Publications | 1993 - 95
Research Publications (1993 - 95)
Patterson, R.T., Barker, T., and
Burbidge, S.M.,1996, Arcellaceans (Thecamoebians) as Proxies of
Arsenic and Mercury Contamination in Northeastern Ontario Lakes.
Journal of Foraminiferal Research (no. 2, April).
Asioli, A., Medioli, F.S., and Patterson,
R.T.,1996, Thecamoebians as the tool for reconstruction of paleoenvironments
in some southern Alpine Lakes (Orta, Varese and Candia). Journal
of Foraminiferal Research.
Reinhardt, E.G., Easton, N., Patterson,
R.T., 1996, Foraminiferal evidence of late Holocene sea-level
change on Amerindian site distribution at Montagu Harbour, British
Columbia. Geographie Physique et Quaternaire.
Patterson, R.T., Guilbault, J.-P.,
Thomson, R.E., and Luternauer, J.L. 1995, Foraminiferal Evidence
of Younger Dryas isochronous cooling on the British Columbia shelf,
west coast of Canada. Geographie Physique et Quaternaire, 49 (no.
Patterson, R.T., Cavazza, W., and
Blenkinsop, J., 1995, Planktic foraminiferal biostratigraphy and
87Sr/86Sr Isotopic stratigraphy of the Oligocene-to Quaternary sedimentary
sequence in the southern Calabrian-Peloritani Arc, southern Italy:
Journal of Paleontology, 69: 7-20
Patterson, R.T., and Burbidge, S.M.,
1995, New Late Oligocene to Pleistocene hyaline calcareous unilocular
foraminifera from DSDP Site 357 (Leg 39) on the Rio grande Rise,
southwest Atlantic Ocean. Journal of Paleontology, 69: 635-655.
Jonasson, K.E., Schröder-Adams,
C.J. and Patterson, R.T.,1995,Benthic foraminiferal distribution
at Middle Valley, Juan de Fuca Ridge: a Northeast Pacific hydrothermal
venting site. Marine Micropaleontology, 25: 151-167.
Clark, F., Patterson, R.T., and
Fishbein, E, 1994, Distribution of Holocene benthic foraminifera
from the tropical southwest Pacific Ocean. Journal of Foraminiferal
Research, 24: 241-267
Reinhardt, E.G., Patterson, R.T.,
and Schröder-Adams, C.J. 1994, Geoarchaeology of the ancient
harbor site of Caesarea Maritima, Israel: evidence from sedimentology
and paleoecology of benthic foraminifera. Journal of Foraminiferal
McKillop,W.B., Patterson, R.T.,
Delorme, L.D., Nogrady, T. 1992 (published in 1994). The origin,
physico-chemistry and biotics of sodium chloride dominated saline
waters on the western shore of Lake Winnepegosis, Manitoba. Canadian
Patterson, R.T., 1993. Late
Quaternary benthic foraminiferal biofacies and paleoceanography
of Queen Charlotte sound and southern Hecate Strait, British Columbia.
Journal of Foraminiferal Research, 23:1-18.
Patterson, R.T., Cavazza, W.,
and Blenkinsop, J. 1993.Tortaguttus stiloensis, a new species
of foraminifera from the Plio-Pleistocene of Calabria, Italy: Transactions
of the American Microscopical Society, 112:168?171.
Evoy, R.W., Moslow, T.F., Patterson,
R.T., and Luternauer, J.L. 1993. Patterns and variability in
sediment accumulation rates, Fraser River delta foreslope, British
Columbia, Canada. Geo-Marine Letters, 13:212-218
Fishbein, E., and Patterson, R.T.,
1993. "Error weighted maximum likelihood (EWML)" a new statistically
valid method to cluster quantitative micropaleontological data.
Journal of Paleontology, 67:475-486.
Mathewes, R.W., Heusser, L.E., and
Patterson, R.T., 1993.Evidence for a Younger Dryas-like cooling
event on the British Columbia coast. Geology, 21:101-104.
Clark, F., and Patterson, R.T.,
1993. A taxonomic key to the unilocular genera of calcareous foraminifera.
Journal of Paleontology, 67:20-28.
Josenhans, H.W., Barrie, J.V., Conway,
C., Patterson, R.T., Mathewes, R.W. and Woodsworth, G.J.
