Geoarchaeology of Johns Bay, Maine

Geoarchaeology of Johns Bay, Maine

Robert S. Young

Daniel F. Belknap Institute for Quaternary Studies, University of Maine, Orono, Maine 04469*

Department of Geology and Institute for Quaternary Studies, University of Maine, Orono, Maine 04469

David A. Sanger Department of Anthropology and Institute for Quaternary Studies, University of Maine, Orono, Maine 04469

This study examines the Holocene history of a glacially-sculpted Maine embayment using both geological and archaeological data bases. High-resolution seismic profiling, in combination with vibracores and Holocene sea-level curves, were used to develop the Holocene stratigraphy and paleogeographic evolution of Johns Bay and Pemaquid Beach, Maine. These geological databases were, whenever possible, integrated with the Johns Bay archaeological database and general archaeological settlement paradigms for coastal Maine. As sea level has risen from its - 65 m lowstand a t the beginning of the Holocene, Johns Bay has evolved from a narrow fluvial system, to an estuary, to its present form of an open embayment. Over roughly the last 4000 years, the Pemaquid Beach area has changed from a forested upland, to a bedrock-pinned freshwater wetland, to a pocket barrier fronting a small salt marsh. The barrier continues to migrate over the salt marsh, which is transgressing the freshwater environments. The first evidence of human settlement in Johns Bay is a t 4000-5000 yr B.P. Archaeological site distribution around Johns Bay has been examined in light of an estuarine embayment evolution model developed for the Maine coast. Sites are concentrated in zone 1 (the inner embayment). This zone is currently experiencing sediment accumulation. Zone 2 (middle embayment) is undergoing erosion, and zone 3 (outer embayment) has been stripped of sediment. Archaeological sites in these outer areas have been eroded. The Pemaquid Beach area has a history of occupation dating back 4000-5000 years. The last 2000 years of this record is found in stratigraphic context in the Nahanada site. The first 3000 years is represented by a collection of artifacts found out of context on the beach in front of the Nahanada site. The artifacts, dated by morphology, present a time continuum from 4000-5000 yr B.P. until the occupation of the Nahanada site. Thus, it i s suggested that the Nahanada site represents the back of a chronologically shingeled settlement area that extended to the 5000 yr B.P. shoreline. Finally, a model for the development of chronologically shingled sites is suggested.

INTRODUCTION This study examines the Holocene history of Johns Bay, Maine using archaeo-

logical and geological databases as an integrated whole, rather than solely

* Current address: Duke University, Dept. of Geology, Durham, NC 27706.

Geoarchaeology: An International Journal, Vol. 7, No. 3, 209-249 (1992) 0 1992 by John Wiley & Sons, Inc. CCC 0883-6353/921030209-41$04.00

GEOARCHAEOLOGY OF JOHNS BAY, MAINE

determining how one has affected the other. The study answers several ques- tions about the Holocene evolution of Johns Bay and Pemaquid Beach:

1. How have the shoreline and associated coastal sedimentary environments changed during the Holocene transgression?

2. Does this description of the geological evolution of the embayment fit the known distribution and preservation of archaeological sites in the Johns Bay area?

3. How has geological change filtered the archaeological record, and how is it likely to do so in the future?

Geological change and human settlement patterns were studied simultaneously. The final synthesis is inherently interdisciplinary: “geoarchaeology” as intended by Gladfelter (1981). The use of an archaeological database as an important tool in paleogeographical reconstruction is uncommon in the geological literature. Sanger and Kellogg (1989) list some examples and present a list of assumptions and conditions that are implicitly, rarely explicitly, involved. The predominant approach is to reconstruct the paleogeography of an area in order to better understand how human adaptive strategies may have changed over time. Yet geologists often ignore the wealth of well-dated paleoenvironmental data that the archaeological record may provide. For example, if it is known that people deposited a substantial number of clams at a site 3000 years ago, then it is very likely that there was a mud flat somewhere nearby at that time. If the paleogeographical reconstruction places the same site on a high energy shoreline 3000 years ago, it may warrant taking another look at the data. Furthermore, Kellogg (1982) indicated that the mere fact that people had chosen a certain plot of land to occupy reflected a number of things about the likely marine environmental conditions directly adjacent to that site during the time of occupation. Given this, it seems natural to examine the archaeological history of an embayment in the process of reconstructing its Holocene geological history.

PHYSICAL SETTING Bedrock strike and differential erosion are the primary controls on the geo-

morphology of the Maine coast (Kelley, 1987). The most recent modification has been the bedrock-guided sculpting by Wisconsin ice. Johns Bay is located within the “strike-parallel” portion of the west-central compartment of the Maine coast, as defined by Kelley (1987) and Belknap et al. (1987b). This compartment stretches from Small Point in the west to Pemaquid Point in the East (Figure 1). The region is characterized by long, narrow, bedrock peninsulas that have experienced strike-parallel, glacial scour during at least the most recent glacial interval. This compartment contains the Sheepscot and Damaris- cotta estuaries, as well as the Johns Bay open embayment. The peninsulas are

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47

46'

45'

444

430

71. 700 69' 68. 67.

OUEBEC

1 !

MAINE i

WEST CENTRAL o a o 80 , KM

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Figure 1. Maine coastal compartments and inland marine limit (modified from Belknap et al., 1987b). The study area is shown as the small box in the strike-parallel portion of the west central compartment.

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL 21 1


blanketed with a thin veneer of till and outwash, while the valleys were only partially filled with sediments upon retreat of glacial ice from the area (Belknap et al., 1987b, 1986).

Late Quaternary Geological History of the Maine Coast The Late Quaternary history of the entire coast of Maine has been summa-

rized in a number of recent papers (Belknap et al., 1987b,1989a, 1989b; Shipp, 1989; Kelley, 1987; Kelley et al., 1986, 1987). As the latest Wisconsin ice retreated across the Gulf of Maine from its maximum extent along Georges Bank and the Scotian Shelf (Pratt and Schlee, 19691, isostatic depression of the coastal Maine land surface initially allowed for a marine invasion. The abundance of washboard moraines and glaciomarine outwash deltas along the coast of Maine suggests a marine-based ice (Hughes, 1981; Borns, 1973). The transgressing sea followed a calving glacial front, passing the present shoreline at about 13,200 yr B.P. This marine incursion reached as much as 100 km inland at present elevations of up to 130 m by about 12,100-12,500 yr B.P. (Stuvier and Borns, 1975; Smith, 1985; Thompson and BORIS, 1985) (Figures 1 and 2). General ice retreat also deposited till and stratified driR (Thompson and Borns, 1985). Seaward of the grounding line a glaciomarine mud was deposited. Bloom (1960) named the now subaerial portion of the mud the Pre- sumpsco t Formation.

