tivity on the carmel faul

eak phases yielded datable samples. Types C, D and E yielded only pre- or
post-break datable samples (i.e. they indicated only one sided constraints on
seismic events). Type C seismites are considered robust indicators of seismic
events as are type D seismites, yet seismites of type D are harder to sample due
to fragments of un-datable material embedded in them. Type E seismites are
fragile stalactites, which are less indicative of seismic events, and therefore their
ages can only be used as corroborative evidence when they are part of a cluster
of samples that have yielded similar ages.
4. A total of 68 speleothem samples was taken and inspected from Denya Cave, 37
of which were identified as seismites; of them, 32 were processed. Ten seismites
are severed stalagmites broken along sub-horizontal plains. Nine seismites of the
32 are severed stalactites of different shapes and sizes. The remaining seismites
are flowstone samples in which breaks and depositional unconformities were
found; some revealed soda straw speleothems embedded in them.
5. U-series age equations are based on the assumption that all 230 Th in the sample
is the product of 234 U decay. Most speleothem samples contain 230 Th, which is
associated with a detrital component that becomes cemented or occluded within
a speleothem. The extent of detrital Th contamination can be monitored by
232 Th, using as a first estimation the ratio 230 Th/ 232 Th. The lower this ratio, the
higher the probability that a detrital 230 Th component exists in the sample,
causing its age to appear older than it is. For most speleothem samples from
Denya Cave a correction for detrital 230 Th was needed.
6. A correction factor for speleothem ages can be determined using the detrital
molar ratio of 232 Th/ 238 U. The most common correction factor for crust value
rocks is 3.8. In a carbonate terrain (e.g. Judean Hills), this correction factor was
determined as 1.8. Correction factors for detrital Th were calculated for ages of
speleothems from Denya Cave, using isochron calculations of isotopic ac<strong>tivity</strong>
ratios for ( 232 Th/ 234 U) vs. ( 230 Th/ 234 U) isochrons. These calculations yielded
different correction factors for different sets of isochrons, all of them extremely
low (between ~0.1-~0.7). These different factors are assumed to be indicative of
more than one phase or origin of detrital matter. It was therefore not possible to
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