1993. Surficial geology of the Queen Charlotte Basin: evidence of
submerged proglacial lakes at 170 m on the continental shelf of
western Canada. Current Research, Paper 93-1A: 186?192
Patterson, R.T., and Luternauer,
J.L. 1993. Holocene foraminiferal faunas from cores collected on
the Fraser River delta, British Columbia: a paleoecological Interpretation:
Current Research, Paper 93-1A:245-254.
as Proxies of Arsenic and Mercury Contamination in Northeastern
R.T. Patterson, T. Barker, and S.M. Burbidge
Journal of Foraminiferal Research (1996) v. 26 (no. 2).
Q-mode cluster analysis of arcellacean populations in three
small lakes (two heavily polluted by mine tailings) near the town
of Cobalt in northeastern Ontario permitted five distinct faunal
assemblages to be recognized and related to ecologic tolerance.
Mine waste and mill tailings were dumped into Crosswise Lake until
1970, and a leaking tailings dam continues to pollute Peterson Lake.
Natural sedimentation is slowly burying the tailings in these lakes
but areas of highly toxic sediments remain exposed in several areas.
Levels of arsenic and mercury contamination in the substrate are
as high as 7110 ppm and 2.54 ppm, respectively, in Crosswise Lake;
and 8330 ppm and 0.77 ppm, respectively, in Peterson Lake (maximum
acceptable concentrations for aquatic life are 50 ppm and 0.100
ppm, respectively). A Contaminated Substrate Assemblage (1), dominated
by Centropyxis aculeata (x=27.5%), Centropyxis constricta
(x=13.5%), and Arcella vulgaris (x=9.7%), characterizes
the most heavily polluted parts of the lakes. Centropyxids, known
to be opportunistic and capable of withstanding hostile conditions,
become less dominant in biofacies found in substrates characterized
by progressively less mine tailing contamination (Mine Tailings
Assemblage , Muddy Substrate Assemblage , and Diatom Mud Assemblage
Unpolluted Gillies Lake was not comparable with Crosswise or Peterson
lakes as a pronounced thermocline results in significantly different
limnological conditions (i.e., very low bottom temperatures and
oxygen concentrations) in that lake. The presence of a Cucurbitella
tricuspis (x=90.3%) dominated fauna (Transported Fauna Assemblage
) in most Gillies Lake samples is enigmatic as no significant
populations of Spirogyra spp., the algae with which the partially
planktic Cucurbitella tricuspis has a symbiotic relationship,
have been observed. We suspect that Assemblage 5 is allochthonous.
The results of this pilot study indicate that arcellaceans are
useful not only to monitor environmental pollutants but to assess
rates of lake remediation.
Thecamoebians as the tool for reconstruction
of paleoenvironments in some southern Alpine Lakes (Orta, Varese
A. Asioli, F.S. Medioli, and R.T. Patterson,
Journal of Foraminiferal Research (1996) v. 26 (no. 3)
A study of Thecamoebians was carried out on three sediment
cores collected in three Northern Italian lakes (Orta, Varese, Candia).
The recognition of distinct morphotypical populations ("morphs ")
within three species of thecamoebians in varying paleolomnological
settings has resulted in a refined understanding of the environmental
parameters controlling their distribution. For example: D. proteiformis
morph "proteiformis" is well adapted to environments rich in organic
matter and sulphides while D. proteiformis morph "rapa" tolerates
polluted and acidified waters (presence of: copper sulfates, ammonium
sulfates, high content of ammonium and nitrite nitrogen, and water
with pH values between 3.9 and 4.5).
Although most questions about the ecology of thecamoebians are
still unresolved, this study strongly suggests that with further
research these Protozoa can be used as a valuable tool for paleoenvironmental
reconstructions and detection of environmental deterioration.
Foraminiferal evidence of late Holocene
sea-level change on Amerindian site distribution at Montagu Harbour,
E.G. Reinhardt, N. Easton, R.T. Patterson
Geographie Physique et Quaternaire. (1996)
Foraminiferal and sedimentological analysis of an underwater
stratigraphic section from an Amerindian habitation site at Montague
Harbour, British Columbia has further documented late Holocene sea
level changes. It appears that part of the documented transgression
was caused by tectonic subsidence of the area (Event 1 at approx.
3500 calendar years BP and Event 2 sometime before 1100 calendar
years BP) and was recognized in the stratigraphic record by rapid
environmental changes. The environmental changes caused by rapid
shifts in water depth were recognized through sedimentological and
foraminiferal evidence. The tectonic subsidence events, coupled
with gentle late Holocene transgression, caused the breaching of
Montague Harbour's northwestern channel. The breaching of the channel
improved water circulation and increased salinity within the harbour.