After 12,000 yr B.P., isostatic rebound, following removal of the ice, initiated a rapid upliRing of the land surface. The result was a significant drop in local relative sea level along the Maine coast. Previously deposited Pleistocene glaciomarine mud and other glacial sediments were reworked by the regressing shoreface and then by subaerial erosion as the sea level dropped. The extent and exact age of the regression is still unsettled (Belknap et al., 1987a), but the best estimate for lowstand is -60 m to -65 m at 9500-10,000 yr B.P.

Throughout the Holocene, sea level has been rising at an ever decreasing rate (although there is evidence for a very recent acceleration) (Belknap et al., 1987a). Time constraints are poor prior to about 5000 yr B.P., but simple determination from the Gulf of Maine relative sea-level curve gives an averaged rate of sea-level rise of about 12.7 m per 1,000 years for the period from 9500 to 5000 yr B.P. Belknap et al. (1987a, 1989b) give radiocarbon-constrained rise rates of 1.44 m per 1000 years for the period from 5000 to 1500 yr B.P. (Figure 3), followed by a “marked” slowing to 0.5 m per 1000 years from 1500 yr B.P. to the very recent. Pleistocene glaciomarine sediments were again reworked during the continuing Holocene transgression. In fact, the shoreface unconformity offshore modern Pemaquid Beach has penetrated glaciomarine mud. In addition, Belknap et al. (1986), Shipp et al. (19871, and Smith (1990) describe an “estuarine/embayment evolution model” for the Holocene transgression. Their view is that sediment depocenters have moved up estuary during the transgression. Fine-grained sediments are temporarily stored (1000-5000

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MAINE COAST L O C A L R E L A T I V E S E A L E V E L 14,000-0 B.P.

EUSTATIC RISE > ISOSTATIC REBOUt@--,

DEGL ACIATION,

100 -4 L - - - - - COASTAL 8 0 - GLACIOMARINE DELTAS I-

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- SEISMIC- GEOMORPHIC INFERENCE

14 12 10 8 6 4 2 0

lo3 RADIOCARBON YEARS B.P.

-80 1 1 1 1 1 1 1 1 1 1 1 1 1

Figure 2. Maine local relative sea-level curve (after Belknap et al., 1987a).



lo3 RADIOCARBON YEARS B. P. 6 5 4 3 2 I 0 1 I 1 1 I I Q-MHW

MAINE . / LOCAL RELATIVE SEA LEVEL

- I

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DATES (MAINE)

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------ TRENDOFRECENT SEA

- 4

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LEVEL DATA ((1500 YRS.)

Figure 3. Maine local relative sea-level change over the last 5000 years (modified from Belknap e t al., 1987a).

years) a t the head of the embayment in marshes and mud flats. The outer reaches of the embayment are stripped of sediments. The primary sources of sediment in this model are Pleistocene bluffs and shoreface erosion.

Seismic Stratigraphy of Other Maine Embayments Critical to this study is the identification of Quaternary stratigraphic units

defined on the basis of seismic facies. Shipp (1989) and Belknap et al. (1987b, 1989a1, discuss how individual seismic facies are defined from the seismic reflection profiling data based on acoustic character. They use a descriptive classification scheme arranged in a hierarchical system to isolate distinct groups of related reflectors (facies). Reflectors are first distinguished by the intensity of the return from the top bounding surface. The greater the acoustic contrast between two units, the more "intense" the top return. Next, the configuration of secondary, internal reflectors is considered (i.e., stratified, massive). Finally, the external shape of the group of reflectors (wedged,

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hummocky) and the frequency and/or setting is observed. Shipp (1989) uses this hierarchical scheme of classification to isolate 12 seismic facies for the nearshore Gulf of Maine. Seven of the 12 units have been observed in the seismic profiling data from Johns Bay. We will restrict our discussion to these seven units (Figure 4).

Unit (BR) gives an intense, sharp return. There are no internal reflectors. It is the ubiquitous acoustic basement. This unit is interpreted as crystalline bedrock. Facies unit (T) has an intense upper reflector with discontinuous internal reflectors. It can occur with a mounded external shape or as a thin veneer covering (BR) (this forms a broad, strong return with a separate bedrock return below) (Belknap et al., 1987b). It is interpreted as glacial till. Unit (GM-D) exhibits a subdued return. I t is highly stratified with a smooth upper surface which follows bedrock topography. Facies (GM-P) also gives a subdued return. Internal reflectors are weakly stratified to transparent. It occurs as fill or sheets conformably overlying (GM-D). Seismic facies unit (GM-D) is interpreted as glaciomarine mud deposited near the ice grounding line, possibly below an ice shelf. Facies (GM-P) is distal glaciomarine mud. These units are capped by a strong reflector diminishing in intensity seaward of the - 65 to - 70 m isobath. This surface represents the unconformity formed during the most recent marine regression. It is initiated by the acoustic contrast between the more compacted pre-Holocene sediments below, with the less compacted Holocene sediments above, as well as a coarsening in the upper part of the Pleistocene section caused by reworking of sediments. This coarsening is seen in vibracores taken from Johns Bay. The upper 2-3 m of Pleistocene sediments coarsen upward from mud to medium sand, with a soil horizon, representing the regressive unconformity, developed on top (Young, 1989).

Seismic facies (SG) gives a strong, often ringing return at the sediment-water interface. It is often highly stratified. Grab samples confirm that it is coarse sand and gravel. Unit (MI gives a more subdued return at the sediment-water interface. It is transparent and ubiquitous at the top of the section. Unit (M) is interpreted as Holocene mud. The final seismic facies is unit (NG). This unit has a moderate, convex-up, “fuzzy” signal. This is an “acoustic wipeout.” Nothing is visible below. It occurs in thick muds usually in the deep parts of channels and valleys. Belknap et al. (1987b) interpret this return as natural gas bubbles trapped within the Holocene muds.

Belknap et al. (1986,1987b, 1989a) and Shipp (1989) have placed these major seismic facies into a general, composite seismic stratigraphic section for the west-central compartment. They describe ubiquitous Paleozoic bedrock at the bottom, occasionally overlain by till, followed by glaciomarine draped and then ponded muds. Landward of the 65 m isobath, this sequence shows subaerial exposure or fluvial erosion at its top. These Pleistocene sediments are overlain only rarely by Holocene sand and gravel, and more frequently by Holocene mud. Thick sections of Holocene mud occasionally contain natural gas.



d

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subdued, stratified, ponded till to sheers. common deep in thick sequences

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w

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BR Figure 4. Composite seismic stratigraphic section of major seismic facies for Johns Bay, Maine. The arrow points to the described facies.

