asscciation for mexican cave studies box 7672 ut station austin ...

TRIP REPORTSDestination: Cueva del Brinco, TamaulipasDate: lhrch 11-20Persons: Jerry Atkinson, Sheila Balsdon, Gill Ediger, Robert Hemperly,Katy Knighton, Thomas Moore, Peter Sprouse, and Terri TreacyReported by: Peter SprouseOur purpose on this trip was to push the leads left in Brinco fromthe previous Thanksgiving trip (see A}!CS Activities Letter J,l5). Hith theheight of the dry season approaching, we hoped for some good caving. Crossingat Brownsville Friday night was easy, except for finding our waythrough Matamoros, that is: We pulled into Victoria in the morning (~1arch12) for breakfast and headed north to Barretal for the long grind intothe mountains. We made it up to Conrado Castillo in a quick 5 1/2 hoursfrom the highway.After morning R&R on ~~rch 13, ~~o te~s entered Brinco. Thomas,Robert, Jerry, and Katy headed to the area past the waterfall. They pushedupstream from the Laguna Verde Cutoff and explored several hundred metersof new passage. Trash in the streamway hinted of another entrance but ifso the cavers stopped before reachinp. it. On the way back, they took awrong turn, accidently liscovering a new and bigger stremm~ay! They exploreddOl~ this until Y~ty took a 3 meter fall into a deep pool. She wasunhurt but shaken, having lost her helmet (poor chinstrap) and light intothe 4 meter deep pool. Meanwhile, Terri, Sheila, and I continued the surveyfrom Eternity Junction, the cave's deepest point at -162 meters. Our surveyended at -179 meters where we encountered sump mud allover the walls inthe dead end Pig Wallow. ~-le wrapped up leads on the way out.The next day was pretty much an R&R day. In the afternoon Terri andI sketch-mapped and partially explored Cueva X, a higher, vadose cavewhich may connect with llrinco. On March IS, caving spirit ran high incaap as Ediger, Jerry, and Robert prepared for a survey trip upstream fromthe Laguna Verde Cutoff. Sheila, Terri, Thomas, and I set off to explorethe entrance in town discovered the previous trip. The first team mappedover 300 meters upstream (but not the downstream way where Katy fell) toa point only 15 meters lower than the entrance. This continues and couldadd depth to the top of the cave when surveyed. Our team found that thearroyo cave in town had a quick end in dirt and debris fill, so we decidedto enter Brinco (sans Terri) to survey from the Laguna Verde, the bestlead. This is a place where a low crawl leads to a waterfall room with astream (the Rio Verde) passage taking off; it had 2 cfs flow in Novemberbut only a garden hose's flow in March. We mapped 40 stations downstreamthrough well-decorated passage with deep green pools. dropping steadily.I explored on past the end of the survey to a narrow squeeze with a goodlybreeze going into it. The next day our same team. plus Robert. returnedto the Rio Verde. We surveyed down to a constriction which had to be enlargedwith a rock to allow passage. I explored on alone through a sharp.swiss-cheesy area. Soon I noticed it was different than up to that point:the water, flowstone, and air movement were missing. So I backtrackeduntil I found a small hole going in the proper direction. This droppeddOlvn several climbdowns to a low rimstone area. Following the air I entereda low pool which I never reached t~e end of. Five to ten meters wideand with water often over my head. I followed The Canal for nearly 200