The salinity changes are reflected in the shift from a low salinity
Cribroelphidium excavatum (Terquem, 1876) phenotype "clavata"
dominated biofacies (1) at the base of the section to a higher salinity
Buccella tenerrima (Bandy, 1950) and Elphidiella hannai
(Cushman and Grant, 1927) dominated biofacies (2) at the top. These
sea-level changes would have eventually forced local Amerindian
settlements inland. The 14C dating of wood and shell, indicates
that the recovery of archaeological remains of the Charles culture
(ca.6500-3200 years BP) requires investigation in deeper waters.
Foraminiferal Evidence of Younger
Dryas isochronous cooling on the British Columbia shelf, west coast
R.T. Patterson, J.-P. Guilbault, R.E. Thomson, and J.L.
G*ographie Physique et Quaternaire, (1995) 49 (no. 3).
Foraminiferal analysis was carried out on a 12,000 - 9,000
years old piston core from Goose Island Trough, Queen Charlotte
Sound, on the British Columbia shelf. Cluster analysis of the data
resulted in the recognition of five separate faunas related to distinct
paleoceanographic phases. These results provide detailed information
on the paleoceanographic conditions that prevailed during passage
of a late Quaternary glacial isostatic forebulge across the region,
and during a cool interval correlatable with the Younger Dryas cold
Passage of the glacial forebulge (beginning 11,470-11,260 years
BP and terminating prior to 10,000 years BP) resulted in a gradual
decrease in water depth to ~75-90 m at the core site, based on sedimentological
data and increasing proportions of shallow-water benthic foraminifera.
In the early stages of the regression, circulation remained
open and salinity at near normal marine levels, as indicated by
the high Shannon diversity indexes (up to 2.5) and the high proportion
of planktic foraminifera. The fall in the proportion of planktic
foraminifera from 11.8 to 2.6% suggests that the area became more
isolated from the open ocean late in the regression. Near glacial
conditions between ~11,100 ? 10,000 years BP at this locality are
unrelated to passage of the glacial forebulge. The presence of very
cold low-salinity water in the area is shown by high proportions
of Cassidulina reniforme and Islandiella helenae.
The depressed salinity and temperature may have resulted from a
modification of regional weather patterns during the Younger Dryas
cold phase. Decreased mean continental summer temperatures could
have reduced the seasonal influence of the North Pacific High and
lengthened that of the Aleutian Low. This would have resulted in
a near continuous surface onshore Ekman transport, which combined
with enhanced coastal runoff, would have effectively blocked the
movement onto the shelf of deep, saline and less cold water of the
California Undercurrent. The resultant isolated inshore basin comprised
of the present-day Hecate Strait and Queen Charlotte Sound is tentatively
named the "Hecate Sea".
By ~10,000 years BP the Younger Dryas?like cooling event had terminated
and weather and oceanographic circulation had returned to near modern
patterns as indicated by the near replacement of Islandiella
helenae by Nonionellina labradorica and by the development
of a modern Epistominella vitrea dominated biofacies. Paleoceaonographic
details associated with the termination of the cooling event are
difficult to determine precisely due to the rapid increase in water
depth at this locality after 10,000 years BP. Once water depth reached
100 m the site may once again have been influenced by upwelling,
resulting in the climate signal blending with a water depth signal.
Planktic foraminiferal biostratigraphy
and 87Sr/86Sr Isotopic stratigraphy of the Oligocene-to Quaternary
sedimentary sequence in the southern Calabrian-Peloritani Arc, southern
R.T. Patterson, W. Cavazza, and J. Blenkinsop,
Journal of Paleontology, (1995), v. 69, p. 7-20
Integration of foraminiferal biostratigraphy, 87Sr/86Sr isotope
stratigraphy and traditional physical stratigraphy has provided
a refined age control of a poorly known Oligocene-to-Pleistocene
sedimentary sequence covering nonconformably the crystalline basement
complex of the Calabria-Peloritani arc (CPA), a continental block
which rifted off the southern margin of the European plate during
Neogene time. In spite of the fossil poor content of the sequence,
the simultaneous use of paleontological and geochemical techniques
have resulted in the following conclusions. 1) The age of an unnamed,
thin calcarenite unit locally present at the base of the sequence,
previously considered Rupelian to early Aquitanian in age, has been
refined to Chattian (27-26 Ma). This calcarenite was considered
a basal, conformable member of the overlying Stilo - Capo d'Orlando
Formation (SCO Fm). However, this study indicates that it is separated
from the SCO Fm either by an angular unconformity or by a disconformity
representing a significant time interval. 2) The SCO Fm has a latest
Chattian/ earliest Aquitanian-Burdigalian age. Previously published
reports suggested deposition over a much longer time span, ranging
from late Rupelian to Langhian. 3) An unnamed deep-marine siliciclastic
unit mostly composed of conglomerate and sandstone and previously
considered Tortonian in age is, in fact, Serravallian to Tortonian.