COASTAL ARCHAEOLOGICAL SETTING The archaeological history of the Maine coast (Table I) has been summa-

rized in a number of recent papers: Sanger (1988a), Sanger and Belknap (19871, Sanger and Kellogg (19891, Sanger and Sanger (19861, and Kellogg

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Table I. A chronology of Maine coastal archaeology.

Time (yr B.P.) Period Culture Tradition

0 Historic

1000 Late Ceramic 2100 Middle Ceramic

Early Ceramic

3000 4000 Late Archaic Susquehanna 5000 Moorehead Phase 6000

7000 Middle Archaic 8000 9000 Early Archaic 10.000 11,000 Paleoindian

(1989). Given the dramatically lowered sea level at the beginning of the Holocene, the initial periods of Maine coastal prehistory are murky. No coastal sites dating earlier than Late Archaic have been found, although occasional Middle Archaic or earlier artifacts have been serendipitously dredged by fisherman (Sanger, 1988a). The question as to whether or not Paleoindians actually inhabited the Maine coast is still open to debate. Oldale (1985) suggested that early Holocene coastal environments were severely stressed by the rapidly changing sea level. Productive coastal environments may not have developed until sea-level rise had slowed. As one of us (Sanger, 1988a) has commented, this assertion is an untested hypothesis. Kellogg (1989) summarized the difficulties associated with specu- lating about pre-late Archaic sites in the Gulf of Maine.

By 5000 yr B.P., the archaeological record of marine-adapted, coastal settlement improves dramatically. The possible reasons for this will be discussed later. The Late Archaic Period is well represented in coastal Maine by the Turner Farm Site (Bourque, 19831, the Nevin Site (Byers, 1979), and the Stanley Site (Sanger, 1975). These sites are characterized by the Moorehead phase occupation, followed at 3800 yr B.P. by the Susquehanna tradition. The two cultural traditions differ in the nature of their marine adaptation (among other things) (Sanger, 1988a). The Moorehead phase shows evidence for sword- fishery, extensive exploitation of cod fish, and some shellfish gathering. The Susquehanna people apparently relied more on inshore fisheries (shellfish, flounder) and terrestrial fauna.

The Ceramic Period in Maine began at 2700 yr B.P. Although there is a large degree of variability in the nature of Ceramic Period coastal sites in Maine, there is ample evidence for a strong marine adaptation. Many coastal shell midden sites date to this period, including the world-famous Damariscotta



oyster shell heaps (Sanger and Sanger, 1986). This strong marine adaptation with extensive exploitation of shellfish continued into the Historic Period and european contact.

STUDY AREA Johns Bay is located within the “strike-parallel” portion of the west-central

compartment of the Maine coast-just east of the Damariscotta River estuary (Figure 1). For the purpose of this study, the western margin of Johns Bay is defined as Thrumcap Island, and the eastern margin is Pemaquid Ledge (Figure 5) . The embayment is about 2 km wide and 6.8 km long. It has a maximum depth of 55 m in the outer reaches, decreasing to a maximum depth of 10 m at its head. Johns Bay differs from the Sheepscot and Damariscotta estuaries in that bedrock control has allowed for the formation of a relatively broad, open embayment, rather than a long, narrow estuary. It is a neutral embayment (Kelley et al., 1986); that is, there is essentially no freshwater input from the Johns and Pemaquid Rivers.

Pemaquid Beach is located in the northeastern quadrant of Johns Bay (Figure 7). It is a crenulate-shaped, pocket barrier fronting a small salt marsh. The inlet to the marsh does not breach the strandline; rather, it is located around a bedrock headland to the west. Pemaquid Beach is really two beaches: a small northwestern beach (125 m) and a larger southeastern beach (450 m). The two sections are separated by a narrow bedrock headland. Sedimentologically , Pemaquid Beach is essentially a closed system. Sediment transport is primarily onshore-offshore, and there is a strong contrast in winter (erosional) to summer (constructional) beach profile (Nelson and Fink, 1978). The southeastern end of the larger beach approaches the classic log- spiral shape. This is formed as waves diffract around a headland to the southeast. An archaeological site, the Nahanada Site, occurs on a 1 m bluff adjacent to this southeastern beach. Analysis by one of us (Young) of the increment borings of trees slumping off the bluff indicate that the bluff is eroding at an average rate of approximately 11.3 cm per year at the northern end and 4.6 cm per year at the southern end. Freshwater peat crops out on the lower beachface indicating the earlier existence of an upland fedbog where Pemaquid Beach now sits. There are scattered stumps rooted in the peat. Finally, a stream flows across the beach just north of the Nahanada bluff, exposing a glacial till lag.

METHODS This study uses three data sources: (1) seismic reflection profiles and vibra-

cores collected by the authors in 1988 and 1989; (2) the archaeological database collected in 1980 and 1981 by a team from the University of Maine led by one of us (Sanger); (3) a selection of artifacts from the Fosdick-Downs collection that were gathered from Pemaquid Beach.

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JOHNS BAY AND VICINITY

Figure 5. Johns Bay and vicinity bathymetry. The Pemaquid Beach area is shown in Figure 7.



SEISMIC PROFILE LINES JOHNS BAY

220

Figure 6. Seismic profile lines and offshore vibracore locations in the study area.

VOL. 7, NO. 3




Seismic Database High-resolution seismic reflection profiles were collected using an ORE Geo-

pulse boomer filtered between 0.7 and 2.0 kHz and a 200 kHz fathometer. Navigation was by Loran C supplemented by line of sight inshore. Figure 6 shows the location of the seismic profile lines run in Johns Bay for this study.

Seismic profile data were interpreted by tracing characteristic acoustic sig- nals and identifying the seismic facies. Profile lines were then digitized manu- ally to determine the depth to the Pleistocene, depth to bedrock, and sediment thickness. A seismic velocity of 1500 m/s was used for all depth calculations. After correcting for tidal variations, the digitized seismic data were used to construct the structure-contour and isopach maps. Depth determinations could not be made in areas of acoustic wipe out. Contour and isopach lines on the map were extrapolated through these small regions. Finally, these data were used in conjunction with sea-level curves and vibracores to create the paleogeographical reconstructions. Vibracores in Johns Bay provide some control on the seismic profiles in this embayment.

