Vibor  Novak

Supervisor:  Willem  Renema

Microfacies  analysis  of  East  Kalimantan  reef  systems  based  on  larger  benthic  foraminifera

Progress  report,

Kiel,  June  2012

Goals

• Building  a  stra9graphic  framework  based  on  biostra9graphy  of  larger  benthic  foraminifera

• Determine  the  affect  of  environmental  change  on  LBF  assemblages

• LBF  evolu9on  through  9me  by  comparing  assemblages  of  different  ages  

• Review,  update  and  correla9on  of  Indo-­‐Pacific  LBF  biozones  with  the  global  stra9graphical  schemes

Progress  (since  Granada)

• Training:– Isolated  LBF  thin  sec9on  (Istanbul,  April  2012)– SIS  (RHUL,  May  2012)– Interna9onal  School  on  Foraminifera  (Urbino,  June  2012)

• Conferences:– Lyell  (March  2012)– EGU  (April  2012)

• Papers:– 3D  Reef  –  almost  finished– Samarinda  biostra9graphy  –  in  progress– Top  Reef  –  in  progress

3D  Reef

• Langhian  age  (late  Tf1,  early  Tf2)

• Nine  lithological  units  (U1-­‐9);  five  facies  types  (FT1-­‐5)

• General  fossil  groups  results:– Two  LBF  assemblages– ScleracTnian  and  octocorals– Melobesioid  CCA  assemblages– Majority  of  bryozoan  species  encrusTng  

beginning

Facies  types• Five  different  facies  types  -­‐  based  on  lithology  and  fossil  content

– BioclasTc  packstone  with  rare  fossils    (BP1;  Units  1  and  2)

– BioclasTc  packstone  with  foralgal  communiTes  (BP2;  Unit  3  and  6)

– Thin-­‐platy  coral  sheetstone  (CS;  Units  4  and  7)

– Platy-­‐tabular  coral  platestone  (CP;  Unit  5)

– Shales  (S;  Units  8  and  9)  

Lepidosemicyclina polymorphaNephrolepidina ferreroi

Flosculinella bontangensis

Nephrolepidina martini

Mesophyllum sp. Foralgalith

Lithoporella sp.

500 µm500 µm

500 µm

Calcareous coralline algae

Representative scleractinian corals of the “fried egg” reef

2 cm

2 cm

1 cm

1 cm

1 cm

1 cm1 cm 1 cm

1 cm 1 cm 1 cm

Representative bryozoans of the “fried egg” patch reef.

500 µm

100 µm 100 µm

200 µm 200 µm 200 µm

200 µm 200 µm 200 µm

200 µm 200 µm

DEPOSITIONAL MODEL

A. Larger benthic foraminifera enter the environment

DEPOSITIONAL MODEL

B. LBF and CCA stabilize the substrate

DEPOSITIONAL MODEL

C. Thin-platy corals colonize the environment

DEPOSITIONAL MODEL

D. Tabular corals growing on thin-platy coral substrate

DEPOSITIONAL MODEL

E. Increase in terrestrial influx, only LBF and CCA occur

DEPOSITIONAL MODEL

F. Surface stabilized, platy corals appear again

DEPOSITIONAL MODEL

G. High siliciclastic input, demise of the reef

Conclusion

• Main  factor  controlling  reef  growth  –  water  transparency

• MesophoTc  reefal  environment  

• Facies  changes  –  variaTons  in  terrigenous  input  

• MulT-­‐taxon  fossil  assemblage  analysis  –  reference  model

• Substrate    stabilizaTon  needed  for  reef  development

Samarindabiostra9graphy

SIS  results

Future  plans

• Conferences:

– ?GSA  2012,  SAGE  2013

• Papers:

– Batu  Pu9h

– New  3D  Reef

– Bulu  limestones  (Java)

– Samarinda  Sr-­‐isotopes

– Comparison  of  LBF  assemblages  of  3D  Reef,  Top  Reef,  New  3D  Reef,  Batu  Pu9h  and  Bulu  limestones