64 THE FLORIDA ANTHROPOLOGIST
2004 VoL. 57(1-2)
Table 1. Miami Circle/Brickell Point Sediment Samples for Particle Size Analysis.
1) Sediment Samples collected 08 May 2002
Be [SY eg itg
1030 Excavation Area 1, Unit 66, N wall, Level 1, 0-25 cm deep in Feature # 690
1031 Excavation Area 1, Unit 66, N wall, Level 2, 25-40 cm deep in Feature # 690
vation Area 2, East wall, bulk sample from 114-120 cm below surface (on bedrock) | 1084
1033 Excavation Area 2, East wall, bulk sample from 114-120 cm below surface (on
exposure)
bedrock) rea 2, East wall, bulk sample from 100 cm below surface (middle of
1034 Excavation Area 2, East wall, bulk sample from 100 cm below surface (middle of
exposure)
1035 Excavation Area 2, East wall, bulk sample from 80 cm below surface (top of
exposure)
1036 Excavation Area 1, S end of concrete footer, bulk sample directly on bedrock
1037 Excavation Area 1, S end of concrete footer, bulk sample from 20 cm above
bedrock
2) Posthole Matrix Samples collected during 2000 excavations (subsampled 09 July 2002)
FS #
313 Op3, Square N52, E120, PH #9, Soil Sample #83, Zone VI, Lvl 1, 29 June 2000, K.
Jones
329
79
3
Table 2. Wentworth Size Classes compared to metric
diameter and Phi sizes.
Wentworth
Size Class millimeters Phi size
GRANULES |__|
P
a
P| Wery coarse
[____ [eaarse [0510 | #11009
[Pedi [025-050 [20+
ine [0.125-0250
1
woe CdSC*d
used than the particle diameter in millimeters or micrometers
(as in Figure 5) is the Phi (@) grain-size scale, which equals
the negative logarithm to the base two of the particle diameter
expressed in millimeters (@ = -log,[particle diameter in mm]).
On the Phi scale, a one-mm diameter particle (at the
boundary between very coarse and coarse sand) has a 9 size
of 0; and the smaller the particle size, the larger the Phi size.
This study focuses on analysis of the sand-size particles (-1o
Op3, Square N52, E120, PH #13, Soil Sample #99, Zone VI, Lvl 1, 29 June 2000,
K. Jones 2
Op3, Square N52.58, E120.37, PH #23, Soil Sample #145, Zone VI, Lvl 1, 8-1-0,
YF
313
41
113
to +49). A summary of the seven size fractions discussed in
subsequent sections is given below, in terms of the three
common grain-size scales.
Mud, the finest fraction, is composed of two particle size
sub-categories, silt (0.0039-0.0625 mm diameter) and clay
(0.0006-0.0039 mm diameter). In these ten samples essen-
tially all of the mud-size fraction is medium to coarse silt, not
easily studied except under a scanning electron microscope,
and not likely to shed much light on the formation of the
midden deposit due to the near impossibility of identifying the
origin of such small particles. All subsequent particle sizes in
this report are expressed in the Phi scale.
In order to summarize and present the distribution of
particle sizes in a sample either graphical or statistical
methods are employed. The most common graphical presenta-
tion is the cumulative particle size curve, which is a curve of
the accumulated weights of the individual size fractions, from
coarsest (here, all sediment particles coarser than -1@) on the
left to finest (here, all sediment finer than +4ยข) on the right.
In theory a cumulative curve should begin at 0 cumulative
percent, but in the analysis of several of these 10 samples the
topmost (coarsest) screen trapped a very large percentage of
the entire sample (e.g., FS 313, 329, 1033). This aspect of the
analysis is considered further below.