Vibracore Database Fourteen vibracores were taken on Pemaquid Beach, in the back-barrier

marsh, and in Johns Bay just offshore of the beach. Offshore vibracore locations are shown on Figure 6; nearshore and onshore vibracore locations are shown on Figure 7. The deepest offshore core was taken in 12.2 m of water. Aluminum irrigation tubing with an inside diameter of 7.6cm was vibrated into the sediments by a gasoline-powered cement vibrator after the method of Lanesky et al. (1979). Offshore cores were taken off the stern of the 10 m lobster boat RIV Lee, employing a SCUBA diver. Following extraction, cores were sealed tightly and transported to the lab, where they were described, sampled, and archived (Young, 1990). Five major lithostratigraphic units were identified for the Pemaquid Beach and shoreface cores, and each unit was interpreted for environment of deposition (Table 11). There are a number of much less frequently occurring lithofacies in some of the offshore cores. The complete vibracore logs are located in Appendix A of Young (1990).

Archaeological Database Kellogg (1982) mapped the distribution of coastal archaeological sites around

Johns Bay. He showed evidence for 49 sites. Almost all of these sites are located in the upper embayment. Is this distribution a result of human preference in settlement area? Probably it is not. This question will be discussed later.

Site 16-90, the Nahanada Site, is located on an eroding bluff adjacent to Pemaquid Beach in the central part of Johns Bay. The site was excavated in 1980 and 1981 by a team from the University of Maine directed by Sanger. They dug 26 pits, 1 m X 1 m of varying depths (usually less than 1 m), representing the depth of cultural horizons. The primary sources of information

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Table 11. Major lithofacies of Pemaquid Beach and the Pemaquid Beach shoreface. Description Interpretation

Medium to coarse quartz sand, moderately well to well sorted, auxiliary mica and lithics <5%, white to light gray, massive to parallel laminations, occasionally coarse lag at bottom. Found at the top of most cores Peat, light to dark brown, very sandy, 20-80% organic by volume, rooted, S. patens and S. alterniflora. Found a t the top of the back-barrier cores Peat, dark brown to black, greater than 90% organic by volume, massive and compact, detrital organics, leaf frags., woody frags., Typha, charcoal at the bottom, occasionally rooted. Frequently grades into facies 4, occasionally unconformably overlain by facies 5 Fine to coarse quartz sand, often silty, moderately sorted, pebble to cobble lag at the top, micaceous, 5-10% lithic fragments, dark brown humic stained at the top, gray at the bottom, massive to planar cross stratification, rooted at the top. Usually overlain by facies 3 Dark gray to black marine mud with occasional coarse lenses increasing in frequency towards the top, occasional dropstones, massive to bioturbated, articu- lated Mya arenaria not in growth position. Most cores

Holocene shoreface, beach, and dune sands

Salt marsh peat

Upland freshwater peat

Regressive Pleistocene sands: representing shoreface, fluvial, and possibly barrier environments. With a soil horizon developed on top

Pleistocene glaciomarine mud

refuse in this unit. Always overlain by facies 2

for this discussion are the excavation field notes and a faunal report by Spiess (1980). The Nahanada Site is a multicomponent site. The first evidence of human settlement in the intact Nahanada Site is at 2000-3000 yr B.P. in the form of a projectile point dated by its morphology. The extent of this early occupation is unclear because of the mixed nature of the site. There is clear evidence for a period of substantial occupation centered around European contact (about 1600 A.D.).

The faunal remains from the Nahanada Site indicate a marine adaptation with a strong terrestrial component. I t is unclear what portion of the 2000 plus years of occupation the faunal remains represent. It has been suggested that the faunal assemblage represents only the most recent occupation. If this is the case, then the nature of the marine adaptation of the 2000 yr B.P. occupation is unknown. Ongoing research may help to resolve this issue at Nahanada.

In 1988, the Fosdick-Downs collection was donated to the University of Maine. The collection is composed of lithic artifacts collected over a period of 15 years from Pemaquid Beach and in front of the Nahanada bluff. All of the artifacts in this collection were found out of stratigraphic context; yet, they are significant for they indicate that the Pemaquid Beach area may have a history of human settlement that predates the artifacts found in the Nahanada Site.

GEOARCHAEOLOGY: AN INTERNATIONAL JOURNAL 223


The artifacts occurred on the beach, mostly in the intertidal zone. Not surpris- ingly, some of them are rounded and nearly unidentifiable. What is surprising is that some of the artifacts show little evidence of rounding. The oldest projectile point in the Fosdick-Downs collection is a Moorehead phase projectile point of about 5000 yr B.P. Classification of all of the identifiable artifacts from the collection produces a chronological continuum from 5000 yr B.P. through the dated occupation of the Nahanada site.

RESULTS Paleobathymetry of Johns Bay

The primary control on the morphology and bathymetry of the Johns Bay embayment is the underlying, glacially scoured bedrock surface. Both the modern bathymetry (Figure 5) and the Pleistocene structure-contour maps (Figure 8) closely mimic this underlying bedrock topography. There are two primary depo-centers in Johns Bay-shown by the thickest accumulation of sediments in the sediment isopach map (Figure 9); a small basin just to the west of Johns Island and the deeper portions of the “channel” that forms the central part of the embayment. The greatest accumulation of Holocene and Pleistocene sediments are in the same location-further evidence for bedrock control of deposition. Fluvial input is negligible today and appears to have been so throughout all but the earliest stages of the embayment’s development. The embayment is relatively shallow. It was totally emergent (with the exception of a poorly defined central valley) at the - 65 m lowstand. Most of Johns Bay is at less than 30 m depth today; thus sediment accumulation appears to be somewhat restricted.

The Johns Bay seismic facies map (Figure 10) shows that the embayment is dominated by Holocene mud. This mud is accumulating natural gas in the previously discussed depo-centers. The outer reaches of the embayment have large exposures of bedrock, subaqueously and as the dominant shoreline. The percentage of exposed bedrock decreases up the embayment. Along the eastern margin, there is a continuous accumulation of subaqueous sand and gravel stretching from Pemaquid Point north to Pemaquid Beach. The modern shoreline here consists of a narrow, gravel to cobble beach fronting a thin, eroding till.

Figures 11 and 12 are ORE Geopulse seismic profiles and interpretive line drawings. Locations of these sections are shown on Figure 8. Seismic profile line JB-88-3 (Figure 11) is a transect crossing the eastern marginal sand feature and the central “channel” of the embayment. This profile exhibits the typical seismic stratigraphy of Johns Bay. Bedrock (BR) is ubiquitous at the bottom of the section. It is draped on the eastern margin with a thin veneer of till (TI probably similar to the thin till covering bedrock on the eroding bluffs of Pemaquid Neck. Pleistocene glaciomarine sediments (GM) overlie these units, thickening into the deep central valley. A strong reflector on top of the Pleisto-

224 VOL. 7, NO. 3


JOHNS BAY DEPTH TO PLEISTOCENE

Figure 8. Johns Bay depth-to-Pleistocene map constructed from seismic profiles. The cross-hatching indicates portions of the record obscured by natural gas.