4) The depositional interval of the "trubi", fine grained marine
deposits, has been independently confirmed to span the Pliocene?Pleistocene.
The results of this study provide a framework for future sequence-stratigraphic
and paleotectonic studies in the area, and prove the effectiveness
of an integrated paleontological/geochemical (87Sr/86Sr ) approach
in the study of fossil-poor sedimentary sequences.
New Late Oligocene to Pleistocene
hyaline calcareous unilocular foraminifera from DSDP Site 357 (Leg
39) on the Rio grande Rise, southwest Atlantic Ocean.
R.T. Patterson and S.M. Burbidge,
Journal of Paleontology, (1995), v. 69, p.635-655
Thirty-two new species of unilocular benthic foraminifera
were described from 50 Late Oligocene to Pleistocene samples from
DSDP Site 357 (Leg 39) on the Rio Grande Rise in the southwest Atlantic
Ocean. These new species make up nearly one-third of the 112 species
of unilocular foraminifers identified in the core. Such a high proportion
of new taxa is not unexpected as the group has been ignored by most
New taxa described include Lagena praemeridionalis, Lagena rotundocostatina,
Exsculptina sicula, Exsculptina umbelliforma Patterson and Cavazza,
Favulina prolatella, Favulina quasiperthensis, Galwayella copiosotubula,
Galwayella oscula, Galwayella spherula, Homalohedra anastomocostata,
Homalohedra goniachrados, Homalohedra gothicofenestella, Homalohedra
polykamptarion, Lagnea congestacolla, Lagnea derbiosa, Oolina curvella,
Vasicostella lecythella, Vasicostella spinulafunda, Fissurina anapetebasilaris,
Fissurina binaroculella, Fissurina favobasella, Fissurina fissuroscula,
Fissurina labeona, Lagenosolenia angula, Lagenosolenia penna, Palliolatella
anfracta, Palliolatella hadrocheilos, Pseudoolina becella, Pseudoolina
oscillum, Parafissurina kladerorhektis, Parafissurina prolatolonga,
and Pseudofissurina plastica. The new name, Lagenosolenia
incompta,a is proposed for Lagena bicarinata (Terquem)
var. polita Matthes, 1939.
Benthic foraminiferal distribution
at Middle Valley, Juan de Fuca Ridge: a Northeast Pacific hydrothermal
K.E. Jonasson, C.J. Schroder-Adams, and R.T. Patterson
Marine Micropaleontology, (1995) v. 25, p. 151-167.
Fourteen benthic foraminiferal bearing surface samples collected
from the Area of Active Venting (AAV) in Middle Valley at a depth
of 2430 m at the northern end of Juan de Fuca Ridge, northeast Pacific
Ocean, yielded 156 identifiable taxa. Sample sites were selected
near active or recently active vents, where temperatures up to 274
degrees C have been measured. Agglutinated foraminifera dominate
within the AAV. However, like the macrofauna observed near hydrothermal
vents, foraminfiera do not venture into the extreme habitats where
temperatures are greater than 20 degrees C. Where clam beds are
found in association with active hydrogen sulphide venting, benthic
foraminifera occur rarely. Low foraminiferal abundance and species
diversity at the immediate site of active venting is attributed
to rapid changes in physical and chemical conditions caused by circulating
hydrothermal vent waters.
Distribution of Holocene benthic
foraminifera from the tropical southwest Pacific Ocean.
