Perub iklim pd Plio-Pleis

[11agt13M 4syawal1434H vbm]
990
MELIHAT PERUB IKLIM PD JAMAN PLIO-PLEIS DI TURKANA BASIN (AFRIKA TIMUR) BERDASARKAN KOMUNITAS FAUNA MAMALIA

ABSTRACT
Paper ini bercerita ttg perub iklim yg terjd pd jaman Pliosen di Afrika yg mengakibatkan betrtambah luasx daerah kering –> MELUASX DAERAH KERING/TANDUS DI AFRIKA (Turkana basin) DISEBABKAN OLEH PERUB IKLIM YG TERJD SEJAK JAMAN PLIOSEN

Unt mengamati perub iklim pd jaman Pliosen tsb dilakukan dg cara mengamati (paleo)ekologi fauna (mamalia) krn dianggap sbg indikator lingkungan yg baik –> BGM?

Perkiraan/perhitungan iklim (curah hujan per th & panjangx masa kering) dipelajari

Biome di Turkana basin berubah dr hutan hujan ke deciduous woodland & savanna dari mid Pliocene ke late Pliocene

INTRO
@Palaeoclimatology menjd bd kajian yg khas dlm bbrp dekade ini
Over the last several decades palaeoclimatology has developed into a distinct research field

@Knp kajian past climatic menjd penting?
Uncertainty about future climatic change is one of the most serious global environmental concerns & the past climatic history offers analogies & comparisons for present and future climatic states (Hay et al., 1997; IPCC, 2001).

@Faktor perub iklim menjd penting krn memp pengaruh thd evolusi mamalia & khusx bg hominid
Beyond that, & apart from the intrinsic scientific interest of palaeoclimate, climatic change has had an important influence on evolution and community change in mammals in general and in hominids in particular (see e.g. Coppens, 1975; Vrba, 1985a, 2000, in press; Vrba et al., 1995; Agustı et al., 1999; Bromage and Schrenk, 1999)

@kasus di Afrika –> perub iklim yg terjd pd masa Plio-Pleis memberikan efek kpd habitat lokal & evolusi mns awal. Masa panas pd jaman Plio berubah menjd dingin dijaman Pleis. Pd masa transisi tsb terjd perulangan panas-dingin. Kondisi iklim panas ini, di Afrika terjd pd jaman Miosen & Pliosen awal
Plio-Pleistocene global climate change is believed to have had an important influence on local habitats and early human evolution in Africa. During the Pliocene there was an important transition from a relatively warm climate, with low ice volume in the Northern Hemisphere, to a generally colder climate in the Pleistocene, with prominent glacial-interglacial cycles accompanied by periodic increase and decrease of polar ice volume (Shackleton, 1995). Within the African context, warm and humid conditions were extensive during the Miocene and early Pliocene (Vrba, 1985b; Yemane et al., 1985; Andrews, 1989; Wolde Gabriel et al., 1994; Burckle,1995;Hill 1995)

@Kondisi ling di Afrika selama Plio akhir & Pleis menjd lebih dingin, kering & more seasonal [ber-musim2, menurut musim} & akibatx kawasan savana & desert menjd bertambah luas terutama di daerah utara &timur
African environments became cooler, drier & more seasonal during the late Pliocene & Pleistocene, which triggered the spread of savannas & deserts in northern (Dupont & Leroy, 1995), eastern (Coppens, 1975;Kappelman,1984; Feibel et al., 1991; Cerling, 1992; Bonnefille, 1995; deMenocal, 1995; deMenocal and Bloemendal, 1995; Wesselman, 1995; Potts, 1998; Bobe and Eck, 2001; Bobe et al., 2002; Kovarovic et al., 2002; Bobe and Behrensmeyer,2004; Suwa et al., 2003; Vrba, 2005, in press) and southern Africa (Vrba, 1974, 1975; Avery, 1995; deMenocal, 1995; deMenocal and Bloemendal, 1995; Potts, 1998).

@Tuj penel adl menilai perub iklim di Afrika timur yg terjd pd masa transisi Plio-Pleis & menilai perkembangan ling savana di sana
The purpose of this study is to assess [menilai] the climatic change of the East African Plio-Pleistocene and the development of the savanna environment in this area of the continent.

