish four groundwater bodies, stratified vertically within the Jujo–Tecominoacan reservoir. Two with low TDS from 10 to 23 g/L are preserved in the upper reservoir section, mainly in Lower Cretaceous and Kimmeridgian strata. For the deeper part of the reservoir, 87Sr/86Sr trends indicate an affiliation of most samples to two independent mixing trends between “intermediate saline” (TDS ∼200 g/L) and hypersaline (>350 g/L) groundwater end-members.

Morphogenesis of the Sarine canyon in the Plateau Molasse, Switzerland : new data from an archaeological site

Abstract. The 50 to 100 metre deep canyon of the Sarine River that develops north of the prealpine front in the Molasse Plateau is classically attributed to postglacial erosion. However, the discovery of a Mesolithic archaeological site (~ 8600 years cal. BP), located at the bottom of the gorge five metres above the actual river bed, has evident implications for the canyons morphogenesis. This new chronological datum indicates that most of the canyon was already formed 8600 years ago, and that only five metres of Molasse have eroded since that time. This implies a dramatically high erosion rate during Late Glacial to early Holocene times 0.9 to 1.48 cm/ year) and, consequently, a very low erosion rate since the Atlantic period approximately 0.06 cm/ year). These new archaeological and geological findings offer exciting perspectives for Quaternary research.

Age of Pre-Neoglacial Cirque Moraines in the Central North American Cordillera

In the western mountains of the United States and Canada are pre-Neoglacial cirque moraines that lie up to about 3 km outside Neoglacial moraines. There is considerable uncertainty as to the ages of the outer moraines and whether or not they are age-equivalent from range to range. The variety of assigned radiocarbon ages found in the literature may be partly due to some authors' use of minimum-limiting dates as near-absolute dates, and use of dates that cannot be definitely related to the deposits in question. With one possible exception, all the dated moraines described in the literature could be as old as the type Temple Lake moraine of Wyoming which has a minimum age of about 11,400 yrs BP based on a recently obtained radiocarbon date. Nearly all paleoecological proxy data from the North American Cordillera, generally derived from continuous sedimentary records, suggest that early Holocene climate was warmer than at present. Global circulation models also suggest an early Holocene thermal maximum in the Cordillera, probably due to Milankovitch forcing. For these reasons a proposal gaining popularity in the literature that widespread "Mesoglaciation" occurred in early Holocene time is premature. We hypothesize that most, if not all, of the moraines in question are correlative and date from Late Pleistocene time.

A 25,000-year record of earthquakes on the Owens Valley fault near Lone Pine, California: Implications for recurrence intervals, slip rates, and segmentation models

Research Article| July 01, 2007 A 25,000-year record of earthquakes on the Owens Valley fault near Lone Pine, California: Implications for recurrence intervals, slip rates, and segmentation models Steven N. Bacon; Steven N. Bacon 1Department of Geology, Humboldt State University, Arcata, California 95521, USA Search for other works by this author on: GSW Google Scholar Silvio K. Pezzopane Silvio K. Pezzopane 1Department of Geology, Humboldt State University, Arcata, California 95521, USA Search for other works by this author on: GSW Google Scholar Author and Article Information Steven N. Bacon 1Department of Geology, Humboldt State University, Arcata, California 95521, USA Silvio K. Pezzopane 1Department of Geology, Humboldt State University, Arcata, California 95521, USA Publisher: Geological Society of America Received: 30 Jul 2005 Revision Received: 29 Dec 2006 Accepted: 24 Jan 2007 First Online: 08 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Geological Society of America GSA Bulletin (2007) 119 (7-8): 823–847. https://doi.org/10.1130/B25879.1 Article history Received: 30 Jul 2005 Revision Received: 29 Dec 2006 Accepted: 24 Jan 2007 First Online: 08 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Steven N. Bacon, Silvio K. Pezzopane; A 25,000-year record of earthquakes on the Owens Valley fault near Lone Pine, California: Implications for recurrence intervals, slip rates, and segmentation models. GSA Bulletin 2007;; 119 (7-8): 823–847. doi: https://doi.org/10.1130/B25879.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Seven trenches in eastern California across the Owens Valley fault near Lone Pine expose two episodes of faulting since early Holocene time in the form of ∼1 m throw in lacustrine beds with liquefaction that were buried and then faulted again ∼1 m by the M 7.5 to 7.75 A.D. 1872 Owens Valley earthquake. Geomorphic maps, applications of sequence stratigraphy, and analyses of radiocarbon from charcoal and tufa deposits indicate that the paleoearthquake, the penultimate event here, occurred between 10,200 ± 200 and 8800 ± 200 cal yr B.P. The cumulative vertical displacement from these last two earthquakes in three trenches averages 2.4 ± 0.3 m (2σ), and the penultimate event has slightly larger displacements. A synthesis of available data indicates that the antepenultimate event was probably as large and occurred between ca. 24,000 and 14,000 cal yr B.P. (2σ). Thus, the two interseismic intervals between the last three surface-faulting earthquakes on the southern Owens Valley fault are each ∼10,000 yr. This ∼25,000-year record indicates that the “two-event” normal-oblique slip rate on the Owens Valley fault near Lone Pine is 1.0 ± 0.5 m/k.y. This result is similar to that of several previous geological studies here, yet it is still slower than slip rates on the northern Owens Valley fault and several factors slower than contemporary geodetic measurements. This study attempts to account for different dating methods and interpretational uncertainties, to acknowledge how little is known about the slip history of the Owens Valley fault and adjacent faults, and to consider the role of segmentation, as well as splay and distributed faulting, in comparisons of displacement data among different sites along the entire ∼100 ± 10 km length of the Owens Valley fault. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Occurrence of the Mytilus edulis complex on Nordaustlandet, Svalbard: radiocarbon ages and climatic implications

