No.6 May 1992

Jamaican Geographer Newsletter of the Jamaican Geographical Society ISS 1017-4753

COASTAL GEOMORPHOLOGY

FIELD TRIP

On Saturday, 211th March, a field trip or­ganized and led by Dr David Miller, left Kingston on a coastal geomorphology field day . TIle route traversed the eastern porti on of the island, travelling north through Junction road, then thro ugh the parishes o f St Mary, Portland and St Thomas, back to Kingst on. The demand for places was enonuous ; do zens of the 69 participants were keen s ixth form g e og ra ph y s tu den ts, re in f o r c i ng th e Council's bel ief that there are no t nearl y enough opportunites ava ilabl e to students to

FIELD WORK

'The only true geographical laboratory is the world outside the classroom '. This statement made in 1954 by a group ofBritisli schoolmasters is arguably still true today. Certainly. (I lor ofthe subject matter relevant to school geography can be discovered ill one's immediate surroundings, Yet, ill Jamaican schools at least, the tradition of learning outside the lassroom. through fieldwork, is no t strong.

Recognising this, the JGS Council mounted two field trips in 1991/92 with 6th form students particularly in mind; a day ill Brown '.'I To w n market, tnd a coasta l geomorphology trip (see pp 6 - 7 for a reproduction ofthe field guide) . III the nexi i.' ~,;u e. we will publish dura collected by st u­dents on the Brown's Town field trip.

Field work is invariably a hassle to or­ganize, and transport costs are lint cheap. BIIt we need much more of it, not less, Will

we need to explore innovative and col­laborative ways of making field teaching and research more effective.

Edi tor

learn abo ut the en viron me nt through fie ld work.

Th e first st op was a t Ann ouo Bay, to examine the bay -head harrier beach, a t the mouth o f the Wag wat er River. Members of th . group wert: sh own no w to identify a bench berm and beach cusps. Th e backshorc, fore ­shore, bre aker , surf and swash zones were also ex plained as well as the different breaker types observed tha t day . This particular beach is a c las t-dominated, sand-shingle beach. A longish walk alon g the beach brought the group 10 the neck cut-off. At this point, the beach no rma lly obs tructs the mouth o f the Wagwatcr Rive r, and und er normal river now condltions, the b erm or beach is inta ct and di v rl th e r ive r a fe w hundred yards west wards , flowing parallel to the beach , before ente ring the Sea through see page . How­ever, a fte r a large tl oocl event, the berm or beach is breac hed . The site o f the neck cu t-off is also su bject to illeg al sand mining.

TIle second stop was at Buff Bay , where ther e is anothe r barrier beach , Here, the beach material is composed of much large r, water­smoo the d rocks and boulders than tha i a t Annouo Bay . Th ese beach boulders consi st o f a larg e nu mber o f geo log ica lly differen t roc ks derived from the vo lcaniclastics , mc tarnor­ph ics and the Wa g va te r an d Ri chmond Formati ons o f the Blue Mountai ns. Several pieces of flint, a very hard ma teria l (and thus not quite as rounded as the other beach material), were als o found, also fro m a local source. H ere, du ring no n- flood conditions, the beach forms a barri er ac ross the mouth of the Buff Bay a nd White Rive rs wh ich bo th sho wed signs of eu trophication throu gh w .ed growth and algal bloo m, the r~,I 1L of the misuse of I'ertilizer and o ther agrochem ica ls within the wa tersheds.

The third stop W:L,> at the mouth of the Ri o Grande. TIle term inus of the Tourist Rafting facility was nearb y . Again, the beach there is dominated by fluvially-derived mat erial from

the Blue and John Crow M ountains. The mouth of the river has a sm all but splendid spit extending westwards and indicating longsh ore drift in that direction. The spit was unusual al the time of our vis it as it displayed a double recurved lateral (a hook at the end of the s pit), ex tending up river. Spits are normal ­Iy cy clica l in nature and the occurrence of one or two barrier islands forming extensions of the spit at this time could indicate breaching by storm waves . So the spi t could have been in eithe r its rebuilding or a recent destructive phas e.

11 the beaches to the west of the Rio Grande as far as Annett Bay are composed o f clastic se diments, mat eri al bro ught down by the various rivers which now northwards from th . Blue Moun tains into the Caribbean Sea on Jamaica 's north coas t. Th e mat erial deriv ed fro m thes e in land areas , on ce it reach es the coast, is carried and deposited con tinuo us ly wes twa rds by longshore drift. TIle beaches to the west of the Rio Grande, therefore, have a tendency to be drift-aligned. To the cas t of the Rio Grande, from Port Antoni o 10 Boston Bay, sw ash -aligned, pock ­et beaches arc to be found within the indented coas tline , TIle sources o f se dime nt found on these beach es are biogenic in or igin, formed from the d isin tegration of marine organisms such as coral, from o the r invert ebrates like sea egg: and molluscs, from cora lline and blue­green calcareous alg ae, and not least , from sea grass .

TIle first s top afte r lunch was at Folly Point.j ust south of Port Ant oni o, where it was possible to look ac ross the bay to the town and to Navy island. At this s it', the beach mat eri al was demonstra ted to be quite different from the s ites visited in the morning, the white sand ma terial being of biogeni c origin.