JOHNS BAY HOLOCENE SEDIMENT ISOPACH MAP

* 52'

,430 so'

69'30' 31'

Figure B, Johns Bay Holocene sediment isopach map constructed from seismic profiles.

226 VOL. 7, NO. 3


JOHNS BAY SEISMIC FACIES

Figure 10. Johns Bay seismic facies map constructed from seismic profiles. The cross-hatching indicates portions of the record obscured by natural gas.



SE DI5 I320 1325 1330 NW - 0 0 G w 0 W u)

20 1“ .- . . . . . .. -. . .. . E W H I-

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a

I- I 2 i % 00 A

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Figure 11. Interpreted line drawing of seismic profile line JB-88-3. The line runs from the eastern margin of the embayment across the central channel. See Figure 6 for location.

cene is interpreted as the regressive/transgressive unconformity. The top of the section is comprised of Holocene mud (MI in the deeper parts and Holocene sand and gravel (SG) at the margins. Muds in the central valley are accumulating natural gas (NG), exhibiting an “acoustic wipe-out.” Pleistocene units are truncated on the southeastern margin by what appears to be a - 30 m shoreline. This coarse-grained feature exhibits a typical shoreline profile-an upper, convex, eroded shoreface with a lower, parallel-laminated accumulation form. This feature was observed in other subparallel seismic lines indicating the probable existence of a continuous - 30 m shoreline along the eastern margin of Johns Bay. It is possible that northward longshore transport of sand along this shoreline was an early sediment source for the Pemaquid Beach sands.

Seismic profile line JB-88-16 (Figure 12) runs from Pemaquid Beach offshore

228 VOL. 7, NO. 3


a I-

2 7 8 - ?

-

I

NE sw

- 0

- 60 'I I

Figure 12. Interpreted line drawing of seismic profile line JB-88-16. The line runs from Pemaquid Beach offshore. See Figure 6 for location.

into Johns Bay. The seismic stratigraphic section in this line is comparable to that in JB-88-3 without the natural gas. Pemaquid Beach is separated from the rest of Johns Bay by an - 8 m bedrock ridge. This forms a small basin just offshore of the beach. The Pleistocene surface in the basin is channelized-as evidenced by several oppositely dipping reflectors in line JB-88-6. The bedrock ridge has been very important in controlling the paleoenvironmental development of the Pemaquid Beach area, and hence, the nature of early human occupation. Vibracore JB-VC-2, taken just seaward of the bedrock ridge, shows an accumulation of sand and gravel that may be a submerged beach similar to the narrow beach along the eastern margin of Johns Bay.

Johns Bay and the EstuarinelEmbayment Evolution Model A three-zoned model has been developed for Maine estuaries and embay-

ments. This model was first suggested by Kellogg (1982) as a classification



scheme for wave energy and coastal erosion variations within Maine embayments. He noted that the outer zone (zone 3) is stripped of sediments; the central zone (zone 2) is dominated by erosion; and the inner zone (zone 1) is not yet eroding. This model has been further modified to include the description of coastal environments in each of the three zones and to include the subaqueous, sediment dynamics within the embayment (Shipp et al., 1987; Belknap et al., 1986,1987b; Kelley, 1987; Smith, 1990). In this refinement of the model, zone 1 is described as an area of temporary sediment accumulation. The sediment eroded from shorelines in zone 2 is transported both offshore and up embayment for temporary storage (thousands of years) in marshes and on mud flats in zone 1. As sea level rises, the three zones shift landward. Sediment deposited in zone 1 is gradually cycled out of the embayment through shoreface erosion during transgression with a long-term net export of sediment (Hay, 1988).

Figure 13 shows an interpreted line drawing of a seismic profile from each zone in Johns Bay. It is apparent that this embayment fits well into the estuarine/embayment model. The mouth of the embayment is primarily exposed bedrock, except for the deepest part of the channel. This is contrasted with the inner embayment where very little bedrock crops out. Here Johns Bay is almost completely blanketed with Pleistocene and Holocene sediments. The central embayment is the transition zone. This can be seen just offshore of Pemaquid Beach where the shoreface is cutting down into Pleistocene glaciomarine sediments, having already removed any Holocene sediments. Bluff erosion is also greatest in this zone. It will be shown that this three-zoned model has important implications for the archaeological record of Johns Bay.

Vibracore Correlation and the Stratigraphy of Pemaquid Beach Figure 7 shows the locations of the vibracores taken around Pemaquid Beach.

The chronology was developed by radiocarbon dating of organic material from the vibracores. The results are presented in Table 111.

A composite stratigraphic section (Figure 14) comprising the five major lithofacies from Table I1 contains Pleistocene glaciomarine mud at the base. The Pleistocene sediments coarsen upwards to medium sand as a result of reworking during the marine regression. Most cores show evidence for the development of a soil horizon on top of the regressive Pleistocene. This is effectively the Pleistocene/Holocene unconformity . Organic material (pine needles and twigs) on top of this unconformity in PB-VC-7 produced a radiocarbon date of 6105 +- 75 yr B.P.

The Holocene section begins with a freshwater peat developed on top of the soil horizon. This peat is dark, and greater than 90% organic by volume. It contains woody material, leaves, and some detrital organics. There are occasional layers of charcoal. This unit represents the formation of a wetland in the Pemaquid Beach basin as the water table rose with rising sea level. The base of the freshwater peat in core PB-VC-7 dates at 3740 -+ 35 yr B.P. Prior to this date, the Pemaquid Beach area was a relatively well drained, forested

230 VOL. 7, NO. 3


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Figure 13. Interpreted line drawings of Johns Bay seismic profiles from each zone of the estuarine embayment model. Note that the middle line has a reversed orientation.

upland. On top of the freshwater peat, in the back-barrier cores, is a sandy, Spurtinu ulternifloru salt marsh peat. The contact between the two units is gradational. This represents increased saltwater input into the back barrier as sea level continued to rise. The base of the salt marsh in core PB-VC-3 dates at 920 2 45 yr B.P. Finally, at the top of the section are shoreface and barrier sands.

