Nineteen-year-old Thura al-Windawi kept a diary during the conflict in Iraq, saying that it was her way of controlling the chaos. The diary, which documents the days leading up to the bombings, the war itself, and the lawless aftermath, puts a personal face on life in Baghdad. As Thura describes her life and that of her two younger sisters, she shows readers the many small details that illuminate the reality of war for Iraqi families, and especially for Iraqi children.
Saturday, August 7, 2010
Thura's Diary: My Life in Wartime Iraq by Thura Al-Windawi
Nineteen-year-old Thura al-Windawi kept a diary during the conflict in Iraq, saying that it was her way of controlling the chaos. The diary, which documents the days leading up to the bombings, the war itself, and the lawless aftermath, puts a personal face on life in Baghdad. As Thura describes her life and that of her two younger sisters, she shows readers the many small details that illuminate the reality of war for Iraqi families, and especially for Iraqi children.
Friday, August 6, 2010
“The last stand of the Pleistocene lake left a shoreline at an elevation of 543m…”
"... indicating a surface area of approximately 236 km3"
Physiographic history of the Afton basin, revisited.
Norman Meek, Department of Geography, University of California, Los Angeles, Ca 90024
Abstract
Surveying errors and interpretative differences between the first two reports (Ellsworth, 1932; Blackwelder and Ellsworth, 1936) on eastern Afton basin indicate that the physiographic history of the basin requires revision. New data indicating offset shorelines and new interpretation of the sediment wedge adjacent to the Manix fault suggest uplift of the Cady Mountains during the middle and late Pleistocene. Moreover, deposits attributed to a lake in the dissected basin may instead be due to local ponding.
Introduction
In 1932, Elmer Ellsworth, a doctoral student at Stanford University, completed an admirable dissertation entitled “Physiographic History of the Afton Basin (Ellsworth, 1932). Because of financial difficulties associated with the Great Depression, Ellsworth left academia to work in the oil business, and the task of further publication on the subject was left to his dissertation adviser, Professor Eliot Blackwelder. Although Blackwelder visited the basin for at least one day in 1931, and again in 1932, his responsibilities as chair of Geology at Stanford (1922-1945) and his fragile health apparently prevented him from independently investigating the basin in detail prior to writing the widely cited summary article “Pleistocene lakes of the Afton basin” (Blackwelder and Ellsworth, 1936).
In the fifty years since its publication, the Blackwelder and Ellsworth article has remained unchallenged. Partly because Ellsworth did not review the article prior to its publication, several important difference exist between the article and his dissertation. These differences, as well as the recent discovery of important elevational errors in the original study, lead to the conclusion that several parts of Blackwelder and Ellsworth (1936) are incorrect, and must now be revised. The purposes of this paper are to discuss the errors in the original study, to note the importance of factual and interpretative difference between the two works, and to provide the result of new surveys and observations of the same features studied by Ellsworth in order to revise the physiographic history of the eastern Afton basin.
“Lake Manix drained to the east, perhaps catastrophically, approximately 18,100 years ago, probably as a result of tectonic movement on the Manix fault or a major increase in river inflow that caused the lake to overflow and out its topographic dam.”
Important Difference Between Ellsworth (1932) and Blackwelder and Ellsworth (1936)
Three differences between the two earliest reports on eastern Afton basin involve critical aspects of basin history. First, Ellsworth (1932, p. 63) suggested that all lakes in Afton basin were probably correlative with substages of the Tioga glacial. Relying on the same evidence, Blackwelder apparently disagreed, correlating the two recognizable lacustrine periods with the Tahoe and Tioga glaciations (Blackwelder and Ellsworth, 1936, p. 463). The correlations in each report were based on qualitative assessments, such as the fresh appearance of the beach ridges and the time believed necessary to erode the basin. The age of the first lacustrine period is still not known even though absolute-age dating techniques have been available for decades. Consequently, previous correlations of lacustrine periods in eastern Afton basin are speculative.
Secondly, Blackwelder and Ellsworth (1936, p. 459) reported the maximum stage of the first lake to be 1795’ (547m). In his dissertation, Ellsworth (1932) did not provide data to support such a statement other than a dished line on one figure (p.23), and in fact, never specifically discussed that maximum stage of the first lacustrine period. Indirectly, he suggested a maximum stage of the first lake by stating that the second lake crested “about 20 feet higher” (Ellsworth, 1932, p. 490). Because Ellsworth provided data indicating that the second lake peaked at 1800’ (548.8m), one can infer that the first lake peaked about 1780 (542.7m). In any case, no evidence was provided to indicate the maximum stage of the first lake, probably because that uppermost shore facies of the first lake have been erosionally truncated in all know exposures.
Finally, Blackwelder and Ellsworth (1936) report a sheet of gravel atop the lacustrine clays “not less than 20’ thick near the middle of the basin and perhaps somewhat thicker toward the margin” (p. 459). In contrast, Ellsworth’s (1932) cross-sections show the same fanglomerate thinning to less than 20’ at distances far removed from the basin center (p. 26).
Surveying Errors in Ellsworth (1932)
Generally speaking, the descriptive data provided by Ellsworth (1932) are reliable, and serve as a simple, but adequate introduction to the stratigraphy of eastern Afton basin (Fig. 1). However, recent repetitions by the author of Ellsworth’s field surveys indicate that his measurements of beach-ridge elevations are erroneous.
Ellsworth reported a maximum elevation of 1800.1’ (548.8m) for north Afton beach ridge, and 1783.2’ (543.7m) for south Afton beach ridge. He also reported closing his survey circuits with net vertical closure error of 0.2’ (0.06m) and 1.2’ (0.37m) respectively (1932, 9. 73).