Fragments of the blue mussel (Mytilus edulis complex) are present on raised beaches in the vicinity of Langgrunnodden and Kinnvika, northwestern Nordaustlandet, Svalbard. Both of these localities are north of 80° N. New radiocarbon age determinations, together with earlier results, show that Mytilus colonies were present in this area for much of the fi rst half of Holocene time—from approximately 9000 to 5800 14C yr BP. Mytilus has also been recorded farther south in Nordaustlandet, at three localities in Wahlenbergfjorden. Age determinations of shells at two of these sites have yielded results in the range of 7400 to 6900 14C yr BP. The arrival of Mytilus to Nordaustlandet coincided with the early Holocene infl ux of warm North Atlantic Water off the west coast of Spitsbergen. The drastic warming in early Holocene time, which resulted in the rapid melt-off of glaciers and ice caps in Svalbard, also facilitated the establishment and perserverance of Mytilus colonies at this high latitude.

Occurrence of the Mytilus edulis complex on Nordaustlandet, Svalbard: radiocarbon ages and climatic implications

Fragments of the blue mussel (Mytilus edulis complex) are present on raised beaches in the vicinity of Langgrunnodden and Kinnvika, northwestern Nordaustlandet, Svalbard. Both of these localities are north of 80° N. New radiocarbon age determinations, together with earlier results, show that Mytilus colonies were present in this area for much of the fi rst half of Holocene time—from approximately 9000 to 5800 14C yr BP. Mytilus has also been recorded farther south in Nordaustlandet, at three localities in Wahlenbergfjorden. Age determinations of shells at two of these sites have yielded results in the range of 7400 to 6900 14C yr BP. The arrival of Mytilus to Nordaustlandet coincided with the early Holocene infl ux of warm North Atlantic Water off the west coast of Spitsbergen. The drastic warming in early Holocene time, which resulted in the rapid melt-off of glaciers and ice caps in Svalbard, also facilitated the establishment and perserverance of Mytilus colonies at this high latitude.

Late Quaternary eolian dust in surficial deposits of a Colorado Plateau grassland: Controls on distribution and ecologic effects