Figure 15 is a transect across the beach and into the nearshore. The unconformity on top of the Pleistocene is the basal unconformity defined by Belknap and Kraft (1985). The ravinement (or shoreface) unconformity is the unconformable contact between shoreface sands and the earlier Holocene environments (e.g.,



Table III. Radiocarbon age determinations from Pemaquid Beach vibracores (ages in radiocarbon years B.P.). SamDle Number Core and Depth Material Date (yr B.P.)

PITT-0474 PITT-0467 PPIT-0471 PITT-0466 PITT-0464 PI'IT-0468 PITT-0469 PI'IT-0465 PI'IT-0470 PITT-0472 PI'IT-0473

PB-VC-3B, 138-143 PB-VC-3B, 143-148 PB-VC-3B, 190-195 PB-VC-4, 80-85 PB-VC-5, 30-40 PB-VC-GA, 132-145 PB-VC-6B, 140-1 50 PB-VC-7, 70-80 PB-VC-7, 180-190 PB-VC-7, 230-240 PB-VC-7. 290-300

Salt marsh peat Salt marsh peat Freshwater peat Salt marsh peat Freshwater peat Freshwater peat Freshwater peat Freshwater peat Freshwater peat Freshwater peat Organic-rich sand

630 f 50 920 f 45

1215 2 50 610 f 60

3420 f 45 3075 f 40 3260 f 40 1510 f 35 3150 f 40 3740 5 35 6105 * 75

~~ ~~

Note: Organic material identified by macroscopic inspection and comparison with locally collected surface samples.

freshwater peat). The ravinement unconformity is separate from the basal unconformity in the offshore core (JB-VC-3) because Holocene fluvial erosion has added some relief to the Pleistocene surface. This has allowed a greater accumulation of Holocene sand. Where there has been no Holocene fluvial erosion, it is assumed that the ravinement unconformity has cut down into the basal unconformity leaving only a thin layer of shoreface sand on top of the Pleistocene. Core JB-VC-3 is roughly in the center of the Pemaquid Beach basin-about 150 m offshore of the beach. None of the nearby barrier or back- barrier environments are present in this core. However, the preservation of the base of the soil horizon on top of the regressive Pleistocene and Holocene fluvial sediments and tree roots in these sediments indicate that these environments were present at this location at one time. Because the basal unconformity is very shallow beneath the entire system, it is apparent that the preservation potential for the modern barrier and back-barrier environments is very small.

There is a small amount of differential preservation along Pemaquid Beach. The salt marsh peat is still present in the upper beachface at core location PB- VC-3. It has been removed by shoreface erosion from the upper beachface at core location PB-VC-6. This indicates that there is some relief on the basal unconformity along the beach (Figure 16). Also in this figure, it is important to note that an earlier analogue, the stream crossing Pemaquid Beach, appears as a channel in the seismic line taken offshore. This and the fact that the stream is bedrock controlled upland from the beach suggest that the stream has existed (in some form) for a significant period of time, probably throughout most of the Pemaquid Beach area's development.

Summary At the end of the Pleistocene the entire Pemaquid Beach area was subaque-

ous. Around 11,000-10,000 yr B.P. the regressing shoreline passed over the

232 VOL. 7, NO. 3


PEMAQUID BEACH COMPOSITE STRATIGRAPHIC SECTION . . . . . . . . . . . . , . * * -

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BARRIER OR SHOREFACE SANDS

RU

SALT MARSH PEAT

FRESHWATER PEAT

BU

REGRESSIVE PLEISTOCENE SANDS (WITH SOIL HORIZON ON TOP)

PLEISTOCENE MARINE MUD

Figure 14. Composite stratigraphic section of major lithofacies from Pemaquid Beach.

Pemaquid area, reworking the recently deposited Pleistocene glaciomarine muds. The rooted soil horizon developed on top of these sediments indicates the development of a well drained, forested upland. By 3800 yr B.P., an upland fen/ bog had formed in the Pemaquid Beach/basin area. This wetland formed as the water table rose in response to the rising sea level. By 900 yr B.P., rising sea level had converted the freshwater wetland to a salt marsh. Pemaquid Beach was now landward of the offshore bedrock high. Over the last 900 years the barrier has migrated landward on top of the salt marsh and freshwater wetland leaving little stratigraphic evidence of the back-barrier environments in its wake.


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Figure 16. Vibracore correlation along the Pemaquid Beach upper beachface and interpreted line drawing of seismic profile line JB-88-14 along the Pemaquid Beach shoreface. PB-VC-6 was slightly higher on the beachface than PB-VC-3.

DISCUSSION Paleogeography of Johns Bay

The paleogeographic reconstructions were built using the Belknap et al. (1987a) sea-level curves, the Pleistocene structure-contour map, the interpreted



seismic lines, and the Pemaquid Beach vibracore transects. Reconstructions were built on an embayment-wide scale at 9000, 7000, and 5000 yr B.P., reflecting three stages in the evolution of Johns Bay. When examining the paleogeographic history of Johns Bay, it is important to consider two facets of the archaeological database: (1) The first evidence for coastal settlement in Johns Bay is at about 4000-5000 yr B.P. (2) All but four of the Johns Bay archaeological sites are located in the upper embayment. Two reconstructions focusing on Pemaquid Beach and the Nahanada Site were constructed at 3800 and 900 yr B.P. The archaeological record from the Nahanada Site and the Fosdick-Downs collection were consulted frequently in the reconstruction of the Pemaquid Beach area paleogeography.

Johns Bay at 9OOO Yr B.P. At 9000 yr B.P., sea level along the coast of Maine was still near its lowstand

( - 60 m). The shoreline was several kilometers seaward of modern Johns Bay. Most of the embayment was emergent. The area was drained by a narrow, fluvial system that occupied the central valley (Figure 17). A small lake or wetland occupied the deep basin west of Johns Island. The region was forested by this time (Kellogg, 1989; Davis and Jacobsen, 1985) and the soil horizon developed on top of the Pleistocene in the Pemaquid Beach cores had probably begun to form. Any human settlement with a coastal marine adaptation dating from this time period would be located several kilometers out in the modern Gulf of Maine.

Johns Bay at 7000 Yr B.P. By 7000 yr B.P. sea level had risen to about - 30 m. Johns Bay had broadened

into an estuary roughly 1 km across (Figure 18). At this time the submerged shoreline feature evident in the seismic profile lines would have existed on the eastern margin of the embayment. This sandy shoreline formed as the rising Gulf waters reworked the glacial sediments draped over Pemaquid Neck. Sedi- ment transport along this shoreline would have been up the embayment. It is possible that this prograding sand feature was an important supplier of sand- sized sediment to the Pemaquid Beach area as sea level continued to rise.

