Processes of Allochthonous Terrane Evolution, Mindoro Island

7/26/2019 Processes of Allochthonous Terrane Evolution, Mindoro Island

1/14

Processes

Allochtho

Terrane E

Mindoro

Philippin

1986 Sarewitz

(Presented by

Roni C.


2/14

! "#e P#i$i%%ine ari%e$ago $iesa$ong t#e e'traordinari$y &o%$e'western boundary between t#eP#i$i%%ine Sea %$ate and t#e)urasian %$ate

! Con*ergen&e between t#ese two%$ates o&&urs in a +-S) dire&tion,ob$ique to t#e trend o t#eP#i$i%%ines, at rates o 8 to 1/&0yr Ran2en et a$., 19834.


3/14

Tectonic Setting! )ast side o t#e ari%e$ago, sout# o

15+, is bounded by t#e PhilippineTrench

! "#ePhilippine Fault (PF)is a a7or$et-$atera$ trans&urrent au$t t#at e'tends

ro ingayen u$ (ayes and ewis,1983, sout# a$ong t#e entire $engt# ot#e P#i$i%%ines to t#e Mo$u&&a Sea(Moore and Si$*er, 198;

! "#e Mani$a "ren runs ro "aiwan toMindoro, and a&&oodates a&ti*e

&on*ergen&e between t#e Sout# C#inaSea and t#e west side o t#e nort#ern


4/14

Geology of Mindoro!


5/14

Generalized pre-Neogene stratigraphic columns of the North Palawan b

Mindoro block as mapped on Mindoro Island. No scale is implied.

Geology of Mindoro


6/14

Distribution of major oshore andsubsurface structures in Mindoro !traits

area and southwest Mindoro coastal plain.

Generalized cross section from Mindoro !traits to"entral Mindoro. !tructural geometries between theManila #rench and the Mindoro !uture are speculati$eand highl% schematic. #here is no $erticale&aggeration.


7/14

!eismic re'ection pro(le M-)* andM-)* e&tension +migrated, acrosstilted basement block on southwestMindoro coastal plain andinterpreti$e line drawing.


8/14

!eismic re'ection pro(le M!-)) +unmigrated,across an as%mmetric half- graben and boundingbasement high in Mindoro !traits andinterpreti$e line drawing of the graben (llseuence. #he pre-/ligocene relief on Mesozoicseismic basement is probabl% due to 0ocene

normal faulting.


9/14

Regional Synthesis and

Paleogeographic Models

"#e +ort# Pa$awan b$o&2 was dis%$a&ed sout#ward in ront o t#e o%ening Sout# C#ina >asin dtie "ay$or and ayes, 198;4 , w#ereas we inter%ret t#e Mindoro b$o&2 as #a*ing s#ared agenera$$y nort#ward otion wit# t#e P#i$i%%ine ari%e$ago and t#e P#i$i%%ine Sea %$ate. "#e Mre%resents %art o a trans&urrent %$ate boundary a$ong w#i t#e +ort# Pa$awan b$o&2 and Minitia$$y 7u'ta%osed, in idd$e to $ate Mio&ene tie.


10/14

Present Tectonic Regime

! "#e %resent %o$e o rotation des&ribingotion between t#e P#i$i%%ine Sea %$ateand )urasia is $o&ated near t#e east &oasto &entra$ ons#u Ran2en et a$., 19834.

! Rotation is &$o&2wise

! ? ange in otion o t#e Pa&i@& %$atere$ati*e to #ot s%ots at A .y. #as beensuggested by Co' and )ngebretson198A4 , w#i ay #a*e been &ou%$ed tot#e ange in otion o t#e P#i$i%%ineSea %$ate.

Predicted latitud


11/14

Rangin et a$. 198A4 #a*e argued t#at t#eMindoro Suture re%resents diseberedo%#io$iti& ateria$ t#at was Bobdu&tedBwestward onto t#e +ort# Pa$awan b$o&2and inter%ret t#e Mindoro Suture as a $ow-ang$e, west *erging t#rust zone.

Rangin et a$. 198A4 a$so in*o2e a stati&%a$eogeogra%#i& ode$ t#at ignores asubstantia$ body o e*iden&e indi&atingnort#ward otion o t#e P#i$i%%ines andP#i$i%%ine Sea %$ate t#roug#out t#e"ertiary

Previous Models

M&Cabe et a$. 198, 1sout#ern terination

"ren as a resu$t o id-Mio&ene &o$$isionPa$awan b$o&2 wit# t#e


12/14

Evolution of the East Side of North

Palawan Block

!chematic paleogeographic model forthe northwest corner of the Philippine!ea at 12 m.%. and h%pothetical model

for transtensile margin at eastern edgeof the North Palawan block.

"#e s#aded zone at t#e east edge o t#e +ort#Pa$awan b$o&2 is an area &reated due totranstension. Di*ergen&e ay be a&&oodatedby ob$ique-nora$ au$ting, or by de&ou%$ed

e'tension and stri2e s$i%.


13/14

Pa$eogeogra%#i& a% o t#e nort#ern P#i$i%%ineregion at 18 .y.

"#e s#aded region on t#e eastern edge o t#e +ort#Pa$awan b$o&2 is an area &reated due to transtension


14/14

Implications "#e geo$ogy o western Mindoro Es$and reFe&ts t#e inde%endent e

te&tonostratigra%#i& terranes and t#eir subsequent aa$gaation.

Many wor2ers #a*e re&ognized t#at stri2e-s$i% te&toni&s ay %$ay atrans%ort.

Stru&tura$ and stratigra%#i& asso&iations &oon$y deeed &on*ergen&e or &o$$ision ay o&&ur wide$y in zones o stri2e-s$i% au$ting

"#e Mindoro b$o&2 #as ost %robab$y been %art o t#e P#i$i%%ine ar&sin&e t#e

Documents

Processes of Allochthonous Terrane Evolution, Mindoro Island