In a semi-arid, upland setting on the Colorado Plateau that is underlain by nutrient-poor Paleozoic eolian sandstone, alternating episodes of dune activity and soil formation during the late Pleistocene and Holocene have produced dominantly sandy deposits that support grass and shrub communities. These deposits also contain eolian dust, especially in paleosols. Eolian dust in these deposits is indicated by several mineralogic and chemical disparities with local bedrock, but it is most readily shown by the abundance of titaniferous magnetite in the sandy deposits that is absent in local bedrock. Magnetite and some potential plant nutrients (especially, P, K, Na, Mn, and Zn) covary positively with depth (3–4 m) in dune-crest and dune-swale settings. Magnetite abundance also correlates strongly and positively with abundances of other elements (e.g., Ti, Li, As, Th, La, and Sc) that are geochemically stable in these environments. Soil-property variations with depth can be ascribed to three primary factors: (1) shifts in local geomorphic setting; (2) accumulation of relatively high amounts of atmospheric mineral dust inputs during periods of land-surface stability; and (3) variations in dust flux and composition that are likely related to changes in dust-source regions. Shifts in geomorphic setting are revealed by large variations in soil texture and are also expressed by changes in soil chemical and magnetic properties. Variable dust inputs are indicated by both changes in dust flux and changes in relations among magnetic, chemical, and textural properties. The largest of these changes is found in sediment that spans late Pleistocene to early Holocene time. Increased dust inputs to the central Colorado Plateau during this period may have been related to desiccation and shrinkage of large lakes from about 12 to 8 ka in western North America that exposed vast surfaces capable of emitting dust. Soil properties that result from variable dust accumulation and redistribution in these surficial deposits during the late Quaternary are important to modern ecosystem dynamics because some plants today utilize nutrients deposited as long ago as about 12–15 ky and because variations in fine-grained (silt) sediment, including eolian dust, influence soil-moisture capacity.

Paleocomunidades vegetales del centro de Tierra Del Fuego durante el Holoceno temprano y tardío

Plant Palaeocommunities of Central Tierra del Fuego during the Early and Late Holocene. This study presents new data for the history of vegetation of central Tierra del Fuego. The goal is to identify the vegetation types before and after the middle Holocene, having in mind previous studies proposing a forest expansion started in early Holocene times following a SW-NE precipitation gradient. Two segments of a Sphagnum peat bog profile (R-2: 54°32’S, 67°04’W), now surrounded by the Nothofagus pumilio (Poepp et Endl.) deciduous forest, were analyzed. The following results were obtained through the modern analogs method: steppe and woodland were found in the older segment and open and closed forest in the younger segment. We concluded that an asynchronous establishment of the involved plant communities occurred. In fact, ca. 7000 years BP, while in other sites of the central island forests were already established, in R-2, located eastwards from those sites, the steppe-woodland ecotone dominated. On the other hand, from ca. 2000 years AP to modern times both open and closed forests covered the central area. The humidity carried by the Southern Westerlies could have influenced the late development of Nothofagus. This study represents an advancement in the knowledge of the vegetation history, and provides new data about the asynchrony in the establishment of communities.

The Transition between the Last Hunter-Gatherers and the First Farmers in Southwestern Europe: The Basque Perspective

The dynamism of the Mesolithic in the Iberian peninsula offers new perspectives for the study of the process of Neolithization. In particular, in the Basque region we observe in Early Holocene times a well-established population that received and adopted Neolithic innovations. The archaeological elements clearly indicate cultural continuity across the transition; here we deal with those related to territoriality, economy, chronology, and lithic and ceramic industries. Whatever the mechanisms by which Neolithic innovations were accessed, these changes were accepted by autochthonous groups that in turn adapted them according to own their tastes and technologies (e.g., with regard to lithic manufacture and pottery decoration). The model presented here is in clear opposition to the "Mediterranean Cardial colonization" model: we do not need to resort to massive demographic movements to understand the progress of the Neolithic within the Iberian peninsula.

Present and former equilibrium line altitudes in the Taiwanese high mountain range