@Sumbangan hsl penel isotop marine pd sedimen laut dlm adl gambaran umum keadaan iklim pd masa Plio-Pleis. Ttp hal ini tdk bs memberikan gambaran laungsung bgm kondisi lingkungan di benua (Bobe & Eck 2001)
Although the relatively continuous marine isotopic record during the Plio-Pleistocene supplies a general climatic background, it does not give direct evidence on continental palae-oenvironments (Bobe & Eck, 2001).

@unt menget kondisi paleo-ling diperlukan data sedimen danau, palinologi ttp data tsb tdk kontinyu sifatx & kadang tdk ada pd daerah tertentu. Sebalikx keberadaan fosil mamalia sering dipake unt rekonstruksi ling atau iklim
Evidence on continental palaeoclimate usually includes data from lake levels, isotope records and palynology. Nevertheless, the continental record is quite discontinuous and these data are seldom available for particular periods or regions. On the other hand, mammalian fossil assemblages have traditionally been considered to be a suitable proxy [wakil] for climatic or environmental reconstructions (for qualitative inference see e.g. van de Weerd & Daams, 1978; Andrews et al., 1979; Legendre, 1986; de Bonis et al., 1992a; Kovarovic et al., 2002; Hernandez Fernandez & Pelaez-Campomanes, 2003; for semi-quantitative reconstructions see e.g. van der Meulen and Daams, 1992; Reed, 1998; ;van Dam and Weltje, 1999; Bobe et al., 2002; Fortelius et al., 2002; Hernandez Fernandez et al., 2003; for quantitative inferences see e.g. Hokr, 1951; Thackeray, 1987; Avery, 1992, 2001; Kay & Madden, 1997; Montuire et al., 1997; Jeannet & Cartonnet, 2000; Hernandez Fernandez & Pelaez-Campomanes, 2005).

MATERIAL & METHODS
Plio-Pleis mammal faunas from the Turkana basin

Modern faunas for comparison

Multivariate analysis of mammalian faunas

PCA A, including both modern & fossil faunas

PCA B including only modern fauna

PCA C including only fossil faunas

Ecological interpretation of the PCAs

Quantitative inference of climatic variables

RESULT
PCA A including both modern & fossil faunas

PCA B including only modern fauna

PCA C including only fossil faunas

Quantitative inference of climatic variables

Validation of the regression models

Environmental change in the Plio-Pleis of the Turkana basin

Comparison w/ previous evidence in the Turkana basin

CONCLUDING REMARKS
_____________________________________________
1271 [2sept13Sl vbm]
@Berdasarkan data dari sedimen laut iklim di Afrika berubah ke arah more arid condition setelah 2.8 mya
==>marine records of African climate variability document a shift toward more arid conditions after 2.8 mya, evidently resulting from remote forcing by cold North Atlantic sea-surface temperatures associated w/ the onset of Northern hemisphere glacial cycles

[13oct13M vbm] Dari data sedimen laut menunjukan paleoclimate di Afrika berubah ke arah kondisi yg lebih kering (more arid condition) terutama setelah 2.8 Ma. Lebih jauh lg terungkap bhw proses evolusi hominid & vertebrat terjd atau berlangsung pd perubahan ling kearah iklim yg lebih kering yg terjd pd 2.8, 1.7 & 1 Ma. Hal ini mengindikasikan bhw terjdx proses SPESIASI pd jaman Plio-Ples berkaitan dg adax perub iklim (abstrak 1271:53)

U/ kasus di Afrika yg beriklim subtropis, data sedimen darat dpt yang menunjang adax kejadian paleoclimate change pd jaman Plio-Pleis sangat sedikit bahkan tdk ada. Lain halx dg data dari sedimen laut yg diperoleh dari kawasan dekat daratan umumx dpt menunjang adax kejadian paleoclimate change pd jaman Plio-Ples di Afrika. Berdasarkan kpd data sedimen laut tsb diperkirakan kawasan yg berada di belahan bumi utara (high latitude) pd jaman Plio-Ples ant 2.8-1 Ma mengalami jaman glasial (es) yg ditandai dg meluasx daratan es di kutub utara & selatan[?]. Akan tetapi u/ kawasan di lintang yg lebih kecil & kawasan tropis efek adax jaman es pd perioda 2.8-1 Ma belum diketahui & masih menjd masalah dlm kajian paleoklimatologi hingga saat ini. Dalam paper ini penulis ingin memakai data sedimen laut yg diperoleh dr pemboran di Afrika barat & timur u/ merekonstruksi adax paleoclimate change khususx di daratan (terrestrial) Afrika pd jaman Plio-Ples. Data tsb jg dipakai u/ merekonstruksi al faunal changes yg terjd pd jaman Plio-Ples. Berdasarkan marine oxygen isotope jaman es yg ada di high latitude mulai terjd pd perioda ant 3.1-2.6 Ma (2,3) & mencapai klimakx setelah 1 Ma (1271:53)
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1281 [2oct13R vbm] TULISAN INI MENJELASKAN VRICA (CALABRIA, SOUTHERN ITALY) DIPILIH SBG STRATOTIPE PLESTOSEN &MENGUSULKAN KRITERIA PLIO-PLES BOUNDARY (d/h NEOGENE-QUATERNARY BOUNDARY)