Recent resurvey of these features indicates that north Afton beach ridge tops out a 542.6m (1779.8’), and that south Afton beach ridge crests at 541.0m (1774.5’). The survey closure errors are 0.11m (0.36’) and 0.03m (0.10’) respectively. The accuracy of the north Afton beach ridge resurvey was independently verified at the beach ridge benchmark by the Los Angeles Department of Water and Power (1779.2’; 542.4m).
There is a possibility that the large surveying errors may not be entirely Ellsworth’s fault, as he mentions using a benchmark at Afton Station reported to be at an elevation of 1425.0’ (434.5m) by the Union Pacific Railroad (Ellsworth, 1932, p. 5). The modern benchmark at Afton Station is at an elevation of 1408’ (429m); NGS/USGS datum), and my casual observations suggest that Afton siding is probably at the same elevation today as in 1931. It is therefore possible that railroad surveyors could be responsible for a major error in the datum used by Ellsworth. However, at least one of Ellsworth’s circuits must have been inaccurate because the measurement errors are not constant.
Apparently failing to independently measure local shoreline features, numerous authors have reported 1800 +/- 5’ (549 +/- 1.5m) shorelines in the Manix basin. Weldon (1982, p. 80) even developed a tectonic hypotheses to explain the reported shoreline elevations. The fact that the maximum shoreline elevation is 543 m, and that the maximum stage of the first lake is unknown, indicates that Weldon’s hypothesis is based on erroneous information.
The reduction in maximum stage from 549 to 543 m also has enormous implications regarding Lake Manix hydrology. For example, lake surface area decreases from about 380 km2 to about 215 km2 (a 44% reduction), lake volume decreases from about 4.55 km3 to about 3.0 km3 (a 34% reduction), and the direction of flow over interfluves reverses in some lake-history reconstructions. Clearly, the original surveying errors have compounded over the years, creating a lake history based more on legend than fact.
Revision of the Physiographic History
The pre-lacustrine stratigraphic sections have not been investigated in detail, and so the physiographic history of the basin prior to the late Pleistocene lakes requires further study. However, preliminary investigations reveal that Ellsworth failed to describe several thick carbonate accumulations in the Brown Fanglomerate (Fig. 2), perhaps mistaking the indurated layers for mudflows (Ellsworth, 1932, pp. 15-16). The carbonate accumulations cement the top of fanglomerate members, and suggest that much of the basin history (early and middle Pleistocene, perhaps extending back into the Pliocene) was characterized by episodic deposition with long intervals of fan-surface stability and carbonate accumulation. As Ellsworth correctly noted (1932, p. 28-29), these fanglomerate deposits provide evidence of post-depositional tectonic folding in eastern Afton basin. There is some evidence east of Afton Station that suggests syn-depositional warping.
The thickness of the uppermost carbonate accumulation in the Brown Fanglomerate marks a lengthy period of surface stability throughout the area, and serves as a crude time-stratigraphic marker. Large boulders of Cave Mountain granite are found south of the Mojave River in the Brown Fanglomerate, indicating that the former basin depocenter was farther south than during the late Pleistocene. Cady Mountains volcanics are comparatively rare in the Brown Fanglomerate southwest of Afton Station. It is therefore unlikely that the Cady Mountain had significant relief in their present position during the deposition of the Brown Fanglomerate. However, increasing quantities of volcanics in carbonate-cemented strata to the east near Afton Canyon suggest that debris was locally shed to the north from the Cady Mountains.
The Gray Fanglomerate is a thick, uncemented, volcaniclastic deposit that overlies the Brown Fanglomerate south of Afton. Notably, the Gray Fanglomerate has only a thin corresponding depositional unit north of Afton Station (Fig. 2). A likely explanation for this difference is that renewed diastrophism has formed a secondary basin between the Mojave River and main trace of the Manix Fault 2 km to the south. In this interpretation, the Gray Fanglomerate is sedimentary fill in a basin formed adjacent to the Manix Fault during late, and perhaps middle Pleistocene time.
This secondary basin may represent a local depression at the surface of a south-dipping thrust fault which uplifted the Cady Mountains, or alternately, it may represent a down- dropped block adjacent to a predominantly strike-slip fault. In either case, continuous deposition is indicated by the relative lack of carbonates in the Gray Fanglomerate relative to the Brown Fanglomerate, and suggests that the Cady Mountains were rapidly uplifted south of Afton during the middle and late Pleistocene.
New shoreline elevation data support this hypothesis of basin development and suggest that tectonic deformation is continuing. Beach remnants south of Afton Station attain a maximum elevation of 541.0 m. Comparative topographic profiles and the relationship of the beach deposit crests to edge of undisturbed fan deposits just to the south suggest that the beach deposits are not highly eroded remnants of much larger feature, but rather, are locally intact and provide accurate lake elevations. The maximum shoreline elevation south of Afton Station is 1.6 m less than the maximum shoreline elevations north of Afton Station, which are all accordant. Because the south Afton beach deposits lie in the middle of the proposed secondary basin, it is likely that the area has dropped approximately 1.6 m in the past 14,000 years in much the same way as during the deposition of the Gray Fanglomerate. Tectonic instability is also suggested by a fault (described by Ellsworth, 1932) with apparent normal offset and a displacement of about 5 m that cuts lake strata in this area.