TIle next s ite was the beautiful pocket beach at Fai ry Hill , which has an impressive s tre tch o f white sand . TIle Urban De velop­ment Co rpo ra tion have slated this location for

Jamaican Geographer (6). May 1992 - 1

Wait-a-bit

tourist development, which would undoubted­ly change the character of the en virons, one of Jamaica's last truly, relatively unspoilt., white sand, public beaches.

At the last SLOp, the fisherman's beach at Manchioneal, those still fit and active had a brisk walk out to the splendid raised reef at Nettle Point This spectacular site has many classic erosional fe atures such as s ta cks, blow-holes and wave-cut notches. TIle young limestone which forms this raised reef is high­ly pitted and pock-marked by chemica l weathering, leading to its j agged appearance underfoot, and making it treacherous to walk on . A lovely Jamaican sunset marked the end of a fascinating da y out, and one full ofinterest and learning experiences in Held geomorphol ­ogy .

'The group returned to Kingston after dark, to reflect and so ak up the information acquired on a long and fairly exhausting (by. Dr David Mi ller, the field trip leader, retired to the Senior Common Room, UWl, to reflect and soak his exhausted vocal chords.

Political Geography Quiz I. What is the most northerly of the new Baltic States?

2. What nationality is the majority of the population of Moldovia?

3. TIle bulk of the Carpathian mountains straddle which country'!

4. What is the predominant relig ion o r Croatia'!

5. Bratislava is the capital of Slovakia or Slovenia'!

6. Budapest consists of which two separate towns, on the banks o f which major European river'!

7 . What is the largest e thnic minori ty in Bulgaria'!

8. What is the capital of Latvia '!

9. Name three contiguous countries where native Macedonians live.

10. Where is the former Kingdom of Bohemia?

2 - Jamaican Geographer (6), May 1992

BROWN'S TOWN FIELD TRIP

On Saturday, March 14, thirty two people journeyed to Brown's Town, St Ann to carry ou t a s urvey of the sphere of influence of the town's market The team was led by Perez Cross and Janet Hyde, both of the Town Plan ­ning Department, and included 22 students f ro m Wolmers High School for Girls, Walmer's High School fo r Boys, Campion College, Alpha Academy and Meadowbroo k High.

Brown's Town is the chiefmarket town for the parish ofSt Ann and attracts both shoppers and vendors from across the island. Market days a re fro m We dnesday to Saturday . Despite the fact that the Wednesday market is much higgcr than on the weekend, the stu­dents were ab le to field enough questionnaires to complete the assignment.

TIle objec tive of the exercise was to giv e s tudents a practical demonstration and ex ­perience in conduc ting questionnaire type research, O nce brie fed , students eagerly fanned out in and around the market to gather data . The responses were generally use ful and ins ightful.

TIle s tudents handled the exercise very well. A post-survey session was held on the following Saturday (March 21st) but unfor­tunately attendance was disappointing. But the enterprising students that did show up we re ab le to summarize the survey results.

ST MARY COASTAL IDKE

On Saturday, November 2nd, over fifty JGS members and friends participated on the second hike of the calendar year , a 1O-lnile coastal trail starting at Do n Christopher's Cove (Robin's Bay) and ending in Port Maria. Its popularity and heavy demand for places req uire d a second bus; other would-be hikers had to be turned down aft er the Thursday deadline passed, as all plac es were tilled and paid for by then .

TIle buses left UWI campus at 7.30am, and the walk commenced aro und 9 .45am. Earl y morning ra in had made the trail wet under foot, and claimed the so le of a shoe within the first

mile. Porrunately, the weather for the rest of tile day was fine, clear, and not too hot.

The sc enery on the hike was as beautiful and as spectacular as promised in Dr Eyre's fie ld guide. Along this part of Jamaica's coastline, tile outcrops of the Richmond For­marion hav e produced rugged cliffs and interesting geological exposures. Many clas­sic features of coastal geomorphology arc to bc observed; stacks, wave-cut notches, horse­shoe shaped embayments, raised coral cliffs, blow-holes and sea caves. The nora and fauna, too, are rich and varied.

The trail follows the route of an old 18th century coas tal road in places, hugging cliff tops then plunging into isolated black sand co ves, occasionally passing through dense rainforest and crossing small river valleys, and alone stage, actually descending to pass along the base of the cliffs, below the high­water tide mark. The trail is best taken at a leisurely pace, to enjoy the many panoramic views of the coas tline. In plac es the hike in­volve.'> short, strenuous cl imbs, but the path is quite safe, even where it is necessary to clutch clumps of guinea grass to neg tiate a badly eroded section.

Having de bussed about half a mile hefore the intended start owing to the muddied state of theroad, the points en route included Sunset Resort ( fo r m e r ly Strawberry Fields), Stileman's Cove, Foster's Cove, Green Bay (the lunch stop) and Mahoe Bay. On the way, we passed isolated fishing communities with genuine dug-out canoes, and rastafarian cam ps . In p laces, the forest was badly degraded, or cleared for cultivation or char­coal, especially over the last few miles before entering Port Maria. On the other hand, a forested area containing thatch palm which seemed to be regularly harvested for roofing material appeared fairly intact.

