Linear Mounds Research Articles

An Inventory of Precontact Burial Mounds of Iowa

A long-term project to map and catalog all precontact Native American burial mounds in Iowa provides information about the number, location, form, survivorship, and rate of loss of mounds. This analysis reveals previously undocumented mound manifestations, including a large cluster of 200 linear mounds along the central Des Moines River valley. Historical records reveal that at least 7,762 mounds were identified at 1,551 sites in Iowa between 1840 and the present. About 47% of the mounds from these sites can be possibly seen in lidar, with 33% of the total clearly seen in lidar. Data show that mound loss over time is linear. Extrapolation of data suggests that at least 15,000–17,000 mounds stood in Iowa in the nineteenth century, but the actual number was likely higher.

TEMPO AND TRAJECTORY OF THE BUILT LANDSCAPE ON TA‘Ū ISLAND, MANU‘A GROUP, AMERICAN SĀMOA: INTEGRATING EXTENSIVE RADIOCARBON DATING WITH JOINT POSTERIOR MODELING

ABSTRACTStone and earthen architecture is nearly ubiquitous in the archaeological record of Pacific islands. The construction of this architecture is tied to a range of socio-political processes, and the temporal patterning of these features is useful for understanding the rate at which populations grew, innovation occurred, and social inequality emerged. Unfortunately, this temporal patterning is poorly understood for many areas of the region, including the Sāmoan archipelago. Here, we describe a project directed toward establishing a robust chronology for the construction of these earthen and stone terraces and linear mounds on Ta‘ū Island. Using recent methodological improvements, we highlight the tempo at which different architectural types were constructed on the island and the implications for understanding demographic expansion and changing land tenure practices in the last 1500 years. This research suggests the construction of architecture was largely confined to the 2nd millennium AD with a small number of terraces plausibly built in the 1st millennium AD. This temporal patterning suggests that a reconfiguration of settlement patterns occurred within West Polynesia as people there moved into other regions of Oceania.

THE EARLY IZAPA KINGDOM: RECENT EXCAVATIONS, NEW DATING AND MIDDLE FORMATIVE CERAMIC ANALYSES

AbstractIzapa is famous for its monumental architecture and extensive corpus of carved stelae dated to the Late Formative Guillén phase (300–100 calb.c.). The site was first established, however, as the capital of a kingdom during the second half of the Middle Formative period (750–300 calb.c.). Little is known of the first centuries of the site's occupation or how this early kingdom coalesced with Izapa as its capital. In 2012, the Izapa Regional Settlement Project (IRSP) excavated 21 test units and ran 10 radiocarbon accelerator mass spectrometry (AMS) dates in order to begin correcting this lacuna. These excavations were the first at the site to screen soil matrices and recover artifact samples that can be quantitatively analyzed.We undertook excavations in areas north and south of Group B, the original center of Izapa. This work dates the northern expansion of the site's main platform (under Mound 30a) to the Terminal Formative Itstapa phase (cala.d.100–300) that resulted in a doubling of the platform's size. Further, we documented that there were three distinct construction episodes in the Terminal Formative expansion and that a central staircase and ramp were built of stone during the second episode. Buried below the Terminal Formative platform expansion was a white clay surface built during the Escalón phase (750–500 calb.c.) and used through to Guillén times. At the long, linear Mound 62 that defines the eastern edge of Izapa's site core, we documented two episodes of Guillén-phase monumental construction. Buried below this construction fill at Mound 62, a hearth feature and stone alignment are dated to the late Middle Formative based on radiocarbon assays and the results of ceramic analysis. Excavations at Mound 72 and 73 documented that Izapa's E-Group (newly recognized with lidar [light detection and ranging] data) was established in the late Middle Formative period and then significantly augmented during the Guillén phase. The architectural program at Izapa saw its apogee during the Late Formative period, but was first established during the preceding centuries of the Middle Formative. Ten new AMS dates confirm the dating of the Escalón, Frontera, and Guillén phases to 750–100 calb.c.Ceramic analysis allowed us to differentiate quantitatively between midden deposits and construction fill through the site's occupation and to recognize domestic versus public spaces during the first centuries of the Izapa kingdom's coalescence. We identify late Middle Formative period middens based on the high density of ceramics in addition to good surface preservation of sherds and a lack of temporal mixing of types. The designation of high-artifact density middens contrasts with the contents of Late and Terminal Formative construction fill with lower ceramic sherd densities and mixing of temporally diagnostic types. Off-mound contexts (where construction fill was mined) had even lower ceramic densities than construction fill and the sherds were very eroded. Analysis of ceramic remains from late Middle Formative period midden deposits also allowed us to infer differences in public and domestic areas of the site during the first centuries of its occupation. Formal and metric variables from these ceramic assemblages identify dish-to-jar ratios that differentiate domestic contexts (with an assortment of vessel forms) from more publically oriented areas of the site (with more serving dishes). The differential distribution of rim diameters of fancy and plain dishes allows us to identify areas of Izapa where domestic activities predominate and indicate that more publically oriented feasting practices occurred at the site center near the main pyramid (Mound 30a) during the late Middle Formative period.