With the development of an estuary in Johns Bay, an environment existed for the exploitation of marine resources. Yet no sites dating from this time period have been found. As is the case with the previous reconstruction, any coastal settlements during this time period would now be submerged. It appears that the eastern margin of the embayment might hold some promise for preservation of marine-adapted sites. The horizontal distance from the modern shoreline of Pemaquid Neck to the paleoshoreline shown in Figure 18 would not have been that great, but the slope would have been quite steep. This is a strong negative factor in selecting a coastal site (Kellogg, 1982). The subaerial Pemaquid Beach region was still a forested upland at this time.

236 VOL. 7, NO. 3


JOHNS BAY AT 9000 BP (-60m)

Figure 17. Paleogeographical reconstruction of Johns Bay at 9000 yr B.P. See Figure 6 for seismic profile line coverage.



JOHNS BAY AT 7000 BP (-30m)

Figure 18. Paleogeographical reconstruction of Johns Bay at 7000 yr B.P. Sea Figure 6 for seismic profile line coverage.

238 VOL. 7, NO. 3


Johns Bay at 5000 Years B.P. 5000 yr B.P. is a critical date for coastal Maine archaeology. Evidence for

marine adapted sites after 5000 yr B.P. increases dramatically in frequency (Sanger, 1988b). The first evidence for human settlement of Johns Bay is from this period in the form of a Moorehead phase projectile point found in front of the Nahanada Site.

There are several reasons for the importance of the 5000 years B.P. date. The biological productivity of the Gulf of Maine may have increased dramatically after this time as a result of increased tidal range (Sanger, 1988a). The rate of sea-level rise began to level off after 5000 yr B.P. This had two important consequences. Coastal sites perched on bluffs near the 5000 years B.P. shoreline may still be preserved; and, as Kellogg (1989) points out, archaeological visibility would be improved as the rate of sea-level rise decreased. Visibility is improved because a given coastal settlement can be occupied for a longer period of time as the rate of shoreline translation decreases.

It is worth noting that the preservation potential for archaeological sites is greatest when the visibility is the lowest. Kraft et al. (1983) point out that rapid sea-level rise increases site preservation potential. This is because shoreface erosion decreases as the rate of sea-level rise increases (Belknap and Kraft, 1981). I t follows that for the period from 9000-5000 yr B.P. the preservation potential of Johns Bay archaeological sites was the greatest; yet the archaeological visibility should be very low because of the rapid shoreline transgression.

Figure 19 is a reconstruction of Johns Bay at 5000 yr B.P. By this time Johns Bay had widened to an open embayment-approaching its present morphology. The Pemaquid Beach area was still forested upland. The Johns Bay shoreline had moved to within a few hundred meters of the Nahanada Site and modern Pemaquid Beach. It appears that the confluence of the stream and Johns Bay would have been an attractive settlement area. It would have been almost identical to the situation of the Nahanada Site today.

Site Distribution Around Johns Bay It is now apparent why the first evidence for settlement in Johns Bay is at

5000 yr B.P., but why are almost all of the sites located in the upper embayment? The answer is in the estuarine/embayment model and the paleogeographical history of Johns Bay. Figure 20 shows the location of archaeological sites around Johns Bay from Kellogg (1982). Sites in the extreme upper reaches are not shown. When the site distribution is viewed within the framework of the estuarine/embayment model, it is clear that most of the preserved sites are located in zone l-the portion of the embayment undergoing sediment accumulation. There are four sites in zone 2 (including the Nahanada Site). These sites are eroding. There are no sites in zone 3, which has been stripped of sediments.

It is also important to note that pre-5000 yr B.P. shorelines around the



JOHNS BAY AT 5000 BP (-lorn)

4 €I OPEN EMBAYMENT

8 Figure 19. Paleogeographical reconstruction of Johns Bay at 5000 yr B.P. See Figure 6 for seismic profile line coverage.

240 VOL. 7, NO. 3


- 5 2 '

-43.50'

Figure 20. Distribution of archaeological sites around Johns Bay in light of the estuarine embayment model.



embayment fall completely within zones 2 and 3. Most of the sediments in these two zones have been removed, or are in the process of being removed. Thus, the chance of finding a submerged coastal site dating from 9000-5000 yr B.P. appears slim.

Paleogeography of Pemaquid Beach and the Nahanada Site At 5000 yr B.P., the Pemaquid Beach area was a forested upland. The shore-

line was just seaward of the emergent bedrock ridge. By 3200 yr B.P., the shoreline was pinned against the offshore bedrock ridge (Figure 21). A freshwater wetland had formed in the basin behind the ridge. The area was drained by a stream that exited through a gap in the ridge. The artifacts in the Fos- dick-Downs collection seem to indicate a continuous chronology of settlement for the area beginning at 4000-5000 yr B.P. The last 2000 years are represented by artifacts in context in the Nahanada Site. It appears that the Nahanada Site represents the last segment of a 5000 year settlement history for the Pemaquid Beach area. The Nahanada Site may represent the back of a horizontally stratified settlement area that extended out to the 5000 yr B.P. shoreline. Admittedly, the archaeological database is sparse; and drawing conclusions about out-of-context artifacts is dangerous. This scenario seems to best explain the archaeological and geological data. Therefore, the area to the southeast of the stream in the 3200 yr B.P. reconstruction is shown as forested upland. It is assumed that this area was 1 or 2 m higher than the nearby wetland, as the Nahanada bluff is today.

By 900 yr B.P. a pocket barrier (Duffy et al., 1989) had formed behind the now submerged bedrock high. The back-barrier inlet had opened north of the beach and a salt marsh had formed behind the main barrier, probably ponded behind a sandy inletlbarrier facing northwest. Essentially, Pemaquid Beach had reached its modern morphology. The only difference was that it was about 80 m seaward of its present location. The upland southeast of the stream has been carved into as the beach’s crenulate morphology developed-supplying sand and artifacts to the beach. Pemaquid Beach is a sedimentologically closed system (Nelson and Fink, 1978). There is little sediment transport into or out of the small crenulate embayment. This suggests that the out-of-context artifacts are, in fact, locally derived.

Development of a Chronologically Shingled Site Considering the paleogeography of Pemaquid Beach and its record of human

settlement, a model can be developed for the formation of a chronologically shingled site. This is an archaeological site where the artifacts are not simply vertically stratified, but, rather, are distributed laterally across the site in some recognizable chronology (Figure 22). For the sake of simplicity, it is useful to think of sea-level rise as occurring incrementally. As each increment of sea- level rise occurred, a decision would have been made whether or not to abandon the site.