The main party finished the hike around 3 .00pm., hai ling at Port Maria's bench bar. Reh ydration rituals were dul y pcrfonncd as members of UIC group s traggled in. At tJ1C

bea ch bar, Yolanda, who had been forewarned some weeks earlier, had cooked delicious por ­tions of peppered bonito and dolphin fish which helped fortify tired limbs.

Wait-a-bit

UII/ch at Green Bay (photo: David Barker)

Hi ndu. Great efforts have been made to focus on the historica l aspects of Bali's culture . A notable fea ture is the 'h ome stay ' , here tourists Ii e with local families. Local coun­cil s, to , ha ve tried to resolve potential conflicts, In temples, for example, dress is restri cted and cameras not allowed.

Februarv 27th, 1992 'The Geography and Culture of India .

His Exce llency. Mr B.M.C. Naya r, the Indian High Commiss ioner , a disti ngu ished hist orian, gave an interesting talk on India .111eaudience heard about India's proud and impres ive con ­trihution to world culture, and an interesting exposi tion of the various cult ural influences from outsi de the Indian su b-con tinent that ha ve affected the course of her his torical development, We a lso were introduced to the so meti mes volatile politic of the region. It vas mentioned that seven scholarship ' wen;

a ailab le to study in India, and members we re inv ited 10 apply.

March 26th , 1992 'Al bania. the las t st ronghold of marxism ill Europe '

Professor Mcycr-Roch ow , Dep t. orZoology , WI , began with recordings of Albanian

music. Albani ans pride themselves as being lllyrians (a pre-He llenistic people). Before

Once again , the JGS is indebted to Dr AbU1 Eyre who not only suggested the trip, but prepared a meticulously detailed route guide for us. Organiza tionally , the success was in par t due to a reconnaissance of the route un­dertaken by David Miller, Balfour Spence, Earnonn Doyle, Larry Neuville :U1d David Barker, a co uple f weeks be fore the hike.

LECTURE SERIES December sn; 1991. 'Geography and Cultu re of Italy'

TIlls talk was given by his Excellency , Me Antonino Provenzano, the Ambassador of Italy. In a wide ranging talk , we were intro­duced us to the many different aspects of Italy 's history . geography and culture, and there were interes ting references to, and lis­cuss ion of the rc zional disparities between the north and the south of the co untry.

January 23rd, 1997 'Tourism and Culture on a small Tropical island: the Bali experience "

Dr Brian Hudson, popular form er lecturer i.1I the Geography Department, WI, present ed a superb slide show on Bali, It is ha If the s ize of Jamaica, but has an equivalent population s ize . Unli ke the rest of muslim Indonesia, Bal i is

tc wi FOUND TION

Tlte JGS CVIU/Ci! i pte etl to announce that the leWI FOUl/dation h provided a small gram 10 allow the ScCI ty to prim extra copies ofthe two Newslett. rs for the y tar 199/~2 (that is. our 25th anniversary 1 sue, Jamaican Geographer II5, and this i. '/It', II 6), Tit purpose is to ensure all libraries ill chools where geography is taught re 'eive these issues ofour Newslet­ter.If'the scheme prov , 'Z eful and popular in Jamaican ichoals. we will endeavour to

ensure that this arran ement is continued on WI annual basis.

In addition, rite ICWI Foundation has kindly made funds available en enable si. schools to become institutional membcrsfor the upcoming JGS year. The chool: . elected for this lCWI schen . will be 011­

nounced at the next AGM.

I am lire rh JT [[ lGS members will endorse the OWl i! in warmly th nking tire lC W/ F, iundauonfor tit tr support towards the enhancement ofgeographical education in our schools.

Editor

communism, the popul ation was lW% muslim. His personal observations and irnpres sions of the country and life of the people in an era where communism was c oll apsing eve rywhere were informative and entertain­ing . Man y people were see ing the visual images of th is once com ple tely is ol at ed Euro pe an coun try , with its Third World economy and life-styles for the firs t time.

May 7rh, /992 'The repercussions of the break-up of the So viet Union 0 11 Cuba'

Senora Maria Va lasquez, Second Sec retary and C ha rg e d ' Affa ires, Cuban Embassy, pres inte d a talk on as pects of lift: in Cu ba in this , thei r most diffi cul t period since the Revolution . TIle impac t of the US economic blocka de has been significant. The talk ended will) a video presentation des igned to attract tourists to Cuba, perh aps signalling one direc­tion in whi ch the uhan .conolllY will move in the future.

Jamaican Geog rapher (6). May 1992 - 3

Campus Geography

BRITISH-CARIBBEAN GEOGRAPHYSEMITNAR

The inau gural Bri tish-Caribbean Ge ography Seminar will be he ld at the Inter-Faculty Lec ­ture theatre , UWI, August 17th-2 1si .The con ­ference i . be ing held und er the auspices of the Institute of British Geogra phers, and is being supported by the British Council and the Com­monwealth Founda tion.