The anthropogenic transformation of an island landscape: Evidence for agricultural development revealed by LiDAR on the island of Efate, Central Vanuatu, South‐West Pacific

ABSTRACTTraditional agricultural systems have been a fundamental research focus of Pacific archaeologists for decades. In many island groups, it has been demonstrated that whole landscapes have been transformed to facilitate increased agricultural production. High‐resolution digital elevation models (DEM) derived from recent LiDAR survey data from Efate, Central Vanuatu, have now revealed that much of that island was completely modified by human activity prior to European contact. There are a range of substantial and more minor linear mound and circular features associated with agricultural development and innovation, of which researchers and contemporary populations are largely unaware. Detailed analysis of the features across one alluvial plain provides some quantification of the scale of landscape modification. These new data radically change perceptions of the Efate landscape and contribute to a range of debates including traditional Pacific Island food production, its surplus and sustainability, sociopolitical development, environmental change and depopulation.

Spatially arranged chains of Ge quantum dots grown on Si substrate prepatterned by ion‐beam‐assisted nanoimprint lithography

AbstractJoint experimental and theoretical study of Ge nanoislands growth on groove‐patterned Si(001) substrate prepared by ion‐beam‐assisted nanoimprint lithography is carried out. Prepatterning procedure includes ion irradiation of Si substrate through imprinted resist mask with linear mounds and subsequent multistep oxidation/etching of irradiated Si domains. It is shown that the temperature of subsequent heteroepitaxy on the groovepatterned substrate affects the location of Ge nanoislands. The effect is attributed to additional surface tensile strain formed inside grooves by residual irradiationinduced defects. The interplay of strain and surface curvature makes the critical size of 3D nanoisland larger at the concave regions in grooves than between them. At lower temperatures this results in nanoisland nucleation at the top of mounds. At higher temperatures due to the intensive migration of Ge inside grooves the formation of large nanoislands in grooves occurs. The effect of temperature on the location and size of nanoislands is described by Monte Carlo simulations. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Model of the evolution of mounds placed in the nearshore

A one-dimensional mathematical model is presented that describes the cross-shore evolution of a long linear mound of noncohesive sediment placed in the nearshore and exposed to non-breaking waves. The equation for the transport rate accounts for wave asymmetry and gravity, and the net rate is expressed by reference to an equilibrium profile shape. Simplifications reduce the governing equation for mound evolution to the diffusion equation, for which analytical solutions are available for various initial shapes of the mound. Temporal and spatial dependencies governing mound evolution are obtained from the analytic solutions; for example, a doubling of the wave height implies a certain mound response in 1/8 of the time compared to the original conditions. The governing equation is also solved numerically in order to avoid schematization of the forcing, initial, and boundary conditions. Both the analytical and numerical models are compared with data on mound evolution from several sites around the world. Model predictions agree with trends in measurements of four mounds at widely different sites. An example is given concerning the application of the analytical model for preliminary mound design. The formulation presented also applies to infilling of dredged trenches with lengths much greater than their widths. (Less)

High density of structurally controlled, shallow to deep water fluid seep indicators imaged offshore Costa Rica