[p.116]
@Sblm Vrica adl di Castella, Calabria zuga

@Ciri bts Plio-Ples adl kemunculan ostracoda Cytheropteron testudo (considered to be a “northern guest”) & mollusc Arctica islandica

@Lokasi Vrica
located 4km south of Crotone in the Marchesato peninsula, Calabria, Italy, consists of open sea deposites preserved ~~~~ the rocks are bathyal, marly & silty claystones (dark grey or blue-grey in colour) w/ interbedded, fairly conspicuous, pale grey-pink sapropelic marker beds. Some very thin sandy horizons & a volcanic ash layer also occur within the section
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[28may11St; 19apr14St vbm] Nm.842
# Penulis menganalisa habitatat berdasarkan phlanx dari bovid. Phx-1 digunakan unt rekonstruksi bgm habitat dari 130 modern bovid specimen DST unt phx2-3
# Analisa paleohabitat ini diperlukan sbg salah satu cara unt ngetes hipotesa ttg hominid biological & technological evolution
# Salah satu cara/method unt analisa paleohabitat adl berdasarkan functional morphology of mammalian postcranila yg mana metoda ini disebut ecological morphology.
# The taxonomic composition of the sample is given in Table 1. Only adult individuals (as determined by complete fusion of postcranial epiphyses) that were documented as wild-caught (non-captive) were included in the sample. Specimens with postcranial pathological pro-
cesses were excluded. The specimens were sampled without regard to sex, since this parameter cannot currently be determined for isolated postcranial fossils.
# Phalanges were also sampled randomly with respect to forelimb and hindlimb, as there is currently no method for determining the placement of isolated phalanges.
# Measurements of a few articulated modern museum specimens suggest that, while forelimb and hindlimb phalanges can di?er in absolute size within an individual, their proportions are relatively constant.
# Ada 4 katagori habitat (habitat grouping scheme or habitat preference information) (p.1105 lihat Tab 1) yi DST
# We used the phalanx measurements and habitat
preference information for a large sample of modern bovids to determine the degree to which habitat could be predicted from themeasurements

PP-LM Forest 36.6#11.4#14.4-55.9
PP-LM Heavy cover 56.3#7.5#41.2-74
Light cover 43.3#8.6#24-56.7
Open 55#10.5#31.2-74

PP-WP
Forest 10.8#3.2#4-14.7
Heavy cover 18.4#3.2#12.5-24
Light cover 11.7#2.5#7.1-16
Open 18.5#5.8#8.9-31.4

PP-WI
Forest 9.5#2.7#3.6-12.9
Heavy cover 16.9#3.5#10.4-23.5
Light cover 9.4#2.1#5.5-13.4
Open 15.2#5.6#6.4-29

PP-WD
Forest 10#2.9#3.8-13.8
Heavy cover 17.9#3.6#10.7-23.5
Light cover 10.9#2.5#6.4-15.2
Open 17.2#5.9#7.5-30.9

PP-HP
Forest 15.7#4.6#6-22.4
Heavy cover 25.2#4.4#16.9-33.5
Light cover 16.2#3.7#8.8-22
Open 23#6.5#11.9-37.6

PP-HI
Forest 11.7#3.5#4.1-17.2
Heavy cover 19.8#3.4#12.8-25.3
Light cover 11.7#2.3#6.8-16.5
Open 17.7#5.6#8.8-31.2

PP-HD
Forest 9#2.7#3.3-13
Heavy cover 14.7#2.6#10.5-19.5
Light cover 9.7#1.7#6-11.7
Open 14#3.7#7.2-23.1
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Fernadez & Vrba (2006) [29-9-16Sl vbm atoen cabut g2 di rs g2 & mulut]


















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