TIle theme of the co nference is 'Environ­ment and Development in small island states: the Caribbean ', and ove r 25 papers wll be presented on a variety of top ics s uch as tour ism and coas tal zone manage me nt, na tura l hazard : and disaster planning, environmenta l degradation, rura l de velopment , agric ulture and national parks .

Caribbean partici pan ts will be from Bar ­hado s, Trinidad, St Vincent, University of Guy ana, College of Th e Bahamas and Uni ve r­sity of the Virgin Is lands, as well as the UWI and other Jamaican professionals . A number of these papers will be presented by gradua tes o f the Geograp hy Department , U WI. Mos t of the non -Caribbean participan ts will be geo g ­raphers from the Unit ed Kingdom, although

geographers from Canada and the United States are also participating.

Conference Registration is from 8.30am on Monday , August 17th , and there is no registrati on fcc . Details of the programme and oth er matters re latin g to the wee k's ac tivities may be obtained from the Geography Depart ­ment, UW I (ph one 92 -72 129, ask for Dr Barke r or D r Mi ller).

DIPLOMA FOR DAY-DAWN SW ON

D ay-Da wn Sim on recentl y completed a one­year pos tgra duate Dipl oma in Cartog raphy at the Internationa l Institute for Aeros pace Su r­vey & Earth Sciences (lTC) , in the Nether ­lands . TIle programme provides ex tensive ex posure (0 modem computer cartography, plus courses on referencing for maps , map symbolization, use of co lour in maps, and map gene raliza tion.

Her project was in Computer Assisted Cartography, on the onccpts and techniques of re-districting , that is , the obj ec tive rea lloca ­tion of Enumeration Distri c t (ED) census bound aries in order to me et specific criteria

regarding average population per ED . The project was based on Jamaican data.

Day -Dawn has since returned to her post at STATIN, and has assisted with the work of the 10S Co uncil this yea r.

M,SC.FOR MICHAEL THARKUR

Michael Tharkur recent ly comple ted an M.Sc in Macroeconomic Policy and Planning in Developing COUlltries, at Bradford Univer­sity in England . TIlC pro gramme included course." on Inte rnational Trade Poli cy, Macro ­economic Analysis, Econ ometrics and Quan­t i tat iv e techniques, and Agr icultural Development and Policy. Mike' s thesi s was , An econometric analysis o f export perfor ­mance in the Jam aican economy' , in which he examined the domestic and external factors which a ffected Jamaica 's export performance b y commodity types, in the context stabilizato n an d structura l adjustment reforms . During h is studies at Bradford, Mike met David Edwards , one of the pioneers of agricultural research in Jamaica in the 19505.

'OME TITBITS 0 GLOBAL WARMING Compiled by Vernon C. Mulchansingh

I, The world consumes the equivalent of 135m bbl of oil per day of which 45 % comes from coal, 32 % from oil and 23 % from natural gas.

2. TIlt: hief contributors to carbon diox.ide emission are USA (26%), former Soviet

nion (21 %),Japan (20%), W. Europe 17%, China 11%.

3 'n ll: TIl.ird World, with 7R% of the world's population contributes 20% of carhon dioxide emissions.

4. Greenhouses gases arc crucial for life on earth, and without them the earth would be 30 degrees Celsius colder on average.

5. There arc 40 types of gases in the 'greenhouse' group.

6. It was Svante Arrhenius, in IR90, wh lfSt rais ed the 'greenhouse ' scare.

7. Six billion tons of carbon dioxide are pumped into the aunosphere every year.

R. TIle carbon dioxide level in the atmos­phere has risen from 250ppm in 1700s to 360 ppm today.

9. Between 1900 -1990, sea level rose 10­20cms. One forecast projects it 10 rise a further 65cms between 2000 - 2100AD.

10. In the next 40 years, world popula tion is projected 10 grow from 5.3 billion 1O c9.0 billion (90% of this increase will occur in underdeveloped countries). Energy con­sumption is projected to increase between 3 and 5 times too.

11. Deforestation has contributed 50% of the carbon dioxide build-up since 1800, and contributes 20% of the carbon dioxide released per annum .

12. If all the land ice melts, sea level would rise eustatically by 200 feet.

13, One hectare (2.2 acres) of forest absorbs 100 tons of carbon dioxide per year.

14. In 1988 alone, the carbon dioxide emis­sions from north America rose by 65 million tons, equivalent to 5 times the absolute in­crease in that year of all African and Latin American countries combined.

15. If the whole world were emiLting carbon dioxide as the Americans do, we would not be emitting 6-7 billion tons per annum, but around 31 billion tons.

Sources of Greenhouse gases released by humans: Industrial energy use 25% Transport (500m vehicles ) 18% Use ojCFCs 17% Agriculture 15% Residential/commercial 14% Deforestation 8% Others 3%

4 - Jamaican Geographer (6), May 1992

The Cockpits

T he Su rv ey D epartm ent, the island' sNew Technology for Geographers larges t ma pping age ncy , is a lso responding po siti vely to the need [or di git al topographic

and cadas tra l data bases and computerised maps. 111c LI S (Land Info rm a tion Systems)

and Mapmakers Day-Dawn Simon

Unit of the Department was es tablished in

U ntil rec ent ly , the on ly way to kee p track v isua lly of lots of diffe rent kinds o f da ta abo ut

a geog rap hica l ar ea wa..s th roug h the usc o f a bas t: map and a series o f overlays, eac h re prc­senting a s peci fic ly pe o f in fo rma tion . W hen mo re tha n two or thr ee o ve rlays an: combined , ho w eve r, m a ps be c o m e con fus ing , thus

rendering an a lys is of da ta d iffic ult. T oday , com puters a re be in g used to cha nge a ll this .