Previously reported values of former equilibrium line altitudes (ELA) for Taiwan are based on sparse field data or extrapolations from Japan or China. This paper presents new calculations based on recently obtained geological data (Hebenstreit, R, Böse, M, 2003. Geomorphological evidence for a Late Pleistocene glaciation in the high mountains of Taiwan dated with age estimates by optically stimulated luminescence (OSL). Zeitschrift für Geomorphologie N.F. Suppl.-Bd.130, 31–49; Hebenstreit, R., Murray, A.S., Böse, M., this vol. Late Pleistocene and Early Holocene glaciations in Taiwanese mountains. Quaternary International) from three Taiwanese mountain massifs ( Nanhuta Shan, Hsueh Shan and Yushan) using established calculation methods (Benn, D.I., Lehmkuhl, F., 2000. Mass balance and equilibrium-line altitudes of glaciers in high-mountain environments. Quaternary International 65–66, 15–29; Porter, S.C., 2001. Snowline depression in the tropics during the Last Glaciation. Quaternary Science Reviews 20(10), 1067–1091). The relationship of annual precipitation and summer (JJA) temperature (Ohmura, A., Kasser, P., Funk, M., 1992. Climate at the equilibrium line of glaciers. Journal of Glaciology 38(130), 397–411) obtained from a 30 year meteorological database is used to estimate the present theoretical (virtual) equilibrium line altitude (ELA t) at about 4000 m over the southern and 3900 m over the northern part of Taiwan. The ELA was 3350–3500 m during Late Glacial to Early Holocene time (11–8 ka). Including a minimum post-glacial mountain uplift rate of 5 mm/a (Lundberg, N., Dorsey, R.J., 1990. Rapid Quaternary emergence, uplift, and denudation of the Coastal Range, eastern Taiwan. Geology 18(7), 638–641); Lin, C.-H., 1998. Tectonic implications of an aseismic belt beneath the eastern central range of Taiwan: crustal subduction and exhumation. Journal of the Geological Society of China 41(3), 441–460) in the calculation, the ELA depression (ΔELA) was 400–550 m during this period. Data from LGM or earlier are still rare, but glacial landforms and deposits indicate the ELA position at 2775–3195 m and the ΔELA of 705–1125 m.

Sedimentologic and paleontologic study of the southeast coast of Buenos Aires province, Argentina: A late Pleistocene–Holocene paleoenvironmental reconstruction

A paleoenvironmental reconstruction of the southeast coast of Buenos Aires province, Argentina, is made mainly on the basis of paleontological and paleoichnological studies, supported by sedimentological analyses and radiocarbon dating. Continental late Pleistocene and continental, transitional, and marine Holocene stratigraphic units are identified. The former comprises fossil mammals and ichnites of 16000–12,000 BP. The continental early Holocene time, ca. 8100 BP, is represented by an interdune paleoenvironment in which shallow brackish ponds were colonized by diatoms, fish, rodents, and birds. A transitional paleoenvironment in the middle Holocene—6930–6570 BP—is recorded by deposits formed by estuarine crabs. During the late Holocene, between 5000 and 4800 BP, a marine transgression was recorded by a rich mollusc fauna.

The Use of Caves in Peninsular Thailand in the Late Pleistocene and Early and Middle Holocene

Caves in peninsular Thailand have a complex history of human use ranging from brief campsites to long-term occupation and from locations of industrial activity to landscapes inhabited by spirit forces. In late Pleistocene times, dating from before than 40,000 B.P. to about 11,000 B.P., caves were used only sporadically as temporary campsites, where people built fires, fashioned tools, and consumed the meals of animal (and presumably plant) products. During early Holocene times, dating from before 11,000 B.P. to about 6500 B.P., many caves were occupied for sufficient duration to have built up sizable midden deposits, occasionally over 1 m thick. Some of these deposits also include burials, usually of single randomly placed individuals with few, if any, grave goods. During mid Holocene times, ca. 6500-3500 B.P., some caves were used as burial grounds, with little if any trace of occupation, whereas others were scenes of domestic activity. Mid Holocene and recent times also saw the use of cave walls as media for paintings, with depictions, often crude, of whole or parts of human figures, fish, birds, and land animals.