The lacustrine history of Afton basin is far more complex than Ellsworth (or I) imagined. Although several buried and/or truncated beach deposits have been discovered at various places and at many different elevations throughout Afton basin, none has yet permitted the maximum elevation of the first lake period in Manix basin to be determined. Only circumstantial evidence, and certainly not the ideal stratigraphic relations shown by Ellsworth (1932, p. 23, p. 26) and Blackwelder and Ellsworth (1936, p. 458), suggests that parts of the major beach ridges in Afton basin could be deposits from the first lacustrine period. To emplace the uniform interlacustrine fan unit on both sides of the beach ridges suggest that the ridges were probably eroded first. My observations of the cross-sectional exposure of the beach ridge north of Afton and stratigraphic sections south of Afton suggest that most of the beach deposits equivalent to the first lacustrine period were erosionally truncated during the interlacustrine interval. Consequently, no maximum elevation can be assigned to the first lake period, but it is probable that the lake attained about the same maximum stage as during the second lacustrine period.
"... indicating a surface area of approximately 236 km3"
Physiographic history of the Afton basin, revisited.
Norman Meek, Department of Geography, University of California, Los Angeles, Ca 90024
Abstract
Surveying errors and interpretative differences between the first two reports (Ellsworth, 1932; Blackwelder and Ellsworth, 1936) on eastern Afton basin indicate that the physiographic history of the basin requires revision. New data indicating offset shorelines and new interpretation of the sediment wedge adjacent to the Manix fault suggest uplift of the Cady Mountains during the middle and late Pleistocene. Moreover, deposits attributed to a lake in the dissected basin may instead be due to local ponding.
Introduction
In 1932, Elmer Ellsworth, a doctoral student at Stanford University, completed an admirable dissertation entitled “Physiographic History of the Afton Basin (Ellsworth, 1932). Because of financial difficulties associated with the Great Depression, Ellsworth left academia to work in the oil business, and the task of further publication on the subject was left to his dissertation adviser, Professor Eliot Blackwelder. Although Blackwelder visited the basin for at least one day in 1931, and again in 1932, his responsibilities as chair of Geology at Stanford (1922-1945) and his fragile health apparently prevented him from independently investigating the basin in detail prior to writing the widely cited summary article “Pleistocene lakes of the Afton basin” (Blackwelder and Ellsworth, 1936).
In the fifty years since its publication, the Blackwelder and Ellsworth article has remained unchallenged. Partly because Ellsworth did not review the article prior to its publication, several important difference exist between the article and his dissertation. These differences, as well as the recent discovery of important elevational errors in the original study, lead to the conclusion that several parts of Blackwelder and Ellsworth (1936) are incorrect, and must now be revised. The purposes of this paper are to discuss the errors in the original study, to note the importance of factual and interpretative difference between the two works, and to provide the result of new surveys and observations of the same features studied by Ellsworth in order to revise the physiographic history of the eastern Afton basin.
“Lake Manix drained to the east, perhaps catastrophically, approximately 18,100 years ago, probably as a result of tectonic movement on the Manix fault or a major increase in river inflow that caused the lake to overflow and out its topographic dam.”
Important Difference Between Ellsworth (1932) and Blackwelder and Ellsworth (1936)
Three differences between the two earliest reports on eastern Afton basin involve critical aspects of basin history. First, Ellsworth (1932, p. 63) suggested that all lakes in Afton basin were probably correlative with substages of the Tioga glacial. Relying on the same evidence, Blackwelder apparently disagreed, correlating the two recognizable lacustrine periods with the Tahoe and Tioga glaciations (Blackwelder and Ellsworth, 1936, p. 463). The correlations in each report were based on qualitative assessments, such as the fresh appearance of the beach ridges and the time believed necessary to erode the basin. The age of the first lacustrine period is still not known even though absolute-age dating techniques have been available for decades. Consequently, previous correlations of lacustrine periods in eastern Afton basin are speculative.
Secondly, Blackwelder and Ellsworth (1936, p. 459) reported the maximum stage of the first lake to be 1795’ (547m). In his dissertation, Ellsworth (1932) did not provide data to support such a statement other than a dished line on one figure (p.23), and in fact, never specifically discussed that maximum stage of the first lacustrine period. Indirectly, he suggested a maximum stage of the first lake by stating that the second lake crested “about 20 feet higher” (Ellsworth, 1932, p. 490). Because Ellsworth provided data indicating that the second lake peaked at 1800’ (548.8m), one can infer that the first lake peaked about 1780 (542.7m). In any case, no evidence was provided to indicate the maximum stage of the first lake, probably because that uppermost shore facies of the first lake have been erosionally truncated in all know exposures.
Finally, Blackwelder and Ellsworth (1936) report a sheet of gravel atop the lacustrine clays “not less than 20’ thick near the middle of the basin and perhaps somewhat thicker toward the margin” (p. 459). In contrast, Ellsworth’s (1932) cross-sections show the same fanglomerate thinning to less than 20’ at distances far removed from the basin center (p. 26).
Surveying Errors in Ellsworth (1932)
Generally speaking, the descriptive data provided by Ellsworth (1932) are reliable, and serve as a simple, but adequate introduction to the stratigraphy of eastern Afton basin (Fig. 1). However, recent repetitions by the author of Ellsworth’s field surveys indicate that his measurements of beach-ridge elevations are erroneous.
Ellsworth reported a maximum elevation of 1800.1’ (548.8m) for north Afton beach ridge, and 1783.2’ (543.7m) for south Afton beach ridge. He also reported closing his survey circuits with net vertical closure error of 0.2’ (0.06m) and 1.2’ (0.37m) respectively (1932, 9. 73).