Thro ug h the use of co m puterised dat a and

automat ed map pi ng , Geograp hic lnformatio n Syste ms (G IS for sho rt) have ha d a trcm en ­

dous im pac t o n the conven tiona l me ans o f p o rt ray ing , ma nag ing a nd m an ipu lat ing geographic in form at ion. Us ing a G IS , it i ~

poss ible to s to rv a ran ge o f d iffe re n t ty pes o f da ta while all o wi ng the vie wing o f a ll, o r some o f the data in a c lea r in icgruted di sp lay . Any

GIS com pr is es co mp u te r equ ip m ent a nd programs d signed to accom plish data in put ,

da la s torag e an d ret riev al, da ta man ipu la tio n and ana lys is, a nd data reporti ng .

A g rea t va rie ty o f da ta art: ofte n hel d in a G IS: to pog raphic , env ironmenta l, ca das tra l,

ad m in ist ra tive , s o ci a l an d eco nom ic da ta ,

am o ng o the rs . M uch of the dat a he ld hy a GI S

,

,IChl~ IIIIIIII I I I I ~ 71]1 t:::Ji.

\ 0 \

is de rived fro m map s , a ltho ug h increas ing ly da ta fro m se ve ra l o the r s ou rc es are used ill a

da ta base . The pro ces s by whic h da ta art:

ca p tured from maps , cove rtcd to co m pu ter­

r c a d u h lc for m , an d w r i t t c n to compui cr -r .ada b lc media (such as ha rd d is k, floppy d is k, ma gn etic tap e o r ma g netic ca s ·

sc tt e ) is kn o w n as d i g i t i z i n ~_' . D igi ti /.ing

represe nts the co nvers ion of map feat ures in to

a series o f X,Y co-ordinates o r d igits (he nce the te rm ' di g itize ') . 1111.: ins tru me n t which p roduces th is conversion is called a digitize r. T he n: a rc two bas ic ty pe s o f dig iti zers: Manual Di gi tizers and Sca n or Au to matic D ig itizers .

In manual digitizing, a hand -hel d c ursor is

moved ov e r 11 lC ma p surface . A po int feature

on a ma p is repres en ted as a s ing le pa ir o f X, Y co -o rdin a tes , whe reas a line on a map is

reco rded as a s tring (a series) o f co -o rd inates , An area on a ma p is repres ented by the s tring o f co-ord inutcs which [orm its bo unda ry . Eve ry I'l:a ture on the ma p is eithe r recorded in the GIS as a po int, a line , o r an area (act ua lly ,

a po lyg on) .

O n the other hand, a uto ma tic dig i tizing, o r s ca un iug , invo lves the sys te mati c mo e mc nt

o f a senso r over a gra phic doc um ent. T he docume n t is illu m ina ted as the sensor passes , and the a mo unt of re fl ec ted o r transmi tted

ligh t reco rded in a ce ll-by -cell fo nnat. Sc an­n ing e na bles the rapi d co nvers ion o f graph ic do .uiucnts to di git al da tu, but despi te thi s , to

reco ns tru c t a m ap fro m a s ca nned image is o fte n pro blema tic ;1I1d no t a lway s h igh ly su e­ccss fu l wi th the techno logy that is avai lab le

today . Ma nua] d igit izing , th o ugh a s lo we r

proc ess by co mpa riso n, prod uces ma]». ur hig he r qu a lity .

O ne of the fas test g ro w ing bran ch es o f co m put ing tod ay is computerised geog rap hy an d mapping , an el the tec hno logy is spread ing rapidity: apart fro m becom ing more a flo r­dable , it all o ws for mass storage o f da ta , s pe edy co m pi la tio n and updati ng and the

ana lys is o f spatia l info rmatio n, wh ic h is es ­S . n t i a l for b e ucr a n d le s s c o s t ly

dec isio n-m a king. In Ja ma ica , these be nefi ts a rc beco m ing mo rt: ap pa ren t a nd several pu b l ic a n d p r iva te sec tor ag e nc ies a rc

res po nd ing by acquiring GI S's [L\ pe rfo rm

bo th o ld a nti ne w tas k." .

Apri l 19RR as a component o f the Jamaica Lan d T iIIing Proje ct , a project a imed at

deve loping a co m prch cns i -c Land Infonna­tion System fo r Jamaica . One o f the fun ctions

o f the LIS ni t is to prod uce di gital cadas tral and top ographic maps . ARC/INFO , an inter­natio na lly po pular GIS, was insta lled in late 19R9 and since the n a nu m ber o f pil o t proj ects

ha ve been unde r ta ke n by the Un it. The projects incl ude the production o f a digital

ca das tra l map o f Eas te rn Kingston at a scale o f I :2 ,500 a nd an int egra led Cadas tra l/Lan d Usc/Flood Z unin g map fo r Po ru norc.