We used high‐resolution mapping to document 161 sites of potential fluid seepage on the shelf and slope regions where no geophysical seep indicators had been reported. Identified potential seabed seepage sites show both high‐backscatter anomalies and bathymetric expressions, such as pockmarks, mounds, and ridges. Almost all identified seabed features are associated with bright spots and flat spots beneath, as mapped within the 3‐D seismic grid. We obtained EM122 multi‐beam data using closely spaced receiver beams and 4–5 times overlapping multi‐beam swaths, which greatly improved the sounding density and geologic resolvability of the data. At least one location shows an acoustic plume in the water column on a 3.5 kHz profile, and this plume is located along a fault trace and above surface and subsurface seepage indicators. Fluid indicators are largely associated with folds and faults within the sediment section, and many of the faults continue into and offset the reflective basement. A dense pattern of normal faults is seen on the outer shelf in the multi‐beam bathymetry, backscatter, and 3‐D seismic data, and the majority of fluid seepage indicators lie along mapped fault traces. Furthermore, linear mounds, ridges, and pockmark chains are found on the upper, middle, and lower slope regions. The arcuate shape of the shelf edge, projection of the Quepos Ridge, and high density of potential seep sites suggest that this area may be a zone of former seamount/ridge subduction. These results demonstrate a much greater potential seep density and distribution than previously reported across the Costa Rican margin.

Role of spinel substrate in the morphology of BiFeO3-CoFe2O4 epitaxial nanocomposite films

Epitaxial thin films of BiFeO3-CoFe2O4 composite were grown on spinel MgAl2O4 substrates with a (001) orientation. The composite formed an intriguing nanogrid structure where perovskite BiFeO3 forms linear mounds embedded in a matrix of spinel CoFe2O4. The structure makes a stark distinction with similar composite films on (001) perovskite SrTiO3 substrates where CoFe2O4 forms nanopillars surrounded by a BiFeO3 matrix. This result shows the interface between the film and the substrate that plays a determining role during the formation of the composite.

The Carstairs Kames (Lanarkshire, Scotland): morphology, sedimentology and formation

The Carstairs Kames have been the subject of debate for over 150 yr. A synthesis of previous work, along with new sedimentological data, is used to reappraise this classic British esker locality. Three morphological elements are recognised: (i) large, sinuous and anastomosing ridges; (ii) large, irregular, linear mounds; and (iii) small, low and irregular mounds. The main ridge system is composed of a core of boulder gravel with sand/pebble gravel above and adjacent to the core. The large, linear mounds contain a varied facies range which include: glaciolacustrine sediments (deltaic sequences, laminites and dropstones); debris flows; and glaciofluvial channel systems. All the deposits, both in the main ridges and in the adjacent linear mounds, contain syn-and post-depositional subsidence structures, including normal faults, synclinal folds and growth faults. A range of potential origins for these landforms is reviewed and it is suggested that glaciofluvial sedimentation in a supraglacial environment, controlled by a topography of ice-cored ridges, is the most appropriate depositional model. © 1997 John Wiley & Sons, Ltd.

Age and isotopic constraints on Pleistocene pluvial episodes in the Western Desert, Egypt

Abstract North Africa has undergone drastic climatic changes over the past several hundred thousand years. The timing of humid intervals called pluvials was investigated by uranium-series disequilibrium dating of travertines from the Kurkur Oasis, Western Desert, Egypt. The youngest and best dated travertines (70–160 ka) are found in Wadi Kurkur and include spring and lacustrine units exposed as 2 to 3 m high terraces. Travertines having an age of approximately 191–220 ka are exposed by differential erosion as linear mounds produced by spring systems over fracture zones in ancient wadis. The oldest travertines, having ages >260 ka, are extensive, cap limestone units above the oasis, and were deposited in paludal and lacustrine environments. Oxygen isotope ratios were measured for the wadi travertines (δ18O values ranging from 16.7 to 19.1‰ SMOW) and for spring mound travertines (18.5–20.5‰). Equilibrium oxygen isotope fractionation calculations indicate that the Kurkur travertines were deposited from waters having δ18O values similar to ancient Western Desert groundwaters (∼ −11‰, Sonntag et al., 1978a,b; Thorweithe, 1990; Sultan et al., 1996). The ages of the travertines correspond to times of monsoonal maxima, eustatic sea level high stands and interglacial maxima. Rainfall producing these groundwaters (and travertines) was significantly fractionated during atmospheric transport, in contrast to modern meteoric waters (−2.09‰, Joseph et al., 1992), implying a distant source for the pluvial waters. Increased precipitation, recharge of Western Desert groundwaters, and resultant travertine deposition are interpreted to be consequences of Milankovitch insolation cycle forcing, through enhanced Atlantic and Indian Ocean monsoons during interglacial time periods.