F. Clark, R.T. Patterson, and E. Fishbein
Journal of Foraminiferal Research, (1994) v. 24, p. 241-267
A suite of 62 surface and near surface samples has been examined
for its benthic foraminiferal faunas. The cores sampled ranged from
110 to 8900 m water depth, and are distributed across the tropical
southwest Pacific Ocean, north and east of Australia. A total of
606 species were identified. Census data was obtained for each sample,
and species found in statistically significant fractional abundances
(88 in all) were analyzed using a new Q-mode clustering algorithm
(Error Weighted Maximum Likelihood [EWML]). Both the full data set,
and an edited data set comprising 44 samples and 39 species, were
analyzed. With the aid of these analyses ten benthic foraminiferal
assemblages were identified. Three manually constrained assemblages,
each represented by a single sample, were recognized. Five statistically
constrained assemblages were recognized, each having a water depth
range coincident with the range of known water masses of the region.
The Astrononion echolsi-Cassidulina teretis Assemblage and
the Nuttalites bradyanus Assemblage were developed in samples
from depths bathed by waters of the Deep Oxygen Minimum, the Epistominella
exigua-Globocassidulina rarilocula Assemblage was developed
in samples from depths bathed by Deep Water, a derivative Antarctic
Bottom Water, and both the Globocassidulina subglobosa-Pseudoparrella
parca Assemblage and the Nuttalides umboniferus Assemblage
were developed in samples from depths bathed by Antarctic Bottom
Water proper. From depths very near the calcite compensation depth
(CCD), a Mixed Calcareous/Agglutinated Abyssal Assemblage was developed
in a pair of samples, whereas below the CCD, the tenth assemblage,
the Abyssal Agglutinated Assemblage, was developed, with only a
few corroded calcareous specimens accompanying the agglutinated
benthic faunas. These latter two assemblages were also manually
Geoarchaeology of the ancient harbor
site of Caesarea Maritima, Israel: evidence from sedimentology and
paleoecology of benthic foraminifera.
E.G. Reinhardt, R.T. Patterson, and C.J. Schroder-Adams,
Journal of Foraminiferal Research, (1994) v. 24, p. 37-48.
Foraminiferal analysis and 14C dating of a core obtained
from the entrance of the ancient harbor site of Caesaria Maritima,
Israel provided paleo-environmental information which has enhanced
previous archaeological intepretations. This integrated micropaleontological-sedimentological
approach presents a new tool for solving marine archaeological problems.
Four distinct sedimentological units related to the harbor's history
were recognized: preharbor deposits, harbor construction rubble,
harbor and post- harbor deposits. The sediments from the active
harbor were characterized by mud, interrupted by intervals of coarse
sand deposited during large low periodicity (25-50 years) storms.
The area outside the harbor moles was continuously under the influence
of wave action resulting in deposition of a coarse sandy substrate.
Sedimentological and foraminiferal evidence as well as 14C dates
indicated that the mud was from the active harbor (commissioned
in 21 BC) and that the harbor was no longer functioning according
to its original design by the mid third century and definitely by
no later than 490 AD. Previous research suggested that the degradation
of the harbor was most likely related to tectonic movement of the
area. However, the timing of this event was not exactly known. Archaeologists
have speculated that the Byzantine Emperor Anastasius I refurbished
the harbor in the early 6th century. The results of this study have
indicated that, even if this reconstruction did occur, the harbor
was not returned to ites original design or function.
The origin, physico-chemistry and
biotics of sodium chloride dominated saline waters on the western
shore of Lake Winnepegosis, Manitoba.
W.B.McKillop, R.T. Patterson, D.L. Delorme, and T. Nogrady
Canadian Field-Naturalist, 1992 (published in 1994). v. 106,
Twenty-three sodium chloride dominated saline sites clustered
along the western shore of Lake Winnipegosis were studied over a
three year period. Sites were classified into four habitat categories
based in part on salinity, which frequently exceeded that of oceanic
environments. The source of the saline waters together with associated
physico-chemical factors and unique biological communities are described.
In addition to an unique flora, members of five animal phyla; Chordata,
Protozoa, Rotifera, Arthropoda, and Mollusca, were present. Of these
only the Mollusca lacked marine representation. Transport of the
marine species by birds from coastal areas is suggested.
Late Quaternary benthic foraminiferal
biofacies and paleoceanography of Queen Charlotte sound and southern
Hecate Strait, British Columbia.
Journal of Foraminiferal Research, (1993) v. 23, p. 1-18.