Book Notes

Book Notes Compiled and written byKen DuBois NegotiatedMemory: Doukhobor Autobiographical Discourse, by JulieRak (UBC Press,Vancouver, B.C., 2004. Photographs, notes, bibliography, index. 192pages. $29.95 paper) The firstDoukhobor immigrants arrived in Halifax in 1899as refugeesfrom religious perse cution inRussia and, theauthor contends, their community has resisted assimilation ever since. Rak shows how theDoukhobors, faced with widespread misunderstanding and resentment of theirculture,have used a variety of autobio graphical forms to successfullypass along tradi tions and beliefs to successive generations. Democratizing the Enemy:The JapaneseAmerican Internment, byBrianMasaru Hayashi (Princeton University Press, Princeton, N.J., 2004. Notes, index. 339 pages. $35.00 cloth) Racism, wartime hysteria, and poor leadership areoftencited as thereasons Japanese Americans were removed from theirhomes duringWorld War II and held against their will in concentra tion camps. But BrianHayashi contends thatthe U.S. government was also acting on a long-term plan forlanddevelopment in the AmericanWest and theAmerican occupation of Japan. A Common Ground: ErbMemorial Union 1950to 2000, byAdell McMillan (ErbMemorial Union, Eugene, Ore., 2003. Photographs, notes. 718 pages. $31.99 paper) McMillan chronicles the history of the Erb Memorial Union at theUniversity of Oregon and itschanging student cultures.The building opened in 1950 but was in the planning stages forover twenty-five years, fueledby thenotion that itwould promote "an appreciation of the other fellow'spoint of view." Chiefs and Generals:Nine Men Who Shaped the American West, edited by Richard W. Etulain and Glenda Riley (Fulcrum Publishing, Golden, Colo. 2004.256 pages. Photographs, maps, bib liography, index. $17.95paper) The latestbook inRichard Etulain and Glenda Riley's Notable Westerners Series, Chiefs and Generals focuses on Indian and U.S. military figuresand the cultures around them.Nine his torianscontributedpieces on Chief Josephof the Nez Perces,Apache Chief Victorio, Ger?nimo, George Armstrong Custer, Lakota Chief Red Cloud, O.O. Howard, George Crook, Ranald Mackenzie, and Nelson A. Miles. Mar mes Rocksheiter:A Final Report on 11,000 Years ofCultural Use, edited by BrentA. Hicks (Washington State University Press, Pullman, Wash., 2004. Charts, tables,photographs, bibli ography. 466 pages. $65.00 paper) Excavation at the Marmes Rocksheiter tookplace over thirty years ago, but this report is thefirst detailed analysis readilyavailable. Also included is the storybehind the remarkable dig. Despite thediscovery of a human presence dating from early Holocene times, archaeologists had to race to complete theirstudybefore theareawas flooded, in 1969,by the opening of the Snake River's Lower Monumental Dam. Letters To theEditor: As a scholar who has spent the last eleven years collecting new data and critically analyz ing published documentary evidence on the public life ofMeriwether Lewis, I read with particular interest,David Nicandri's article, "The Columbia Country and theDissolution of Meriwether Lewis" (OHQ 106:1,Spring 2005). I Letters 517 ...

Erosional channel incision and the origin of large sediment waves in Trondheimsfjorden, central Norway

An erosional channel and upslope-climbing sediment waves have been observed in Ytre Orkdalsfjorden and the marine fjord branch Gaulosen off the mouth of Gaula River in Trondheimsfjorden, central Norway. The submarine channel (up to 100–150 m wide and 12 m deep) is interpreted as the pathway of hyperpycnal flows and turbidity currents. It can be traced for 20 km on the seafloor from the mouth of Gaula River down to 500 m of water depth. Based on swath bathymetry and seismic data, the sediment waves are shown to have an accumulated thickness of 50–60 m. They are up to 8 m high, have up to 1-km-long crests, and wavelengths of 100–900 m. The sediment waves are attributed to hyperpycnal flows and turbidity currents overflowing the banks of the channel. Many of the sediment waves were instigated by pre-existing topography created by mass movements since early Holocene times.

The Underwater Archaeology of Paleolandscapes, Apalachee Bay, Florida

Submerged prehistoric sites investigated in northwest Florida along the margins of the drowned Aucilla River channel (or PaleoAucilla) extend our understanding of prehistoric settlement patterns and paleolandscape utilization. Bifacial and unifacial tools indicate Late Paleoindian and Early Archaic logistical activities at these sites, as well as later Middle Archaic occupations. Other evidence for terrestrial conditions at these sites include extinct and extant terrestrial faunal remains, in-place tree stumps, and possible eroded middle Holocene shell middens. This report outlines the methodologies used for site investigations, and then discusses the geomorphic setting, character, cultural-historical connections, and timing of full inundation for these offshore sites. During late Pleistocene and early Holocene times, the coastline was much farther out on the continental shelf, and this segment of the PaleoAucilla was forested and well inland. Later, during the middle Holocene stages of transgression, the segment was more of a wide grassy marsh with brackish water tidal creeks and oysters. In this continental shelf setting, submerged archaeological sites remain in clustered arrays accessible by underwater archaeological methods, and the data provide a critical supplement to our present understanding of late Pleistocene and early Holocene settlement patterns and paleolandscape utilization.