Recent resurvey of these features indicates that north Afton beach ridge tops out a 542.6m (1779.8’), and that south Afton beach ridge crests at 541.0m (1774.5’). The survey closure errors are 0.11m (0.36’) and 0.03m (0.10’) respectively. The accuracy of the north Afton beach ridge resurvey was independently verified at the beach ridge benchmark by the Los Angeles Department of Water and Power (1779.2’; 542.4m).
There is a possibility that the large surveying errors may not be entirely Ellsworth’s fault, as he mentions using a benchmark at Afton Station reported to be at an elevation of 1425.0’ (434.5m) by the Union Pacific Railroad (Ellsworth, 1932, p. 5). The modern benchmark at Afton Station is at an elevation of 1408’ (429m); NGS/USGS datum), and my casual observations suggest that Afton siding is probably at the same elevation today as in 1931. It is therefore possible that railroad surveyors could be responsible for a major error in the datum used by Ellsworth. However, at least one of Ellsworth’s circuits must have been inaccurate because the measurement errors are not constant.
Apparently failing to independently measure local shoreline features, numerous authors have reported 1800 +/- 5’ (549 +/- 1.5m) shorelines in the Manix basin. Weldon (1982, p. 80) even developed a tectonic hypotheses to explain the reported shoreline elevations. The fact that the maximum shoreline elevation is 543 m, and that the maximum stage of the first lake is unknown, indicates that Weldon’s hypothesis is based on erroneous information.
The reduction in maximum stage from 549 to 543 m also has enormous implications regarding Lake Manix hydrology. For example, lake surface area decreases from about 380 km2 to about 215 km2 (a 44% reduction), lake volume decreases from about 4.55 km3 to about 3.0 km3 (a 34% reduction), and the direction of flow over interfluves reverses in some lake-history reconstructions. Clearly, the original surveying errors have compounded over the years, creating a lake history based more on legend than fact.
Revision of the Physiographic History
The pre-lacustrine stratigraphic sections have not been investigated in detail, and so the physiographic history of the basin prior to the late Pleistocene lakes requires further study. However, preliminary investigations reveal that Ellsworth failed to describe several thick carbonate accumulations in the Brown Fanglomerate (Fig. 2), perhaps mistaking the indurated layers for mudflows (Ellsworth, 1932, pp. 15-16). The carbonate accumulations cement the top of fanglomerate members, and suggest that much of the basin history (early and middle Pleistocene, perhaps extending back into the Pliocene) was characterized by episodic deposition with long intervals of fan-surface stability and carbonate accumulation. As Ellsworth correctly noted (1932, p. 28-29), these fanglomerate deposits provide evidence of post-depositional tectonic folding in eastern Afton basin. There is some evidence east of Afton Station that suggests syn-depositional warping.
The thickness of the uppermost carbonate accumulation in the Brown Fanglomerate marks a lengthy period of surface stability throughout the area, and serves as a crude time-stratigraphic marker. Large boulders of Cave Mountain granite are found south of the Mojave River in the Brown Fanglomerate, indicating that the former basin depocenter was farther south than during the late Pleistocene. Cady Mountains volcanics are comparatively rare in the Brown Fanglomerate southwest of Afton Station. It is therefore unlikely that the Cady Mountain had significant relief in their present position during the deposition of the Brown Fanglomerate. However, increasing quantities of volcanics in carbonate-cemented strata to the east near Afton Canyon suggest that debris was locally shed to the north from the Cady Mountains.
The Gray Fanglomerate is a thick, uncemented, volcaniclastic deposit that overlies the Brown Fanglomerate south of Afton. Notably, the Gray Fanglomerate has only a thin corresponding depositional unit north of Afton Station (Fig. 2). A likely explanation for this difference is that renewed diastrophism has formed a secondary basin between the Mojave River and main trace of the Manix Fault 2 km to the south. In this interpretation, the Gray Fanglomerate is sedimentary fill in a basin formed adjacent to the Manix Fault during late, and perhaps middle Pleistocene time.
This secondary basin may represent a local depression at the surface of a south-dipping thrust fault which uplifted the Cady Mountains, or alternately, it may represent a down- dropped block adjacent to a predominantly strike-slip fault. In either case, continuous deposition is indicated by the relative lack of carbonates in the Gray Fanglomerate relative to the Brown Fanglomerate, and suggests that the Cady Mountains were rapidly uplifted south of Afton during the middle and late Pleistocene.
New shoreline elevation data support this hypothesis of basin development and suggest that tectonic deformation is continuing. Beach remnants south of Afton Station attain a maximum elevation of 541.0 m. Comparative topographic profiles and the relationship of the beach deposit crests to edge of undisturbed fan deposits just to the south suggest that the beach deposits are not highly eroded remnants of much larger feature, but rather, are locally intact and provide accurate lake elevations. The maximum shoreline elevation south of Afton Station is 1.6 m less than the maximum shoreline elevations north of Afton Station, which are all accordant. Because the south Afton beach deposits lie in the middle of the proposed secondary basin, it is likely that the area has dropped approximately 1.6 m in the past 14,000 years in much the same way as during the deposition of the Gray Fanglomerate. Tectonic instability is also suggested by a fault (described by Ellsworth, 1932) with apparent normal offset and a displacement of about 5 m that cuts lake strata in this area.