A high resolution analysis was carried out on the foraminiferal
faunas from the 13,000 ? 9000 years B.P. piston core END 84B-10
from Goose Island Trough, Queen Charlotte Sound, on the British
Columbia shelf. Cluster analysis of the data resulted in the recognition
of five separate faunas related to distinct paleoceanographic phases
during the late Quaternary history of the site. In particular, these
results provide detailed information on the paleoceanographic
conditions that prevailed in the area: (1) during passage of a late
Quaternary glacial forebulge across the region; and (2) during development
and waning of the west coast Younger Dryas?like isochronous cooling
Passage of the glacial forebulge across this core site (beginning
11,470-11,260 years B.P. and terminating prior to 10,000 years B.P.)
resulted in a gradual decrease in water depth to 70?85 m, based
on sedimentological data and increasing proportions of Buliminella
elegantissima. In the early stages of the regression circulation
remained open and salinity at near normal marine levels despite
the emergence of a number of nearby large islands, as indicated
by the high Shannon?Weiner diversity indexes (up to 2.5), the high
proportion of planktic foraminifera, and the presence of deep shelf
phenotypes of Cribroelphidium hallandence. However, the continued
emergence of nearby islands began to constrict local waterways,
as suggested by the fall in the proportion of planktic foraminifera
from 11.8 to 2.6% over the course of the regression.
Near glacial conditions between 11,260 ? 10,000 years B.P. at this
locality are unrelated to passage of the glacial forebulge. The
inundation of very cold water over the area is evidenced by the
presence of high proportions of Cassidulina reniforme and
Cassidulina helenae. Abundant Cassidulina helenae is
also indicative of depressed salinities The presence of some temperate
species provides evidence that any local glacial advances were restricted
to coastal fjords, some distance away. The observed depressed salinity
and temperature regime may have resulted from a slight modification
of existing regional seasonal weather patterns associated with the
hemispheric, or global, climatic changes accompanying the Younger
Dryas cooling event. Decreased mean continental summer temperatures
could have resulted in a reduced influence of the North Pacific
High and a lengthening of the seasonal influence of the Aleutian
Low. Oceanographically this would have resulted in a near continuous
onshore Ekman flow and resultant downwelling, carrying cold, low
salinity surface plumes to depth.
By 10,000 years B.P. the west coast Younger Dryas?like cooling
event had terminated and weather and oceanographic circulation had
returned to near modern patterns as indicated by the near replacement
of Cassidulina helenae by Nonionellina labradorica and
the development of a modern shelf Epistominella vitrea dominated
Tortaguttus stiloensis, a new
species of foraminifera from the Plio-Pleistocene of Calabria, Italy
R.T. Patterson, W. Cavazza, and J. Blenkinsop
Transactions of the American Microscopical Society, (1993) v.
112, p. 168?171.
Tortaguttus stiloensis, a new species of benthic foraminifera
is described from Middle Pleistocene sediments of Calabria, Italy.
This species is characterized by radiating elevated costae on the
surface of a double marginal carinae connected by numerous cross?struts.
Patterns and variability in sediment
accumulation rates, Fraser River delta foreslope, British Columbia,
R.W. Evoy, T.F. Moslow, R.T. Patterson, and J.L. Luternauer
Geo-Marine Letters, (1993) v. 13, p. 212-218
Minimum sediment accumulation rates on the Fraser River delta
foreslope exhibit a high degree of spatial variation, with accumulation
rates ranging from 0.50 to 3.0 cm/yr. Accumulation rates generally
increase towards Sand Heads channel, the active foreslope depocenter.
Sedimentation rates and patterns and micropaleontological assemblages
are interpreted to reflect reintroduction of older sediment from
upslope via slumping and sediment-gravity flow processes. Such processes
account for the bulk of sedimentiton in much of the subaquaeous
delta. These processes provide a mechanism for sand bypassing of
the delta plain and foreslope and for deliver of coarse-grained
sediment directly to prodelta and basinal environments.
"Error weighted maximum likelihood
(EWML)" a new statistically valid method to cluster quantitative
E. Fishbein, and R.T. Patterson
Journal of Paleontology, (1993), v. 67, p. 475?486.
The advent of readily-available computer-based clustering
packages has created some controversy in the micropaleontological
community concerning the use and interpretation of computer based
biofacies discrimination. This is because dramatically different
results can be obtained depending on methodology. The analysis of
various clustering techniques reveals that in most instances, no
statistical hypothesis is contained in the clustering model and
that no basis exists for accepting one biofacies partitioning over
another. Furthermore most techniques do not consider standard error
in species abundances and generate results that are not statistically
relevant. When many rare species are present, accumulated statistically
insignificant differences in rare species can overshadow the significant
differences in the major species leading to biofacies containing
members having little in common.