Th e lar gest projec t to date ai ms to digi tize

all 20 shee ts o f the ne w I :50,000 metric se ries topog raph ic maps to in ternational standards of accu racy . TIll: project is a welcom e under­

lakin g and the resul tant digit a l map will be a

very usefu l too l for p lanners , cnvi ro nmcn­

ralists, geograp he rs , e ng ineers and a large group 01" ' o ther users already opera ting in a co m puterised cnv iro nmen t.

T he new com puter technology ope n 10

ge og ra phers today s ho uld no t o nly be seen as a ne w a nd etfic ient tool whi ch enables th em to perfo rm their j o h m ore cred ita bly , bu t is

a lso a chal lenge to each to maximise the

ca pabil iti es 01" the techno logy lor the better­

me nt of the d isc ipline .

Duy -Da wu is Hea d of th e Cartog rap liy Unit, S TA TIN.

Jam aican Geog rap her (6), May / 992 - 5

Classroom Geography

Guide to the Coastal Features from Annatto Bay to Manchioneal

David Miller

This guide provides students with an introduc­n O li to the energy inputs wit hin the coastal s ystem ofthe area, to the nature and so urces of coastal sediments. and to prominent coas tal lundforms.

Energy inputs

Waves arc gene rated by win d which trans fers energy to the wat er by variations of pressure across the water. Waves in deep water arc osci lla tory but they suffer modificati on when entering sha llow water to fonn trans la tory waves. When a wave brea ks, a range of di f'­tcrcnt breaker types occur. Sp illing breake rs arc ass ociated with hig h, short waves and nat bcuchcs with onshore wind conditions ; they gene raII. break some dis tance from the shore with water spilling down the fron t o l' thc wave. Plllllt;illg breakers arc cha racter ised by a dis ­lind crest which falls vertica lly , trapping air pockets. Th ey occur on beaches of rclativ .ly low gradient, offshore wind co nditions and lo ng low d eep wate r s wells . Collapsing breakers are intermedia te between plunging :UH! surging types where the wav e fron t curves over to form an abreviatcd plunging wave . Surging breakers are associated with s teep grad ient beaches and have a smoo th sli ding movem ent; the wave runs close to the S hO tT

before breaking.

Shallow wa ter waves ind ue • nears hore cir­culatory cu rrent generation, which can Ill" divided into long -shore cu rrent s , which move pa ra l le l to t he coas t and are ge ne ra te d landward of the breaker zone and rip currents, which mov e norma l 10 the coast (that is, a t a right angle to it) from the bea ch scawards , On ;111 inde nted coas tlin e, long-shore curren ts move from headlands in to bays and rip cur­rents pass scawurds at the bay- heads. On s traight coas tlines, long-shore current s arc generat ed at localities o f higher breakers and rips pass sea war ds at lower breaker he ights.

r5 - Ja maica n Geog rapher (6), May 1992

Tides

Tides arc peri odic rises and falls o f sea level which occur twice dai ly . Th ey increase the vertical height over which wave and current act ion lakes place and, more importantly, ex ­tend the hori zon tal surface of wave action.". Tides arc the product of gmvitational aura e­tio ns of the s un , moon and ea rth. Sprin g (hig her than norma l) an d neap (low er than normal) tid's occur every 14 days . The tidal range in the Caribbean is small, and apart from in some enclosed hays and estuaries, tidal forces are not s ignifican t as a geom orp hic age nt.

Coastal sediments

Energy inputs such as waves , currents and tides arc linked to the landforms of LJ Il: coas t by coas ta l sedi ments . Coastal depositional landforms would be non-existent unless rocks were broken down an d transported t ) the coast. Sed iment grains can be grouped into two bas ic cat egor ies, roc k-detrita l grains or clasti c sediments, and grains composed o f CaCOJ or bioge nic se di ments, ma de up of broken shells and other inver tebrate remains . Also, in some trop ical local ities , CaCOJ sedi­ments may be precipitated to form oolites wh ich an.. not direc tly formed by biogeni c processes .

Coas tal erosion is responsible for an insig ­nificant proportion of the tota l input of marine sediments. Even in temperate latitudes , where wave energy is highest, only about 5 % arc acc ounted for by d irec t co asta l e ros ion . Glob a lly, rivers supply over 90 o/t, of total marine sedi ment in put, with g laciers and biogenic so urces next ill import ance .

TIle coastal area from St . 1argaret"s Bay to Annouo Bay is dominated by clas tic sedi­me nts derived from the Bille Moun tains via till: Wagwarcr, Pcn car , Dry , Buff Bay , Swift and Rio Grand e Rivers. To Ille eas t of the Rio

Grande, the pocket -beaches wi thin the in­dent ed coastline from Port Antonio to Boston Bay arc charact erised by biogeni c sed iments, as is the beach at Long Bay . TIle few streams draining th e John Crow Mountains a rc ephemeral so inland clasti c so urces an: less significant.