The lacustrine history of Afton basin is far more complex than Ellsworth (or I) imagined. Although several buried and/or truncated beach deposits have been discovered at various places and at many different elevations throughout Afton basin, none has yet permitted the maximum elevation of the first lake period in Manix basin to be determined. Only circumstantial evidence, and certainly not the ideal stratigraphic relations shown by Ellsworth (1932, p. 23, p. 26) and Blackwelder and Ellsworth (1936, p. 458), suggests that parts of the major beach ridges in Afton basin could be deposits from the first lacustrine period. To emplace the uniform interlacustrine fan unit on both sides of the beach ridges suggest that the ridges were probably eroded first. My observations of the cross-sectional exposure of the beach ridge north of Afton and stratigraphic sections south of Afton suggest that most of the beach deposits equivalent to the first lacustrine period were erosionally truncated during the interlacustrine interval. Consequently, no maximum elevation can be assigned to the first lake period, but it is probable that the lake attained about the same maximum stage as during the second lacustrine period.
Calico Early Man Site
This web site describes and analyzes the Calico Archaeological Site and the Calico Lithic Industry, which have been controversial since they appear to support the presence of tool-makers in California’s Mojave Desert some 200,000 years ago–nearly twenty times more remote in time than the generally-accepted date for the earliest human arrivals in the Americas.
About the Site
One of the most controversial archaeological sites in the Western Hemisphere is located in the Mojave Desert of California, near the town of Barstow. The site, in low hills east of the Calico Mountains, displays evidence for the presence of tool-making humans in the Americas some 200,000 years ago, far earlier than any Western Hemisphere site that has been accepted by the majority of the archaeological community. The Calico site has been developed since 1964 by Ruth DeEtte Simpson with the active involvement of Louis B. Leakey, one of archaeology’s greatest names, famed for his pioneering work on the African Paleolithic at Olduvai Gorge in Tanzania.
Controversy centers on two issues: the authenticity of the Calico lithic artifacts and the age of the deposits in which the artifacts are found. At present, more than 11,000 inferred chert and chalcedony tools and detached flakes have been recovered from trenches and pits up to 10 meters deep, excavated in alluvium and fanglomerate cemented to an almost rocklike state by calcium carbonate either leached downward from the surface or deposited by capillary rise from an ancient high water table. The artifacts identified range from crude choppers, scrapers, and handaxes to delicate gravers, reamers, and burins. There is a conspicuous absence of spear or projectile points in any form, suggesting that the artifacts were those of a culture based on collecting rather than the pursuit of large animal prey.
The objective of this internet site is to permit interested parties to view the controversial Calico Site specimens, to answer specific questions about them and their geological context, and to open an informed dialogue about their origin and wider implications.
The site is dedicated to the memories of “Dee” Simpson and Louis Leakey, who had the courage to persevere in the face of academic criticism and even derision. We remember when Alfred Wegener’s “preposterous” theory of “continental drift” was derided similarly, eventually to be reincarnated and embraced as the ruling geological paradigm in the form of “plate tectonics”–a term and concept yet unknown when work at the Calico Site was beginning.
CAUTION!
It is easy to scoff at the Calico “tools” the first time one sees them. They are far from the familiar beautifully-crafted arrowheads and spear points we find in surface and near-surface Indian/PaleoIndian sites across North America. A variety of evidence (presented on subsequent pages) indicates that the Calico tools are some 200,000 years old. Thus they have little resemblance to Indian/PaleoIndian material, which has a maximum age of 11,000-13,000 years. To compare the crude Calico tools with finely-worked Indian/PaleoIndian projectile points is to compare technologies separated in time by well over 100,000 years.
A much more appropriate comparison is with the crude choppers, scrapers, and hand axes of the Old World Paleolithic (Acheulean, Clactonian, etc.), well illustrated in Francois Bordes’ “The Old Stone Age,” or by Googling “Acheulean” (see “image results”). Looking at 200,000-year-old tool assemblages from well-authenticated Old World sites, one sees that Old World Paleolithic tools are, in fact, the very tools unearthed at Calico. Observers familiar only with the North American Neolithic toolkit of refined arrowheads and spear and dart points, will not easily recognize Paleolithic artifacts, which include no projectile points at all. Before assessing the Calico material, such observers should consult illustrations of accepted 200,000-year-old artifacts–the Old World Paleolithic.
In fact, the Calico Site appears to open the door to the New World Paleolithic!!!
Introduction
The North American Great Basin is an arid expanse that reaches from northern Mexico to southern Oregon. It is presently a land of desert shrubs and isolated mountain ranges separated by arid basins that often contain salt flats or parched clay pans. However, it was not always so. At times in the past it has been a brushy landscape spattered with lakes, large and small, and rich with animal life including extinct forms of bison, horses, camels, mammoths, and their predators. In most lowlands, some 15,000 years of Late Pleistocene and Holocene alluvial deposition has effectively buried and sealed earlier sediments and possible traces of a human presence in the region in Pleistocene time–the “Ice Age”–when tool-making humans were present throughout the Old World and when the Great Basin was not the desert it is today.
However, in the Manix Basin (Lower Mojave River Valley) of San Bernardino County, California, close by the Calico Mountains, a fortuitous combination of environmental factors have exposed a series of deposits that represent more than 350,000 years of Quaternary history. Within these deposits are rocks that, if found outside the Western Hemisphere, could easily be regarded as having been artificially modified to form stone tools, or lithic artifacts.
The obvious antiquity of the geologic deposits containing these objects has caused the most influential North American archaeologists to reject them as artifacts. They are rejected on the basis of where they are more than what they are. Consequently the objects have been regarded as geofacts: artifact-like forms produced by natural geologic processes. On the other hand, many European and Asian scholars familiar with Old World Paleolithic technology do indeed recognize many of the Calico specimens as authentic lithic artifacts, implying a human presence in the Americas for a span of time vastly longer than that generally accepted.