A statistically-based "error-weighted maximum likelihood" (EWML)
clustering method is described that determines biofacies by assuming
samples from a common biofacies are normally distributed. This method
also weights species variability to be inversely proportional to
measurement uncertainty. The method has been applied to samples
collected from the Fraser River Delta marsh and shows that five
distinct biofacies can be resolved in the data. Similar results
were obtained from readily available packages when the data set
was preprocessed to reduce the number of degrees of freedom. Based
on the sample results from the new algorithm, and on tests using
a representative micropaleonotological data set, a more conventional
iterative processing method is recommended. This method, although
not statistical in nature, produces similar results to EWML (not
commercially available yet) with readily available analysis packages.
Finally, some of the more common clustering techniques are discussed
and strategies for their proper utilization are recommended.
Evidence for a Younger Dryas-like cooling
event on the British Columbia coast.
R.W. Mathewes, L.E. Heusser, and R.T. Patterson
Geology, (1993) v. 21, p. 101-104.
Two independent paleoclimatic records from the Pacific coast
of Canada indicate that a late-glacial warming trend was interrupted
by a return to colder conditions between about 11,000 and 10,200
radiocarbon yr. B.P., correlative with the classical Younger Dryas
chronozone of the North Atlantic region. Fossil benthic foraminifera
from three cores from the continental shelf dated by accelerator
mass spectrometry show peak abundances of the cold-water indicator
species Cassidulina reniforme at this time. Fossil-pollen
spectra from two sites on the Queen Charlotte Islands record a shift
from forest to open, herb-rich vegetation after 11,100 year B.P.,
probably in response to colder and wetter conditions identified
by pollen-climate transfer functions. These preliminary data for
a cold oscillation between ca. 11,000 and 10,000 yr ago in the northeast
Pacific argue that this deglacial phenomenon was not restricted
to the North Atlantic, but was a hemispheric -- and possibly global
A taxonomic key to the unilocular genera
of calcareous foraminifera.
F. Clark and R.T. Patterson
Journal of Paleontology, (1993), v. 67, p. 20-28.
Taxonomic keys are rarely used as an aid to the identification
of foraminifera. Such keys become increasingly attractive, however,
as the number of taxa which must be distinguished becomes large.
The proliferation of known genera over the last 25 years is nowhere
more apparent than in the unilouclar foraminifera, where the number
of genera has risen from five to 46. We present herein a dichotomous
key in which any species may be assigned to its proper genus by
progressing through a series of steps, consisting of paired statements,
in which only one choice is made at a time.
Surficial geology of the Queen Charlotte
Basin: evidence of submerged proglacial lakes at 170 m on the continental
shelf of western Canada.
H.W. Josenhans,J.V. Barrie, C. Conway, R.T. Patterson R.W.
Mathewes, and G.J. Woodsworth
Current Research, (1993), Paper 93-1A, p. 186?192
A high resolution marine seismic and sampling program in
the region was carried out during a 12 day cruise aboard the research
vessel CFAV Endeavour. Preliminary results indicate that grounded
glaciers deposited sediments in the deep troughs which indent the
continental shelf as far west as the shelf break. Offlapping till
tongues found in the troughs indicate that ice retreated stepwise
from Queen Charlotte Sound at the closed of the last (Late Wisconsinan)
glaciation. Detailed studies of submerged shoreline deposits define
the volume and frequency of failure of steeply dipping prograde
sand and gravel deposits.
Holocene foraminiferal faunas from
cores collected on the Fraser River delta, British Columbia: a paleoecological
Current Research, (1993), Paper 93-1A, p. 245-254.
Interpretation of sedimentary environments are made based
on the foraminiferal faunas recovered from four cores (FD90-A, FD90-B,
FD91-1, and FD91-2) collected on the Fraser delta. These relatively
short cores (<55 m) are primarily comprised of prodelta sands
overlying ancetral Strait of Georgia mud and silt. The muds and
silts are characterized by a low diversity foraminifera fauna, dominated
by Buccella frigida, Cribroelphidium excavatum, and Elphidiella
hannai. This fauna is typical of low salinity, neritic depth conditions.
foraminifera are virtually absent from the prodelta sands as the
winnowing conditions prevalent during deposition of this unit made