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I admit it. I've been slacking. But I've partially caught up on my
backlog of references, so here are a few new ones. I'm now trying to
include abstracts wherever possible, so I'm not posting these as I find
them anymore. The abstracts take time! But don't worry, you'll all still
get them all (eventually)!
DA OCT 01 1996 v 11 n 5
AU McLaren, Digby J.
TI Mass Extinctions Are Rapid Events
DA OCT 01 1996 v 11 n 5
AU Aslan, Andres
AU Behrensmeyer, Anna K.
TI Taphonomy and Time Resolution of Bone Assemblages in a Contemporary
Fluvial System: The East Fork River, Wyoming
AB Experiments that recorded the dispersal of 142 bones within a
meandering, 2030 m-long reach of the East Fork River, Wyoming over a
13-year period provide a basis for interpreting distribution patterns and
time averaging in fossiliferous channel deposits. Results show that light
and porous bones, (e.g., vertebrae, patellae, and phalanges) were
transported farther than heavy bones (e.g., limb bones and mandibles).
Dispersal patterns of bones from individual experimental sets representing
point sources demonstrate that bones became sorted by size and shape within
1 to 2 years and that sorting patterns varied according to initial channel
position. The combined distribution of bones from all the experimental
sets, however was unsorted and generally random, suggesting that unsorted
fluvial bone assemblages reflect multiple bone sources and differences in
the time at which bones enter the channel.
Estimates of time-averaging of potential and observed natural bone
assemblages in. the East Fork River and the South Platte River range from
10(1)-10(4) years. The upper limit for this estimate is controlled by both
the age of fossiliferous floodplain deposits that border the rivers and by
the ability of the rivers to rework these floodplain. deposits. The lower
limit reflects either the scarcity of bones in the floodplain sediments or
the inability of the rivers to rework these older bones; in this case
channel bone assemblages should represent only remains from deaths in the
channel or remains that were transported into the channel from adjoining
land surfaces, resulting in. short intervals of time-averaging
The East Fork study further suggests that sandstone geometry, paleosol
development, and the sedimentary context of fossil occurrences cart be used
to evaluate time-averaging in ancient fossiliferous channel deposits.
Fossil bone assemblages that are present exclusively in ribbon-shaped
channel deposits associated with weakly developed paleosols and
unfossiliferous floodplain deposits should represent shorter time intervals
than similar fossil assemblages associated with Sheet sandstones and
moderately developed paleosols with abundant fossils.
JT Chemical geology.
DA SEP 30 1996 v 131 n 1 / 4
AU Lim, B.
AU Cachier, H.
TI Determination of black carbon by chemical oxidation and thermal
treatment in recent marine and lake sediments and Cretaceous-Tertiary clays
AB Several sample treatments and analytical methods for the measurement of
black carbon in a wide variety of sediments were considered in which the
removal of organic carbon is a critical step in the procedure. A
comparison between chemical oxidation and thermal treatment was conducted
and the latter was shown to be inappropriate due to the polymerisation of
organic matter. Using acid dichromate oxidation, reactive kerogen was
separated from black carbon in a variety of lake and marine, and recent and
ancient sediments with relatively small and quantifiable losses (1-6%) of
black carbon under carefully controlled reaction conditions.
JT Insight on the news.
DA NOV 18 1996 v 12 n 43
AU Horvitz, Alan
SU The battle over bones
DA SEP 30 1996 v 262 n 1 / 4
AU Uchimura, H.
AU Kono, M.
AU Tsunakawa, H.
AU Kimura, G.
AU Wei, Q.
AU Hao, T.
AU Liu, H.
TI Paleomagnetism of late Mesozoic rocks from northeastern China: the role
of the Tan-Lu fault in the North China Block
AB Paleomagnetic studies were performed on Jurassic, Cretaceous and
Tertiary rocks sampled from the Qitaihe area in Heilongjiang and Benxi area
in Liaoning Provinces, northeast China. Both locations are near the
Tancheng-Lujiang (Tan-Lu) fault system; Benxi is close to but on the
eastern side of the fault while Qitahe lies between two major branches of
the northwestern extension of this fault. In Mesozoic rocks, secondary
magnetization in the present field direction was observed, but it was
possible to retrieve the primary components by taking the high-temperature
portion of the demagnetizing spectra. The Mesozoic poles thus obtained,
especially those for the Cretaceous, deviate from the paleomagnetic poles
of similar ages from the central part of the North China Block (NCB),
Siberian Block or South China Block (SCB), Although the distances to the
poles (flattening) are quite similar, the Benxi pole suggests a small
clockwise rotation with respect to the central NCB poles, while the the
Qitaihe poles indicate a much larger rotation in the opposite direction.
It is shown that the deviation of the Benxi pole is similar to that
observed for the Korean Peninsula and Shangdong Province, which all lie to
the east of the Tan-Lu fault in the NCB, The Qitaihe pole position is quite
different from the poles either west or east of the Tan-Lu fault. From
these observations, it is concluded that a left-lateral strike-slip
movement at the Tan-Lu fault system since the Cretaceous is the cause of
systematic deviation in the position of the poles obtained from east of the
fault including the Benxi area, while anomalous direction of Qitaihe rocks
may represent a small scale rotation within the Tan-Lu fault system. The
estimation of the movement along the Tan-Lu fault depends on which branch
of the fault system is considered most active. If the main branch is
assumed to be the place of slip, the movement can be represented by an
Euler pole which lies to the south of Honshu Island (20 degrees N, 150
degrees E), with an estimated total displacement of 800 km since the
JT Proceedings of the Royal Society of London
DA OCT 22 1996 v 263 n 1375
AU Sole, R.V.
AU Bascompte, J.
AU Manrubia, S.C.
TI Extinction: bad genes or weak chaos?
JT Current Science
DA 1996 v 69 n 12
AU Garg, Rahul
AU Jain, K.P.
TI Significance of the terminal Cretaceous calcareous nannofossil marker
_Miculi prinsii_ at the Cretaceous-Tertiary boundaryin the Um Sohrhyngkew
section, Meghalaya, India
AB A diagnostic Calcareous nannofossil assemblage, representing the
terminal Maastrichtian _Micula prinsii_ zone, is discovered below the
iridium-spike bearing clay-layer in the Um Sohryngkew section, Meghalaya.
Its significance for the precise demarcation of the K/T boundary, providing
crucial evidence for the presence of the youngest Cretaceous sediments in a
continuous, bioturbation-free calcareous shale sequence, is demonstrated.