Battlefield Palynology: Reinterpretation of British Earthworks, Saratoga National Historical Park, Stillwater, New York

Pollen analysis was done on a core through a linear mound formerly identified as a 1777 British earthwork at Saratoga National Historical Park. Documents indicate that the British earthwork was built in a forest in a sparsely settled region. Pollen data record a 71-year reforestation sequence under the mound, indicating that it cannot be a Revolutionary War earthwork.

Aeolian Dunes

Technology Today Series articles provide useful summary informationon both classic and emerging concepts in petroleum engineering. Purpose:To provide the general reader with a basic understanding of a significantconcept, technique, or development within a specific area of technology. Aeolian dune deposits of windblown sands are important reservoirs in someparts of the world. The giant Groningen gas field in Holland and the Leman Bankgas field in the North Sea both contain Rotliegendes formation sandstones laiddown on land by winds. These types of deposits require large volumes of drysand and sufficient wind velocities to move the sand. Such conditions areusually found in desert areas (e.g., the Sahara Desert) and along coastalbeaches (e.g., Padre Island, TX). Crescent-shaped, or barchan, dunes are common(see Fig. 1). Other dune shapes are long, linear mounds, which were depositedeither transverse or longitudinal to the wind direction. The sands in the dunesare generally well sorted and range from fine to coarse sizes. However, thedeposit may also contain dry stream beds (wadis) or dry lakes where poorlysorted channels of sand and gravel are found or where thin layers of silts andclay were left. Dunes laid down on deserts may form regional sand sheetshundreds to more than 1,000 ft [300 m] thick covering hundreds of square miles. Those formed on coastal barrier islands may contain individual bars only a fewfeet thick and less than 100 ft [30 m] wide. Lateral and vertical continuity ofsands is generally good but is sometimes severely limited by postdepositionalcementation. Medium- to giant-scale cross-bedding with dips of 20 to 30 degrees[0.35 to 0.52 rad] is commonly observed (see Fig. 2). Horizontal laminae ofclay/silt deposits may be preserved as vertical barriers in some aeolianformations (see Fig. 3). Lateral communication may also be poor in somelow-permeability reservoirs, such as the Leman Bank, as evidenced by the muchlower permeabilities calculated from well tests than those from arithmeticaverages of core data. The geologic models for high- and low-quality aeoliandune reservoirs are shown in Figs. 4A and 4B, respectively. High-qualitydeposits have well-sorted to extremely well-sorted sands. They have widespreadlateral continuity with minor reductions in horizontal permeability resultingfrom cross-bedding. Vertical continuity may be good but occasionallyinterrupted by isolated, horizontal shale beds. Both continuity andpermeability can be poor in low-quality deposits. Development of production, and location and completion of wells in high-quality deposits, are relativelystraightforward. Because of the good continuity of sands, aquifer performanceand recoveries by natural waterdrive may be high. The lack of vertical barriersin high-quality deposits often requires that the wells be completed to minimizeconing of the invading fluid. In low-quality dune deposits where cementationand shale beds are frequent barriers, however, effective drainage of allregions and productivity can be severe problems. In these, an early integratedprogram of coring, logging, and well testing should be carried out indeveloping the field. Analysis of the data by teams of geophysicists, geologists, and engineers can improve understanding of reservoir continuity toaid in locating and completing additional wells and in evaluatingfluid-injection projects. After the field goes on production, surveillanceprojects. After the field goes on production, surveillance programs of periodicpressure surveys and well tests are especially programs of periodic pressuresurveys and well tests are especially important in providing data fordeveloping more-effective depletion plans for maintaining the desiredproduction rates and achieving the highest economical recovery. p. 11