EL Nino Influence on Holocene Reef Accretion in Hawai'i

New observations of reef accretion from several locations show that in Hawai'i accretion during early to middle Holocene time occurred in areas where today it is precluded by the wave regime, suggesting an increase in wave energy. Accretion of coral and coralline algae reefs in the Hawaiian Islands to- day is largely controlled by wave energy. Many coastal areas in the main Ha- waiian Islands are periodically exposed to large waves, in particular from North Pacific swell and hurricanes. These are of sufficient intensity to prevent modern net accretion as evidenced by the antecedent nature of the seafloor. Only in areas sheltered from intense wave energy is active accretion observed. Analysis of reef cores reveals patterns of rapid early Holocene accretion in several loca- tions that terminated by middle Holocene time, ca. 5000 yr ago. Previous anal- yses have suggested that changes in Holocene accretion were a result of reef growth ''catching up'' to sea level. New data and interpretations indicate that the end of reef accretion in the middle Holocene may be influenced by factors in addition to sea level. Reef accretion histories from the islands of Kaua'i, O'ahu, and Moloka'i may be interpreted to suggest that a change in wave energy con- tributed to the reduction or termination of Holocene accretion by 5000 yr ago in some areas. In these cases, the decrease in reef accretion occurred before the best estimates of the decrease in relative sea-level rise during the mid-Holocene high stand of sea level in the main Hawaiian Islands. However, reef accretion should decrease following the termination of relative sea-level rise (ca. 3000 yr ago) if reef growth were ''catching up'' to sea level. Evidence indicates that rapid accretion occurred at these sites in early Holocene time and that no permanent accretion is occurring at these sites today. This pattern persists despite the availability of hard substrate suitable for colonization at a wide range of depths between � 30 m and the intertidal zone. We infer that forcing other than rela- tive sea-level rise has altered the natural ability to support reef accretion on Hawaiian insular shelves. The limiting factor in these areas today is wave energy. Numbers of both large North Pacific swell events and hurricanes in Hawai'i are greater during El Nino years. We infer that if these major reef- limiting forces were suppressed, net accretion would occur in some areas in Hawai'i that are now wave-limited. Studies have shown that El Nino/Southern Oscillation (ENSO) was significantly weakened during early-mid Holocene time, only attaining an intensity similar to the current one ca. 5000 yr ago. We speculate that this shift in ENSO may assist in explaining patterns of Holocene Hawaiian reef accretion that are different from those of the present and appar- ently not related to relative sea-level rise.

Vegetation and climate changes in the Changjiang (Yangtze River) Delta, China, during the past 13,000 years inferred from pollen records

A high-resolution pollen record from 2 boreholes from the Changjiang (Yangtze River) delta shows a series of well-defined changes in vegetation and climate over the last 13,000 yr . In latest Pleistocene to early Holocene time (12,900– 10,300 cal yr BP), pollen dominated by the xerophytic herb Artemisia and common conifers indicate coniferous forest and grasslands and a cool, dry climates, possibly represented by the Younger Dryas. From 10,300 to 9000 cal yr BP, a warm, wet climate fostered the development of mixed broadleaved evergreen–deciduous forests to grow on the grasslands and surrounding hills and uplands. From 9000 to 7600 cal yr BP, the dominance of conifers and the reduction in broadleaved evergreen trees pollen suggest cool, dry conditions. The mid-Holocene “hypsithermal” (7600– 4800 cal yr BP) is represented by a large expansion of subtropical evergreen–deciduous broadleaved forests. Between 4800 and 1300 cal yr BP, which corresponds to a Neoglacial period elsewhere, conifers are dominant, along with common herbs, whereas the area with broadleaved evergreen trees shrink under the cool, dry conditions. The first occurrence of Fagopyrum pollen at 4500 cal yr BP suggests human influence. The significant change in arboreal and herbaceous pollen after 1300 cal yr BP reflects widespread intensive human influence.