The following outlines the setting of the Manix Basin and presents the evidence for occupation of California’s Mojave Desert by tool-fabricating beings at a time equivalent to the classic “Stone Age” in the Old World.
The Setting
The Manix Basin, a structural depression in the central Mojave Desert, bounded by the barren Calico, Paradise, Alvord, Cady, and Newberry Mountains, is the third and lowest major valley of the Mojave River. This withering exotic stream rises in the San Bernardino Mountains, some 200 km to the southeast, and generally carries only a small flow of subsurface water into the Basin. Exceptional storms in the headwater area generate flood flows that occasionally fill the Mojave River channel out to and beyond the town of Barstow. However, surface flow at Barstow is rare.
Some 400,000 - 500,000 years ago, factors relating to elevation and drainage patterns, annual precipitation, mountain snow pack, cloud cover and evaporation were such that the Manix Basin became the site of a freshwater lake known as Pleistocene Lake Manix. The size of the early lake, fed by the inflow of a much enhanced Mojave River, is uncertain, and the early lake is known only by local exposures of its sediments. Lakes persisted in the basin until Late Pleistocene time. The last stand of the Pleistocene lake left a shoreline at an elevation of 543 m (Meek 1989, 1990), indicating a surface area of approximately 236 km2, and a volume of approximately 3.15 km3. Lake Manix drained to the east, perhaps catastrophically, approximately 18,100 years ago, probably as a result of tectonic movement on the Manix fault or a major increase in river inflow that caused the lake to overflow and wash out its topographic dam (Meek 1989, 1990, 1999).
Meek, N.
1989 Physiographic History of the Afton Basin, Revisited. In The West-Central Mojave: Quaternary Studies Between Kramer and Afton Canyon, edited by R.E. Reynolds, pp. 78-83. San Bernardino County Museum Association, Redlands, California.
Meek, N.
1990 Late Quaternary Geochronology and Geomorphology of the Manix Basin, San Bernardino County, California. Unpublished Ph.D. dissertation, University of California, Los Angeles.
Meek, N.
1999 New Discoveries About the Late Wisconsinan History of the Mojave River System. In Tracks Along the Mojave: A Field Guide from Cajon Pass to the Calico Mountains and Coyote Lake, edited by R.E. Reynolds and J. Reynolds, San Bernardino County Museum Association, Redlands, California.
Evidence of the history of Lake Manix remains in the clay, silt, sand, and gravel sequences of the Manix Formation, which contains remains of numerous Rancholabrean animals ranging in age from approximately 20,000 years to well in excess of 350,000 years before present (Jefferson 1968, 1985a, 1985b, 1987, 1989, 1991). The richest fossiliferous section has been well dated by radiocarbon dating, uranium-series techniques, and trace element correlation of a volcanic tephra to a source well dated by the potassium-argon (K/Ar) method. Among the fossils recovered are camel, horse, mammoth, ground sloth, saber-tooth cat, dire wolf, short-faced bear, coyote, flamingo, pelican, eagle, swan, geese, mallard duck, ruddy duck, canvas-backed duck, double-crested cormorant, grebe, crane, seagull and stork. This fauna would have been a bountiful resource for any humans in the vicinity of the lake.
Jefferson, G.T.
1968 The Camp Cady Local Fauna from Pleistocene Lake Manix, Mojave Desert, California. Unpublished Master's thesis, University of California, Riverside.
Jefferson, G.T.
1985a Review of the Late Pleistocene Avifauna from Lake Manix, Central Mojave Desert, California. History Museum of Los Angeles, Contributions in Science 362:1-13
Jefferson, G.T.
1985b Stratigraphy and Geologic History of the Pleistocene Manix Formation, Central Mojave Desert, California. In Cajon Pass to Manix Lake, Geologic Investigations along Interstate 15, compiled by R.E. Reynolds, pp. 157-169. San Bernardino County Museum, Redlands, California.
Jefferson, G.T.
1987 The Camp Cady Local Fauna Paleoenvironment of the Lake Manix Basin. San Bernardino Museum Association Quarterly 34(3-4):3-35.
Jefferson, G.T.
1989 Late Pleistocene and Earliest Holocene Fossil Localities and Vertebrate Taxa from the Western Mojave Desert. In The West-Central Mojave Desert: Quaternary Studies Between Kramer and Afton Canyon, edited by R.E. Reynolds, pp. 27-40. Special Publication, San Bernardino County Museum Association, Redlands, California.
Jefferson, G.T.
1991 A Catalogue of Late Quaternary Vertebrates from California: Part One, Nonmarine Lower Vertebrates and Avian Taxa. Natural History Museum of Los Angeles County, Technical Reports, No. 5.
Three separate associations of lithic artifacts are recognizable in the Manix Basin. These are described in the following section.
Manix Basin Artifact Assemblages
Three separate assemblages of lithic artifacts can be distinguished in the Manix Basin. The youngest are Indian and Paleo-Indian, consisting of pottery sherds, spear points, arrowheads, knives, and debitage, all of which lie loose on the surface, and lack significant discoloration by iron- and manganese-rich rock varnish. Such artifacts may range in age from 200 years to a maximum of about 8,000 years.
Clearly older is the Lake Manix Lithic Industry, including artifacts found on and just below the surface at elevations above 543 m, the shoreline elevation of Pleistocene Lake Manix, which drained approximately 18,000 years ago. Artifacts of the Lake Manix Lithic Industry exhibit rock varnish patinas on both their buried and exposed surfaces and are often found embedded in desert pavements, unlike the Paleo-Indian artifact assemblage. The Lake Manix artifacts are described in more detail on the next screen.