Sediment Size

As a re ult o f the diverse sources of coastal sedime nt s a lo ng the SI Mary -Portland coastline, the gra in s ize of the beach sedim en ts varies somewhat. In clastic derived areas, the beach sedim en t is a bim odal sand-slungle mix , containing up to 60 % coarse fragments (gravel to cobbles less than 2mm in diameter) . Cob­bles may be chaucr-rnurkcd.

Beaches

Beach pro fi les vary accord ing to the nature of the mat erials and three common beach types may be identifi ed liS sand , s h ing le and landward shin g le ridge with bro ad sand apron. Shingle beaches arc us ua lly Sleeper than sand, attributed to the differi ng wave energies re­qu ired to move the material, but a lso to the rate of pe rcolation through the material and to wave act ion and tidal influences .

Steep beach profiles like those from An­none Bay to t Margaret's Bay on Jamaica 's northeast coast huve a marked landward ridg e or bar: the berm (swash-bar) , which is a flat­lopped feature at the limit of the wave swash. Stee p beaches also often possess a pron ounced break in s lop e at the positi on of breaking waves : the beach-step , Th e transiti on from s teep to gentle beaches is marked by remo val of the berm and bar deposition just below low- tide leve l: the long-shore hal'. Shallow beaches such as the pocket beaches 10 the cast o f St Margnrcts Bay may have a tlat low -tide terra ce wh ich is occasionally crossed hy shore­pa ra llel rid ges an d runnels, These pro file di lTsrcnces arc controlled by va riati on in wav . ene rgy , wave . tccpness and type, sedime nt variability and sediment transp ort processes.

Ma ny of the bea ch es display rhythmic: C/l SpS which gene rally rang l: from 1m-60m , consist ing of coarse sediment CIISPS (or horns) separat ed from each o ther by small bays of li ner sand. TIlt: oncoming wave divides into

Classroom Geography

two flows which tum and coalesce in the back­wash forming a broad channel. TIle div ision of Ilow causes a drop in veloc i ty wh ich forces the coarser sed ime nts to be Icpos ired in the ho m..s As the returning backwash coa lesces , an in­crease in velocity sweeps the bays clear of fresh se diment an d ac ts as a mini -rip. Som e­times , fin e r s ed imen t is de p os i ted just sc awards of the cus p. Belich cusps arc fa n ne d at loca lities su bjec t to long wa ve cres ts ap­proaching normal to the coast. Their even sp ac ing is ex plai ned by the fact that the re is a regular a ltcma tion in (he he igh t of the onco m­ing waves (swell) ca used by the presence o f sta nding edge-wa ves (c res ts developed a t right angles to the shore).

Although many beaches ma y show rhy th ­mic fea tures , the overall shape has a tendency to be curv ed or arcua te , This is the case fo r the small bea ches cas t of Po rt An toni o which arc co nta ined wit h in boundi ng head lands and referre d to as pocket bcuchc..s. As waves pass in to a bay , they unde rgo wavc- re lrnctio n, whi c h ca uses the wave c rest s 10 become curved and the beach a ligns itsel f to this cur­v a t u re . These po c ke t h c a c h c s arc swash-aligned, whils t the mo re open beaches from St Marga ret's Bay wes twards have a tendency to be drift -aligned.

Detached beaches include fea tures such as spits , cuspate forela nds , ta mba las, ncs ses and barr ier islands, all o f whic h de pend to a certain ex te nt o n lo ng-shore mov e ment (drif t) o f mater ia l. Small spits ca n occasi ona lly be se en at the mo uths o f many o f the rivers wes t of St Margaret's Bay , es pecia lly the Rio G rande , and to a lesser extent the Swi ft and Buff Bay Rivers . More com mon, however, arc hay-head barrier beaches or bars , which form a com­plete barrier of sand and shi ng le across the mou ths of rivers, the product of bo th fl uvial depos ition and longsh or e drift. A c1a..ssi c bay ­head barrier beach occ urs a t the mo uth o f the Wngwater River in Anna tto Bay .

Cliffs, Headlands , Stacks and Blow-Holes

Cliffs arc co mmo n features o f the coas tline from Port An tonio to Manchioneal du e to the geo logical characteristics of the coast and the exposure to oncoming swell generated by

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FIgUre 1 Outline map of eastern Jamaica.showing the route taken and the principal field localities

prevailing winds fro m the ENE. Two gro ups o f processes act simultaneously ; at the base of the cliff, marine act ion causes erosion and transporta tion, whils t high er up the cliff su b­ae r ia l weath erin g an I mass m o ve m e n t processes supp ly debris to the waves . The shape or fon n of the cl iff is therefore the resu lt o f the relative impo rtance of the two proces­ses, together with geo log ical influences . TIle form o f most cl iffs in the area sugges t marine ac tion predom ina tes though the up per par ts arc sculptured by honeyco mb weathering of the limestone clif fs.

T he coas tline fro m Port An to n io to Manc hioneal d isp lays crcnulntions f varying scale which refl ect differential erosion along litho logical and structural patterns such as joints and faults . This has led to the develop­ment of headla nds . Several rocky islet", pillars or s tacks can be seen on this part of the coas t, isola ted hy pre ferentia l wave ero ion, whilst a natural arch occ urs near North Boob y Point. Blow-hole s, a hole whi ch has been formed by partial sea -cave collapse thro ugh which air and poss ibly water are forced by wave and tida l action, also occur a t Goat Pen Hole and Hal es Hole, near Manchioneal.