242 VOL. 7, NO. 3


PALEOGEOGRAPHY OF PEMAQUID BEACH

Figure 21. Paleogeographical reconatructions of Pemaquid Beach at 3200 and 900 yr B.P. See Figures 6 and 7 for seismic and vibracore coverage.



SEDIMEXT LAG FROM TIME 1 OCCUPATION

SEDIMENT LAG FROM TIME 2 OCCUPATION

Figure 22. Conceptual model for the development of a chronologically shingled archaeological site.

The Nahanada Site rests on a bluff that overlies a gradually sloping bedrock surface extending 30-40 m offshore. At 3200 yr B.P. the bluff probably extended to the toe of the bedrock slope. With each incremental rise in sea level, the inhabitants of the site would have been able to simply “take one step back” on the bluff. Even though the toe of the bluff was eroding (and still is), this broad, gradually sloping surface would have allowed the inhabitants to move back with the bluff front for a period of 4000-5000 years. During this time, Pemaquid Beach was migrating from offshore of the bedrock high into its present position. Access to the beach environment during this entire 4000-5000 year period was possible. There would have been no obvious geomorphic reason to abandon the Nahanada Site. The result is a record of settlement with the most recent

244 VOL. 7 , NO. 3


SITE DbRING TIME 2 ASD TIME 3

TIME 1 -MH\N SITE DCXING TIME 1

Figure 23. Conceptual model for the development of steeper slope archaeological sites.

artifacts in context on the remaining bluff and the earlier artifacts spread out as a lag in front of the retreating shoreline.

This picture can be contrasted with the eastern and western margins of Johns Bay south of the Nahanada Site. Here the bedrock surface slope is very steep. Scattered terraces exist that may have provided an area for settlement. Yet, because of the steep slope behind these terraces, there would have been little room to simply “step back” on a site as sea level rose. The site would be abandoned much sooner than a site with a gradually sloping surface such as the Nahanada Site (Figure 23).

A site that rests on a flat surface such as a coastal plain would experience a different set of circumstances. Here, an increment of sea-level rise would inun- date relatively more land surface than the previous two scenarios, and the site would be quickly overtopped. Barring unusual geomorphic circumstances (e.g., the location of a site in a protected back-barrier environment), this type of site would also be abandoned much sooner than a site located on a gradually sloping bluff surface. The potential for the development of a chronologically shingeled site is also poor. In this case, its final preservation potential would be deter- mined by the depth of shoreface erosion among other factors (Kraft et al., 1983).

The first step in examining this model will be to choose a number of existing coastal Maine archaeological sites looking for those that sit on gradually sloping bedrocklbluff surfaces. Most of these sites would have a fairly recent record of settlement in stratigraphic context. This study suggests that searching just offshore or in front of these sites might turn up evidence of earlier settlements that have been left as an erosional lag.

CONCLUSIONS High-resolution seismic profiling, in combination with vibracores and Holo-

cene sea-level curves, has been used to develop the Holocene paleogeographic



evolution of Johns Bay and Pemaquid Beach, Maine. These geological databases were, whenever possible, integrated with the Johns Bay archaeological database and general archaeological settlement paradigms for coastal Maine. The following conclusions can be drawn:

1. As sea level has risen from its - 65 m lowstand at the beginning of the Holocene, Johns Bay has evolved from a narrow fluvial system, to an estuary, to its present form of an open embayment.

2. The Pemaquid Beach area has changed from a forested upland, to a bedrock-pinned freshwater wetland, to a pocket barrier fronting a small salt marsh. The barrier continues to migrate over the salt marsh, which is transgressing the freshwater environments.

3. The first evidence of human settlement in Johns Bay is at 4000-5000 yr B.P. This is due to a number of factors: (1) A decrease in the rate of sea- level rise allowing increased archaeological visibility and the possible temporary preservation of archaeological sites perched on bluffs. (2) Sites prior to 5000 yr B.P. are submerged and probably eroded. (3) A possible increase in biological productivity of the Gulf of Maine after 5000 years.

4. Archaeological sites in Johns Bay are concentrated in zone 1 (inner embayment) of the estuarine/embayment model. This zone is currently experiencing sediment accumulation. Zone 2 (middle embayment) is undergoing erosion, and zone 3 (outer embayment) has been stripped of sediment. Archaeological sites in these outer areas have been eroded. In comparable zones elsewhere on the Maine coast intact sites should be few in number.

5. The Pemaquid Beach area has a history of occupation dating back 4000-5000 years. The last 2000 years of this record is found in stratigraphic context in the Nahanada Site. The first 3000 years is represented by a collection of artifacts found out of context on the beach in front of the Nahanada site. The artifacts, dated by morphology, present a time continuum from 4000-5000 yr B.P. until the occupation of the Nahanada Site. Thus, it is suggested that the Nahanada Site represents the back of a horizontally stratified settlement area that extended to the 5000 yr B.P. shoreline.

Of equal importance to the above conclusions, is the interdisciplinary meth- odology used. Typically, paleogeographical reconstructions are built by a geolo- gist to examine the changing paleoenvironments of a given area, and, maybe, to shed some light on the archaeological record. The approach taken in this study was to weigh the databases evenly. For example, in developing the history of the Pemaquid Beach area, the geological and archaeological data were considered simultaneously and the concepts for the paleogeographical and archaeological changes were developed concurrently. The resulting view of the area's geological and archaeological evolution is a synthesis in which each database derives the maximum benefit from the other.

246 VOL. 7, NO. 3


This investigation was carried out as part of the research efforts of the Institute for Quaternary Studies and the coastal and marine geology program of the Department of Geological Sciences a t the University of Maine. The project was made possible by support from University of Maine Center for Marine Studies, Geological Society of America, University of Pittsburgh Radiocarbon Lab (Dr. Robert Stuckenrath Jr., Director), and the University of Maine Darling Marine Center. Our thanks to L. K. Fink.

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Kellogg, D. (1989). Prehistoric landscapes, Paleoenvironments, and Archaeology of Muscongus Bay, Maine. PhD. Dissertation, University of Maine, Orono.

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Kraft, J.C., Belknap, D.F., and Kayan, I. (1983). Potentials of Discovery of Human Occupation Sites on the Continental Shelves and Nearshore Coastal Zone. In P.M. Masters and N.C. Fleming, Eds., Quaternary Coastlines and Marine Archaeology, pp. 87-120. New York: Aca- demic Press.

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Receiued Nouember 4,1991 Accepted for publication January 30, 1992


Documents

Geoarchaeology of Johns Bay, Maine