The controversial Calico Lithic Industry artifacts are present within a severely eroded deposit that appears to be the remnant of an ancient alluvial fan that was formerly connected to the Calico Mountains, north of Yermo. The fan remnant–the so-called Yermo Fan–consisting of round-crested ridges and narrow gullies, is now well separated from its original source by uplift and erosion that has completely destroyed the original fan form, exposing the material upon which the fan was deposited. The objects identified as artifacts have been recovered from the nested Pleistocene mud and debris flows composing the original fan. The fan deposits are cemented throughout by calcium carbonate older than the limit of radiocarbon dating (~40,000 yrs), beneath a surface soil having an estimated age of 100,000 years. The deposits have been dated to 135,000 years by thermoluminescence (TL) dating and to about 200,000 years by uranium-series analysis. It is the objects found in these deposits that are in question. Are they artifacts or geofacts? If they are artifacts, they appear to be close to twenty times the age of the oldest North American artifacts that have achieved general acceptance–the Clovis tool kit.
The Lake Manix Lithic Industry
Surface sites of the Lake Manix Lithic Industry have been recorded in the northern half of the Manix Basin (Simpson 1960, 1976; Alsoszatai-Petheo 1975, Binning et al. 1985). They are devoid of pottery, shell objects, and projectile points. Lithic artifacts, fashioned primarily of chalcedony, chert, and jasper, include large oval bifaces, scrapers of several forms (end, straight, concave, pointed, convex, pointed, and plano-convex), cutting tools, choppers, chopping tools, large stout picks, gravers, cutting tools, rotational tools, and flakes, as well as cores, anvils and hammerstones.
Simpson, R.D.
1960 Archaeological Survey of the Eastern Calico Mountains. The Masterkey 34(1):25-35
Simpson, R.D.
1976 The Manix Lake Industry: Early Lithic Tradition or Workshop Refuse? A Commentary on W. Glennon's Article. Journal of New World Archaeology 1(1):63-66.
Alsoszatai-Petheo, J.
1975 The East Rim Site, California (S.B.C.M. 1803): An Early Western Lithic Co-Tradition. Unpublished Master's thesis. Eastern New Mexico State College, Portales, New Mexico.
Binning, J.D., R.S. Brown, N. Meek, and E.B. Weil
1985 Intermountain Power Project (IPP): The Cultural Resources Studies of the Ground Electrode Facility at Coyote Lake, San Bernardino County, California. Prepared for City of Los Angeles, Department of Water and Power by Applied Conservation Technology, Inc., Westminster, California.
Manix Lithic Industry artifacts are often found incorporated into desert pavements, and usually exhibit rock varnish on both their buried and exposed surfaces: sporadic black, manganese-rich varnish atop orange, iron-rich varnish on exposed surfaces, and orange, iron-rich varnish on surfaces in contact with the soil. Younger Paleo-Indian artifacts found at lower elevations along the river and in sand dune sites are not varnished, nor are they incorporated into desert pavements.
Based on a dated pollen profile at site CA-SBR-2120 and the occurrence of this assemblage above the most recent shoreline elevation of Pleistocene Lake Manix (543 m), the Lake Manix Lithic Industry is inferred to be at least 18,000 years old.
The presumed eastern extension of the Yermo Fan, known as The East Rim Site (CA-SBR-2120), is a lithic workshop with bifacial and unifacial artifacts as well as debitage on and beneath a desert pavement surface to a depth of 15 cm (Alsoszatai-Petheo 1975). Recovered pinyon and juniper pollen suggests occupation 17,000 - 34,000 years ago. Unifacial artifacts include choppers and end, side, and convex-edged side scrapers. Bifacial artifacts include chopping tools, generalized bifaces, wedge-shaped bifaces, ovate bifaces, cutting tools, and utilized flakes. Unflaked artifacts include hammerstones, pecking stones, and pointed tools. Rare specimens include multiple scrapers, tortoise scrapers, gravers, pointed scrapers (borers), and keeled scrapers.
Tuesday, July 27, 2010
I watched Julie & Julia and thought what a fun and delicious thing to do.
So,
Pates and Terrines (Pates et Terrines)
The memory of a good French pate can haunt you for years. Fortunately they are easy to make, and you can even develop your own special pate maison. Do not expect a top-notch mixture to be inexpensive, however, for it will contain ground pork, pork fat, and usually veal, as well as cognac, port, or Madeira, spices, strips or cubes of other meats, game or liver, and often truffles. It the mixture is cooked and served cold in its baking dish it is called either a terrine or a pate. If it is molded in a pastry crust, it is a pate en croute. A boned chicken, turkey, or duck filled with the same type of mixture is a galantine. Pates and terrines will keep for about 10 days under refrigeration; they are fine to have on hand for cold impromptu meals, since all you need to serve with them are a salad and French bread.
Wine to serve with pates include the dry whites such as Chablis or Macon, roses, or one ff the light regional wines such as Beaujolais or Chinon, or a good domestic wine of the same general types.
A Note on Pork Fat
Fresh pork fat is an essential ingredient for the type of meat mixture which goes into a pate. Blended with the meats, it prevents them from being dry and gives them a lighter texture. Cut into thin sheets, bordes de lard, it is used to line the inside of a baking dish. The best is fat back - lard gras. This comes from the back of the pig next to the skin. It is firm and does not disintegrate as easily as fat from other parts of the animal. Fresh fat back is unfortunately difficult fo find in America outside of areas catering to special clienteles. Alternatives are fat salt pork simmered for 10 minutes in water to refreshen it and remove the salt, or fat trimmed from fresh ham, or from around a fresh pork loin. Thick strips of fat bacon, simmered for 10 minutes in water to remove the smoky taste, may be used to line a baking dish.
