Page 132 - Carbonate Sedimentology and Sequence Stratigraphy

CHAPTER 7: SEQUENCE STRATIGRAPHY OF THE T FACTORY 123

well
A) Lh-11-1-4
1.0 sec

drowning

exposure

base carbonate

1 km

B)
1230
13 Heterostegina sp.
δ C gamma ray Miogypsinids Spiroclypeids Planktonics
(‰VPDB) (gAPI) Lh-11-1-4
1240
drowning unconformity shales
rhodoid rudstone
1250

1260

1270

coral facies
1280

skeletal grainstone grainstone
1290

1300

1310

1320

1330

depth (m)
-8 -6 -4 -2 -1 0 % 0 40 80 0 40 0 40 0 40 80

Fig. 7.20.— A) Drowning unconformity (and type-3 sequence boundary) in seismic profile of Miocene Liuhua platform, South China
Sea. Note asymmetry of the record: stationary, elevated rim on the left and backsteps on the right . Starved sedimentation and marine
erosion pervailed for some time before hemipelagic shale covered the platform. After Erlich et al. (1990). B) Borehole data from Liuhua
platform indicate probable exposure at surfaces within the carbonate platform but no evidence of exposure was found at the drowning
unconformity. Foraminifera indicate gradual deepening by decrease of Miogypsinids and increase of Spiroclypeids and Heterosteginids
as well as plankton. After Erlich et al. (1990) and Sattler (2005), modified.