Biogenic Features

Offshore fringing reefs are common eastwards o f S t Margaret' s Bay but due to increased sedimenta tion to the west they are less ev ident. TIle coast line from Fairy Hill to Manchioneal is emergent (features once bel ow sea level arc no w emerged ). This is the result of local tec­toni c up lift s upe ri m posed upon eustatic changes in sea level. Uplift has resulted in the de velopment of raised-reef terraces which mark fanner sea lev els. As uplift is unidircc­tional, the highest terraces will be the oldest, though a st epped sequence is not as well deve loped here :15 around Oracabessa. The lim it o f Olest ep is marked by present sea cliffs whi lst the te rrace o ften displays a pitted su r­face, the prod uct o f solutionnl action , as at Ne ttle Point Beachrock (biogenic sand ce­mented by CaCOJ) is also a significant feature bet ween high and low water mark in many of the pocket beaches .

TIle seascapes of the St Mary and Portl and provid e an exc ellent opportuni ty for geo g­raph y s tude nts to study a range of coastal processes, sed iments and landform s. TIle im­prints of isostatic mov ement a nd eus tati c sea-level cha nge arc also clearly visibl e.

Jamaican Geog rapher (6), May / 992 - 7

Look Behind

C~BEANGEOGRAPHY

VOLUME 3 NUMBER 3 lARCH 1992

This issue contains the following articles

Intensified Dependence on a maturing minin J sector r the Jamaican Bauxite Levy

R.M.Auty

Adaptation to agrtcultural change among Garifunu women in Hopkin's, Belize

Elail/e Bli. \

The Land apes of Cayuna: .Jamaica throuuh the senses 01" .Iohn Hearne

Brian LHudson

I't:.....ticldes, People and Ihe Environment in ' I Vincent

Lawrence S. Grossman

Geography ill the Caribbean Iassroom canlam s the article

Industrial Free Znn~ ' in the Dominican Republic

Milagros Nanita -Kennett

In ad lirion, the book review section has been expanded. Caribbean Geogruphy is edited from the Department of Geography, UWI, ind published by UWIPA.II is avail ­able al a 50% discount to JGS members

CONTRmUTIONS TO NEWSLETTER

Short articl es, ne ws items , commentaries on publ ish ed maps , reports and books , o r just lcu crs to the editor, a re wel com e. Don 't he shy about putting pen to paper, contribute

now, ami co ntrib ute to your Soci ety 's o wn sustainable dev elopment.

8 - Jamaica n Geographer (6), May 1992

MEMBERSHIP CARDS

The Counc il has decided to re-in trod uce membership cards fo r the year 1992-93.1llcse will he i. sued on recei pt of your s ubscription renewals. A principal reason is thai the Coun­cil has renegotiated a number of discounts from stores and other business establ ishmen ts on beha lf o f JGS members . Discounts on the pu rch ase o f su ch goods :U1d services wil l re ­quire proof of membership , via a valid mem­bership card. Details of the discount sc heme will he announced in Iuc cou rse.

OEOGRAPHICAL

G eogra phical, fa r ill . rl y Geographical Mag ar inc (GM ), has once again changed us lonnat, to reflect tlu: fact it is no t only a pub li ca t io n o f th e Roy a l Geog raph ica l Society , bu t is now jointly published hy the BBC. It remain s a highly readab le , topical, co lour ma gazine with a wid e readership .

In a lso co nta ins a te .hnical sec tion called . A' Level Ana lys is; si x pages packed with

data, maps, tables and conce pts in physi cal and human geography , tailored 10 the needs o f sixth form ers . II is an ideal publica tion for your schoo l library , or the reception area of an office complex .

Subscription deta ils are avail ahl e from the Ro a l Ge o g ra p h i c a l So c ic ty , or fro m Geographical, ls t Floor, Steph enson House, Brunei Cen tre , Blctchley, Milton Keyn es , MK2 2EW, United Kin gdom .

Quiz Answers

I . Es tonia

2. Rumanians

3. Ukraine

4. Roman Catholic

5. Sluvakia

6. Buda :U1d Pe l., on the banks o f the Danube

7. Turks

8, Riga

9. Yugoslavia, Greece, Bulgaria

10. Eastern part of'Czecko lovakia

EVENING LECTURES

Thu rsday evening at 6.00pm in the Geog ­raphy Department , UW I, is becoming a regular o nce-mo nthly venue for our evening lectu res, during the acad em ic year. Watch out next semes ter (term ) for a new series o f talks, s lide shows a nd lec tures, arranged by Council. If you have any sugges tions fo r topics or speake rs , ple as e contac t a mem ber of the Co unci l,

Jamaican Geographer

ISSN 1017 ­ 4753

Editor:

Add . ..:

David Barker

Department of Ge grnphy , the University of the West Indi es, Mona , Kingston 7, Phone 92-72129

Typesetting:

Printing:

PMLM LId.

Univ ersity Printery, The University of' The Wcst Indies, Mona, Kingston 7. Jamaica .