Fish
parts
preserved in sandstones and conglomerates were recovered from the
Triassic Lockatong Formation of the Newark Supergroup. Data
recovered
from this unique lacustrine strandline setting were examined using
sedimentologic and taphonomic methods to accurately interpret
conditions that caused (permitted) accumulation.
Within the Lockatong Formation, reoccurring Van Houten cycles are
subdivided into three divisions (D): lake transgression (D1),
high-stand (D2), and regression or lowstand facies (D3). The
Triassic
fish-part sandstones and conglomerates are composed of
disarticulated
skeletal remains of multiple fish species.
The fish-part sandstones and conglomerates occur at the transition
from
D1 to D2 and are found above a fluvial intraformational conglomerate
composed of diverse mudstone clast types derived from the underlying
D3. Fish-part sandstones and conglomerates occur as continuous or
lenticular graded beds. Normal graded beds are prevalent and consist
of
both sedimentary clasts and disarticulated fish parts. Within a bed,
the clasts and fish parts do not grade synchronously due to density
differences. Either wave ripples or current ripples cap the graded
beds, indicating shallow water deposition. In addition, large fish
pieces associated with rooted mudstones can be present in lieu of
ripple facies, indicating subareal exposure. By using the fish kills
in
the Salton Sea as a modern taphonomic analogue we propose that a
mass
kill of Triassic fish species took place in the lacustrine Lockatong
Formation. After death, decomposition and bloating of the fish led
to
floatation. Fish carcasses were driven shoreward by waves, probably
storm-generated. The remains were disarticulated and reworked as lag
concentrations that are recorded in the normal grading of the
sediments
and fish part clasts. The intermixing of interformational clasts and
fish parts reflects the impact of the storm washover into the
associated fluvial systems.
Strandline
deposits of the Salton Sea, California: An integrated analogue for
Triassic fish-part conglomerates of the Newark Basin
Fish
parts
preserved in sandstones and conglomerates were recovered from the
Triassic Lockatong Formation of the Newark Supergroup. Data
recovered
from this unique lacustrine strandline setting were examined using
sedimentologic and taphonomic methods to accurately interpret
conditions that caused (permitted) accumulation.