Discussion

T he P resident thanked Dr Magraw for an interesting contribution to the complex problems provided by the Durham Permian and for release of the information on the N.C.B. offshore borings. In the light of Dr Magraw's structural sections (which could be taken to imply an early phase of folding) he asked for confirmation that the sub-Permian floor was still plane, and he enquired whether the ridges of Yellow Sands showed internal sedimentary structure—in particular dune-bedding. H. E. W ilson enquired for more details about the external structure of the basal sandstones. It seems inconceivable that an extensive dune area, of hundreds of square kilometres, could be submerged by an encroaching sea and still retain its dune form. Many of the photographs suggest a resemblance to the Dunnage Formation in Newfoundland and the Disturbed Beds of Denbighshire, and this might indicate a tectonic, rather than straightforward sedimentary, origin. D enys B. S mith writes: I warmly welcome the release of so much new data from this region, which goes far towards confirming that the Permian sequence there is generally similar to that in central and east Yorkshire, where the full English Zechstein sequence is present. I also welcome Dr Magraw’s confirmation of the view presented in several recent publications that the basal Permian (Yellow) Sands are distributed in linear mounds on a flat or gently-sloping peneplane. However, his reinterpretations of the stratigraphy and sedimentary history of Permian marine strata in NE Durham are less acceptable, involving as they do a return to concepts prevailing

Cirencester: The Restoration of the Roman Town Wall, 1967-68

N November 1967 the Ministry of Public Building and Works began the restoration of a section of the Roman Town Wall at Cirencester. The section was along the north-eastern defences of Corinium Dobunnorum, northwards of a point about 550 ft. to the north of the Verulamium Gate.* The wall at this point, with an earth rampart on the inside and an accumulation of its own tumble and other debris on the outside, formed a linear mound about 9 ft. high. The nature of this mound and the position of the wall within it had been determined by excavations carried out in 1960 by Mr. J. S. Wacher, F.S.A., for Cirencester Excavation Committee.' Although nothing of the wall survived above the top of the mound, its full width was exposed in plan when in 1965 the land was being prepared for house-building and the top 2-3 ft. of the mound were bulldozed off and deposited at the sides; a small square turret was also revealed on its inside. In 1966 excavation of this turret and the exposed wall by Mr. P. D. C. Brown for Cirencester Excavation Committee showed that there were two types of wall present-'wide' and 'narrow'-and five recognizable construction phases for the defences :2 (i) The creation of a clay and gravel bank 6 ft. high, presumably to be connected with the diversion of the R. Churn along a new ditch round the periphery of the town; (ii) The erection of the tower on the crest of this bank, on footings which were cut through it, and the piling of a turf and clay rampart which embraced the tower; (iii) The cutting away of the front of the rampart and turret which were then faced with a stone wall 4 ft. wide, and the subsequent heightening of the rampart behind this wall; (iv) The removal and replacement of parts of the 4 foot wall with one which was over 7 ft. wide at the top of the rampart, increasing its width towards the foundations by a series of offset levels at the back, and further heightening of the rampart;

The Globeville Neighborhood in Denver

G LOBEVILLE is an old ethnic community distinctive in modern Denver for just that reason. Among the residents of other sections of the city it is known as a German-Polish working-class residential neighborhood of several thousand persons in the packing-house district. Globeville is now in the second generation beyond the immigrant experience, and distinct departures from the past are taking place. As the old-line families move to the suburbs or pass away, a new group, the Mexican-Americans, is replacing them. Recently, out-migration has been accelerated by the construction of an elevated Interstate Highway through the very heart of the community. Herein lies a fascinating theme for the cultural geographer. What is the spatial expression of such an ethnic community, and how do areal patterns reinforce the identity of a social group? What, indeed, are the neighborhood groupings and patterns in Globeville and how have they changed during the process of invasion? Finally, what is to be the fate of this aging ethnic neighborhood now rudely cleft by a linear mound of dirt and concrete?

10 Summary, Comparisons, and Conclusions

The excavated portion of the Belcher Mound site seems to represent the ceremonial and possibly civil center of a small agricultural community located in the overflow valley of Red River. The village was scattered along the east bank of a stream which presently is inactive but apparently during the life of the site was the main course of Red River, building up its natural levee during the time when the mounds were being constructed. The prehistoric and protohistoric Caddoan inhabitants of the village were primarily farmers, but they were also hunters, fishermen, and gatherers of native foods. Although a riverine people, they left considerable evidence of extensive overland trade and contact.The mounds, originally two which were later incorporated into one linear mound, were habitation substructures built up by accretion which resulted from the covering over of successively burned structures. This burning seemingly related to ceremonies attending deaths of important individuals, and burials in pits sunk through the covered-over burned structures accounted for most of the burials found in the site. A few individual burials were placed beneath house floors or at random in the mounds during construction.