Recipe from Mastering the Art of French Cooking by Julia Child, Louisette Berthalle and Simone Beck.
Monday, July 26, 2010
Geology Lesson - Igneous Rocks
Igneous focks are formed by the solidification of molten rock material.
Intrusive igneous rocks - When molten materials from Earth's interior cool without breaking through the Earth's crust, they are surrounded by insulating rocks and they cool very slowly. Slow cooling allows the crystallizing minerals to form in chemical and crystalline purity. The slow accretion of chemicals to the crystal lattice allows large crystals to grow.
Extrusive igneous rocks - When magma is forced upwards and leaks or is blasted out onto the surface, although chemically the same as the intrusive type above, these volcanic rocks are markedly different in appearance. The molten mass is quickly chilled by the cold rock surface over which it flows. The minerals freeze before they have an opportunity to grow into large crystals. The resulting rock is dense or even glassy, with few or no visible crystals.
Fortunately, there are certain similar characeristics between the intrusive and extrusive igneous rocks. Since they share the same fundamental chemisty, their classification systems can be shared. The rocks are named on the basis of their chemistry. Some have an abundance of light-weight silica. This creates a low density rock with only a few dark iron- or magnesium-bearing minerals. Other, silic-poor, aare dense and dark. They are rich in dark ferro-magnewium minerals. The names reflect this simple difference in chemical components. But all is not black and white in the real world of rocks. There are many shades of gray, and we have names forthe gray rocks as well.
So, here comes the good stuff.
The so-called crust of the Earth is about 20 mi. thick under the continents but averages only some 4 mi. beneath the oceans. It is formed mainly of rocks of relatively low density. Beneath the crust there is a layer of denser rocks called the mantle which extends down to a depth of nearly 2000 mi. Much of the molten rocks material which goes to make up the igneous rocks is generated within the upper parts of the mantle. This material, which is called magma, migrates upward into the Earth's crust and forms rock masses which are known as igneous intrusions. If magma reaches the Earth's surface and flows out over it, it is called lava.
Within some lavas, fragment of dense, green-colored rocks are sometimes found which consist principally of olivine and pyroxene. These fragments (xenoliths) are thought to represent pieces of the mantle, carried upward by the migrating magma.
The great majority of lavas consist of the black, rather dense rock called basalt, and most petrologist consider that the primary molten rock material which comes from the mantle has a composition which is near to that of basalt. Although basalt is the most abundant of the lavas, granite is by far the commonest of the intrusive igneous rocks. Granite is mineralogically and chemically different from basalt and for many years geologist have wrestled with the problem of how the two rock types are related. If basalt is assumed to derive from the mantle, is it likely that granite, whcih is of a quite diifferent compositon, could also come from the mantle?
Intrusive igneous rocks - When molten materials from Earth's interior cool without breaking through the Earth's crust, they are surrounded by insulating rocks and they cool very slowly. Slow cooling allows the crystallizing minerals to form in chemical and crystalline purity. The slow accretion of chemicals to the crystal lattice allows large crystals to grow.
Extrusive igneous rocks - When magma is forced upwards and leaks or is blasted out onto the surface, although chemically the same as the intrusive type above, these volcanic rocks are markedly different in appearance. The molten mass is quickly chilled by the cold rock surface over which it flows. The minerals freeze before they have an opportunity to grow into large crystals. The resulting rock is dense or even glassy, with few or no visible crystals.
Fortunately, there are certain similar characeristics between the intrusive and extrusive igneous rocks. Since they share the same fundamental chemisty, their classification systems can be shared. The rocks are named on the basis of their chemistry. Some have an abundance of light-weight silica. This creates a low density rock with only a few dark iron- or magnesium-bearing minerals. Other, silic-poor, aare dense and dark. They are rich in dark ferro-magnewium minerals. The names reflect this simple difference in chemical components. But all is not black and white in the real world of rocks. There are many shades of gray, and we have names forthe gray rocks as well.
So, here comes the good stuff.
The so-called crust of the Earth is about 20 mi. thick under the continents but averages only some 4 mi. beneath the oceans. It is formed mainly of rocks of relatively low density. Beneath the crust there is a layer of denser rocks called the mantle which extends down to a depth of nearly 2000 mi. Much of the molten rocks material which goes to make up the igneous rocks is generated within the upper parts of the mantle. This material, which is called magma, migrates upward into the Earth's crust and forms rock masses which are known as igneous intrusions. If magma reaches the Earth's surface and flows out over it, it is called lava.
Within some lavas, fragment of dense, green-colored rocks are sometimes found which consist principally of olivine and pyroxene. These fragments (xenoliths) are thought to represent pieces of the mantle, carried upward by the migrating magma.
The great majority of lavas consist of the black, rather dense rock called basalt, and most petrologist consider that the primary molten rock material which comes from the mantle has a composition which is near to that of basalt. Although basalt is the most abundant of the lavas, granite is by far the commonest of the intrusive igneous rocks. Granite is mineralogically and chemically different from basalt and for many years geologist have wrestled with the problem of how the two rock types are related. If basalt is assumed to derive from the mantle, is it likely that granite, whcih is of a quite diifferent compositon, could also come from the mantle?
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